R&D INTO STAND-ALONE PV SYSTEMS FOR EXPORT

ETSU S/P2/00205/REP

Contractor IT Power Ltd

The work described in this report was carried out under contract as part of the New and Renewable Energy Programme, managed by the Energy Technology Support Unit (ETSU) on behalf of the Department of Trade and Industry. The views and judgements expressed in this report are those of the contractor and do not necessarily reflect those of ETSU or the Department of Trade and Industry.

First published 1996 CONTENTS

^COMPLETE REPORT NOT AVAILABLE ELECTRONICALLY*

EXECUTIVE SUMMARY i

Introduction i The Technology i Applications i User Experiences ii The Market iii Barriers to the Uptake of PV iii PV Economics iii Technical Regulations and Standards iv

1. INTRODUCTION AND BACKGROUND 1 1.1. Introduction 1 1.2. Purpose of this Report 3 1.2.1. Background 3 1.2.2. Aims of the Report 3 1.2.3. Benefits to the UK PV industry 3 1.2.4. Deliverables 4 1.2.5. Meetings 4 1.3. The IEA Photovoltaic Power Systems Programme 5 1.4. Aim of Task III 5 2. PHOTOVOLTAIC TECHNOLOGY 7 2.1. Background 7 2.1.1. Mono-crystalline silicon cells 8 2.1.2. Poly-crystalline silicon cells 8 2.1.3. Amorphous silicon cells 9 2.1.4. Photovoltaic modules 10 2.2. The Solar Resource 10 2.2.1. Definition of Terms 10 2.2.2. Energy from photovoltaic modules 11 2.2.3. System sizing 12 2.3. Stand-Alone PV Systems 12 2.3.1. Definition of a PV system 12 2.3.2. PV system components 13 2.3.3. Sizing 15 2.3.4. Installation 16 2.3.5. Maintenance requirements 16 2.3.6. Operating PV systems 17 2.3.7. PV system applications 17 2.4. Environmental and safety considerations 18 2.4.1. PV modules and the environment 18 2.4.2. Energy payback ratio of PV modules 19 2.4.3. Environmental concerns of PV system components 19 2.4.4. CO2 emissions 19 2.4.5. Safety issues 20 2.5. Future development 22 2.5.1. Future Prospects for Module Efficiencies and Costs 23 3. APPLICATIONS FOR STAND-ALONE PHOTOVOLTAIC SYSTEMS 25 3.1. Introduction 25 3.2. Service Applications 25 3.2.1. Telecommunications 25 3.2.2. Cathodic Corrosion Protection 26 3.2.3. Telemetry Systems 27 3.2.4. Navigation Aids 28 3.2.5. Pumping systems 29 3.2.6. Water treatment systems 32 3.2.7. Refrigeration systems 33 3.2.8. Battery charging systems 35 3.2.9. Health care 37 3.2.10. Other systems 37 3.3. Isolated Buildings 38 3.3.1. Solar Home Systems (SHS) 38 3.3.2. Remote Area Power Supply (RAPS) Systems 40 3.4. Island Systems 41 4. BALANCE OF SYSTEM COMPONENTS AND APPLIANCES 43 4.1. Introduction 43 4.2. Inverters 43 4.3. Batteries 45 4.4. Charge Controllers 49 4.5. High Efficiency Appliances 51 4.5.1. Products which are widely available 51 4.5.2. Appliances Required for PV Systems 52 4.5.3. Appliances only required for RAPS-type PV systems 53 4.5.4. Appliances currently being researched 53 4.5.5. Developing Countries - appliance availability 53 5. STAND-ALONE SYSTEMS INSTALLED AND USER EXPERIENCES 54 5.1. Introduction 54 5.2. Service Applications 54 5.2.1. Industrial Systems 54 5.2.2. PV Systems in Agriculture and Fisheries 59 5.2.3. Health Care 60 5.2.4. Drinking Water Supply 63 5.2.5. Consumer Applications 66 5.3. Isolated Buildings 66 5.4. Island Systems 73 6. THE PV INDUSTRY AND MARKET 76 6.1. Historical review of Global PV market development 76 6.1.1. Non-electrified populations: a primary PV market potential 80 7. BARRIERS TO THE WIDER DISSEMINATION OF PV SYSTEMS 82 7.1. Introduction 82 7.2. Results from Survey 82 7.2.1. General Barriers 83 7.2.2. PV company activities 84 7.2.3. Government involvement with PV 85 7.2.4. Utility involvement with PV systems 85 7.3. Technical factors 87 7.3.1. Inherent limitations of solar energy 87 7.3.2. Site and geographical locations 88 7.3.3. Quality of systems 88 7.3.4. Warranty on PV modules 89 7.3.5. Size range of systems 89 7.3.6. Quality of installation 89 7.3.7. Maintenance and after-sales services 89 7.4. Economic Factors 90 7.5. Social factors 90 7.5.1. User participation 90 7.5.2. Local management 91 7.5.3. Educational requirements 91 7.5.4. System abuse 91 7.5.5. Negative social effects 92 7.6. Institutional factors 92 7.6.1. Operational constraints 92 7.6.2. Price & financing constraints 97 8. PV ECONOMICS 102 8.1. Introduction 102 8.1.1. Financial or economic 102 8.1.2. Cost-effectiveness 103 8.1.3. Life-cycle costing 105 8.1.4. Example life-cycle costing : PV lighting kit vs. 2 kerosene lamps 106 8.1.5. Example: comparison of portable lighting systems 108 8.1.6. Life-cycle cost and sensitivity analysis for other PV systems 110 8.1.7. PV pumping system vs. diesel pumping 110 8.1.8. PV refrigerator vs. kerosene refrigerator 111 8.1.9. Critical factors affecting PV system economics 113 8.1.10. Financing options 114 9. TECHNICAL REGULATIONS AND STANDARDS 118 9.1. Introduction 118 9.2. IEC - International Electrotechnical Commission 119 9.3. European Community - ESTI- JRC Ispra 119 9.4. PV module qualification testing 119 9.5. PV system monitoring 120 9.6. Missing Standards for PV systems, typical application designs andBOS components121 9.7. Electrical safety standards applicable to PV technology 122 9.7.1. Protection of human beings against electric shock 122 9.7.2. Protection against overload and short-circuit conditions 123 9.7.3. Lightning and overvoltage protection 124 9.8. Conflict areas between electrical safety standards and PV technology 124 9.8.1. Peculiarities of PV technology 124 9.8.2. Protective measures for Personal safety 124 9.8.3. Overcurrent and short-circuit protection 126 9.8.4. Overvoltage protection 126 10. CONCLUSIONS AND RECOMMENDATIONS 128 10.1. Experiences 128 10.2. Applications 128 10.3. Environmental impact 129 10.4. Installation, operation and maintenance 129 10.5. Critical factors 129 10.6. Economics 130 10.7. Institutional barriers 132 10.8. Future needs 133 11. SOURCES OF FURTHER INFORMATION 134

FIGURES 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, 2-8, 3-1, 3-2, 3-3, 3-4, 8-2, 8-3, 8-4, 8-5 NOT AVAILABLE ELECTRONICALLY

TABLE 2-1 NOT AVAILABLE ELECTRONICALLY EXECUTIVE SUMMARY

INTRODUCTION

Photovoltaics (PV) are used to power a wide variety of applications ranging from small consumer products such as pocket calculators, to the supply of whole villages. One of the primary applications of PV systems is to provide power at locations where mains electricity is not available. Such systems are commonly called stand-alone PV systems. This report presents the current status of PV technology, describes typical applications and experiences with installed stand-alone systems, and then looks at economic issues and barriers to the wider utilisation of PV systems.

Research on stand-alone PV systems is included in the International Energy Agency’s (IEA) Photovoltaic Power Systems (PVPS) programme. This report has been prepared by IT Power for the Energy Technology Support Unit (ETSU) on behalf of the Department of Trade and Industry (DTI) under Agreement No. S/P2/00205/00/00. It describes the work carried out by IT Power over the period February 1994 to April 1995 for the UK participation in Task III of the International Energy Agency’s Photovoltaic Power Systems Programme (IEA-PVPS).

In order to obtain a comprehensive picture of the status of the technology and the market for stand-alone PV systems, a survey was carried out as part of this research programme. Issues such as real and perceived barriers to the use of PV systems and experiences of actual PV users were also examined. It is intended that this document presents a detailed status report on stand-alone photovoltaic systems.

THE TECHNOLOGY

Photovoltaic cells absorb light and convert it directly into electrical energy. For most applications, a number of cells are combined to form a PV module. Commercially available modules use monocrystalline, polycrystalline or amorphous silicon technology, although other thin-film technologies such as for instance cadmium telluride will soon be available.

The energy output of PV cells or modules varies with the amount of light they receive. In order to obtain a constant supply of electricity, some form of energy storage is required. Usually rechargeable batteries are used for energy storage. Charging of the batteries needs to be controlled. If AC electricity is required, an inverter is also required. Therefore a typical stand-alone PV system usually consists of a PV array made up of one or several PV modules, a battery and a charge controller, and often also an inverter. These components are all readily available as commercial products. The quality of these products varies - they are available as high-quality industrial components, but cheaper consumer-quality products are also on the market. Further research is necessary for all components in order to improve their performance and quality.

APPLICATIONS

There are numerous applications where stand-alone PV systems can be used as a power supply option. They can be categorised into service applications, isolated buildings and island systems.

i Service applications comprise industrial systems such as telecommunications or telemetry systems or navigation aids, and remote rural applications such as water pumping/treatment systems or systems for health care, for instance vaccine refrigerators. Further applications are for consumer products like PV-operated fans or clocks.

There are tens of thousands of stand-alone PV systems installed in countries all over the world. Navigation aids like off-shore buoys are used even in countries as far north as Finland. Monitoring/telemetry systems are used in large numbers for weather stations, traffic counters, gas pressure monitoring or radiation monitoring in France, Germany, the UK and many other countries. Cathodic protection systems are used to protect oil and gas pipelines in the Middle East or oil platforms in India. PV pumping systems are used for irrigation, livestock farming and supply of drinking water in many developing countries, but also in developed countries, for instance the Netherlands. In Zaire, Uganda, the Gambia, Indonesia, Pakistan and many other countries PV-powered medical refrigerators are used for the conservation of blood and vaccines. In other countries PV is used for water treatment or lighting of clinics and health centres.

In Isolated buildings, requirements range from low-power applications, for example rural electrification in developing countries or for leisure homes in the developed world, to fully electrified buildings with the same appliances as a house connected to mains electricity. In Indonesia, for instance, over 10,000 houses have a small PV system, in Finland a similar number of systems supply holiday houses. In Italy and in the French Overseas Territories a large number of houses are equipped by a larger PV system, providing the users with the same comfort as they might enjoy in a grid-connected house.

Island systems are defined here as larger systems supplying, for instance, a remote village, a hotel complex or a small factory. The term ‘island’ refers to an area cut off from conventional electricity supply, not necessarily an island surrounded by the sea. Island systems are usually one-off designs with a relatively large PV generator. Often a back-up generator (e.g. a diesel gen set) is also integrated into these systems. Several such systems are installed in Italy, Greece and Japan.

USER EXPERIENCES

As with any new technology, there have been reliability problems with PV systems in the past. Some of the reliability problems can be attributed to non-technical reasons: often there is insufficient or no user training, manuals are either not written clearly or not available at all. Battery failure, for example, sometimes occurs because users bypass the low-battery disconnect switch or because users acquire more appliances than the system is designed for.

In addition, it is usually the case that components other than the actual PV modules lead to system failures. Nevertheless this tends to reflect poorly upon PV systems in general which has highlighted the need for improving the complementary components (batteries, inverters, end-use appliances etc.) to improve the overall reliability of systems. The quality of systems and components is improving constantly, however, and PV systems are often the most reliable power supply option compared to the alternatives available. This is reflected in the attitude of the users, who are generally satisfied with the performance of their systems.

Users of stand-alone PV systems in isolated buildings highlighted various positive aspects of PV in comparison to the alternative power supply options such as improved safety and a

ii perceived improvement to their quality of life, cost competitiveness and the continuous availability afforded by the battery storage system.

Some negative aspects were identified, however, including a failure to rectify identified system problems - which highlights the need for adequate maintenance and support mechanisms. A need for a greater variety and/or availability of DC appliances is also evident.

THE MARKET

The market for stand-alone PV systems is large. Stand-alone PV systems comprise around 80% of the global market for PV applications and the value of this total market has been estimated at approximately £480 million for 19951. PV becomes more cost-effective the more remote an appliance is and the less energy it requires. This is illustrated best by a calculator, which requires so little energy that a small PV cell is more cost effective than a primary battery or mains power supply available only a few metres away. Unlike grid- connected PV systems which require either a subsidy or a PV enthusiast, stand-alone PV systems are usually used because they are the most cost-effective solution. Therefore the market for these systems is self-sustaining.

BARRIERS TO UPTAKE OF PV

There are many obstacles hindering the market development of PV technology, varying in nature from technical limitations to social, institutional or economic problems.

Analysis of the responses to the survey on the use of PV systems in stand-alone and island applications indicates that in most countries the major barriers to the the more widespread installation of PV systems are related to costs. Although in certain respects, the costs of PV remain high, particularly the initial capital outlay, often there is a misperception that PV is uneconomic. The ‘real’ costs barrier, will gradually be overcome as system prices decrease, for instance through the introduction of mass-production of modules. Financing and credit mechanisms aimed at overcoming the inability to raise sufficient capital to purchase a PV system are also extremely important devices for the dissemination of PV technology, particularly in developing countries. The ‘perceived’ barriers can be overcome through programmes of education or awareness campaigns to inform potential users of the true costs of different forms of power generation.

PV ECONOMICS

The report outlines a methodology for determining the cost-effectiveness of stand-alone PV systems relative to other power supply options. The importance of assessing these options based on a full economic appraisal is presented. The inclusion of external effects such as health and safety or environmental benefits, security of supply or employment creation, which may not be reflected if the analysis is made solely on financial grounds, generally improve the economic viability of PV over the alternatives.

1 The Photovoltaic Industry: An Analysis of Strengths, Weaknesses, Opportunities & Threats, PV-UK, September 1994, ITP 93479.

iii Whilst life-cycle costing (an economic analysis which includes the initial and all future costs incurred over the operational life of a system) often indicates stand-alone PV systems to be the most cost-effective power supply option for remote rural or island electrification, the relatively high initial capital cost of such systems remains a strong disincentive to PV uptake. This is particularly true for the majority of potential owners in rural communities of developing countries. Various financing options for overcoming this barrier are discussed and highlights suitable examples of some succesfully implemented financing schemes.

TECHNICAL REGULATIONS AND STANDARDS

As with any other potentially hazardous item of equipment, an awareness of standards and recommendations for the correct and safe installation and connection of PV systems is vital. This not only helps to ensure that PV system installers, operators and users are not endangered and that equipment is not damaged due to faulty or incorrect installation, but for developers it is essential that they are able to refer to best practice guidlines so that they may take all necessary precautions to avoid dangerous and/or costly problems at a later date.

The report highlights the activities of the main organisations involved in the development of international standards applicable to PV installations and highlights the need for appropriate standards for Balance of Systems Components (batteries, inverters, charge controllers etc.) to eradicate failures in poor quality equipment which are currently seen as the major cause of technical problems in PV systems.

iv 1. INTRODUCTION AND BACKGROUND

1.1. Introduction

Nearly two billion people in the developing world live without electricity. In towns and cities supplied by the grid, electricity provides light for homes and offices, it powers industry and communications, it allows entertainment via TV and radio, it runs hospital equipment, and it pumps clean water. In remote rural areas, the standard of living and the hopes of economic advancement are severely limited without access to an electricity supply, so it is not surprising that rural populations continue to drift steadily towards the urban areas.

Rural electrification programmes continue to be an important part of national economic planning, but the high cost of installing new generating capacity and extending the grid to remote areas is often prohibitive. Despite the large sums invested over the past 30 years, many rural areas are still without electricity. Faced with foreign exchange shortages and more pressing national priorities, many developing country governments are abandoning rural electrification as a priority, unless funding is provided from sources outside the country, such as multilateral, bilateral and donor funding agencies.

The use of solar electric, or photovoltaic (PV), systems for the provision of electricity is an increasingly important alternative and has proven to be a cost-effective solution where full- scale electrification is impractical for economic reasons or improbable for political reasons.

Environmentally sound and durable, photovoltaic systems of less than a few kilowatts are ideally suited to conditions that prevail in the rural areas of developing countries. They are now technically proven, commercially available and economically viable for a wide range of applications. The main advantages and disadvantages of PV systems are summarised in Table 1-1

Photovoltaic systems are used primarily in rural areas to provide sustainable power for lighting, water pumping and refrigeration. Hundreds of thousands of PV systems are currently in use around the world, yet this number is insignificant compared to the overall potential.

Rural electrification using solar energy also creates employment, which increases the economic and social prosperity of the rural population and helps reduce the migration to urban areas. The local manufacture of PV system components, such as lights, regulators and even PV modules is feasible and has been undertaken in several countries. Jobs have also been created for installation and maintenance technicians.

Given the important role electricity can play in improving living conditions and facilitating economic development, PV needs to be considered seriously for rural electrification.

1 Table 1-1 Relative merits of photovoltaic modules

Advantages

PV modules...

□ generate electricity without moving parts, and produce no noise, smoke or fumes

□ allow independent power to be generated where no mains power is available

□ are light, easily installed and readily adjustable for maximum output

□ are robust, reliable, and weatherproof, so have long lifetimes

□ require insignificant maintenance work apart from occasional cleaning

□ have no fuel costs and low maintenance costs; once installed they produce virtually 'free' electricity

□ produce direct current (DC) electricity, which can directly charge storage batteries

□ are modular units, so extra PV modules can be added to suit electricity and budget requirements

□ can reduce running times, and fuel and maintenance costs of petrol or diesel generators if used in conjunction with them

Disadvantages

□ have a relatively high capital cost compared with many other types of generation, costing about US$4.5-5.5f per peak Watt (1994) for the larger modules (although the real cost is falling)

□ produce a direct current DC output and therefore require additional equipment (i.e. regulator, inverter) to produce 'mains equivalent' 240V alternating current (AC) output

□ produce energy only during daylight and have a lower energy output in winter and during cloudy weather, so usually require battery storage or a backup petrol or diesel generator

t This report makes use of two units of currency: the US dollar (US$) and the European Currency Unit (ECU) At the time of this report, the conversion rate is approximately 1.3US$ « 1ECU

2 1.2. Purpose of this Report

1.2.1. Background

This report has been prepared by IT Power for the Energy Technology Support Unit (ETSU) on behalf of the Department of Trade and Industry (DTI) under Agreement No. S/P2/00205/00/00. It describes the work carried out by IT Power over the period February 1994 to April 1995 for the UK participation in Task III of the International Energy Agency’s Photovoltaic Power Systems Programme (IEA-PVPS).

Task III deals with stand-alone PV systems, i.e. systems which are not connected to the electricity supply network. IT Power was awarded the above contract by ETSU to carry out a survey on stand-alone PV systems as one of the initial activities of this programme. The report uses this world-wide survey to present detailed results on the state of the art of stand­ alone PV systems.

Of all the IEA-PVPS activities, Task III is the most closely related to to commercial PV markets. More than 80% of the present PV market size can be allocated to stand-alone PV systems and this trend can be expected to continue in the short and medium term.

Task III activities are carried out by the following participating countries: Canada, Finland, France, Germany, Italy, Japan, Korea, Netherlands, Portugal, Spain, Sweden and the UK. The UK’s participation is funded by the DTI, the ODA and the UK PV industry.

1.2.2. Aims of the Report

This final report has the following aims:

□ to give a brief introduction to photovoltaics (PV)

□ to provide data on stand-alone PV systems which are currently in use

□ to outline user experiences with stand-alone PV systems

□ to identify barriers to the wider, appropriate use of PV systems and to assist in removing them

□ to provide information on the world market for stand-alone PV power systems

□ to provide information on the state of the art of stand-alone PV power systems technology

1.2.3. Benefits to the UK PV industry

The UK has benefited from participation in Task III in the following ways:

□ Information exchange on experience gained by participating countries about the market for stand-alone PV systems;

□ Immediate access to the results of other National PV Programmes;

3 □ Advance information about new products and components;

□ Market intelligence through international contacts;

□ Participation in other world-wide PV programmes, e g. EU ‘Power for the World’ and the World Bank ‘Solar Initiative’.

□ Reports and dissemination of information to further promote PV technology.

1.2.4. Deliverables

Documentation and publications that have been produced or co-produced by IT Power as part of the Task III programme include quarterly management reports to ETSU and the ODA as well as half yearly reports from the Operating Agent. In August 1994 a brochure describing Task III activities was published on behalf of the ODA and in September 1994 a flyer was released to raise awareness in the UK. This was extended to provide international coverage of Task III the following year.

In September 1994 IT Power developed the Master Questionnaire which was circulated to users of stand-alone PV systems in all participating countries. The results of this survey were produced in April 1995 and in October 1995 a book summarising the systems studied was published entitled Examples of Stand-alone Photovoltaic Systems.

The ExCo Meeting in April 1995 provided the opportunity to establish a strategy for the extension of Task III Activities to developing countries. The market for stand-alone PV systems in these countries is significant; around two billion people in the developing world are not yet connected to a national electricity grid and would benefit considerably from the installation of stand-alone PV systems.

In addition to the above, a number of reports describing the state of the art of BOS components, for example batteries, inverters and charge controllers, have been produced. The findings of these reports are summarised in this report.

1.2.5. Meetings

The following meetings have taken place over the course of the Task III programme:

Date Place Purpose October 1992 Rome (Italy) First Experts’ Meeting May 1993 Cadarache (France) Second Experts’ Meeting December 1993 Eversley (UK) Third Experts’ Meeting January 1994 Sophia Antipolis (France) Technical Meeting April 1994 Utrecht (Netherlands) Fourth Experts’ Meeting December 1994 Oahu (USA) Fifth Experts’ Meeting April 1995 Newcastle upon Tyne (UK) PVPS ExCo: Developing Countries Workshop May 1995 Karlsruhe (Germany) Sixth Experts’ Meeting June 1995 Harwell (UK) Presentation to SEAC July 1995 Capenhurst (UK) Presentation to the PV industry

4 November 1995 Kobe (Japan) Seventh Experts’ Meeting

1.3. The IEA Photovoltaic Power Systems Programme

The IEA carries out a programme of energy R&D collaboration among its member countries. This includes joint research and development of new and improved energy technologies. The Photovoltaic Power Systems (PVPS) programme is one of the most recent agreements to be established. The details of the collaboration and the responsibilities of the participants are spelt out in the ‘Implementing Agreement’.

The programme is split into six individual research projects (Tasks). Task III deals with the use of PV systems for stand-alone applications. For the purpose of Task III, stand-alone PV power systems are split into three categories:

□ Service applications, such as telecommunications, water pumping, remote sensing, lighting etc.

□ Isolated buildings, such as houses, small hotels, health centres, schools, town halls

□ Island systems, such as villages, desalination plants, hospitals, farms, factories. These systems are often a combination of PV with a diesel or wind generator (hybrid systems). In this context, island means a location surrounded by an un-electrified area, not necessarily the sea.

1.4. Aim of Task III

The overall aim of Task III is to advance the state of the art of stand-alone PV systems. Further important objectives are to achieve exports from participating countries and to promote and facilitate the appropriate use of PV in developing countries, particularly for the benefit of people in rural areas without access to an electricity grid. This includes the promotion of large-scale PV electrification programmes. Another aim of UK participation is to obtain up-to-date market and technology information for the PV industry. This information will be widely distributed.

These objectives are to be achieved by various activities of the participating countries, such as:

□ collecting all relevant data on stand-alone applications, island systems and isolated buildings

□ identifying the major barriers, both technical and non-technical, to the wider dissemination of such PV systems

□ comparing the various procedures for implementation, operation, and maintenance of these systems and improving them

□ developing more reliable designs and operational strategies which are less costly and time consuming

□ standardising methods of planning and evaluating systems

5 □ evaluating the efficiency and reliability of specific components

Special attention is to be given to reliability, training, social acceptance, human involvement and financing systems.

In order to obtain a fairly comprehensive picture of the status of the technology and the market for stand-alone PV systems, a survey was carried out among the countries participating in Task III. Issues such as real and perceived barriers to the use of PV systems and experiences of actual PV users were also examined. An analysis of the responses to the survey has highlighted the areas which require further work in order to increase the use of PV in stand-alone applications. The next phase of Task III will concentrate on these aspects.

Particular emphasis will be given to the appropriate use of PV systems for the benefit of developing countries, especially for people in rural areas without access to an electricity grid. To assist this process, a second survey has been prepared and distributed to developing countries. The responses to this will be used to assess the needs and preferences of potential users in developing regions, and will help to demonstrate the best way of meeting such requirements. This will also be of benefit to the PV industry in the IEA member countries as new business opportunities will be identified.

6 2. PHOTOVOLTAIC TECHNOLOGY

2.1. Background

Photovoltaic cells are semi-conductor devices which absorb light energy and convert it into electrical energy. The photovoltaic effect was first discovered by the French scientist Becquerel in 1839. The first practical photovoltaic devices were selenium and cuprous oxide cells, used for photographic meters and light sensors.

Light to electricity efficiencies were about 1% in the early 1940's. It was not until the late 1950's that crystalline silicon solar cells were developed with high enough efficiencies to be used as power generators for the US space programme. The first solar powered satellite, Vanguard 1, was launched in 1958. After some pioneering terrestrial applications of photovoltaics in the 1970's, PV module manufacturing matured in the beginning of the 1980's with the introduction of automated production plants.

The majority of modem PV cells have silicon as their base material, either mono-crystalline or poly-crystalline. Recently there have been significant developments in the use of thin-film technologies, using Amorphous Silicon, Cadmium Telluride, Copper Indium Diselenide and other semiconductor substances as the base material. To date, these thin-film technologies have not been able to achieve the higher efficiencies of crystalline silicon cells, which are now achieving over 21% efficiency for mono-crystalline in research conditions and up to about 15% for commercially available modules.

Figure 2-1: Efficiencies of PV Cell Technologies

■ Commercial □ Best Practical Crystalline □ Laboratory Silicon □ Theoretical

Thin FUn s CIS

CdTe

T ( 0% 5% 10% 15% 20% 25% 30% 35%

7 Figure 2-1 summarises the current efficiencies of the various PV cell technologies, ranging from commercially available modules to the theoretical maximum for each semiconductor. It should be observed that commercial modules are still only achieving about half their theoretical maximum efficiency.

2.1.1. Mono-crystalline silicon cells

A mono-crystalline silicon cell is made from a highly pure, thinly-sliced single silicon crystal wafer. The surface of the silicon is treated in various ways to make it respond to sunlight by developing a voltage between the front illuminated face and the back surface. A network of fine metallic conductors is applied at the front of the cell and the back is metallised all over. An anti-reflective coating is then applied to the front surface. Mono-crystalline cells have a uniform blue colour. A cell of 10 square centimetres and 18% efficiency will produce a maximum of 1.8 Watts with a voltage of 0.5 Volts under full sunshine. The individual cells are electrically connected together in series, and encapsulated to form a module (see Figure 2-2 and Figure 2-3).

2.1.2. Poly-crystalline silicon cells

A poly-crystalline silicon cell has a lower manufacturing cost than a mono-crystalline cell, as it is cut from a cast ingot made up of multi-crystalline silicon, and is generally square in shape. The cells are still blue but display a pattern similar to that of a piece of galvanised metal. The cell efficiencies of poly-crystalline silicon are slightly lower than for mono­ crystalline.

Figure 2-2: Crystalline silicon photovoltaic cell

NOT AVAILABLE ELECTRONICALLY

8 Figure 2-3: Construction of a photovoltaic module

NOT AVAILABLE ELECTRONICALLY

2.1.3. Amorphous silicon cells

The only thin-film modules currently in large scale production are made from amorphous silicon (a-Si). About one third of the cells sold in 1990 were thin-film amorphous silicon, but these were almost entirely for the consumer products market.

In a thin-film module, a layer of semiconductor material typically only 1 micron thick is deposited directly onto a sheet of support material, usually glass. The materials and manufacturing costs per unit area therefore have the potential to be much lower than for crystalline modules.

The main stumbling block for amorphous silicon is its low efficiency which degrades by 30­ 40% during its first year of operation. Installed a-Si modules have exhibited stabilised efficiencies of around 4%, although 6% efficiencies are claimed for more recent production modules and more than 12% has been achieved in the laboratory.

An important new technique aimed at producing more efficient thin-film modules is to create multi-junction cells. This involves building up layers of thin-film cells, each one sensitive to a different part of the light spectrum. More of the total light energy is converted into electricity and it appears that degradation is not so severe. Experimental multi-junction cells have exhibited stable efficiencies of 10%.

9 2.1.4. Photovoltaic modules

In a photovoltaic module, photovoltaic cells are electrically connected in series, in parallel, or a combination of both, to generate electrical power at an appropriate voltage.

A photovoltaic module of either mono or poly-crystalline silicon typically comprises 36 cells connected in series to achieve a voltage of 16 to 18 V, suitable for charging a 12V battery. A typical module is 0.4m x 1.0m in size and will produce a maximum of 50 to 70 Watts of direct current electricity. Since in some applications, such as portable lamps, a 50W module is much larger (and more expensive) than necessary, smaller modules are manufactured which use half-cells or quarter-cells to achieve the same voltage but with a quarter or half the power.

Amorphous silicon modules can easily be manufactured at the required voltage and power by literally cutting the module to size. Amorphous silicon modules are most commonly manufactured in sizes ranging from less than a Watt (e.g. for a solar calculator) to sizes up to a maximum of 50 Watts.

The current from all types of PV module is transmitted via a junction box attached to the back of the module. Each module can either be used individually to generate electricity, or connected in series and/or parallel with other modules (to form an array) to produce a higher electrical output.

All PV modules are encapsulated in a clear weather-resistant laminate, and usually enclosed in a sturdy, corrosion resistant frame. Most modules are designed to have a lifetime of up to thirty years. Figure 2-3 illustrates the construction of a PV module.

2.2. The Solar Resource

2.2.1. Definition of Terms

The output of a solar array is directly proportional to the amount of sunlight (solar irradiance,) falling upon it. It is therefore essential when specifying a PV system to ascertain the amount of solar radiation which falls on the site under consideration.

Solar irradiance is measured in units of Watts per square metre (W/m2) and varies depending on time of day, season, latitude, physical geography and climate.

The solar irradiance at ground level is made up of a direct component and a diffuse component. The sum of these two components on a horizontal plane is termed the global irradiance. The diffuse component can vary from about 20% on a clear day to 100% in heavily overcast conditions.

On a clear day in the tropics, with the sun overhead, the global irradiance can exceed 1000 W/m2; in northern Europe it rarely exceeds 900 W/m2.

Of most importance is not however, the instantaneous solar irradiance at a site, but the total solar energy received in a day over a specific area. This is known as the daily average solar irradiation or insolation and is measured in kilowatt-hours per square metre per day (kWh/m 2/day) or, less commonly, in MJ/m2/day. On a horizontal surface in the tropics, the

10 Figure 2-4: Examples of daily & hourly variation in solar radiation Note: Irradiation given in MJ/m2 can be converted into kWh/m 2 by dividing by 3.6

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insolation is typically 5-7 kWh/m 2/day, but on a winter's day in northern Europe it can be less than 0.5 kWh/m 2/day.

Figure 2-5 illustrates daily & hourly variations in solar radiation. On the hourly graph, the global solar irradiance is given by the upper curve and the diffuse component is the lower curve. On the monthly graphs, only the global irradiation (i.e. diffuse + direct component) is given.

2.2.2. Energy from photovoltaic modules

Modules are rated in terms of peak Watts (Wp). This is the power a module will produce in full sunshine, defined as 1000W/m2, which is roughly equal to the intensity of the sun at noon. Hence a 50Wp module will produce about 50W of electricity in full sunshine.

In order to maximise the solar energy capture, it is usual to position a PV module to face south in the northern hemisphere, and north in the southern hemisphere. To further optimise the amount of energy extracted, the module can be mounted on a tracking device so as to continuously face the sun through the day, though this is not practical in most cases.

11 The best compromise for a fixed solar panel is to make it face square to the sun at noon. If the module is inclined from the horizontal at an angle corresponding to the latitude of the location, then it will be square to the sun at the equinoxes (March 21 and September 21). A steeper angle gives more output in winter, a shallower angle gives more output in summer.

In the equatorial and tropical regions, modules should not be mounted dead flat but have a tilt angle of at least 10° to ensure good run-off of rain and better cooling. As a PV module will give more power if cooled, it is advisable to allow free air circulation all around the module.

2.2.3. System sizing

Accurate sizing of a PV array is normally done by the system supplier (who will determine how many modules are needed for a given energy requirement in a given location). The following formula is a simple way of estimating the daily energy output of a PV module.

Estimating module output:

Module output (Wh/day) = Module power rating (Wp) x Insolation (kWh/m2/day)

Where: Module power rating is given by the manufacturer

Insolation in the plane of the module is determined from meteorological data

For instance, if the daily insolation is 3 kWh/m2/day at 30° inclination, facing south, a 50Wp module installed in this plane will produce 50 x 3 = 150Wh/day.

The energy calculated above is the approximate energy produced per day by a PV module. In practice, the energy production also depends on the module temperature. Subsequent energy losses in other components of a PV system (e.g. voltage drops in cables, energy losses in the battery) will also have to be taken into account in the overall sizing of a PV system to produce the required power to run the appliances.

2.3. Stand-Alone PV Systems

2.3.1. Definition of a PV system

The term system is used to describe the complete set of equipment used in converting sunlight into the final requirement such as lighting, water pumping, refrigeration and power supply.

PV is mainly used with stand-alone systems to provide a power supply independent of any grid. Stand-alone systems are the main concern of this report. However, PV arrays may also be used as a central generator connected to a local grid network or a power station to supply power to the mains grid. A stand-alone PV system comprises four main components as summarised in Table 2-1 and described in more detail below.

12 Table 2-1 Components of PV systems

Component Summary PV array □ PV modules connected together and fixed onto an inclined support structure Power conditioning □ Depending on the application, may include some or all of the following. equipment: Batteries □ Necessary if storage of electrical energy is required; should be avoided if not essential due to additional cost and maintenance requirements Charge Regulator □ Protects batteries from over-charge / over-discharge Maximum power point □ Electronic device which adjusts module voltage to keep the system tracker operating at maximum power Inverter □ Converts DC current to AC; preferable to use DC appliances and avoid the need for an inverter. Cabling □ Connections between system components Load or end-use □ Most commonly lights, pumps, refrigerators and domestic appliances; equipment should be as energy efficient as possible

2.3.2. PV system components

PV Arrays are normally fixed, with the modules mounted onto a support structure which is oriented to face the sun and inclined at or about the angle of latitude to maximise the amount of solar radiation received over the year.

In some circumstances, it is advantageous to mount the modules on a support structure that tracks the sun throughout the day. Under clear sky conditions, the output from a tracking array is more uniform and can exceed that from fixed array by at least 20%. However, in view of the additional technical complications, higher capital costs, and the increased need for skilled technicians and maintenance, tracking systems are generally not appropriate for remote sites.

For some applications where the PV system is very small (e g. a lantern) or where the need for electricity is only intermittent (e g. livestock watering) a portable PV array may be appropriate. The array might be mounted onto a trailer which can be moved from site to site as required (e g. for a pumping system).

Batteries are used to store electrical energy. Some applications need an electric supply at times when no electricity is being produced by the module, for example night lighting. In other cases the supply of electricity needs to be constantly available, for example, for refrigerator or telecommunication loads. These applications require batteries to store electricity.

Batteries come in all shapes and sizes, each designed to suit a particular use. The characteristic of greatest importance for use with PV, is the ability to be repeatedly charged and discharged without damage. Other important features are the storage capacity of the battery, the ability to hold charge when not in use, to be charged and discharged with minimum loss of electrical energy and to operate for long periods with little or no maintenance.

13 Batteries with a medium to long life-cycle (i.e. 500 to 1000 charge-discharge cycles) are best suited for PV systems. However their cost is high (which limits their widespread use), and there are few manufacturers producing this type of battery. Two principal battery types are used with PV systems: lead-acid and nickel-cadmium.

The choice of batteries for a PV system deserves close attention, not only because they can consume typically 25% of the capital cost of a stand-alone system, but also because they are the least reliable system component with the shortest lifetime. Poor battery performance over the life of PV systems can lead to a considerable increase in overall capital investment.

Charge Regulators are required for battery-charging systems, particularly those using lead- acid batteries. Their main purpose is to monitor the state of charge of the batteries and prevent possible damage caused by over-charging or discharging.

A Maximum Power Point Tracker is a an electronic device, usually incorporated into larger PV systems, which automatically adjusts module voltage and current to keep the system operating at the maximum power point of the I-V curve. Its cost is often not justifiable for small stand-alone systems.

Inverters are made of electronic solid-state components. They are necessary only when

Figure 2-5: Various configurations of PV systems

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14 alternating current (AC) electrical appliances are to be used, such as normal domestic appliances and some pump types. As significant energy losses are always incurred in the conversion process from DC to AC current, it is advisable to try using DC appliances instead of AC ones and avoid using an inverter whenever possible.

Cabling is an essential part of a PV system and includes the cables, the cable fixtures and electrical overload protection devices. It needs to be durable enough to last the life time of the PV module and should be sized to avoid significant voltage drops.

2.3.2.I. Component lifetime

Component lifetime is an important parameter with a direct bearing on the overall cost- effectiveness of PV systems. Although lifetimes depend on the quality and type of components, it is possible to give a range a lifetimes for most of the components, including the end-use equipment. PV module lifetime is expected to be up to 30 years. Other component lifetimes vary from less than one year for a load such as an incandescent lamp and up to 20 years for cabling. Table 2-2 below gives the expected lifetimes of the main components.

2.3.3. Sizing

The size and composition of a PV system will depend on the irradiation of the site and the electricity requirements of each individual application. This should take into account the energy efficiency of all components.

Equipment with the lowest power consumption for a given service is preferred to minimise the load on a PV system and to reduce its size and costs.

It is advisable to ask at least two manufacturers or suppliers for a detailed sizing of the required system.

15 Table 2-2 Lifetimes of PV system components

Components Expected lifetime with present technology The PV array 10 to 30 years for crystalline modules 5 years minimum for amorphous silicon modules Power conditioning equipment: Charge Regulator 5 to 15 years Maximum power point tracking 5 to 15 years

i Batteries 1 to 3 years for automotive batteries 3 to 5 years for 'solar' (low-antimony) batteries 5 to 10 years for stationary battery (with shallow cycles) Inverter 5 to 15 years Cabling 10 to 20 years Load or end-use equipment 1000 hours of use for standard incandescent lamps 2000 hours of use for halogen incandescent lamps 8000 hours of use for fluorescent lamps 5 to 10 years for pumps 10 years for refrigerators 10 years for most others systems The lifetime of a battery depends upon many factors such as the frequency and depth of charge/discharge cycles, temperature, maintenance, etc. Therefore only a broad indication of expected life-times is given.

2.3.4. Installation

The installation of a PV system does not represent any major problems but does require trained people (technicians with a basic training in electricity), adequate tools and logistic support. For the best long term results, it is advisable to install PV systems with the same care and precautions as conventional power supply systems.

2.3.5. Maintenance requirements

In general, the overall maintenance required by a PV powered system is much less than similar systems powered by conventional sources such as diesel or petrol generators. However PV modules and systems require minimum but essential maintenance. A summary of the maintenance requirements of PV systems follows.

The PV array needs only a regular cleaning with a damp cloth once every two to three months. In especially dusty regions or during dry season months, cleaning may need to be more frequent. A periodic visual check for terminal corrosion and loose wiring is advisable as well as making sure that growing trees do not block the sunlight from the modules.

The power conditioning equipment including the regulator, maximum power point tracker, sealed batteries and inverter need only regular routine checks by qualified electricians. However, vented batteries need regular and essential maintenance. This consists of topping up the batteries with distilled water, checking and removing any build up

16 Figure 2-6 Battery maintenance: checking the level of charge

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of corrosion around the terminals, and ensuring the casing is sound without cracks or leakage. Cabling does not require regular maintenance but simple visual checks to detect any damage such as gnawing by rodents.

End-use equipment does not need specific maintenance related to PV-powered operation as, in general, these components are similar to those used with systems powered by conventional power supplies. Specific maintenance requirements are dealt with in the sections describing PV system applications.

2.3.6. Operating PV systems

The operation of a PV system is straightforward in most cases, limited to the use of switches, opening of a tap, etc. However, to ensure the reliable running of any system, the user must be taught clearly how to operate it and carry out the necessary maintenance.

Probably the best way to train the user is during installation and routine maintenance by a technician. A user's manual and a poster permanently fixed nearby are essential to reinforce important messages.

2.3.7. PV system applications

In principle there are few limitations on the equipment that can be powered by PV because the output can normally be adjusted to meet any kind of requirement. PV is most advantageous and cost-effective for low-power remote applications, and there are large number of commercial systems which now exploit PV as their power source. The following sections summarise the important features of various applications.

17 2.4. Environmental and safety considerations

2.4.1. PV modules and the environment

Photovoltaic modules are silent in operation and environmentally benign. They do not burn fuel, so emit no CO2 or noxious gases. They are mechanically safe as they use toughened tempered glass and have no moving parts.

The vast majority of PV modules utilise crystalline or amorphous silicon cells, which exhibit no environmental hazards during operation, even in the event of a fire. Silicon is a very stable material and its release into the environment poses no hazards. In the production of silicon cells the hazards are similar to those encountered in the micro-electronics industry, and monitoring and control procedures are well established.

PV modules made from cadmium telluride or copper indium diselenide (both yet to be commercialised) are potentially more hazardous because they use hydrogen selenide and cadmium during manufacture and will require controlled disposal or recycling at the end of the module life. As the control strategies for handling similar potentially hazardous materials are well-established in other industries, the environmental hazards are expected to be negligible with proper monitoring, control of production and recycling of scrap modules.

Figure 2-7: Energy ratios of PV modules

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18 2.4.2 Energy payback ratio of PV modules

All manufacturing processes require an input of energy. The energy payback ratio of a PV module is the electricity produced over the lifetime of the module as a ratio of the energy used in its manufacture. It is clearly essential that the ratio should be considerably greater than unity for PV to be a viable energy technology.

The energy payback ratio depends on the type of PV cells considered and on the location of the PV module, which directly affects the amount of electricity that will be produced. Hence the sunnier a country, the higher the ratio.

For most developing country environments the energy ratio is typically in the region of 10 to 25 according to the type of PV cells, as illustrated in Figure 2-7. This is significantly better than ten years ago, due to decreases in manufacturing energy intensity, and increases in module efficiency.

2.4.3. Environmental concerns of PV system components

A PV system is composed of a PV module connected to various other appliances or components, such as lamps, pumps, control units and very often batteries. Such components can present various environmental hazards in themselves, for example the improper disposal of high efficiency lamps containing mercury.

Lead-acid batteries require particular attention because they already represent a potentially damaging threat to the environment through their increased use throughout the developing world. The uncontrolled disposal of batteries can cause environmental damage if the chemicals are allowed to filter into the ecosystem. All types of batteries need to be disposed of safely and where practical lead-acid batteries should be given to local battery manufacturers for lead and plastic casing recycling.

PV systems which rely on batteries for the storage of energy will tend to increase the overall use of batteries in the developing world. However the dissemination of local PV battery charging stations (described in Table 3-3) would help to reduce the distances that large batteries are being transported and encourage the use of re-chargeable small batteries.

PV systems which recharge nickel-cadmium batteries (ni-cad) as an alternative to the use of disposable primary cells would be major environmental improvement. In the majority of cases, it would also be more cost-effective. However, the eventual disposal of ni-cad batteries must be carefully monitored to prevent cadmium contamination.

2.4.4. CO2 emissions

A thorough study would be necessary to work out the precise CO2 emissions attributable to PV systems, especially if this were to include the energy content of all sub-systems (batteries, control units, etc.)

However initial approximations of the CO2 emissions per kWh produced over a 20-year module lifetime can be estimated based on data from existing PV manufacturing plants. The results are presented in Figure 2-8, along with data from conventional fossil fuel power

19 plants, and confirm that the CO2 emissions relating to the lifetime of a PV system are negligible when compared with fossil fuel electricity generation.

It is worth noting that the CO2 emissions for PV would be zero if the manufacturing energy were produced from renewable energy sources, including PV itself.

2.4.5. Safety issues

PV systems do not present any major safety hazards. However PV arrays and systems are as potentially dangerous as any other electricity supply of similar voltage, capable of giving an electric shock if bare wiring is touched while the module is connected to the system. However small PV systems operate at low voltage (12 or 24 Volts), so the risk of electric shock is minimal. There are no recorded incidences of fatalities caused by PV systems.

Batteries represent the greatest safety hazard. Care is needed when using vented (i.e. unsealed) batteries, because not only is the battery acid extremely corrosive, but also hydrogen gas is produced which is highly flammable and potentially explosive when mixed with air. Care should therefore be taken to avoid naked flames or sparks in the battery enclosure, especially if the battery is housed in a confined space. For the same reason, battery storage areas should be well ventilated. Sealed batteries contain the electrolyte in 'dry' form so can not leak, but care must be taken not to damage the casing. Safety hazards can be significantly reduced if the systems are installed by trained technicians and operated by trained users.

Figure 2-8: Greenhouse Gas Emissions

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20 2.5.

21 Future development

In the past ten to fifteen years there have been remarkable technical developments in photovoltaic modules and systems. Sunlight-to-electricity conversion efficiencies have increased steadily, while costs have fallen dramatically. The progress is such that almost every month new efficiencies are announced for different materials. This is significant, as a higher efficiency means that more power can be generated from the same cell area, leading to lower unit costs. Advances in the design of the manufacturing machinery and production methods have also brought cost reductions.

Price has historically been the main barrier to widespread commercialisation of photovoltaics. In 1975 the price was over US$30 per peak Watt. 1986 provided the turning point for module price versus module efficiency, with increases in efficiency and decreases in price occurring since then. Improvements in the manufacturing technology and production volumes have resulted in a 1994 international price of US$4.5 - 5.5 per peak Watt for the most common size modules. At this price photovoltaics is economically competitive on a life-cycle cost basis for most small-scale off-grid energy requirements when compared to the common alternatives of grid extension or engine-generator sets, as will be shown later. Figure 2-9 illustrates the price and efficiency improvements of the last 15 years.

The R&D currently being undertaken on different types of PV materials and encapsulation methods is likely to lead to lower prices in the longer term. Work being done on cadmium telluride thin-film modules by BP Solar in the UK, and other organisations in the USA and Japan, promises to provide higher efficiencies and lower costs of PV material. At present there are no modules available commercially, though it is expected that they will be on the

Figure 2-9: Developments in PV Module Price and Efficiency

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22 market within five years. Advanced research is also being undertaken on copper indium diselenide thin-films by the University of Northumbria; commercial production of modules using this technology is also some years away.

2.5.1. Future Prospects for Module Efficiencies and Costs

2.5.1.1. Crystalline Silicon

Efficiency

Recent work on crystalline silicon technology has focused upon improved anti-reflection coatings (ARC), front-electrode design and surface texturing to improve light capture. Silicon reflects about 30% of the incident light and means must be found to reduce this to as low a value as possible, certainly below 5% or so. This is being attempted by using an anti­ reflection coating on the surface and/or by texturing the surface in the form of small pyramids.

The grid of metal contacts on the top surface also reflect the incident light. The size of these contacts can not be reduced too much or the series resistance will rise and dissipate the power from the cell. The grid-lines are applied by silk-screen printing, and the limitations of this technology have dictated the minimum thickness of the lines. However recent advances in silk-screen technology have enabled the printing of finer grid-lines which maintain a high thickness. Grid-lines have already been reduced by some manufacturers from 350 microns to 250 microns - adding almost 0.5% to module efficiencies - and further reductions to 150 microns are expected in the next few years.

Another recent innovation is the introduction of a back surface field. Impurities are added to the rear of the cell to create a heavily doped p-type region which sets up a positive electric field. The field acts to reflect free electrons back towards the p-n junction - which they must cross in order to contribute to the output of the cell. Experiments have demonstrated that a full 1% addition to the cell efficiency can be expected using a back-surface field, and this modification can be applied using existing equipment.

A recent innovation known as laser grooved buried cell technology has been to form grooves in the cell surface and to deposit the metal contacts into these grooves, effectively turning them on their side. The metal coverage on the surface is reduced in this way from about 5% to under 1%. With these techniques the total reflection can be reduced to around 2%, giving a module efficiency of 14-16%, although costs of manufacture are presently higher than for conventional modules.

Production Costs

Attempts to reduce the cost of crystalline silicon cells continue to revolve around the gradual improvement of production techniques that have existed since the 1970s - techniques which are inherently expensive.

Sawing of wafers

The greatest potential for near-term cost savings probably lies in improved sawing techniques. A conventional diamond saw is around 0.3mm thick and cuts 0.5mm thick wafers. The wafers are then lapped and polished to 0.3mm thick to remove the surface

23 damage caused by sawing stresses. This technique can produce around 1200 wafers per metre length of boule. A new technique of multi-wire sawing produces wafers about 0.3mm thick, giving around 2400 wafers per metre length of boule. This doubling of wafer production has had a major effect on reducing the production cost of cells.

There have been many attempts to circumvent the slicing step, by growing ribbons of silicon or vacuum casting individual wafers. A potentially important development in the ribbon silicon field in 1994 was the purchase of Mobil Solar Energy Corp. by ASE Americas Inc. (a collaboration between Deutsche Aerospace and Nukem). ASE will be continuing development of the edge-defined film ribbon silicon process. Spin-casting of wafers has been under development in Japan and is reported to be showing good commercial promise.

2.5.I.2. Thin-film materials

Thin film materials, in particular amorphous silicon, copper indium diselenide and cadmium telluride could realistically lead to much lower flat-plate module costs in the near future.

Efficiency

Much research is ongoing into methods of stabilising the efficiency of commercial amorphous silicon modules. The optimum top layer material has yet to be discovered, with the result that the action of light absorption leads to performance degradation during the first year of operation down to a value of 3-5% for single junction modules. It is expected that commercial modules will have stable efficiencies of 8% by 2010.

Both CIS and CdTe are likely to offer strong competition to a-Si once volume production is undertaken because of their higher stable efficiencies (around 10%).

Production Costs

The main cause for optimism is that the techniques used to produce thin films are particularly well suited to mass-production. The active material can be sprayed directly onto glass or metal in a continuous process - replacing the slow batch processing of crystalline cells. It is envisaged that eventually thin-film cells will be produced at the end of a float glass production line with a throughput of a few million square metres per year.

The thin film a-Si market received a boost at the beginning of 1995 when the US Enron and Amoco Corporations announced a PV joint venture with Solar ex for the large-scale production of multijunction a-Si cells. Funding was agreed for a manufacturing facility of 10MWp capacity. This will serve as a pilot plant for a larger facility - possibly 100 MWp/year - which should enable module manufacturing costs to be reduced to below $1.00/Wp.

It is expected that CIS and CdTe thin-films will eventually prove even cheaper to manufacture than a-Si because they do not require the vacuum processes needed for a-Si, although the raw materials are somewhat more expensive.

24 3. APPLICATIONS FOR STAND-ALONE PHOTOVOLTAIC SYSTEMS

3.1. Introduction

There are numerous applications for stand-alone PV systems. PV is used to power a wide range of service applications as well as individual houses or groups of houses, up to the supply of whole villages. Stand-alone PV systems are used in the UK as well as being exported to countries all over the world. This section illustrates many applications which use stand-alone PV systems.

3.2. Service Applications

Service applications include industrial applications such as telecommunication or cathodic protection systems as well as applications for rural areas such as refrigeration, pumping or water treatment systems. Service applications have been the most important commercial market for the PV industry. The systems are purchased routinely and are generally accepted as being reliable and cost effective. Some applications such as water pumping still have scope for improvements. For many service applications, high reliability of the power supply is a very important factor. Vaccine refrigerators or lighthouses are examples where the power supply has to be extremely reliable.

3.2.1. Telecommunications

Principle and technology □ Telecommunication systems usually have a relatively constant energy demand. In order to obtain a continuous power supply, storage batteries are used □ A charge controller is needed to control battery charging Range of size □ 50 Wp to 20 kWp Number of systems world­ □ Many thousands wide Specific maintenance □ No specific maintenance requirements. The battery requires some maintenance requirements (checking electrolyte levels, topping up electrolyte). If maintenance-free batteries are used, this does not apply Examples of capital costs □ $ 10/ Wp for the complete PV power system (FOB) (US$) Typical applications □ Microwave repeater stations □ Transceivers □ Rural telephone networks □ Emergency telephones □ Rural radio/television □ Broadcasting systems Reliability / maturity of □ Reliable and proven technology technology

Today, telecommunication links are of vital importance. This also applies to remote areas without access to an electricity network. In order to connect more densely populated centres,

25 telecommunication links often go through remote areas and repeater stations along the way require electric power. In these cases, PV offers a reliable source of power.

3.2.2. Cathodic Corrosion Protection

Cathodic protection (CP) systems are used to protect metallic structures against corrosion caused by chemical reaction between the structure and the surrounding medium, e g. soil or water.

Principle and technology □ An electric current flows from a sacrificing anode through the surrounding medium to the protected structure, which acts as cathode. □ The current varies with weather conditions and has to be controlled □ A battery is used for storage to ensure the availability of power during night­ time and periods of low insolation Range of size □ 1 to 10 kWp Number of systems world­ □ Several thousands wide

Specific maintenance □ No specific maintenance requirements. The battery requires some maintenance requirements (checking electrolyte levels, topping up electrolyte). If maintenance-free batteries are used, this does not apply Examples of capital costs □ $ 10/ Wp for the complete PV power system (FOB) (US$) Typical applications □ Oil or gas pipelines, well heads □ Locks □ Bridges and other steel structures Reliability / maturity of □ Reliable and proven technology technology Comments □

26 3.2.3 Telemetry Systems

Telemetry systems are used in many different areas to monitor and record or transmit data.

General Information □ There are many applications for PV powered telemetry systems. For example, in the UK weather monitoring systems are used by the Meteorological Office and the water companies. Principle and technology □ Telemetry systems are used to collect data, for instance by measuring physical properties. The data is then recorded, transmitted to a central station or used to initiate some action. □ Often telemetry systems are situated in remote area without a conventional power supply. In this case, PV provides a reliable source of power. Range of size □ 10 Wp to a few 100 Wp Number of systems world­ □ Innumerable (Precise figure unknown) wide

Specific maintenance □ No specific maintenance requirements. The battery requires some maintenance requirements (checking electrolyte levels, topping up electrolyte). If maintenance-free batteries are used, this does not apply Examples of capital costs □ $ 10/ Wp for the complete PV power system (FOB) (US$) Typical applications □ Weather monitoring to collect meteorological data □ Monitoring of pressure in gas pipelines □ Radiation monitoring □ Traffic monitoring Reliability / maturity of □ The technology is mature and reliable technology Comments □

27 3.2.4 Navigation Aids

Navigation aids such as buoys, light houses or light vessels are used along coastlines all around the world. As these systems are often some way off the coast, they are remote by nature. PV provides an ideal solution to the problem of providing power to navigation aids.

History / recent □ Conventional navigation aids use oil or gas lamps, or are sometimes connected developments to mains electricity. Principle and technology □ Navigation aids consist essentially of the power supply system (e.g. PV module, controller and battery) and a lamp. Range of size □ 50 Wp to about 5 kWp Number of systems world­ □ Tens of thousands wide

Specific maintenance □ Battery maintenance (checking electrolyte levels, topping up electrolyte). Often requirements maintenance-free batteries are used. □ Lamps needs to be replaced regularly. Examples of capital costs □ $ 10/ Wp for the complete PV power system (FOB) (US$) Typical applications □ Coastal lights and buoys □ Boat lights □ Terrain avoidance lights (on lulls for aircraft) □ Hazard and direction beacons □ Railway crossing lights □ Tunnel lighting Reliability / maturity of □ The technology is mature and reliable technology Comments □ The use of PV instead of lamps burning gas or oil reduces the number of necessary maintenance visits considerably. In addition there are savings in fuel. PV-powered electric lamps also more reliable in storms than gas or oil lamps.

28 3.2.5 Pumping systems

Drinking water is one of the most basic of human needs, yet today over half of the people in the developing world do not have access to a safe and reliable water supply. Access to potable water can make a vital difference to the health and quality of life of a rural community. In many areas water exists below the ground, and throughout the developing world the most widespread way of raising it to the surface is still by hand pump or with the assistance of animals.

Solar pumping systems are an alternative to traditional systems, including diesel pump sets. They were first introduced in the late seventies, and since then manufacturers have refined their products to provide increased performance and reliability. Solar pumps can pump water from boreholes, open wells, rivers and canals to provide safe water. This can be combined with water treatments according the quality of the water needed. More than for most other

History / recent □ Pioneered in the 1970's in the Sahel region of West Africa developments □ Borehole centrifugal pumps used to be the type most widely used, originally coupled to surface mounted DC motors. Recent installations have changed to using pumps with submerged AC or DC motor/pump sets □ In 1990/91 a range of small DC submersible pumps with only 80 -160Wp of modules were introduced on the market Principle and technology □ Comprises a PV array connected to an electrical motor driving a centrifugal, reciprocating or diaphragm pump via a power conditioning unit (i.e. inverter / maximum power point tracker) □ Most large PV pumps (e.g. water village supply) installed today utilise AC submersible motor-pump sets powered from the PV array via an inverter □ No need for batteries because pmnped water is used as a means of energy storage □ Exist in various configurations; see Figure 3-1 Range of size □ 0 to 120m of pumping head (most cotmnon size is below 50m) □ 0 to 700nv7day (most cotmnon size is < 75nr'/day) □ 20Wp to 50kWp Number of systems world­ □ > 20,000 (Annual sales exceeded 7000 units in 1992) wide Specific maintenance □ None (same as conventional pumping systems: check strainers and filters, requirements cables/ropes, support wire, water leaks, non-return valve, motor-bushes, safety- cut out, etc.) Examples of capital costs □ $10-55/m 4 with an irradiance of 6kWh/m2/day (small systems (FOB) (US$) generally cost more than larger ones in $/m 4.) □ $2000 for 2nr7day and 30m head (i.e. $3 3/m4) □ $15,000 for 20 nr’/day and 30m head (i.e. $25/m 4)1 Typical applications □ Village potable water supply □ Irrigation of vegetable garden or small pieces of land □ Livestock watering Reliability / maturity of □ Excellent technology Comments □ Many of the components (particularly the storage and settlement tanks) can be obtained and assembled locally.

29 pumping systems, a PV pump usually requires donor financing because of its relatively high capital cost (e.g. US$15,000 for 20m3/day of water from a depth of 30m). It should be noted however that the cost of a PV pump is quite often comparable with the cost of providing the borehole for the pumping system.

Solar pumps have proved to be one of the most appropriate technologies for village water supplies in situations where hand-pumps are unable to meet demand. PV pumps can be used to pump from boreholes, open wells and rivers, the most common applications being village water supplies, irrigation and livestock watering. Less common applications include drainage pumping and water circulation for fish farms. The important features are summarised below, and Table 3-1 compares PV pumps with alternative pumping systems.

Capital costs for pumping systems are normally given in US Dollars per m3 of water per metre of height pumped, or $/m 4. For example, a requirement of 2m3/day at a head of 30m, with a price of $3 3/m4, means that the pump will cost $3 3/m4 x 2m3/day x 30m = $2000. Capital costs are also sometimes given in $/Wp which indicates the system cost in relation to the cost of the PV array (e.g. a PV pumping system might typically cost $13/Wp with a module cost of $5/Wp).

Table 3-1 Relative merits of different pumping systems

System Advantages Disadvantages

PV pumps □ Unattended operation (or almost) □ High capital costs □ Low maintenance □ Water storage required for cloudy □ Easy installation periods □ Long life □ Repairs often need skilled technician □ No fuel costs □ High reliability □ Environmentally benign

Diesel pumps □ Easy installation □ Fuel supplies can be erratic and □ Low capital cost expensive □ Widely used □ High maintenance costs □ Short life expectancy □ Noisy & polluting

Hand pumps □ Local manufacture possible □ Often inefficient use of boreholes □ Relatively easy to install and □ Only low flow rates are achievable maintain □ Loss of human productivity □ Low capital cost □ No fuel costs □ Environmentally benign

30 Figure 3-1: Configuration of motor/pump sets

NOT AVAILABLE ELECTRONICALLY

31 3.2.6. Water treatment systems

History / recent □ First systems in the 1970's (along with pumping systems) developments □ In 1992, commercialisation of self-contained PV powered systems for emergency relief needs, combining a chlorinating plant and a pumping system Principle and technology Several principles exist: □ Chemical dosing (e.g. chlorination: purification of water by calcium hypochlorite or sodium hypochlorite (Javel water), injection proportional to the water flow (e.g. 1 litre/150m"' of water). PV is used to power injection pump (low energy consumption). □ Ultraviolet sterilisation: killing of waterborne bacteria and other micro­ organisms by UV illumination, PV is used to power UV tubes (e.g. 60W for 2nv7h). □ Slow-sand filtration: removal of suspended solids, but also water-borne bacteria. Water passes from a header tank through a filter to a supply tank. PV is used to pump water to the header tank. □ Reverse osmosis: based on the principle of filtration through semi-permeable membranes at high pressure; PV is used to power the high-pressure pump. High energy consumption (e.g. 5-10kWlVm 3). □ Ionisation process: release of metallic ions from electrodes that kills micro­ organisms. PV is used to power the ionisation electrodes. □ Aeration system to oxygenate waste-water (e.g. for fish-farming). □ All systems possibly combined with water pumping systems. Range of size □ 5 litre/hour to many cubic metres per day Number of systems world­ □ Hundreds wide Specific maintenance □ No specific requirements requirements Examples of capital costs □ Depends strongly on principle of treatment (fairly cheap for chlorination, (FOB) (US$) expensive for reverse osmosis system) Typical applications □ Treatment of polluted water □ Water desalination Reliability / maturity of □ Identical to similar water treatment systems powered by conventional energy technology / environment sources Comments □ Many of the components can be obtained and assembled locally

32 3.2.7 Refrigeration systems

The running principles of PV-powered refrigerators are similar to domestic refrigerators, except that DC motors are used for the compressors. These systems can significantly improve the services of health, food, livestock and agricultural programmes. For example refrigeration is required for immunisation programmes to keep vaccines within a 0-8°C temperature range throughout transportation and storage. PV refrigerators are now often preferred because the performance of refrigerators fuelled by kerosene or bottled gas can be inadequate due to inaccurate temperature monitoring and fuel shortages.

History / recent □ Pioneered in the 1980's developments □ In 1993, launching of more efficient compressor controllers and CFC free compressors Principle and technology □ 12V or 24V compression refrigerator linked to batteries and PV modules via a charge regulator and a compressor controller; low energy, due to high levels of insulation around the storage compartment □ Some refrigerators include a freezer compartment for ice pack freezing (WHO/UNICEF requirements). Other systems have separate units to provide solely for refrigeration or freezing □ For food cold stores, standard AC compressors plus an inverter are used Range of size □ 25 to 200 litres storage capacity with ice production rates of up to 5 kg per 24 hours for this range □ lOOWp to 300Wp for the range of size above □ Cold stores - array rating varies with storage volume Number of systems world­ □ > 10,000 (4000 for human vaccine and blood refrigeration) wide Specific maintenance □ Regular defrosting, temperature checks essential for vaccines requirements □ Less frequent maintenance than for kerosene or gas refrigerators □ Requires a technician with electricity and refrigeration knowledge for repairs Examples of capital costs □ $3500 to $6000 for a 50 to 120 litre capacity (including PV modules, battery, (FOB) (US$) refrigerant cabinet and all BOS components) Typical applications □ Refrigeration of human vaccines for immunisation prograimnes □ Refrigeration of human blood □ Refrigeration of livestock vaccines □ Domestic refrigerators for remote buildings □ Agricultural cold stores (few coimnercial products) □ Ice production (few coimnercial products) Reliability / maturity of □ Good reliability, better than kerosene refrigerators technology / environment □ Life-time limited only by the life-time of battery □ Contains CFC, but will be replaced by a CFC free refrigerant fluid (i.e. R134b) within a few years Comments □ Can be locally manufactured / technology transfer possible

33 Figure 3-2: PV refrigerator

NOT AVAILABLE ELECTRONICALLY

Table 3-2 Relative merits of different refrigeration systems for vaccine storage

System Advantages Disadvantages

PV refrigerators □ High reliability, hence low □ Increased user training requirement vaccine losses □ Repairs often need skilled technician □ Good temperature control □ High capital cost □ No fuel costs □ Low maintenance □ Long life

Kerosene refrigerators □ Simple installation □ Problems with fuel quality □ Relatively low capital cost □ Poor temperature control □ Poor reliability □ Fuels supplies can be erratic and expensive n High maintenance costs

Conclusion: The reduced vaccine losses due to the better reliability and temperature control of PV refrigerators means that a more effective and sustainable cold chain is achievable.

34 3.2.8. Battery charging systems

There is a huge demand in developing countries for small quantities of electricity to power small torches, radios, TV and lights. This is apparent from the continuous transport of batteries from rural areas to grid-connected towns, the numerous shops offering a battery­ charging service, and the vast quantity of small 'throw-away' primary cells bought by rural people.

PV battery-charging systems, charging either small rechargeable cells (e g. ni-cad batteries) or standard lead-acid automotive batteries, can provide an efficient and cost-effective alternative to the wasteful procedures followed at present.

PV battery-charging systems are in fact the most reliable of the PV systems discussed in this section due to the fact that they themselves require no batteries.

History / recent □ Has recently been introduced for income generation purposes in several health development centres in Zaire and Senegal Principle and technology □ Consists of a PV array with or without charge regulator with two connectors (e.g. 'crocodile' type). The connectors are connected to batteries brought by private battery owners paying for the service □ Charging current depends on irradiation and size of modules; small systems can recharge small ni-cad batteries while bigger systems can charge lead-acid car batteries Range of size n 2 to 50Wp for small ni-cad batteries □ lOOWp up to a few kWp for car batteries Number of systems world­ □ Several thousands wide Specific maintenance □ None requirements Examples of capital costs □ $30 for a IWp individual ni-cad battery charger (FOB) (US$) □ $400 to $600 for a 40 Wp community ni-cad battery charger □ $2000 to $3000 for a 300Wp community car battery charger Typical applications □ Charge of 'car type' batteries for domestic use (TV, radios, lights, etc.) □ Generation of income for local community or health centre by replacing coimnercial grid-connected charging station □ Charge of small dry-cell secondary batteries for powering flashlight, radios, etc. Reliability / maturity of □ Highly reliable system, very simple. technology / environment Comments □ The most cost-effective PV system available today in terms of $/kWh of energy supplied

In the Dominican Republic over 200,000 battery-powered radio/cassette players are used in rural areas. Most are powered by dry cell batteries, each typically consuming between 4 and 40 batteries per month. Disposal of the 40 million batteries used in rural areas each year in the Dominican Republic poses a large environmental hazard. The introduction of PV systems to charge reusable ni-cad batteries could help alleviate this situation. Note that ni-

35 Figure 3-3: Community battery charging system

NOT AVAILABLE ELECTRONICALLY

cad batteries need to be disposed of carefully after the end of their life-time to avoid cadmium pollution.

Table 3-3 Relative merits of different battery charging systems

System Advantages Disadvantages

PV battery charging □ High reliability □ High capital cost station n Good charge control □ Charging time varies with sunshine □ No fuel costs □ Low maintenance □ Increased life of batteries □ Avoided transportation □ Simple installation

PV charging station in □ Charging possible at night □ Risk of battery theft/loss during grid-connected town or n Widely in use transportation via diesel generator □ Charging price follows electricity or fuel costs □ Extremely poor energy efficiency over the cycle of charge/discharge

36 3.2.9 Health care

Energy requirements for health services in rural areas are small in relation to all their other needs, but of great importance. The constant availability of a quality energy supply in health centres and hospitals can improve the delivery and availability of health services to rural populations. Improvements in health are reflected directly in terms of increased agricultural productivity and enhanced educational performance.

PV systems in health facilities can supply energy for lighting, vaccine storage, blood and drug refrigeration, sterilisation, radio and telecommunications. In larger hospitals, it can also supply energy for radiology, laboratory equipment, water pumping, water treatment and passive ventilation.

3.2.10. Other systems

A large number of other commercial systems use PV as their power source. These include agricultural systems such as water pumping for livestock watering, irrigation schemes and fish-farms, and power for food processing activities such as crop drying or milling. Other agricultural applications include lighting for farm houses and refrigeration of animal vaccines. PV systems also provide remote power for insect traps, bird-scarers and electrified fences (a 10 Wp module can electrify several kilometres of fencing).

Industrial systems □ Ventilation systems □ Large air-conditioning systems (compressors, pumps, fans) Agricultural systems □ Electrified fencing □ Livestock tracking systems □ Drying system (for powering ventilation fans) □ Food processing (grain grinding, maize shelling) □ Water tank ice preventers Consumer products □ Small battery chargers □ Watches, clocks □ Toys □ Radios, door bells □ Automobile ventilator

37 3.3. Isolated Buildings

Domestic PV systems can be as small as a lighting system or large enough to power all the requirements of a grid-connected home. For the following, a Solar Home System (SHS) is defined as small systems using only one or two modules to power lights and possibly radio and/or television. A Remote Area Power Supply (RAPS) system is defined as a larger PV system capable of supplying electricity to some or all appliances typically used in houses connected to mains electricity.

In domestic applications the electrical loads which must be met by the PV generator are more variable and unpredictable than with service applications. Additionally the individual user has a significant influence on the load(s).

3.3.1. Solar Home Systems (SHS)

Most people in developing countries have access to some form of lighting but it is often of poor quality, and at a high cost relative to their income. PV lighting can be a cost-effective alternative solution to flame-based lighting systems and is likely to lead the way for the widespread introduction of PV into off-grid areas.

Figure 3-4: Solar home system

NOT AVAILABLE ELECTRONICALLY

38 History / recent □ In the 1970's lighting was one of the first applications for PV in developing developments countries, usually brought in by missionaries □ In the 1990's, energy efficient electronic compact fluorescent lamps (CFL) were launched on the cotmnercial market Principle and technology □ A system comprises one or more PV modules, a battery bank, a charge controller, several lamps and associated wiring and fittings, other DC appliances such as televisions, radios, fans, etc. □ Lamps are mostly of the fluorescent or low-voltage halogen type due to their high efficiency □ For large systems, AC lamps are suitable, such as CFLs Typical size □ Modules ranging from 30 to 100Wp, a 50 to 100 Amp-hour battery, a regulator and 2 to 3 fluorescent lamps, and perhaps a socket for 12V DC appliances (e.g. TV or radio) Number of systems world­ □ Several thousands world-wide, increasing very rapidly wide Specific maintenance □ Battery maintenance requirements □ Similar to any lighting system: cleaning of lamps to maximise light output and replacing faulty lamps Examples of capital costs □ $350 to 700 for a ‘lighting kit ’ (40Wp, 100Ah battery, 3 lamps and wiring) (FOB) (US$) □ $100 to 250 for a portable lamp □ $20 to 40 for a torch Typical applications □ Electrification of rural houses, particularly in developing countries □ Holiday homes in remote locations Reliability / maturity of □ Very high reliability, weakest component is the battery technology / environment □ Fluorescent lamps contain mercury and should be disposed of carefully to avoid pollution Comments □ Modularity - the system can be up-graded very easily □ Choice of level of illuminance and type of lamp is essential □ Most components can be produced in developed countries

In developing countries, the majority of rural people rely on kerosene lamps or batteries for their lighting needs. The energy consumed for lighting in rural households however is only a fraction of that consumed for cooking. Hence energy considerations for rural lighting have usually received less attention from rural workers compared to other sources of energy demand.

There is however great scope for energy efficiency improvements in lighting systems. For example, by replacing a kerosene lamp, currently used by hundreds of millions of people, with a PV-powered 4W fluorescent lamp, the energy to light efficiency of the system is multiplied by a factor of 100, the light output is increased by a factor of 2 and the primary energy use for running the lamp is reduced to zero.

39 Table 3-4 Relative merits of different lighting systems

System Advantages Disadvantages

PV lighting □ Good light output □ High capital cost □ Low maintenance □ Battery storage required for cloudy □ Easy installation periods and at night □ No fuel costs □ Maintenance essential □ High reliability □ Repairs often need skilled technician □ Modularity □ Environmentally benign

Flame-based lighting □ Low capital cost □ Low light output sources: kerosene □ Local manufacture possible □ Low energy to light efficiency or gas lanterns, □ Widely available □ Fuel supplies can be erratic candles, etc. □ High running costs □ Polluting, fire hazard

Large-scale PV Electrification

An important objective of the PV community is to encourage and facilitate the use of PV systems for large-scale electrification, particularly in developing countries. The benefits of such actions, for both the rural population of the developing countries and the PV industry have been well presented. Declarations have been made (eg. the Montreux Challenge) which are receiving support from international donor agencies.

The Power for the World initiative of the European Union is an effort to supply electricity to the more than one billion people without electricity today. The premise behind this action is that a well distributed and decentralised electricity system of low capacity for basic minimal needs is the only system which could be implemented in a time frame of 20-25 years, because a conventional electric grid development would be too costly and time-consuming. Therefore the proposed technical option is PV. In order to meet basic electricity needs in the villages of the developing world, it is estimated that an installed power of 10Wp per capita is sufficient and this amounts to 10GWp globally. The cost would be $60 billion (this is equivalent to 3% of energy investments in developing countries). The EU is currently funding a preparatory study phase of work, which involves interaction with the international financing institutions.

3.3.2. Remote Area Power Supply (RAPS) Systems

Residential buildings not connected to any electricity supply network form an important and growing PV market. There is growing use of PV in houses in developing countries in suburban areas where grid-electricity supply is unreliable. Utilities sometimes use PV as an alternative to the extension of the electricity supply network.

40 History / recent development Principle and technology □ Consists of a PV array, battery bank, charge regulator and usually an inverter. □ Often a diesel generator serves as back-up system □ AC and/or DC appliances such as: lights television, radio, video recorder fans and ventilation system circulation pumps for solar water heating systems power tools Range of size □ 500 to 3000 Wp Number of systems world­ □ Thousands wide Specific maintenance □ Battery maintenance requirements Examples of capital costs □ $12,000 for a 800Wp system (FOB) (US$) □ $20,000 for a 1500Wp system Typical applications □ Electrification of remote houses Reliability / maturity of □ Highly reliable system technology / environment Comments □ Modularity - the system can be up-graded very easily

3.4. Island Systems

It is important to note that in this context, the term Island does not necessarily refer to a location surrounded by the sea, but to a location surrounded by an un-electrified area. This might include for instance, villages, hotels and other industries in addition to islands surrounded by water. Such locations are typically in developing countries where diesel generators would normally be used for electricity supply.

PV could have a significant impact in Island settings in developing countries, and this is an extremely large potential market for the PV industry. Efforts are continuing to improve designs for PV Island systems to achieve lower capital and maintenance costs and increase performance and reliability. Such developments are vital if PV is to gain acceptance by public utilities and international financing institutions who have a significant role to play in the development of this market.

41 History / recent development Principle and technology □ Consists of a PV array, battery bank, charge regulator and usually an inverter. □ AC and/or DC appliances as required by the application □ Usually a diesel generator serves as back-up system Range of size □ up to 20 Wp or sometimes more Number of systems world­ n wide Specific maintenance □ Battery maintenance requirements Examples of capital costs □ variable; depends on system configuration (FOB) (US$) Typical applications □ Electrification of small villages, particularly in developing countries or on islands □ Hotels, schools, small factories Reliability / maturity of □ Highly reliable system technology / environment Comments □ Modularity - the system can be up-graded very easily

42 4. BALANCE OF SYSTEM COMPONENTS AND APPLIANCES

4.1. Introduction

As covered in section 0, there are four main categories into which the components of stand­ alone PV-powered systems can be grouped.

□ Photovoltaic component - PV modules / arrays

□ Power conditioning equipment - batteries, inverters, charge regulators, etc.

□ Cabling - cables, electrical protection equipment, etc.

□ Load - end-use appliances

Together, the power conditioning equipment and cabling form the “Balance of System” (BOS) of the complete PV-powered supply system. This chapter, which presents the results of the Task III Survey specifically relating to the BOS and Load components, offers an overview of the technology currently available in the surveyed countries and identifies various further developments that would assist in the promotion and uptake of stand-alone PV systems.

4.2. Inverters

Inverters are increasingly incorporated in PV systems (especially in isolated buildings), so that a.c. electrical appliances can be used. The technology is changing rapidly. Research is required to test and compare small inverters in terms of efficiency, performance and life.

A large number of PV inverters for stand-alone systems is available from various manufacturers in many of the participating countries. Table 4-1 contains the main characteristics of inverters available in various countries.

Table 4-1 Survey of inverters for stand-alone PV systems

Country Manufacturer Nominal Input Output Output Efficiency /type power voltage voltage waveform at 90% P (watts) (volts) (volts) (%) Canada Statpower / 800 12 115 Modified Prowatt sinewave Finland Oy Suomen 120 12 220 Block wave 80 Inverters Ab 24 85 200 12 220 Block wave 81 500 12 230 Sinewave 78 In Finland, Prowatt (Canada) or Trace (US) inverters are often used.

43 Country Manufacture Nominal Input Output Output Efficiency at r / type power voltage voltage waveform 90% P (watts) (volts) (volts) (%) France Sunwatt 600 12,24 230 Sinewave 91 1,000 12,24 230 Sinewave 92 1,100 12,24 230 Sinewave 92 2,000 24-60 230 Sinewave 93 3,300 48-60 230 Sinewave 93 3 x 2,000 24-60 3x230 Sinewave 3 x 3,000 48-60 3x230 Sinewave Sat el 500 48 220 1,000 48 220 81 1,600 48 220 81 modular system; can be combined up to 16 kVA Energies 100 - 12,24 230 Nouvelles 2,000 Germany Dorfmuller 10,000 24 - 192 230 Sinewave 96 Solaranlagen Siemens Solar 600 - 24 230 Sinewave about 85 1,500 IBC 300-900 12,24 220 step-shaped about 90 Solartechnik 1,500- 24,48 220 about 92 5,000 Michel Solar 1,000 24 230 90 Electronics HN Electronic 150/200 12,24 230 Modified about 90 Components sinewave Schulz 10 - 6,000 12-60 115/230 Sinewave about 68 Electronic 500 - 24-386 115/230 Sinewave about 93 25,000 Italy Seira Elettron. 10,000 120 220 Sinewave 89 Industrial srl Japan Japan Storage 5,000 216 110/220 Sinewave 90 Battery Co.

44 Country Manufacture Nominal Input Output Output Efficiency at r / type power voltage voltage waveform 90% P (watts) (volts) (volts) (%) Netherl. Mastervolt / 100 - 12,24 110/230 Modified up to 97 Mass 4,500 sinewave Victron / Atlas 300- 12 230 Trapezoidal 92 1,600 300- 24 230 Trapezoidal 92-94 4,500 1,500- 48 230 Trapezoidal 92-94 3,000 Victron / 350- 12,24 230 Sinewave 90 Phoenix 1,500 1,000 48 230 Sinewave 92 US Trace 400 12,24 240 Modified sinewave 2,000 12-48 240 Modified sinewave UK Douglas 125 - 12-220 220/240 Modified 85-92 22,500 sinewave & sinewave Tornado 100 - 12,24 240 Square, semi­ 86-92 4000 sine & sinewave

4.3. Batteries

Different types of batteries (automotive flat plate, low maintenance, maintenance - free, sealed lead-acid, tubular plate etc) need testing together with state-of-change indicators. Previous work has shown the battery to be the most likely component to fail. In a stand­ alone PV system, the battery is generally the component with the shortest life.

Table 4-2 summarises some of the main characteristics of batteries manufactured or sold in the participating countries.

45 Table 4-2 Survey of batteries for stand-alone PV systems

Country Manufacturer Battery type Avail. Avail. Special features or cap. packg. Brand name (Ah) (cells) Canada Surette Lead acid 200- 3,4,6 lead antimony for Flooded 1,000 deep discharge Johnson Sealed lead acid, 135 3 lead calcium grids Controls gelled electrolyte Rocket Lead acid 317 1 Flooded GNB (US) Sealed lead acid, 114 6 Absolyte IIP glass mat separators C+D (US) Sealed lead acid 87 6 lead calcium Liberty Thermo-teck Flooded lead 58 6 electrolyte contains (US) acid oil to reduce gassing Trojan (US) Flooded lead 342 1 lead antimony grid acid Sunlyte Sealed lead acid 63 6 pos. pi - low antim. neg. pi - lead calc. Delco (US) Sealed lead acid 64 6 lead calcium grid Alco (US) Flooded lead 168 3 rubber separators acid Finland SEF Flooded lead 338 - 1 low antimony acid 1260 positive plate SGF Flooded lead 59- 3/6 low antimony acid 303 positive plate C+D (US) Sealed lead acid 25 - 3/6 lead calcium Liberty 1000 200

46 Country Manufacturer Battery type Avail. Avail. Special features or cap. packg. Brand name (Ah) (cells) France CFEC Flooded lead 105 1 Special solar MFX Steco 3000 acid plane plate CFEC Sealed lead acid 1.2- 1 - 6 Plane plate Saphir 460 CEAc Fulmen Sealed lead acid 150- 6 tubular plate Solar 3500 CEAc Fulmen Sealed lead acid 139- 1 tubular plate EXE 3300 Oldham Sealed lead acid 200- 1 tubular plate HVTS-TUS 3000 Oldham MTS Sealed lead acid 58 - 3/6 tubular plate 300 Germany Panasonic Sealed lead acid 1.2-65 2-6 LCR/LCL/ ECS series Hagen OGi or Flooded lead 12.5 - OPzS acid 2000 Hoppecke Flooded lead 150 - OPzS Solar acid 3000 Hoppecke Flooded lead 68- Mini Solar acid 150 Hoppecke Nickel 20- FNC Cadmium 530 Sonnensch. Sealed lead acid 160- 3/6 Dry fit Solar 200 Sonnensch. Sealed lead acid 5-190 3/6 Dry fit A200 Sonnensch. Sealed lead acid 200- 1 Dry fit A600 3000 Varta bloc Flooded lead 12.5 - 1-3 acid 2000 Varta OPzS Flooded lead 50- 3/6 bloc acid 300 Varta OPzS Flooded lead 20- 1 tubular plates tubular acid 12000

47 Country Manufacturer Battery type Avail. Avail. Special features or cap. packg. Brand name (Ah) (cells) Germany Varta T/TP Nickel 10 - 1 Cadmium 1250 Italy Fiamm Magneti Marelli Tudor Steco Japan Japan Stor. Flooded lead 35 - 1 Electrolyte agitator Batt Co Ltd acid 1950 (optional) SUB Switzerland Compact Pow Flooded lead 26- (Oerlikon) acid 7000 UK BP Solar Flooded lead 53/80 6 cycle life: 400+ Solarbloc L acid (75% discharge) BP Solar Flooded lead 35 - 1/3/6 cycle life: 1,500 Solarbloc P acid 661 (75% discharge) BP Solar Flooded lead 310 - 1 cycle life: 1,350 Powerbloc S acid 3500 (75% discharge) Yuasa Sealed lead acid 4 - 130 3/6 NP/NPC Other makes are commonly used in the UK (e g. Fulmen, Sonnenschein, SEC) US SEC Flooded lead 158 - 6 acid 1264

Research and Development

In France research is carried out on accelerated ageing tests, new techniques to prevent stratification and new techniques to determine the state of charge of batteries.

In Japan work on measuring the ampere-hour balance and work on specific gravity measurement using refraction is carried out.

Wishes

The survey identified the following as potential improvements on the design of common storage batteries:

□ Modularity - it should be possible to extend the battery size when the size of the PV generator is increased.

48 □ Cell repair or replacement - Rather than changing the whole battery bank, ways of changing failed single cells should be found.

Estimation of Storage Requirements

Energy storage requirements are typically 7 days for solar home systems and 10 - 15 days for service applications.

4.4. Charge Controllers

Controllers are an essential component of stand-alone PV systems, and are used to protect the battery against over-charging and over-discharge. After batteries, they are probably the most frequent cause of system failure. There is a very large number of different products on the market, with variations in quality from very poor to excellent. This has caused problems particularly in developing countries where local assemblers/manufacturers have purchased cheap/low -quality controllers from abroad. Some have started their own manufacture and there is collaboration with UK suppliers.

New technical solutions are emerging, as a result of research into electric vehicles. This Activity will collect information and data on existing controllers and their performance and reliability. It will also examine emerging products.

Information onExisting Products

The charge controllers available vary considerable in terms of size, cost and the market they are aimed at.

Charging Methods: The most common charging methods used are:

□ Shunt or series interrupting regulators (using PWM)

□ Sub-array switching (used for larger systems)

□ MPP Tracking

Maximum current: The maximum input/output current varies from as little as 1 Amp to several hundreds of Amps.

Input and Output Voltages and Voltage Setpoints: Commonly used nominal output voltages (battery voltages) are: 6, 12, 24, 36, 48V Input voltages obviously relate to the output voltages. Most controllers do not incorporate any voltage conversion, hence the input voltage is higher than the nominal battery voltage to allow charging of the battery. DC-to-DC converters are designed as buck or boost converters. For buck converters the input voltage has to be higher than the output voltage, for boost converters it is lower. The voltage regulation setpoint varies from 13.8 to 14.9V per 12 V nominal voltage. It can be higher for boost charging. Some controllers have an adjustable voltage regulation setpoint. The voltage regulation hysteresis varies from 0.5 to 2V per 12 V nominal voltage. Some controllers have an adjustable voltage regulation hysteresis.

49 Voltage regulation temperature compensation is usually set between -3 and -10mV/°C/cell. Not all controllers incorporate temperature compensation. For several controllers this information was not available.

Load Disconnect: Most charge regulators have a load disconnect, usually at a fixed voltage of around 11.5V per 12 V nominal voltage. Some controllers offer an adjustable voltage threshold, sometimes the voltage is dependent on the current. Load reconnect is typically set at around 12.5 to 13 V, sometimes it has to be done manually.

Standby current: The standby current varies from 10mA to 160mA.

Operating Temperature range: The operating temperature is typically in the range -10 to 50°C, but can be lower or higher.

Indicators and enclosure: For the lower price range of controllers, one or more LEDs are standard indicators. Other controllers incorporate volt or ampere meters, digital displays. The enclosures vary considerably depending on the application and price of the regulators. IP54 protection enclosures are available.

Protection features: Protection features generally include a blocking diode as reverse polarity protection. Other protection features include fuses, power surge/lightning protection, overload protection

Special features: The following special features are incorporated in some controllers:

□ Maximum power point tracking

□ Programmable voltage settings

□ Full data logging/monitoring facilities

□ Various alarms

□ Boost charge facility

□ Gassing control

□ Generator start signal for diesel gen set

Prices

Prices for charge controllers vary as much as the different models. They start at about US$ 50 or less.

Ongoing R&D Activities

□ State-of-charge determination (Research in this area is ongoing in several countries)

□ Integrated Ampere-hour counter

□ Comparison of charging methods and control strategies

50 □ Programmable voltage setpoints

□ Blocking diode with low voltage drop

□ Controllers with low stand-by current

4.5. High Efficiency Appliances

There are large differences between the efficiency of electrical appliances (e.g. incandescent lamps versus fluorescent lamps). The use of highly efficient appliances can have a dramatic effect on the size (and hence cost) of a PV generator required. In isolated buildings, a "high efficiency" approach to electrical equipment can reduce the energy requirements to 20% - 50% of the amount required using conventional appliances.

Selection of the most efficient appliances will have a major effect on the penetration of the potential PV market. This requires information and data to be available to aid selection. There is also scope for further development of higher efficiency devices.

Products can be split into three categories:

□ small appliances for developing countries, for use in SHS

□ domestic appliances such as refrigerators, freezers, lights, TV sets, washing machine, iron, audio and video, etc. for use in RAPS systems. This is an increasingly important issues when looking at PV and hybrid RAPS homes in more affluent countries such as Australia, where grid extension to remote areas is prohibitively expensive, but the desire for electrical appliances is the same as in grid-connected areas.

□ small appliances for outdoor needs in western countries (e.g. camping, leisure boats etc.)

In the following, the results from the survey of Task III are presented.

4.5.1. Products which are widely available

Various products are available in all of the participating countries, but are not necessarily manufactured in these countries. The returned questionnaires contain some data on size, energy consumption, etc. of the appliances, but this is far from being comprehensive.

□ DC lighting. DC lighting components are available in a wide variety of types and shapes. The power ranges from 5 to about 20W. However, not all DC lights have an efficiency as high as it is required for PV systems. Portable Lanterns are also sold by several manufacturers.

□ Refrigerators. Some efficient DC refrigerators are available (For medical/ domestic use). In some countries, fairly efficient AC devices are sold, such as the Sunfrost refrigerators, which, it is claimed, use less than one tenth of the energy of conventional refrigerators and are easy to power with a small PV array. These refrigerators are available in size up to 19 cubic feet, and have both freezer and fridge compartments.

51 Power consumption for low-voltage DC refrigerators (12 or 24V) were between 0.4 and 0.75 kWh/day. For a freezer or for a combined refrigerator/freezer 0.8 to over 1 kWh/day were given. The devices are in the order of 100 to 300l. Some larger devices consume less power than smaller ones even in absolute terms which indicates that not all devices are as efficient as they could be.

□ Radios and televisions. 12V DC televisions are available, but usually only with a small screen (18 to 28cm). The power consumption ranges from under 10 to about 50W. The supply voltage can usually be between 11 and 16V to allow for the voltage fluctuations of a battery. There are also energy efficiency AC TVs on the market which are used with |PV systems (e.g. in Finland).

□ Fans. Fans can be obtained in all countries.

□ Water pumps. Water pumps are generally available in a fairly wide power range.

□ Washing machines. These devices are usually capable of using pre-heated water, as PV electricity is too expensive to be used for this purpose. there are both AC and DC models available.

4.5.2. Appliances Required for PV Systems

The following are appliances which are appropriate for PV-powered systems, but are not available in some of the participating countries.

□ Refrigerators/freezers. There is a need for a wider range and market availability of high efficiency DC refrigerators and freezers.

□ DC washing machines. The devices should be capable of using pre-heated water. A wider range of small capacity efficient washing machines is required. In some countries (particularly Germany), fairly efficient AC washing machines are sold. However, these are usually aimed for grid-connected houses and often heat the water electrically.

□ DC dish washers. There are some fairly efficient AC dishwashers on the market. there does not seem to be any DC machines on the market.

□ Radios/televisions. Obtaining 12V DC radios and TVs is a problem in some countries. There seems to be a market for good quality televisions with a medium size screen, which are not commonly available. Germany has 5 manufacturers who produce DC TVs with 23 & 25 cm screens, and one produces a 28 cm screen. Japan has 2 companies who manufacture colour DC TVs with 20 cm screens.

□ Microwave oven. DC microwave ovens are available in some, but not in all countries.

□ Vacuum cleaners. Only small devices for use in cars are available. For isolated houses, larger DC vacuum cleaners are required.

□ Chargers for power tools. Chargers for power tools are not available in all countries.

52 □ Alarm systems. There seems to be a market for alarm systems powered by low- voltage DC.

□ Lights. There is a very wide range of lights available both as AC high efficiency and DC efficient in all countries. These come as kits, individual lamps, and as systems.

□ Irons. DC irons are not available. There is interest in their development in at least one country.

4.5.3. Appliances only required for RAPS-type PV systems

The following DC applications do not appear to be available, and are not required for low- load PV-powered systems. However, for RAPS-type systems there is a need for these appliances:

□ Toasters

□ Dryers

□ DC sewing machines

□ Hair dryers

□ DC video recorders

More research needs to be undertaken to ascertain the users needs.

4.5.4. Appliances currently being researched

From the questionnaires, there does not seem to be any substantial research being carried out into high efficiency appliances. GENEC (France) and INETI (Portugal) are carrying out a research programme on the development of high-efficiency appliances for solar houses (TVs, Freezers, etc.). The returned questionnaires do not cover all the research which is carried out in the field of domestic AC appliances.

4.5.5. Developing Countries - appliance availability

At this stage, the survey relates only to countries participating in Task III of the IEA’s PVPS programme. As a result, the availability and affordability of appropriate high efficiency appliances in developing countries can not be reported authoritatively. Additionally, many of the appliances mentioned above are, at this time, not particularly relevant for developing countries where the priority is largely to supply minimum basic lighting requirements, and perhaps radio or TV facilities.

However, practical experience indicates that various basic appliances may be available but this varies widely from one country to another. It is intended that the follow-up survey which has been distributed to developing countries to assess the experiences and requirements of PV users in these areas will shed more light on the availibility of appliances, and will help to indicate how the supply mechanisms can be improved where needed.

53 5. STAND-ALONE SYSTEMS INSTALLED AND USER EXPERIENCES

5.1. Introduction

The best way of appraising the performance of stand-alone PV systems in practical situations is undoubtedly to approach the actual system users for their first-hand assessment. The survey employed this approach with a questionnaire devoted to user experiences, the ultimate objective being to identify:

□ the needs of the users of the PV systems

□ the level of user satisfaction

□ operational procedures associated with PV systems maintenance

□ which components have failed most often in the past

□ why components failed

Responses to the questionnaire on user experiences were received from Canada, Finland, France, Germany, Italy, Japan, Korea, The Netherlands and the UK. The systems considered ranged from small (ie. one or two modules) to medium sized systems of several kWp. The battery voltages range from 12V to over 200V, and the battery capaciy from 100 to several thousand ampere hours. Pumping systems without a battery were also considered.

5.2. Service Applications

There are several tens of thousands of PV installations for service applications.

The survey carried out by Task III of the IEA’s PVPS programme produced a wide range of responses depending upon the country, size and type of system as detailed below. All responses quoted good reliability for each product described. Most systems required yearly maintenance checks and reported the most likely cause of problems to be the battery.

5.2.1. Industrial Systems

PV systems powering industrial applications such as remote telecommunications equipment, data acquisition systems, navigational aids, etc., are similar in developed countries and in developing countries. They differ only because of their adaptation to the local climate or to survive transport difficulties. PV is normally chosen as power supply option on the basis of higher cost-effectiveness than either the grid or a diesel generator.

Industrial systems are usually owned by larger organisations, for instance private telecommunications companies, oil/gas companies or state authorities. The designers of such systems have a background in engineering and a reasonably good understanding of the power demand of the appliances and other requirements. Often considerable expertise has been built up over the years.

54 These organisations usually also have set procedures for system maintenance. Often the application itself needs regular maintenance, so the PV system receives some attention at the same time, even if this only consists of a visual check and topping up of the battery. This means that PV systems powering industrial applications are often designed and maintained better than many systems for other applications.

In Table 5-1 a range of industrial stand-alone PV systems used in many different countries of the world are described.

Navigation and transport aids such as coastal navigation buoys, railway signals, terrain avoidance lights, rural airfield lights, illuminated windsocks at small airfields, light beacons on desert tracks, emergency phones and highway signals are now widely powered by PV wherever installed in remote off-grid areas. PV is recognised as the best option for off-shore navigational aids because the need to make refuelling visits is eliminated. PV-powered offshore navigation aids are also more reliable in storms. Not only are these devices used in the equatorial countries, but also throughout the coast of Europe and North America, even at high latitudes. The National Board of Navigation in Finland operates 1,600 navigational aids powered by PV.

There are numerous and diverse off-grid telecommunications applications powered by PV. The high reliability of PV has resulted in the technology becoming the conventional and preferred power option for mountain-top microwave repeaters world-wide, whilst PV is also having a significant impact for powering transceivers for communications between security posts (e.g. national police rural stations) and other institutional buildings in the central urban areas. The Pan-African telecommunications link (PANAFTEL) is reliant on PV at key repeater stations, whilst small transceivers are in use in Gambia and the Sudan, with several thousand in use world wide.

PV is used in many countries to power various telemetry andmonitoring applications. PV proves to be a reliable power source for these applications. For very low power applications, PV can be cost-effective in built-up areas with an electricity distribution network only a few metres away.

PV-powered cathodic protection systems have been successfully utilised in many countries to protect steelworks from corrosion.

55 Table 5-1 Industrial Systems

Application Country Description Comments

Navigation Canada Navigational lighting systems for coastal regions using These systems are the Aids sealed lead acid batteries and Solarex modules with a cheapest available option nominal power rating of between 17 and 35 Wp. Around 2,400 systems are installed off the Canadian coast with an estimated market potential of 0.1 MWp. These systems are funded by the coast guard budget. Navigation Finland Navigational lights and beacons rated at 48 Wp with Market strengths of these Aids around 12 V, 70 Ah storage. Around 200 systems sold systems tend to be due to per year with an estimated 1600 installed to date. the distance from the local Estimated market size of 2 MWp world wide. electricity network. Cost effective application with reduced maintenance. Systems are highly reliable.

Navigation Netherlands Light buoy/beacon: buoys powered by 4 x 20 Wp Main advantage of PV is Aids modules, beacons by 1 x 45 Wp module, both systems that maintenance trips are having around 12 V, 600 Ah battery storage. About reduced. Weakest 1050 such systems installed in the Netherlands. PV component found to be system cost of 3,640 ECU; estimated market size of 120 plastic cover. MWp. Navigation United Marine buoys situated around the UK coast are supplied Aids Kingdom by PV. 2-3 modules of 36 Wp with around 12 V, 80 Ah storage (gel lead acid batteries) are used. Around 320 systems are installed around the coast of England and Wales; additional systems are used around the coastlines of Scotland and Northern Ireland. Navigation United Light houses and light vessels with modules rated at Aids Kingdom 600 to 3,200 Wp with 24 V, 1000 to 2000 Ah storage are also used by the UK coast guards. About 8 systems are in use. Navigation France 2000 buoys are in operation in France and Overseas Aids Territories

Telecommunic France Transmitters, repeaters etc., using between 10 and 40 a-tions systems modules depending upon system rating with around 24 V, 800 Ah lead acid battery storage. Estimated size of world market at 3 MWp Telecommunic France Radio beacon: market of around 200 systems world a-tions systems wide; cost of investment 17,500 ECU Telecommunic France Satellite receiver station: around 10 such systems have a-tions systems been installed in France indicating an estimated market of 500 world wide; cost of investment 130,000 ECU

Telecommunic Japan Kyocera module power rating ranging from 50 to 200 ations systems W with 24 V, 40 Ah lead-acid battery storage. Estimated 500 installed per year in Japan indicating a total of 6000 systems in remote areas. Largely government funded.

56 Application Country Description Comments

Emergency France 2000 highway emergency telephones are installed in telephones France.

Emergency Finland Power rating between 30 and 80 Wp with 12V, 500 - Market strengths of these telephones 800 Ah storage, tubular plated, lead-acid batteries. The systems tend to be due to number installed is estimated at 30 in remote areas of the distance from the local Finland with a peak market size of 10 kWp, although electricity network. planned extension of the conventional telephone network Particular advantages is likely to limit this potential. Funded by Finnish include reduced Telecom. maintenance in spite of higher initial costs. Telemetry Finland IR (infra-red) movement sensors with 50 Wp rating Market strengths of these installed with public funding on National Park land, systems tend to be due to private property and border areas to count or control the distance from the local numbers of people entering or exiting an area. Market electricity network. size estimated at 100 systems installed or 5,000 Wp.

Telemetry Finland Radiation monitoring for nuclear power stations; 102 Advantage of PV system systems Wp per system with around 12 V, 200 Ah storage. due to isolation from grid Approximately 5 installed in Finland.

Monitoring Netherlands Monitoring cabins powered by 348 Wp PV system with Advantage of PV due to 12/24 V, 2-3 x 230 Ah storage. 8 systems installed in the distance from electricity Netherlands; estimated market size of 60 kWp. System grid. cost of 3,500 ECU. Monitoring United Automatic weather stations: The UK Meteorological Kingdom Office is operating automatic weather stations throughout the country. About 17 remote stations are powered by 18 Wp Solarex modules. A 12 V, 100 Ah deep cycle battery is used. There is a market for such systems in most industrialised countries. Monitoring United Gas pressure monitoring systems are used by gas utilities Kingdom to ensure constant gas pressure in pipelines. Again, due to their small power requirement, PV power supply is an economical option even relatively close to the electricity network. PV arrays are rated at 10 to 50 Wp with 12 V, 40 - 60 Ah storage batteries. In the UK, a few hundred systems are installed. Monitoring United Traffic counters: Fixed as well as mobile PV-powered Kingdom traffic counting systems are in use to monitor traffic flows on UK roads.

Monitoring Germany Measurement of radio-active substances in hospitals and industry. Instrument rating of 15 Wp with 24 Wh lead acid battery storage.

Monitoring Germany Roadside speed monitoring and digital display unit. Radar system employed to monitor vehicles and warn speeding traffic. Potential funding from government transport department and traffic policing budget. Cathodic India Offshore oil platforms are protected by PV-powered CP Protection systems Cathodic Pakistan CP systems are used to protect pipelines in the Badin gas Protection fields.

57 Application Country Description Comments

Cathodic China Protection of lock gates Protection

Motorway Korea Low pressure sodium lights powered by 10 x 43 Wp lighting system modules with diesel back-up and 12 V, 10 x 100 Ah lead-acid batteries, where the PV array contributes around 90% of the energy consumed. In total 388 of these systems have been installed in Korea implying an potential market of 1 - 2 MWp. Security lights various PV is used to power remote lighting and alarm systems countries operated by infra-red detectors. There are now many solar street lights installed, providing security and light for people in both rural and urban areas. Signalling France Several transportable PV signalling systems are used to systems protect workers on highways.

Railway Zambia/ PV has been used for many years to power railway signalling Zimbabwe signalling systems. Railway United Railways greasing systems are used for rail and flange greaMMg Kingdom lubrication to reduce wear. Due to their small power requirement, PV power supply becomes economically viable within a very small distance from the electricity network. The size of the PV module is typically around 12 or 24 Wp.

Heating Finland Heating elements employed to thaw road drainage Market strengths of these systems with power rating around 180 Wp. Prograimne systems tend to be due to still in demonstration phase; a few are installed as test the distance from the local sites. Potentially a large market in Scandinavia and electricity network. Canada. Could be funded by road maintenance authorities. Timetable Germany 2.5 Wp rating using 6 V, 1800 mAh NiCd battery Easy to install, illumination storage. Potentially large market which could be funded maintenance-free. by public transport organisations. Investment cost around 1300 ECU. Parking meter France 1000 systems are installed in France.

Example for the reliability of PV systems: Offshore navigation aids Finland

The National Board of Navigation in Finland operates 1,600 navigational aids powered by PV. Table 5-2 illustrates system failures which occurred and the reasons for the failures.

Table 5-2 Failure analysis of PV systems used to power Finnish navigation aids

Nature of failure Reason for failure Total no. of systems No. of failures Failed battery (lead acid) End of lifetime 120 20 Failed battery (NiCd) Handling errors 1480 5 Failed controller Defective solderings 1600 100 Broken PV module Vandalism 1600 3 System error Undersized PV array or battery 1600 30

58 5.2.2. PV Systems in Agriculture and Fisheries

PV systems are in operation world-wide to provide power for many of the processes necessary for agricultural production. Table 5-3 gives an overview of systems used.

Table 5-3 Experiences with stand-alone systems in the agricultural and fisheries sector

System Application Country experiences Coimnents / findings

Pumping Irrigation of large Many countries especially in sub-Saharan Demand for irrigation water fields, but also small Africa e.g. Mali, Senegal - Vegetable garden varies throughout the year, vegetable gardens irrigation requires relatively small systems and depending on the crop (cash crops) are being favoured over large irrigation requirements and seasonal schemes. climatic fluctuations; good system sizing is crucial.

Pumping Livestock watering Many countries - Water usually pumped into a Such systems require little storage tank, to be used as required by the attention. The farmer has more livestock. flexibility in tending livestock, allowing time for profitable activities in other areas. Pumping Livestock watering Netherlands - Water pump for cattle: low head Weakest component found to be pump and cattle trough powered by 40 Wp the pump incurring yearly array with 12 V, 160 Ah lead-acid battery maintenance costs of around 90 storage. Around 10,000 already installed in the ECU for spare parts. Netherlands at a cost of 2,500 ECU each; potential market in other low lands in the order of 2 MWp. Water Water circulation Few countries treatment and aeration for fish farms

RefrigerationAnimal vaccine Zaire - several hundred systems installed for a Higlily reliable and cost-effective storage livestock project in Kivu region. per vaccine dose. Also in many other African countries.

RefrigerationCold store for food Giglio Island in Italy - demonstration unit with Generally, units are not "off-the- storage a 45kWp array and 275 nC cold store. Few shelf items. Very expensive due demonstration units. to high energy consumption.

RefrigerationIce-production for Egypt - A PV-diesel hybrid system installed on Ice production requires large storage and transport the Red Sea coast in Egypt for demonstration amounts of energy and hence of fish purposes in 1986. few PV products are available commercially.

Lighting Remote farm houses Many countries - thousands of units installed. In most cases, highly reliable and and sheds cost-effective.

Lighting Lights on fishing Few countries - Suspended lights used to attract boats insects which then attract fish. Grain mill Burkina Faso - grain mill operating Most systems need a large successfully for eight years in Tangaye, battery bank. Burkina Faso. Part of a 3.6kWp PV system High capital costs (not widely including a water pump. Overall availability available). has been reported as over 90%. Mali, Senegal, Sudan, Zaire - similar units operating successfully.

59 5.2.3. Health Care

Many stand-alone PV systems are used in health care. Medical refrigerators are one well- known example.

Table 5-4 reports on experiences with PV systems in the health care sector.

Table 5-4 Experiences in the Health Sector

System Application Country experiences Coimnents / findings

Lighting Health centre and Zaire - 750 PV lighting systems in Provision of reliable and good hosnital: health centres and clinics, installed by quality lighting for health General lighting of the Ministry of Health, with funding centres have contributed convalescence rooms from the European Development Fund, significantly to improved with small night lights (in conjunction with 100 vaccine patient care in rural Zaire. for corridors etc. refrigerators). Task lighting for Health centres equipped with 4 to 10 8W Lighting in staff housing proved examination, surgery fluorescent lamps. to be a great incentive for and delivery rooms Prograimne managed by British firm. IT professional staff to work (or to Staff housing: Power Ltd; modules, charge controller, continue to work) in rural areas. batteries supplied by a French PV firm; General lighting with 2- luminaires made in UK. 3 low-power lamps

Lighting Health centres Lesotho - All newly built and remote Government initiative that could health centres must include PV systems. be repeated elsewhere.

Lighting Staff housing, health Morocco - 200 systems funded by centres and hospitals USAID (lighting kits and portable lamps) to be installed in 93. Lighting Hospitals Zimbabwe - PV lighting systems used for emergencies in hospitals.

Lighting Health centres and Sahel countries - several hundred Project funded by the EC. other community lighting systems currently being buildings installed (CILSS/PRS project).

Lighting Portable lamps for Yugoslavia, Somalia and Experience shows there is a health centres and staff Sudan - 300 units (UNICEF) need for high quality, durable use portable lamps for health centre Haiti - 120 units applications. Senegal - several hundred units (GTZ and French co-operation)

Refrigeration Conservation of Gambia - 60 units installed in health vaccines and blood facilities.

Refrigeration Conservation of Zaire -100 vaccine fridge units installed The maintenance prograimne vaccines and blood along with the lighting systems in health organised and financed by the centres and clinics. Refrigerators implementing agency manufactured by the local firm FNMA, contributed to the success of currently the sole firm in a developing this prograimne. country to manufacture PV refrigerators Training of technicians and to WHO standards. 300 PV refrigerators users was essential for proper now installed in Zaire. installation and continued maintenance. System Application Country experiences Coimnents / findings

60 Refrigeration Conservation of Uganda - 180 units already installed by Good reliability according to vaccines and blood 1991, another 200 planned. WHO evaluation (1991) .

Refrigeration Conservation of Zambia - 200 units (combined with PV Project in progress, funded by vaccines and blood lighting systems) to be installed in health EC. centres by end of 93. Refrigeration Conservation of Indonesia - 370 units installed by 1993. Some reliability problems vaccines experienced with first 100 units (WHO evaluation, 1992). Refrigeration Conservation of Pakistan - UNICEF and other agencies Procurement criteria of units vaccines and blood such as the Aga Khan Foundation. based mainly on reliability. Refrigeration Conservation of Sahel countries - 110 units currently Project CILSS/PRS funded by vaccines and blood being installed. EC.

Refrigeration Conservation of Africa - Projects involving significant Maintenance programmes not vaccines and blood numbers of units now underway in always planned. Chad, Ghana, Kenya, Mozambique, Eritrea and Sudan. Refrigeration Portable cooling system A portable cooling system for long Lightweight, low power distance transportation of medication consumption, no batteries etc. is manufactured in Germany. required, free of CFCs. Refrigeration Medical/domestic refrigerators for medical or for domestic refrigerators use are manufactured in the United kingdom. battery Income generation for Zaire - WHO pilot project. In Zaire, first results very charging the health centres Other projects in Sri Lanka, Dominican encouraging following WHO Republic. evaluation in 1991. battery Income generation for Sahel countries - several dozen units Project CILSS/PRS funded by charging health centres currently being installed. EC. Pumping Water supply for health See Table 5-6 on water supply. Rarely installed exclusively for facility health facilities. #ater Purification of water Limited experiences. treatment for medical purposes See section 0 water treatment systems Communic­ For regional and remote Gambia, Zaire, Mali, Central African Missionaries and NGOs ations health facilities e.g. for Republic - commonly use PV-powered disease surveillance PV-powered radio incorporating a 12V VHF transmitters. battery charger Others: Laboratory use Eritrea - several hospitals entirely PV- Encouraging results, the number microscope powered (project managed by Dulas of installations in Eritrea is on light, eAz Engineering, UK). the increase. Zaire - several hospitals.

61 Case Study: Lighting and Vaccine Refrigeration in Zaire

In 1984, as part of World Health Organisation's Expanded Programme of Immunisation, the European Development Fund provided finance for the world's largest rural health care project to equip health centres in Zaire with photovoltaic systems to be used for vaccine refrigeration and lighting. A total of 750 lighting and 100 refrigeration systems were scheduled to be installed. As well as the direct medical benefits, the programme aimed to improve working conditions to encourage doctors and nurses to accept posts in rural areas.

A team of engineers from the Ministry of Health installed the first 170 systems in selected rural health centres. As a result of this pilot project, it was decided to contract NGO's and private firms to carry out the remaining installations between 1988 and 1990.

The many positive results achieved by this project were principally due to the strict attention paid to installation standards, and to the permanent on-site presence of an engineer trained during the pilot installations. The devotion of the Zairian technicians also played a major role in ensuring the success of the project.

The EC also financed a three-year maintenance program for the 850 installed systems. Each regional maintenance base included a technician, who supervised the installations in that region, an office, a workshop, a 4-wheel drive vehicle, and a stock of spare parts.

The following successes and failures of PV system components have been noted from the programme:

□ The PV modules have been highly reliable. A few of the 400 modules have needed replacement by-pass diodes, burnt out by heavy lightning.

□ Some batteries failed earlier than expected due to under-sizing in some locations and low quality batteries.

□ There were a few charge regulator failures due to lack of lightning protection; these were prevented later with the fitting of cheap varistors.

□ Some refrigerant fluid leaks occurred due to evaporator corrosion, solved by re­ designing the evaporator.

□ A number of other failures occurred due to lack of user understanding of the system.

The EC funded programme, along with other smaller international programmes, resulted in more than 2000 lighting systems and 300 vaccine solar refrigerators being installed in the health sector. In 1991, the World Bank agreed to finance a telecomms programme for the supply of VHF transceivers powered by photovoltaics for rural health zones. The national office of the Expanded Programme of Immunisation is planning to install more PV refrigerators.

As part of the above programme, it was decided to generate a surplus of energy at selected health centres by installing a PV array more powerful than was necessary to run the refrigerator. The spare electricity was then sold to the local population in the form of charged batteries and a pay-as-you-watch television room. This was seen as a way of dividing the

62 initial cost of the PV systems and covering recurrent expenses for running the systems. The extra costs and benefits of this innovation are summarised in Table 5-5.

After a study examining the local market and evaluating the potential clientele, a selected health centre was equipped with a 360Wp battery charger capable of charging one 12V battery per day, a 60Wp charger of nickel cadmium batteries (200 size D ni-cad batteries per day) and a TV with video player (240Wp).

Several pilot battery-charging systems are now operating in Zairian health centres and have functioned without major technical problems. The demand is now greater than the capacity of the system to recharge batteries. Despite a slow start on the rental of nickel cadmium batteries, local people are beginning to accept that these batteries are more durable and less expensive than the dry cells they can buy locally. The TV and video player is used to show educational videos as well as videos for the general public who pay an admission fee. The income generated from these activities contributes to the overall function of the hospital and health district.

Table 5-5 Advantages of cold chain refrigeration system combined with battery charger

PV refrigerator PV refrigerator and alone battery charger FOB price (US$) approximately $4000 approximately $6000 Transportation and □ Highly variable depending upon the situation, installation costs but practically identical in both cases. Maintenance costs □ Similar in both cases; the charger is simple and highly reliable and the maintenance activities are conducted simultaneously Benefits to the health □ Reliable energy □ Reliable energy centre supply for the cold supply for the cold chain chain □ Regular weekly income of $10 to 20 □ Greater appeal of health centre to local people Benefits to the □ Availability of good □ Availability of good population quality vaccines quality vaccines □ Local access to electricity for the rural community

5.2.4. Drinking Water Supply

Thousands of PV pumps for village water supplies have been, or are currently being, installed world-wide for potable water supply in Africa, Asia, and South America. Several PV pumping experiences are collated in Table 5-6.

63 Table 5-6 Drinking water supply systems

System application country experiences comments / findings

Pumping Village water Morocco -100 PV pumps, majority in the range PV systems with sun-tracking supply 0.5 to lkWp. have proved less reliable than fixed arrays.

Pumping Village water Sahel - Prograimne Regional solaire (PRS- Largest PV aid prograimne to supply CILSS) - 829 pumps to be installed, first systems date (See Case Study: installed in 1991. Experience in Mali).

Pumping Village water India - Largest concentration of solar pumps, Good responses have been supply with more than 1000 systems. In many instances, reported along with wide user modules and systems have been indigenously acceptance. designed and manufactured by Central Electronics Limited (CEL).

Pumping Village water Mali - 200 PV pumps now installed (in the 1.0- Monitoring of 66 of the PV supply 1.5kWp range). Technology was first introduced pumps in Mali coimnenced in in 1977 by the Mali Aqua Viva project. Initially 1983. Recent analysis over a financed by NGO's, with the support of UNDP, six year period showed a EDF and bilateral co-operation prograimnes of mean time between failures in the USA, France and Germany. Co-ordinated excess of 30,000 hours, since 1979 by the national organisation (Direction (better than diesel pumps in National de L'Hydraulique et de l'Energie). the region). Typical time to Imolementation strateev respond and to repair a PV pump was 4 to 10 days (but in Village communities involved in the prograimne a few cases over 3 months). from the beginning. Much of the present emphasis Technical training provided by the project in Mali is now on providing promoters. Villagers appoint a committee to better infrastructure support manage the pump. Payment is either a yearly fee, including training, parts or proportional to water used, collected by supply and service capability. committee. Typically a village committee would collect US$500 / year.

Water Village water Indonesia - several installations (e.g. treatment supply with demonstration project, Kedung village. West water Java, 25nvVday. sand-filtration station). treatment

Water Village water Senegal - a few systems installed; 360, 720 and Self-contained systems ideal treatment supply with 1080 Wp (pumping + filtration + chlorination). for emergency relief. water Similar systems planned for Burkina Faso, Benin, treatment Mali.

Water Desalination Ohshima Island, Japan - installation of a 25kWp High cost due to high energy treatment for production system with a daily production of 5m3 of potable consumption of the of potable water. desalination process. water Other PV desalination installations can be found in Australia, Indonesia and the Middle East.

64 Case Study: Experience in Mali

Mali is the best documented success story in the field of PV pumping. More than 200 photovoltaic pumps are now installed, the majority having PV arrays in the range 1.0 to 1.5 kWp.

The technology was first introduced in 1977 by the Mali Aqua Viva project. Initially financed by non-governmental organisations the project's success with photovoltaic pumps attracted the support of the United Nations Development Programme, European Development Fund and bilateral co-operation programmes of the USA, France and Germany. A national organisation to co-ordinate photovoltaic water pumping was established in 1979 under the management of the Direction National de L'Hydraulique et de L'Energie (DNHE).

Monitoring of 66 of the photovoltaic pumps in Mali commenced in 1983. Analysis over a six year period showed 37 failures with a mean time between failures in excess of 30,000 hours, better than diesel pumps in the region. The failures were all in the pump motors and sub-systems; very few problems were reported with the PV modules. The typical time to respond and to repair a photovoltaic pump was 4 to 10 days (but in a few cases over 3 months). A 4-10 day typical repair time is however inadequate where there is no other source of water available and much of the present emphasis in Mali is now on providing better infrastructure support including training, parts supply and service capability.

In Mali the village communities become involved at the start of a new PV pumping project. Familiarisation usually takes place during the initial meetings between the project promoters and the villagers to ensure the needs and resources of the villagers are well understood. Technical training is provided by the project promoters and typically the villagers will appoint a committee responsible for the management of the pump andthe water it provides.

The committee collects payment from the users either as a fixed fee per year or proportional to water used (number of 10 litre containers filled). Typically a committee may collect $500 per year but collections of over $1000 in a year occur also. The villagers are also willing to make an initial payment to secure a reliable source of clean water in addition to the on-going charge.

Following on from the success of photovoltaic pumping in Mali, the world's largest developing country photovoltaic project is being funded by the European Communities, as a component of the 6th European Development Fund (EDF) regional programme to combat desertification in the Sahel and West Africa. Approximately $35 million was allocated to the regional agency CILSS (Commit Inter-Etats pour la Lutte contre la Secheresse dans le Sahel) for the procurement of 829 photovoltaic pumping systems and related equipment for water and electricity supply in Burkino Faso, Cape Verde, Chad, Gambia, Guinea Bissau, Mali, Mauritania, Niger and Senegal.

The strategy for the CILSS project is founded on:

Initial contribution: each community must pay a substantial initial contribution (i.e. a minimum of 10% of the value of the system, or in some cases, equal to the sum of the annual maintenance and replacement costs) prior to installation of the system to create a sense of ownership and to ensure that the community is motivated and financially capable of taking maintenance responsibilities.

65 Recurrent expenses: for the project to be sustainable, the running cost of the equipment is substantially borne by the beneficiaries of the system, including operating expenses, maintenance, repair and replacement costs. Finance is raised through water sales (approximately $l/m 3) or payment of fixed fees ($6/month per family).

After-sales services: for each country, the supplier company in charge of installation must have a local country representative who is in charge of system maintenance and offers a five- year guarantee for continuous functioning of the system. Break-down repairs are to be performed within 48 hours.

Concentration areas: installation of many units within a given area assists the implementation of after-sales service at a cost affordable to the rural population.

5.2.5. Consumer Applications

There are many PV-powered consumer applications, such as calculators or watches. A variety of less well known applications are listed in Table 5-7.

Table 5-7 PV-powered consumer applications

Application Country Description Coimnents

Vent for car Germany consume around 10 Wp Independent of battery so can be interior powered when car is stationary Fans for cars / United Small fan used to increase ventilation rate to green houses Kingdom avoid overheating in summer Solar clock Germany very low energy consumption, 1000 hours Advantage of high reliability storage. Solar powered Germany 15 Wp rating using 6 V, 180 mAh NiCd Easy to install, reduces air roller blind battery pack (sufficient storage for 100 blind conditioning load, no need for closures). cabling. Motorised cafe Germany 16 Wp rating with 24 V, 6 Ah storage. Advantages: automation of product parasol Potential market in hotels and cafes in warm with no cabling requirement. climates. Garden lights United Used to illuminate garden paths, patios, etc. Kingdom Garden pumps United Used for fountains etc. Kingdom

5.3. Isolated Buildings

Domestic energy usually includes the energy required for cooking, food storage, water supply, bathing, washing, lighting, entertainment, education, and finally for space heating or air-conditioning.

66 PV technology is suitable to provide energy for many of these applications through domestic home systems, lighting systems, refrigeration systems and battery charging systems.

PV systems for household use already contribute significantly to the energy requirements and improved quality of life of a growing number of people in rural areas. Regardless of the size of a domestic PV system, the electricity provided allows families to increase their standard of living in a number of ways. It can add productive hours to the working day, and in the home, it facilitates activities such as studying, handicrafts, seed sorting and sewing.

There are now many thousands of such systems in use around the world. In developing countries there are projects which each involve the installation of more than 1000 systems (and sometimes more than 5000 systems) either completed or in progress in countries such as China, Kenya, Sri Lanka, India, Indonesia, French Polynesia and Zimbabwe. User experiences have generally been good - especially with lighting systems - and have frequently generated a demand for more systems in the localities where they have been installed.

Table 5-8 shows examples of PV systems for isolated buildings. The systems referred to are either Solar Home Systems (SHS), generally comprising 1-2 modules and 100Ah / 12V battery, or Remote Area Power Supply (RAPS) which are larger domestic systems as used for example in remote and island areas of Australia.

The widespread implementation of domestic PV systems in Sri Lanka is then described as a case study, as reported by the Solar Electric Light Fund.

Table 5-8 Domestic PV systems for isolated buildings

System Application Country experiences Coimnents / findings

SHS Generally lighting Kenya - 15,000 PV home systems installed Systems sold on a coimnercial and TV by 1992. In 1986, the Kenyan government basis. removed import taxes on PV modules High demand from rural based leading to a noticeable increase in sales, teachers, businesses, families of linked also to improved Kenyan economy. urban workers and government Many suppliers, installers throughout the employees. country. Manufacture of local 'solar' battery. SHS/RTPS All domestic French Polynesia - more than 2500 homes As a coimnercial project, high systems appliances, on the islands have been PV-powered with level of uptake with favourable including AC (TV, 2 to 20 roof mounted modules, first responses. Video, kitchen installations in the early 80's. The scheme Owner-users have reported PV to appliances, etc.) had a 25% state grant with the remainder be less expensive than diesel. coming from private resources or loans. Training of technicians ongoing For a 140Wp stand-alone system, users for over 10 years. High must pay $8/month for purchase and maintenance due to inverter maintenance. failures. System Application Country experiences Coimnents / findings

67 Lighting of homes Dominican Republic - In 1984, a PV rural Success due to sustainable with 3 to 5 electrification project was set up with demonstration projects in schools fluorescent or USAID money to install 30-50 Wp PV and community centres, incandescent lamps, lighting systems. community revolving funds, 50% of installations The income from charging for these training of local technicians, include a 12V systems has allowed further equipment to involvement of local B&WTV be bought and the project is now self­ entrepreneurs. Problems exist with financing, with more than 1500 systems poor quality of local batteries and now installed. need of continued training.

Lighting of homes Zimbabwe - 3000 private home systems GEF project administrated by the with low-power installed so far on a coimnercial basis. World Bank/UNDP is the first of efficient lamps: Locally assembled PV modules by its kind. It is part of a world-wide 80% with radio, Solarcomm, many BOS components locally effort to displace C02 emissions 50% with TV manufactured. from sources such as kerosene In 1991, GEF project initiated to facilitate lighting. the installation of 25,000 private home and community systems.

Lighting, TV and Mongolia - approximately 3200 portable Portable PV systems are radio for Nomadic PV systems now in use particularly suited for Nomadic tents - energy by some of the 81,000 families relying on families. The Mongolian requirement of 150- animal husbandry. These Nomads move Government plans to provide 200 WlVday their tents ('Gers') up to 30 times per year. electricity to all rural families including the Nomads to reduce A single PV module of only 40-60 Wp is rural migration. sufficient to meet family requirements, and the system can be dismantled and moved with the family. DANIDA currently developing a PV project with IT Power assistance. Lighting and TV Indonesia - Lebak project, more than 500 Project successfully uses houses equipped. 10,000 systems in use revolving fund financing scheme. overall in 1993.

Lighting and TV Mexico - 27,000 systems installed by 1993, systems often larger than 50Wp.

Lighting of homes Brazil - many thousands of systems Marketing campaign using display with low-power installed by 1992 by privately-owned lighting system kits for farm stores efficient lamps Brazilian firm Heliodynamica, protected by all over the country. a 20 to 40% duty.

Prograimne of 1000 systems currently Complaints that local industry being implemented with US DoE aid needs to be protected against money. donation of PV systems from aid prograimnes. Lighting of homes Bolivia high plateau - 1000 lighting Project success based on with low-power systems installed by 1992 by a joint project assessment of mean family efficient lamps involving a local co-operative, Madrid income ($280/year) and a University and Spanish aid agency. Users community co-operative owning paid an installation fee of $80 fee, plus and maintaining the systems. $ 1/month for maintenance. Revolving fund type projects currently planned. System Application Country experiences Coimnents / findings

68 SHS Lighting of homes Sri-Lanka - 4000 systems installed as of Grass-root presence of local with low-power 1992. Installations on the increase. Local companies was essential. efficient lamps PV module assembly. SHS Lighting of homes Rwanda - 1500 systems installed in 1991 Involvement of a private bank with low-power via a financing scheme was essential. efficient lamps 'The Union of Popular Banks' which Concentration of at least 5 systems provided loans to purchase systems costing per village was essential to $560 over 12-37 months with instalments minimise over-head loan costs. ranging from $14 to $40/month. Initial cash payment of 20%. Lighting Portable lamps for India - 850 units introduced at subsidised Villagers willing to buy more domestic use prices in the state of Maharastra in 1991. lamps at subsidised prices. battery Recharging of Thailand - several 500Wp battery charging Project initiated as an alternative charging privately owned systems installed by the Ministry of Rural to lighting using automotive station batteries to power Electrification, with Japanese seed funding. batteries, recharged in nearby 12 V lamps Other installations in many African towns. countries: Zaire, Senegal, etc.

SHS Summer cottages Finland - Some 16,000 to 20,000 summer Maintenance problem: Battery cottages are powered by small PV systems freezing. This occurred in a few (1-3 modules). cases where the battery was used 6,000 of these systems are 51-53Wp NAPS heavily in late autumn, followed systems. by very cold weather and nil insolation in Dec/Jan .RAPS' Autonomous Finland - 10 houses have a PV generator of systems houses with gensets about 300Wp RAPS Autonomous PV French Overseas Territories - 5000 houses systems systems were equipped with 400 to 800 Wp each. None of the systems have a back-up generator. RAPS PV systems to Germany - PV systems from 3 to 5 kWp to systems supply various supply pub for walkers, foresters house and houses a farmstead RAPS Autonomous PV Italy - about 150 houses were equipped systems systems with PV systems of various size, ranging from 350 Wp to 3.6 kWp. The majority of systems were in the upper range, above 1.5 kWp. None of the systems have a back-up generator. RAPS Autonomous PV Japan - A mountain lodge is supplied by a systems systems PV system with a generator of 69.8 kWp. The system has a diesel back-up generator. RAPS Autonomous PV Netherlands - 12 houseboats/barges are systems systems supplied by PV generators of 400 to 1200 Wp each.

69 User Experiences with PV systems for Isolated Houses in Developed countries

The following information on user experiences was collected as part of the survey carried out for Task III of the IEA’s PVPS programme. It therefore relates to PV systems installed in the participating countries, but the problems experienced are of general interest.

Background information:

In all cases studied, the users were described as non-technical people. The size of the buildings covered varies considerably, the norm being houses inhabited by 4 people. However one building is able to accomodate 1500 people. Generally, most of the buildings are reported to have a year round load and the building is occupied full time, although others are used primarily in the summer as recreational homes.

Overwhelmingly, AC appliances are used within these buildings. In some examples, there is only a refrigerator, but in the majority of cases, there were kitchen & service appliances, refrigerator and power tools.

Maintenance problems:

Various ‘one-off’ problems caused by poor weather, combined with irregular maintenance procedures were reported, including damage to modules when snow penetrated the terminal box, and a battery freezing after a period of extremely heavy usage which was followed by a long period of insufficient insolation.

The input of the system user in respect of system maintenance is an important factor. This is exemplified by a number of the questionnaire responses. For instance, in one industrial case where there was a high turnover of staff, difficulties in retaining a sufficient level of awareness of maintenance procedures resulted in poor maintenance and less than exceptional system operation.

Batteries were identified as a problem area in several instances, and correct control devices for there recharging were deemed particularly important for ensuring the best operational life.

There was an indication that when the user is also the owner, operational problems are reduced, perhaps because there is a higher level of commitment in ensuring that maintenance procedures are adhered to. However, if systems do fail, and the users believe that the systems will be repaired quickly, then they will not do anything to try to rectify matters themselves.

User satisfaction:

Of those who answered this question (6 systems), the majority said that they were happy (2 rating) with their system. One said that they were very happy (1 rating), and one said that they were mildly happy with the system (3 rating) It has not proved possible to identify factors which consistently result in user satisfaction or dissatisfaction. However, on the positive side, aspects such as improved safety and a better quality of life were highlighted - including a perceived improvement in comfort due to reduced noise levels compared to conventional power generation means. PV was designated

70 to be very cost competitive compared to the grid when power requirements are low, and the continuous availability afforded by the battery storage system is also beneficial.

Some negative aspects were identified, however, including a failure to rectify identified system problems - which highlights the need for adequate maintenance and support mechanisms. Another comment indicated a need for a greater variety and/or availability of DC appliances.

Reasons for installing PV:

When asked why PV was selected as the chosen power supply option, cost competitiveness emerged as the main factor, PV being the cheapest means of meeting the demand for electricity. Environmental protection aspects were also high on the list of reasons for purchasing PV. It appears that ‘peer acceptance’ does contribute to the wider uptake of PV systems, several users suggesting that they purchased a PV system because their neighbour also owned one. However, there would appear to be some room for a more targeted approach to PV systems marketing, as only one response specified a good sales person as the reason for purchasing.

Case Study: Domestic PV Systems in Sri Lanka

Sri Lanka is probably the most impressive example of the implementation of domestic PV systems, where in 1986 a newly-formed company, Power & Sun (Pvt.) Ltd., now Power and Light Co. (Suntec) Ltd catalysed the now thriving Sri Lankan PV market.

Suntec have now installed about 2000 domestic and lighting systems, and have been instrumental in the rehabilitation and after sales service of approximately 1000 more (whose modules they fabricated under contract). The local BP Solar representative, Sunpower Systems Ltd, have also installed about 500 home lighting systems.

In view of this rapid commercial success, several international donor agencies are now aggressively pursuing PV programs in Sri Lanka. BP Solar Australia, with assistance from the Australian Aid Agency (Aust Aid), is completing an infrastructure development program which has installed 69 water pumping, refrigeration, hospital, school and community centre systems using 750 BP modules made by Suntec under license. They also have plans to implement a programme that will install 25,000 home lighting systems on the island. The Dutch company R&S have plans to install another 6000 systems with assistance from Shell and Philips. Meanwhile, the Solar Electric Light Fund is supporting two locally-organised initiatives through Sri Lankan NGO's, Solanka and the Sarvodaya Shramadana movement.

Sri Lanka's PV experience is unique in that the PV technology evolved to meet a demand that was already in place. Before Suntec began selling modules, 400,000 people in rural areas were using lead-acid batteries to light their homes and power televisions. Locally-made 12V DC fluorescent lamps were available from a government-supported cottage industry.

Lighting, 12V DC televisions (assembled locally), and radio, are the most popular home system applications. A survey conducted in 1989 found that 54% of Suntec customers had battery-powered TVs before purchasing their PV system. There are also a number of rural customers who use small fans in their systems.

71 Business use of PV is also popular. Small shops use lights to stay open longer, and radios to attract customers. Farms use lights in milking stalls and to keep chicken coops lit for higher productivity. Several tea estates use PV to light up their labourers' quarters. The Ministry of Education is sponsoring solar-powered village TVs which will transmit an extended school program after normal school hours. The wildlife department is now using PV to light game park bungalows.

Suntec's main strategy has been to educate the market in rural areas through targeted advertising and promotion. Its customers are mainly rural households with monthly incomes over Rs. 3000 ($71) in areas where there is no prospect of main-line electricity - a market estimated as 360,000 households.

For lighting, Suntec sell an 18 Wp three-light system for about $350 and a 35 Wp six-light system for $600. System buyers include farmers, small businessmen, teachers and small landowners. Over 80% of customers either pay cash or arrange an informal loan with the dealer, payable over several months. About 10% of customers use small loans offered by commercial banks. One such loan is the People's Bank program launched in June 1989, which lends up to Rs. 20,000 (80% of system cost) at 19% interest with a five year repayment period. A total of about 150 loans have been taken up so far. According to Suntec, apathy and lack of support from the finance institutions at branch level has impeded growth of the bank finance schemes.

Suntec's clear commitment to the technology has resulted in a population much more aware of solar electricity - even the utility has acknowledged the role for PV. The Minister of Power and Energy initiated a proposal to funding agencies for the electrification of 50,000 homes using solar electricity. Furthermore, the Sri Lanka experience has received attention from a number of development agencies, and is being used as a model for programmes in other Asian countries.

Summer Cottages in Finland

Table 5-9 gives data on failures of summer cottages installed in Finland. The figures relate to 10,000 systems installed, which represent the main supplier’s systems. In total, it is estimated that 16,000 to 20,000 summer cottages have a small PV system. The users stated that they are satisfied with their systems.

Table 5-9 Failure rates of small domestic PV systems in Finland

Nature of failure Total no. of systems No. of failures PV array failure 10,000 8 Controller failure 10,000 114 Battery failure 10,000 32 Inverter failure about 1,000 10

72 5.4. Island Systems

Table 5-10 shows various examples of island systems. Quite a few of the systems described are one-off demonstration projects. Two systems have been reproduced a few times, but none of the systems exist in large numbers. Although the term ‘island systems’ means an area isolated from any electricity grid, many of the systems described are actually on islands in the sea. There is very little feedback on the performance of the systems described.

PV systems in Education: In schools and other educational institutions, PV systems are being used to power lighting, overhead fans, radio and television, and some items of science equipment. PV lighting can increase study time and allow for evening classes and training. In developing countries, there are thousands of schools with PV lighting and/or PV-powered TV. For example, the Kilwa Medical Technical Institute in Shaba, Zaire has its largest classroom lit by a PV lighting system. Student nurses now use this room for study in the evenings.

Table 5-10 Examples of island systems

Application Country Description

Health Zaire Several PV systems are being used in Zaire to power community film and education video equipment in health facilities. As well as showing popular and educational films, the World Health Organisation is able to utilise this service to broadcast health information prograimnes to rural communities. PV in educationMali In the remote village of Tourakoro in Mali, the installation in a classroom of just three 13W, high efficiency, electric lamps powered by a photovoltaic module had a major impact on village life. Teachers could provide evening courses for pupils preparing for national exams, and as a result the students performed for the first time with 100% pass-rate. They could also initiate a literacy course for adults who were too busy to attend daytime courses. The classroom also became a coimnon room for all evening meetings and social events.

Use ofPVto Canada PV island systems are not currently in use at present. However, PV could support diesel be used to support remote diesel grids in northern Canada. The systems grids would not use a battery, the diesel generator would run continuously as it does now, and the PV output would reduce fuel consmnption. The diesel generators used typically have a nominal power of 300 kW to 2 MW. Due to the high cost, this is a future application which is not used yet. It could also be used in developing countries. Depending on the location, the PV output would be 1 kWIVWp per year or more. The potential market for this kind of system is estimated to be 17 MWp in northern Canada.

PV/diesel hybrid France A 2 kWp PV system supplies lighting, refrigerator, freezer, office systems for equipment etc. A 1 kVA diesel generator which runs only about 3 hours a remote hotels day is used for the dishwasher, washing machine etc. The typical battery size is 24V and 1000 Ah. Additional smaller PV systems with their own battery might be used to supply smaller loads. Around half a dozen hybrid systems of this kind are installed. The largest market potential for such systems is in small and remote tourist centres. Kaw Village in This system has a 15 kWp PV generator. It supplies a village with 40 Guyana houses. La Pallisade This is a PV/diesel hybrid system with a 12kWp PV generator.

73 Application Country Description

Glenans Islands This is a hybrid system utilising PV, wind power and a diesel generator. Hybrid system Germany A hybrid system supplies a small village with ten permanent inhabitants and Flanitzhiitte up to 50 holidaymakers in the summer from PV and a motor generator powered by LPG (Liquefied petroleum gas). The system is operated by the utility Bayemwerk AG and was installed in 1993 to replace an overhead line in need of repair and restoration. System characteristics: PV generator 42 kWp Battery capacity 2 units of 216V, 1,100 Ah each Battery type sealed lead acid (gel type) LPG generator 40 kVA Annual PV output approx. 40 MWIVyear

PV/diesel hybrid Italy In 1984, a PV plant was set up to feed power into the existing diesel grid system on which supplies about 30 houses on the island. The PV system is operated VulcanoIsland by the utility ENEL. System characteristics: PV generator 80 kWp Battery capacity 260V 2,800 Ah Battery type lead acid Diesel generator 20 kVA Annual PV output 90 MWIVyear PV/diesel hybrid Japan This system was built as an R&D project. A PV system forms the main system on power source, with a smaller diesel generator as a back-up power source. Zamami Island The system characteristics are: PV generator 51.5 kWp Battery capacity 272V 1,120 Ah (10 hour rate) Battery type lead acid, tubular plates Diesel generator 20kVA Annual PV output 38 MWIVyear PV/diesel hybrid This system was also built as an R&D project and, although considerably system on larger, it is similar to the system on Zamami Island. Again, the PV system Mivako Island forms the main power source, with a smaller diesel generator providing back-up power. The characteristics of this system are: PV generator 750 kWp Battery capacity 392V 4 x 1,950 Ah (10 hour rate) Battery type leadacid, tubular plates Diesel generator 300 kW Annual PV output 195 MWIVyear

74 Application Country Description

PV/diesel hybrid Korea This system was installed in 1993 by the Korean utility Korea Electric system on Hodo Power Corporation. The inverter efficiency of this system could be Island improved. The system characteristics are: PV generator 100 kWp Diesel generator 100 kVA Battery capacity 540V 2,700 Ah Battery type semi-sealed lead acid Annual PV output 110 MWIVyear There are three similar systems installed in Korea. PV/wind/diesel Netherlands This is an autonomous hybrid system to supply the Nautic School on hybrid system on Terschelling. Recommendations for future systems are to user better Terschelling modules and a simpler systems design. The system characteristics are: Island PV generator 44 kWp Diesel generator 50 kVA Wind turbine 75 kVA Battery capacity 360V 250 Ah Total annual electricity demand 110 MWIVyear

75 6. THE PV INDUSTRY AND MARKET

6.1. Historical review of Global PV market development

As shown in Figure 6-1, there has been a steady growth in the PV market over the past 12 years. Annual PV shipments reached almost 70 MWp in 1994, a 15 % rise on 1993. The world growth rate is expected to be sustained at between 10-15% in the coming years.

Figure 6-1: Historical shipments overview for commercial modules in MWp for main PV applications

Year

Grid-Connect, small scale Remote houses Village Power Military/ signalling Water Pumping Cathodic protection Solar Home Systems Communic. Consumer Indoor Grid-Connect, medium-large scale Camping Boating Leisure Other remote

76 In the early eighties, the PV market was dominated by the large-scale market segment. Since then, the Communications market segment, and generally all stand-alone applications, have clearly taken the lead. The largest four PV application market segments are currently (in order of decreasing size):

□ Communications;

□ Leisure, boating and caravaning (mainly industrialised countries);

□ Solar home systems (major part in developing world);

□ Water pumping (developing world).

On a world-wide basis, the grid-connected market segment (both large-scale and diffused small-scale) represents only roughly 10% of the market demand. However, in industrialised countries and specifically Europe, its share in sales is significantly higher, and it is expected to grow strongly in the next decade.

The three main regions for the production of PV modules are Japan, the USA and Europe. The EC has sustained the highest growth rate in recent years. However, there is an increasing number of PV module manufacturers in the developing world, for example in Brazil, India and Zimbabwe, as listed in Table 6-11. There are also a number of other companies located in developing countries who sell PV modules and equipment, but undeveloped national infrastructures limit their access to major markets.

Asia/Pacific, Europe and North America consume approximately equal shares of the world market, with Africa, Japan and South America/Caribbean region accounting for less than 10MWp each (Figure 6-2).

In developing countries, the market is either derived from country aid programmes, as in most sub-Saharan countries, or by private initiatives, for example in South Africa, Morocco, Tunisia, Kenya and Zimbabwe. Usually the types of system installed reflect the immediate needs of the population: private and community lighting, water pumping systems and vaccine refrigeration.

Future trends

In the future, rural electrification and water pumping projects are expected to increasingly use PV systems as an economic and effective means of supplying electricity to those rural areas which will never be connected to the grid. In many developed countries, this phenomenon is already starting to occur, with utilities providing PV systems for remote homes where they decide that grid extension would not be feasible. Increasingly, local utilities in the geographically larger states in America and Australia are finding this a viable option, and it is expected that this trend will be adopted in developing countries.

Large PV utility-scale applications are still at embryonic stages, though such systems are being installed in the USA by state utility companies, and within the Swiss Energie 2000 programme. The development of the PV-USA research and demonstration programmes, the 0.5MW Mont Soleil PV plant in Switzerland, and the development of the Toledo PVI 1MW power plant in Spain highlight that, in the not so distant future, PV power plants will be

77 technically competent and economically viable to be considered as large power generating sources connected to the grid or providing the power for isolated large demand areas.

PV is also being developed as an integrated cladding component, both for domestic roofs and as exterior cladding for commercial and industrial structures. Such a cladding would provide an alternative to conventional cladding materials, as well as generating electricity to be used by the building or sold to the grid. The potential of such a development is great as it avoids taking over additional space in order to generate electricity (unlike a conventional power station).

Figure 6-2: 1992 World PV Market

Total 59.1 N.America 20%

Asia/Pacific/ Japan 31%

78 Table 6-11: PV manufacturing capacity in developing countries

Country Manufacturer Capacity (MW)

Algeria UDTS/HCR 1.0 Argentina Solartech 0.1 Brazil Heliodinamica 1.0 China Baotou Solar 0.3 China Beijing General Research 0.1 China H Vamie PV 1.0 China Harbin Solar 1.0 China Kaifeong Solar 0.1 China Nanjing Solar 0.1 China Ningbo Solar 0.3 China Shanghai 901 0.1 China Shenzhen Daming 1.0 China Wuhan Chanjiang 0.3 China Xinjiang Semiconductor 0.2 China Yunnan Semiconductor 1.0 India BHEL 0.5 India CEL 1.5 India REIL 1.0 India Suryovonics 2.0 India TATA BP Solar 1.0 India Udhaya Semiconductors - Indonesia Centronix 0.1 Iraq Al Mansour Factory 1.0 Oman Oman Chemical 1.0 Saudi Arabia BP Solar Arabia 1.0 Saudi Arabia DSSP 1.0 Singapore Hoxan 1.5 Sri Lanka Power & Sun 0.3 RSA Voltaic 0.1 Thailand BP Thai Solar 0.2 Tunisia University of Tunis 0.1 Venezuela Venergia 1.0 Zimbabwe Solar comm 0.5

Note: The manufacturing capacity is usually the maximum output of the process line with one shift for one year. To date, most of the companies above do not produce at their maximum capacity for various reasons (e.g. lack of demand, unreliability of process, etc.)

79 6.1.1. Non-electrified populations: a primary PV market potential

Unlike the industrialised OECD countries with their electrification networks developed near to saturation, in the third-world in particular, a significant share of the population lives in areas without electricity supplies. Of these the majority will probably never be connected to a large-scale electricity network, since such connections will remain uneconomic. The lack of electricity and related commodities contributes consistently to rural migration and urbanisation tendencies - that is the trend of rural populations to abandon living in rural areas and to migrate to the cities in the hope of gaining access to a better quality of life. To counteract this phenomenon and its associated consequences, there is a recognised need to improve living conditions in rural areas, to stimulate local economic development, and to provide rural populations with access to basic infrastructures such as safe water, illumination, education, health, sanitary services, communications, safety, etc. At present the only means of achieving these goals in non-electrified rural populations in non-OECD countries are either through kerosene fuelled devices (lamps and refrigerators), disposable batteries, or else, in a few cases, diesel or gasoline fuelled generator sets (gen-sets). Even so, especially in small scale applications, presenting a daily energy demand of only a few kWhs, the service reliability of gen-sets has proven to be very low, and their operation to be surprisingly expensive when the needs for fuel, lubricants, spare parts and maintenance in general are accounted for. Where a suitable solar resource is available (from tropical to moderate climate zones), and specifically for micro-scale applications (in the range of a few kWh per day) solar PV systems are not only to be considered technically viable, but economically they are also a much more appropriate solution for such power supply problems, despite their apparently high capital investment cost. This is due to their unparalleled simplicity, very high reliability (if adequately sized and designed) and extremely low maintenance requirements. The main disadvantage of solar PV technology (which also applies to wind-power) is that currently its (small level of) diffusion throughout rural territories in the third world has not yet allowed the creation of a network of technical support services sufficient to ensure adequate technical assistance, maintenance, application engineering and installation services. Additionally, the diffusion of this new technology is suffering from a lack of financing services which would allow rural families interested in purchasing their own PV system to overcome the initial investment.

6.1.1.1. Economic development potential of PV technology

There are a number of ways in which PV technology can stimulate local economies, particularly in rural areas of developing countries:

□ Creation of local employment, both direct (manpower for manufacturing, distributed local manpower for installation and maintenance services) and indirect, since the availability of PV power allows for improved productivity in rural areas and the creation of a diffused rural economy based on so-called “cottage industries” (as a typical example, an electrically powered loom or sewing machine allows relevant productions to increase highly their productivity). As much of this work would be traditionally udertaken by women, PV systems can also contribute to female development;

80 □ The possibility to provide alternative solutions for the problems related to rural electrification allows a reduction of social and political pressure on decision makers, who otherwise have to opt for uneconomic investments in electric power network extensions. At the same time PV electrification affords a much better use of financing resources made available by national and international development agencies for rural electrification purposes, by increasing (for the same financial input) the number of beneficiaries;

□ The resulting improvement in living conditions of rural populations relieves the pressures of migration from rural areas towards urban centres, thereby resulting in a marked improvement in the overall social, demographic and economic balance of the nation. In the long run, the possibility for autonomous electrification of rural populations may be expected to significantly counteract the present trend in developing countries towards urbanisation;

□ Apart from the obvious advantages of avoided pollutant emissions (and noise) from conventional power generation facilities, the otherwise uncontrolled disposal of disposable batteries (toxic waste) by rural populations is also avoided.

□ The modularity of PV systems allows for a very smooth and gradual introduction - distributed both territorially as well as over time. In fact, unlike conventional energy systems, solar PV applications need no large investments concentrated in a certain region and during a very limited time period of perhaps only one or two years. On the contrary, it is possible to dilute the introduction of PV technology over a long time period, which has the added advantage of offering long-term continuity in local employment required for their gradual installation and maintenance.

81 7. BARRIERS TO THE WIDER DISSEMINATION OF PV SYSTEMS

7.1. Introduction

The most obvious ingredients to any successful market application are appropriate technology matched to user needs, cost effectiveness, simple access (purchase and installation), effective and simple exploitation (operation and maintenance). The PV industry is rightly focused on reducing costs and developing user-friendly designs. However, developing a simple, reliable and low cost PV system is only part of the equation.

Generally speaking the barriers hindering the market development of PV technology may be of technical, social, institutional or economic nature. In this section, the results of a recent survey of stand-alone PV systems will be used to draw some conclusions concerning the barriers to wider dissemination of PV systems. The general factors affecting the viability of PV systems will then be considered.

7.2. Results from Survey

The survey of PV stand-alone activities carried out in 1994/5 included one set of questions focusing specifically on the barriers to the wider dissemination of PV in each country. The results of this section of the survey are summarised below.

Canada, Finland, France, Germany, Japan, Korea, Netherlands, Portugal, United Kingdom responded to this questionnaire, the aims of which were to:

□ discover what type of barriers affected the wider dissemination of PV in each country (e.g. technical, financial, cultural, structural, institutional etc.)

□ determine how to overcome these

□ assess the role of government in the successful dissemination of PV systems

□ ascertain the level of utility interest in stand-alone PV systems

Again, the survey relates specifically to the countries participating in Task III of the PVPS Programme. However, it is important for the future success of the stand-alone PV systems market worldwide, and for the satisfaction of the system users, that the barriers and problems identified within the ‘domestic’ markets are not replicated elsewhere. Many of the findings and recommendations resulting from this questionnaire offer important insights for PV manufacturers, installers and so on. If they are able to address and overcome the barriers identified ‘in their own back-yard’, it will increase the potential for avoiding similar obstacles in other areas, for instance in developing countries.

Undoubtedly there will be various other barriers that are specific to particular countries or regions that have not emerged as a result of this questionnaire. The follow-up survey of developing countries should identify these region-specific problems and provide a more complete picture of the actions to be taken in such cases.

82 7.2.1. General Barriers

Of the responding countries, the total installed capacity ranged from ~ 135 kW in Portugal to 16 MW in Japan. For the two countries with the highest number of installations, Japan and Germany, grid-connected PV systems make up the majority of applications. Focusing on stand alone applications, the proportion of the market for each application was found to vary for each country (Figure 7-1).

There were a variety of reasons identified in the responses to the survey as to why some markets have developed within some countries and not others. Two main themes emerged:

□ in the UK and Finland, customer preferences for PV systems have been the market stimuli. In Finland it has been private owners of summer cottages; in the UK, service applications such as navigation aids and remote monitoring constitute the largest markets.

□ in the other countries, government support, programmes of the European Union, and electric utility support have been responsible for stimulating the market in these countries.

The main barrier to the deployment of PV systems in most countries seems to be related to the cost of PV systems. These are either real (because of competition from grid electricity, such as in Finland) or perceived (lack of information exchange on economics). High grid density in Japan and Korea restricts the need for PV stand-alone systems, though in both cases, the utilities are very positive towards the deployment of island and grid-connected systems.

In the UK and France, the electric utilities do not favour PV systems within their distribution areas either for stand-alone or grid-connected applications. In Germany, lack of available modular systems and lack of trained electricians to install systems are considered to be inhibiting market growth.

In many countries, lack of appropriate financing and/or incentive schemes for PV purchasing and insufficient information dissemination activities are also seen as hindering market development. In Portugal and the UK, government support is restricted to demonstration and R&D projects. France provides financing for installations in its overseas territories. However, in other countries such as Germany, Japan, Korea and the Netherlands, the government is providing financial incentive schemes for most PV installations, as well as to demonstration and R&D programmes and projects.

In all other instances, it is the private sector (both commercial and domestic) who have paid for the 100% purchase of PV systems.

83 Figure 7-1: Installed Stand Alone PV Applications

D ISLAND ■ ISOLATED BUILDINGS □ SERVICE

7.2.2. PV company activities

The data provided in response to the questionnaires was not complete for this section. However, it is possible to highlight a number of trends.

□ Each country has at least 5 PV companies operating within it, though these do not necessarily include PV cell and/or module manufacturers.

□ These companies range in size from small, country-specific PV suppliers to large, multinational PV corporations.

□ There are very few installers in each country.

□ All countries have a variety of BOS manufacturers, primarily battery manufacturers who also sell outside the PV industry.

84 Most countries have PV courses for installers and/or maintenance engineers, which are funded primarily by the government. (This is in contradiction to the lack of installers cited as a barrier earlier.) Many countries do not have PV engineering courses at university level.

7.2.3. Government involvement with PV

All national governments of responding countries have a ministry responsible for energy. In all cases, this is not its sole function. In the majority of countries, it is also the ministry responsible for renewable energy (or a department within it). Few countries have a ministry responsible for rural electrification, and where this is the case, it is also the ministry/department responsible for overseas aid. In some countries, the same ministry has responsibilities which include energy and aid (e.g. Japan).

All countries have a government policy for renewable energy; most also have one for PV as well. The detail and targets in these vary.

The amount and type of support for PV varies amongst the governments. Canada, Germany, Japan, Korea and the Netherlands receive the most support, including support for financing schemes. Only the governments of Finland, Netherlands and UK appear to have commissioned studies into the barriers inhibiting market growth for PV systems.

7.2.4. Utility involvement with PV systems

In three countries (France, Korea, Portugal), there is only one electric utility. Four countries have less than 20 electric utilities, and in two there are more than 20 (Finland, Netherlands).

In most countries, it is believed that, with utilities, senior decision-makers and engineers do have knowledge about PV, though this expertise varies as does the willingness to implement PV projects. This expertise has been gained primarily through seminars and conferences, though in the UK there is a direct action through Task I PVPS to undertake PV information sessions with executives of the Regional Electricity Companies (RECs).

In Japan, Netherlands and Korea in particular, the utilities positively support PV within their energy mix. In Japan, however, this is only for grid-connected systems; in Korea it is for island systems; and in the Netherlands it is for predominately grid-connected systems.

In those countries where utilities have a negative opinion about PV, the reasons for this include the perceptions that PV is:

□ not an economic solution

□ too expensive

□ in competition to grid extension

□ not relevant as an electricity generation option

The attitude of utilities towards PV does not seem to correlate to the ownership status of the utilities or the control of their budgets. Some are wholly owned by the national, state or municipal government (or a combination thereof); others are privately-owned.

85 According to the questionnaire replies, the most appropriate PV stand-alone systems for utilities in the future include:

□ PV power plants

□ RAPS houses

□ small lighting systems

□ community lighting systems

□ small power supply options

□ rural electrification

□ island systems

□ PV cladding

The type of technical information on stand-alone systems which the utilities require includes:

□ data on real costs, including life-time analysis

□ system reliability and performance

□ safety aspects

□ information on BOS components (particularly inverters)

□ system configuration, sizing etc.

□ quality assurance

The following Table 7-1 shows the number of utilities, by country, which have PV stand­ alone or island systems. Utilities in Japan, Germany, Netherlands, Finland and Portugal have grid-connected systems. In Finland and Portugal, these are small demonstration systems. In Japan, Germany and Netherlands, these systems are numerous and the result of a proactive government and utility policy for PV.

86 Table 7-1: Utility Installations (stand-alone systems only)

Type of system Application Number

Service applications

Canada • water pumping

• communications • sectionalising switches

Finland • Fault detector in 20 kV grid 1

• grid connected 30 kW, with battery 1

France • aerial warning lights

Germany • few

Korea • aerial warning light systems 2

Netherlands • remote application sluices ~ 10

Isolated buildings/homes

Canada • remote electrification 5 - 10

France • remote homes 50 in 1995

Island systems

Canada • remote grid 2

Korea • Hodo Island 100 kWp 1

7.3. Technical factors

7.3.1. Inherent limitations of solar energy

The output of a PV system is limited by the intensity of sunlight reaching its modules. When compared with highly concentrated fossil-fuel energy sources, solar energy can appear to be a rather weak alternative. One square metre of PV module can generate a maximum of 150 Watts of electricity, equivalent to 1 kWh per day in the sunniest regions. For the same electricity output, a diesel generator would consume half a litre of fuel per day.

The diffuse nature of the solar resource is a major reason why PV is best suited for low power, decentralised applications. Remote stand-alone PV systems are most successful when designed to perform a certain small and well-defined task, such as provide lighting for 6 hours per day, or pump a certain amount of water per week. PV is not best suited as a 'general' electricity supply, and many projects in which PV power plants have distributed electricity through small-scale village grids have met with problems due to villagers behaving as if the provision of electricity was infinite.

87 For example in French Polynesia, where a French aid programme installed a number of PV systems in remote villages, a study carried out after 10 years found a general displeasure with PV. This was because there had been a general perception that the systems would provide electricity for more services (lights, TV, washing machines etc.). When it was realised that this was not possible, PV was seen as inferior to either grid connection or the more abundant supply from diesel generators (despite a high fuel cost).

7.3.2. Site and geographical locations

The precise location of a proposed PV installation will effect its specification in a number of ways. In sunnier locations, PV systems can have smaller arrays and smaller battery banks, so the total investment costs (and replacement costs) are reduced. It is essential to obtain accurate solar irradiation data in advance of sizing the system because it will have a direct bearing on the total cost. It may also affect the operation of the system because an over­ estimated solar resource will lead to premature battery failures which, for example, might cause a loss of vaccines stored in a PV refrigerator.

Local climatic conditions may also influence the quality of equipment chosen. PV systems are now commercially available which are designed to withstand the worst possible conditions (i.e. sea salt corrosion, high altitude, strong winds, extreme temperatures, etc.). Despite higher investment costs, these durable systems will be more cost-effective in the long run.

A further consideration is the transportation of equipment to site. Access to rural areas can be difficult in anything larger than a 4-wheel drive vehicle. The equipment will therefore need to be in reinforced packages of a manageable size in order to avoid transport damage.

7.3.3. Quality of systems

A large number of commercial PV systems are now available worldwide, and, as with any other product, there is also a range of available quality. To ensure the long-term success of a PV project, it is important to select PV systems of adequate quality, preferably approved systems (i.e. following a defined standard). Systems should be well-designed and properly sized for the specific need. They also need to be long-lasting, repairable by local technicians and user-friendly.

Most PV modules are manufactured according to USA or European standards, and their quality is very high. International standards also exist for certain other system components. For example, the World Health Organisation, in collaboration with UNICEF, has set international standards for PV refrigerators. WHO/UNICEF funded projects will now only use PV refrigerators that have received WHO approval. This has raised the standard of available products.

However international standards do not always exist for PV system components, such as power conditioning units, cabling and lights. This has led to the situation where the quality can vary significantly between several apparently similar devices, or between the various components within a single system. The issue of standards is discussed further in Chapter 0.

To avoid purchasing inadequate systems or components, it would be advisable to prepare a set of technical specifications to define the standard required for a given application.

88 7.3.4. Warranty on PV modules

It is desirable to select PV modules that offer long warranty clauses. The majority of manufacturers offer warranties for their modules for a period of ten years for crystalline silicon modules and five years for amorphous silicon modules. Some manufacturers are currently extending their standard ten year warranty to twenty years.

As mentioned above, quality PV modules have reached high levels of reliability. Indeed, in many applications (such as for gadgets and leisure applications) the quality and reliability of commercially offered (crystalline) PV modules goes beyond the need. In many systems, the battery has now become the weakest link in the chain. Batteries in PV installations typically have a lifetime of between 1 and 5 years.

It is true that manufacturers' warranties may be of limited use in remote areas because the cost of returning a faulty module may be prohibitive, and few warranties will cover transport and/or shipping costs. Nevertheless, such a long warranty does at least give an indication of the confidence that manufacturers place in their product.

7.3.5. Size range of systems

PV systems are now manufactured in a wide range of shapes and sizes. However, the range of PV products available in some countries, especially developing countries, is still relatively limited. The widespread adoption of PV in developing countries will largely depend on the availability of reliable commercial products over a wide range of size and price to match the needs and incomes of the largest number of people, communities and institutions. Lighting applications currently exhibit the broadest range of available sizes, with torches and portable PV lamps developed for people with lower incomes, and fixed PV lighting systems for those with higher incomes. In terms of units sold, lighting systems are by far the most common application for PV in developing countries. It is an advantage that many PV systems are also modular, so can be upgraded if financial circumstances improve.

7.3.6. Quality of installation

Most PV systems (with the exception of portable lamps) require proper installation. Systems which have not been installed correctly are unlikely to operate satisfactorily. Installing a PV system does not usually pose any major problems, especially when they are sold in 'kits' and the kit contains all the necessary components along with instructions in the appropriate language. In the case of domestic lighting kits, the installation can be done by the owner. For community installations, e.g. for a hospital or school, the installation should be carried out by qualified technicians with the same thoroughness as for a conventional power supply system.

7.3.7. Maintenance and after-sales services

PV systems have in the past been 'over-sold' as requiring no maintenance. Although it is true that the maintenance requirements are minimal, they are also vital. Research and development into 'maintenance-free' equipment is currently being carried out but it remains tomorrow's technology. It should be stressed that the maintenance of a PV system must be planned in advance, including the arrangement of the necessary finance.

89 An adequate after sales service is also essential for the durability and continuity of a PV system. In particular, spare parts must be commercially available at reasonable cost. The few PV systems that do not offer an after-sales service should be avoided.

7.4. Economic Factors

The most significant economic barrier hindering the development of PV technologies is without doubt its high cost in comparison to conventional bulk energy sources such as coal, oil and nuclear, as well as hydropower. This is the reason why many decision makers in national and international energy planning authorities, utilities and other energy institutions still today assign little importance to PV power developments.

In certain cases, stand-alone PV systems are competitive with conventional energy sources. However, in purely financial terms, PV costs do often exceed those of conventional energy sources.

It should be noted that a purely financial analysis does not provide the whole picture and excludes certain issues (such as transmission costs, and externality costs). If these additional cost parameters are taken into consideration, many more PV systems would become competitive compared with conventional energy sources. The economics of PV systems is investigated in more detail in Chapter 0.

7.5. Social factors

It is important during the formulation of a PV programme in a developing country to examine what the social effects of the programme are likely to be, beyond the direct benefits provided by the PV technology. In particular, assessments need to be made of the indirect social effects, positive and negative, of implanting new PV technology within a community or institution, and the social structures that will need to be in place for the PV system(s) to be operated with maximum success.

Some of the important social factors that need to be considered during the formulation of a PV project are summarised below.

7.5.1. User participation

To maximise the social benefits of a PV programme, it can not be over-stressed that the ultimate users of the system should be consulted throughout the planning process. The needs, preferences, and abilities of the local people need to be investigated and discussed because it is they who will use, maintain, guard and take pride in the system.

As an example, the siting of a PV pump for irrigation should be determined by all the farmers who will use water supply, not just those with the most land and resources. The legalities of who owns the land and/or the rights to the water should be investigated as well as who is in a financial or geographic position to benefit from the pumped water.

90 7.5.2. Local management

Where a PV technology, such as a water pump, will benefit an entire community, a local organisation needs to take responsibility for ensuring that the technology is managed and utilised according to the needs and preferences of the entire community. Such an organisation must be representative of the entire community so that all community members have the right to influence the use of the system. The organisation may need to define the hours of operation of the system, the tariffs that might be levied (e.g. for water or battery­ charging), and the maintenance to be carried out and by whom. The presence of such an organisation can help to ensure that the system, and any revenue it generates, will benefit the entire community, not just a privileged few.

Such a community organisation is essential in situations where the local people will be contributing to the financing of the system. It will need to be set up well in advance of system installation, probably during the planning phase with community representatives.

7.5.3. Educational requirements

The introduction of any new technology must be accompanied by an educational programme for those who will use, maintain and benefit from the technology. This may initially focus on training for the immediate users and maintenance personnel, but should also include some general education for the entire community on energy conservation and the use of solar energy technologies.

It is particularly important for the users to understand the limitations of PV so that they don't have unreal expectations concerning the amount of electricity which the PV system can supply. Otherwise this can lead to dissatisfaction with PV, because, as has been experienced in areas connected to the grid, provision of electricity leads to higher and higher consumption patterns. If a new user has the perception that the system will provide more than it is capable, then a negative attitude towards PV may soon become apparent.

An educational programme, especially technical training, will require significant financial and human resources and must be budgeted for in the project plan.

7.5.4. System abuse

The electricity from a PV system with batteries and battery-charger can quite easily be diverted from its intended use. Unfortunately such abuses occur even with the co-operation of those who are relied upon to monitor and protect the systems. For example the battery of a PV system may routinely be used to start vehicles, thus damaging the battery and preventing its prolonged use. Or an engineer on a routine maintenance tour may find the District Medical Officer selling cold beer from the vaccine refrigerator, yet have no authority to take action against the offender.

Any project or programme involving PV systems will need to take onto account the potential abuses that might occur and should consider establishing a set of rules and regulations governing their use. It may be possible to set up an external body capable of levying sanctions of some sort against known offenders.

91 7.5.5. Negative social effects

The advantage of PV technology from one perspective, can be considered a disadvantage from another. For example, installing lighting systems in the accommodation of professional staff at a rural hospital provides a great convenience and can serve as an incentive to work in such remote, rural areas. Surrounding villagers however might resent the fact that they are not allowed access to the same technology. Hence the need to examine the wider social effects of the service provided by the PV technology. Will it further stratify a community by increasing the differences between rich and poor? Will it place a financial burden on poor people through an increase of local taxes? Will it force people to 'participate' in a project from which they will not benefit? Such questions must be addressed if one is to assess the net benefits of the service provided by PV technology.

7.6. Institutional factors

There are many institutional barriers hindering the widespread use of PV systems. These operate on many levels, from grass-roots contact with possible customers to political, country-specific agendas. They can be obstructions inherent in a programme, such as lack of adequate financing, or obstacles which only become apparent when a project is in execution.

7.6.1. Operational constraints

There are many operational barriers which have prevented the widespread use of PV. In themselves, they individually have a varied effect upon the market depending on location and context; collectively they have had a major negative impact.

7.6.1.1. lack of knowledge

Lack of knowledge, misunderstanding and bias have acted as deterrents to the wider utilisation of PV, on technical, social, economic, financial and environmental grounds. Thoughts such as: it's too expensive; it doesn't work; we don't have enough sunshine; the technology is too complicated; it's not appropriate are just some of the arguments which have been used against PV in the past, these observations often being based on incorrect information or biases.

Because energy is relevant to many departments and disciplines (such as agriculture, resource planning, health, environment etc.) professionals in a sector outside energy often do not know enough about PV to specify project applications. There are many instances where staff have received misinformation about the use, operation and/or costs of PV systems, and thus do not consider the technology as a possible solution to the problem with which they are dealing.

Even within energy ministries in many countries, there is a low level of knowledge on the technical advances and different applications of PV, which once again acts as a deterrent to project development.

As international loan and aid institutions contribute significantly to sectorial programmes within developing countries, a programme which ignores PV, or has the equipment wrongly specified, has a significant negative effect. For instance, in the health sector, the safe storage

92 of vaccine is vital to the success of immunisation programmes. If it is not kept at between 0 - 8 o C throughout the cold chain process (delivery from manufacturer to recipient), then the vaccine will deteriorate and become useless. In most developing countries, constant refrigeration temperatures are either intermittent (due to availability of kerosene) or unavailable, thus significantly reducing the value of the country's immunisation programme.

The traditional development model for electricity utilities is to electrify the areas with the highest number of customers first (and thus receive the highest return on capital), which means that rural populations, especially those in remote areas, do not have access to a reliable source of energy. In many cases, this further marginalises the already disenfranchised, and can contribute to lower standards of living in these areas and a lower GNP per head for the country as a whole. PV has been proven to be able to provide an alternative to no electrification in rural areas in certain circumstances.

7.6.1.2. environmental and social benefits of solar are unknown

Decision-makers responsible for development programmes are often unaware of the environmental and social benefits of PV systems. Direct social benefits of PV relate primarily to rural electrification, where people can be given access to lighting systems, water pumping, vaccine refrigeration, battery charging etc., all powered by PV and all either previously unavailable or available only at high economic or social (time) cost. This can lead to improved health of the population (through access to immunisation, clean drinking water and increased food production), their welfare (through increased employment and flow of money through the community) and education (through access to lighting for evening study and increased time for children to go to school through lessened requirements for fetching water).

The employment generated by PV systems can facilitate the creation of wealth in remote areas. For example, a project which incorporates PV not only requires the modules, but also simple wiring, structures to hold the modules in place, motors, inverters and other equipment. With provision for technology transfer and training, much of the equipment, routine maintenance and installation for the project could be supplied locally from within the village. This could lead to increased employment and higher skills training. In the macro sense, this increased employment leads to a higher flow of money in the area, and trained technicians can act as role models for younger people and have a positive effect upon attitudes to schooling and higher education.

7.6.1.3. solar energy is viewed as high risk

PV-powered systems are still perceived by the majority of people as 'high risk' technologies and systems. Dissemination activities need to be undertaken to dissipate fears which decision-makers may have, such as PV being an inferior technology, or that it is too 'high tech' for remote areas; or that it just does not work.

7.6.1.4. perceived lack of prestige and political profile

For many decision-makers, PV systems have not yet achieved 'star status', as a prestigious technology with which to be associated. This attitude is undergoing change internationally, due to increased awareness of environmental problems and the high national and international profile of many 'solar and environmental champions'. The Earth Summit in

93 1992, the UNESCO Solar Summits, and the increasing profile of PV within the national programmes is raising the image of PV.

There are occasions in the political arena when quantity becomes more expedient than quality. In other words, for a given budget, it is sometimes seen as higher profile to install a large quantity of cheap equipment rather than a smaller number of more expensive and reliable PV systems.

7.6.1.5. disregard of PV as an option

In most countries national and/or regional governments have so far not made PV an integral part of their energy strategies. This is due to a variety of reasons, including those noted previously.

For governments of developing countries, the challenge is to provide a reliable supply of electricity to the burgeoning rural population, many of whom are increasingly forced to farm marginal land and thus have a reduced ability to pay for services such as connection to the electricity grid. PV is not the only answer to problems of rural electrification, but it does have many advantages.

Historically, public utilities have opted for large-scale investments in incremental power generation, transmission and distribution, supported by government financing and multilateral and bilateral development agencies. Small-scale PV projects do not fit into this development trend.

7.6.1.6. conventional criteria for rural electrification

Many governmental authorities are taking positive steps to electrify rural areas in their regions. A typical approach is to award a concession to a private enterprise, who will provide all the necessary investments.

The most commonly used approach used to quantify a level of energy service provided is to use the quantity of energy consumed (in kWh for electricity) as the basic parameter. In the context of rural electrification, this approach results in users with higher energy demands (such as larger farms, rural enterprises, richer residential households) being favoured over smaller users. Also, low priority will be assigned to energy savings and rational use of energy.

An improved overall service would be provided if priorities were focused, not on the quantity of sold energy, but on the number of days electrification is made available to the maximum number of consumers. This would tend to favour small electrification units, and the provision of electrical services to as many people as possible. PV energy systems would be well suited to this type of electrification system.

7.6.1.7. lack of integrated resource planning

In the 1990s, integrated and sustainable energy planning requires minimising ecological risk while maintaining development opportunities. It also requires an synthesised approach to other fields of policy, as energy cuts across almost all other sectors, just as energy cuts across all areas of human activity. For PV, this is particularly true in the health, rural development

94 and agriculture sectors. With an integrated planning approach it is possible to identify correct resource requirements for PV in terms of local expertise, manufacturing, installation/technical services, technical and institutional education.

7.6.1.8. time horizons

A sustainable energy economy which includes PV needs to have a realistic perspective on time scales for both project implementation and economic achievement. For most PV applications, the technology is already available on the global market. However, to facilitate a viable local industry in the short term (product acquisition), medium term (training) and long term (R&D, manufacturing), issues must be addressed in terms of energy policy, programmes and projects and cross-cutting sectorial issues, such as employment and the provision of local services.

If these time scale issues are not taken into consideration, together with the fact that PV systems incur an initial high cost at time of installation but have very low running costs thereafter, it is likely that PV could be disregarded from the country energy agenda.

7.6.1.9. lack of commercial activity

An example of how the lack of commercial activity can be a barrier to the dissemination of PV can be found in Mongolia. More than 80,000 families in Mongolia are nomadic livestock herders, and thus grid-connection is not possible for them. As a result of demonstration programmes supported by the government, UNDP and Japan, there are now more than 3000 small PV systems in use in the countryside. The systems range from 10 - 200 Wp, and are used to provide electricity for lighting, TV and radios. User acceptance is good as the systems, apart from supplying basic electricity requirements, are portable and modular, and the population have a good understanding of PV.

Yet a recent mission financed by Danida to the Gobi region found little evidence of commercial activity, and no infrastructure set up to provide for the procurement of new systems, spare parts, repairs or even replacement batteries. The principal source of supply of batteries is Ulaanbaatar, the capital, which can be several hundred kilometres from the users of the PV systems. This has resulted in some systems performing poorly because they are using batteries which are at the end of their useful life.

Whilst a joint venture for the manufacture of PV modules has been set up (and also one for small wind generators), often the entrepreneurs have found it more profitable to trade in livestock products and other goods than in the 'difficult' market of PV systems. In part this is a result of a lack of training in market development and a lack of knowledge of market economy mechanisms. For example, many potential users of PV and wind systems are willing to pay a high price (e.g. 3 - 5 head of livestock for a small 50W wind charger), yet suppliers are still selling at prices much below the possible market price. If this higher price were charged, then it could stimulate enough profit to enable the necessary financing of infrastructure requirements.

Lack of accessible after sales service has been sited in other situations as being a barrier to further market development. In most situations it can be easily overcome through making sure that training of local technicians is undertaken and the infrastructure to supply spare parts is put in place as part of the PV programme.

95 7.6.1.10. increased work burden and morale problems

In developing countries the salaries of personnel are generally very low, hence their motivation to do their job may not be very high. Thus, to add an extra - and unpaid - task of maintenance to their workload can lead to either still lower morale or the job simply not being done. This can happen in the health and agriculture sectors, where regular maintenance of the PV system is required to ensure that the system remains functional. The development of maintenance-free PV systems would be one immediate way to overcome these problems. Another would be to make maintaining PV systems the responsibility of either the system supplier, or of a specialist maintenance organisation.

7.6.1.11. incorrect costing of projects

Too often only the initial capital cost to purchase equipment is included in the project/programme budget. Many times in the past, a programme/project which includes PV equipment has forgotten/omitted budget allocations for training of local maintenance engineers and end users. It is often assumed that PV systems require no maintenance, when in fact they do require a minimal amount of maintenance over their lifetime.

There are many thousands of PV systems around the world, especially in developing countries, which are not working due to lack of simple maintenance (e.g. adding water to batteries, checking cabling, cleaning panels). This can give the false impression that PV as a technology does not work.

7.6.1.12. policy and price distortions

Subsidies to conventional energy generators and tariffs on renewable energy system components are critical financial barriers which can hinder the wider dissemination of PV applications. Taxes on PV equipment add unnecessarily to its capital cost and make stand­ alone PV systems appear even more expensive when compared to end-user costs for grid- connected electricity.

There are instances where direct subsidies were given for PV - this was especially prevalent in the aid programmes of the 1970s and '80s, when many 'free' PV systems were given to beneficiaries. However, these programmes had a number of negative effects:

□ beneficiaries often were not consulted as to their needs and energy requirements.

□ beneficiaries often did not have the financial resources to maintain the equipment donated.

□ there was little sense of ownership of the equipment and therefore little sense of responsibility for it.

□ an unrealistic price expectation for PV was created, by which PV companies/traders found it very difficult to sell to rural populations in developing countries, as the people's expectation was that they would receive it free from an international aid agency or NGO.

96 Today there are programmes which subsidise PV financing options. If the subsidy is an initial seed grant to kick-start a programme, but is not used to subsidise lending rates, then it does not create unrealistic future price expectations. However, if the fund subsidises PV installations directly (such as charging very low rates of interest), then it is possible that the negative experiences of the 1970s and 1980s, as described previously, could be recreated. If the lending institution cannot cover its own costs through proper interest charges, the programme/project will remain reliant on external financing, which is not seen as desirable for sustainable long term development or bringing self-determination to local communities.

7.6.1.13. inadequate programme structure

There are times in programmes and projects when it is unclear who has what responsibility, especially when it come to issues of funding for repair and maintenance. PV systems do have routine maintenance and the occasional system repair requirements, and, although these may be small, adequate provision must be made in the programme structure to allow these to be carried out. In the 1980s especially, it was not uncommon for equipment to be delivered, installed and left, with no training of local technicians and no provision in the programme budget for recurrent costs. In one extreme case, a health centre in Southern Africa was equipped with a PV lighting and refrigeration system. The keys to the system were not given to the health centre, no-one was trained in operation of the system or its maintenance (and it was inaccessible anyway), so the system failed after a very short time due to these non­ technical - but vital - project issues.

7.6.1.14. NGO involvement

In the main, NGOs have not been large purchasers or promoters of PV, for two main reasons:

□ high perceived cost of PV

□ low knowledge level about the technical ability and operating reality of PV systems

7.6.2. Price & financing constraints

Some of the broad institutional issues affecting the financing of PV projects are summarised below. Specific financing mechanisms are examined in the subsequent section on Economic Factors.

7.6.2.1. lack of free market in energy sector

At present, there are often hidden and direct subsidies given to fossil fuels. For instance, many developing countries have subsidised kerosene prices; most developed countries have indirectly subsidised electricity prices, through mechanisms such as life-cycle cost accounting. Distribution losses and outage costs (such as occurs in Manila daily) are often not costed in, nor are the costs for replacement of plant. This means that there is no incentive for the private or public sectors to try and spend more money on an energy source if more convenient and cheaper fuels are available.

For unbiased decisions to be made by both end-users and institutions, the real costs of all types of energy generation must be available and comparable. All short and long term externalities of energy use should be included (e.g. environmental degradation, resource

97 depletion, wealth creation). New methodologies need to be developed and initiated to facilitate this.

7.6.2.2. competition for capital

There is competition for available capital to finance income generating projects which compete with PV. This is both on an individual level as well as from a lending perspective, with the typical lender looking to make the highest gain on capital, and typical borrowers looking to direct income-generating activities (such as the purchase of seeds).

7.6.2.3. tax on imports causes prices to be higher.

Whilst import taxes may protect local industries, they can also take PV out of the financial range of many people.

7.6.2.4. availability of appropriate finance

PV technologies suffer from a lack of adequate financing and loan/credit schemes allowing potential user categories (such as rural families and small communities living in non- electrified areas of often low level of economic development) to access the capital needed for the installation of a PV Energy system. Although, in many countries, such potential PV users face higher energy expenses (eg for kerosene or throwaway batteries) than would be required for a PV system, the initial capital outlay is too great.

Finding workable solutions to this problem must be a priority. The financing of small purchases in developing countries is not unique to PV, and it is possible that lessons can be learnt from other sectors, such as micro-enterprise or agriculture.

Financial mechanisms which could assist in this process (discussed further in Chapter 0) include: revolving credit funds, local financial co-operatives, tax relief, special grants, and increased appropriate banking services. Linkages also need to be made between these small- scale financing options and international financing mechanisms, such as bilateral and multilateral agencies.

Groups such as NGOs and private companies are capable of managing PV schemes, but often lack the necessary capital resource to do so. This can be overcome by the creation of non- formal channels of lending for rural populations.

Without a banking (loan) recovery system which is suitable for the majority of potential (usually rural) purchasers, which has an appropriate repayment scheme, and appropriate loan size (often very small), then PV is restricted to those people who can pay cash or wealthier people who have access to formal lending institutions and collateral requirements.

Small borrowers tend to avoid formal lending institutions, as they usually have little experience with the systems of lending which they require and thus are unsure or afraid to either deposit or borrow from such institutions. However, larger/richer lenders are familiar with such systems and many have already used them to fund PV installations, such as in Zimbabwe and South Africa, as well as developed countries.

98 Subsidised credit

Special mention must be given here to subsidised credit. There has been much debate across development sectors about the merits or otherwise of subsidised credit. Prior to the mid- 1980s, subsidised credit loans were a normal part of many aid and development programmes. In the 1980s this system became more challenged and many studies were undertaken to ascertain the real effects of subsidies for development programmes. Today, the prominent view is that subsidies of this type do not help those people targeted within a project. The reasons for this conclusion are:

□ Low-priced credit can generate excess demand, necessitating rationing. This can lead to corruption and political intervention, and reduce the borrowers repayment level.

□ Subsidies can lead to over-optimistic expectations, and are very hard to phase out.

□ Low interest rates give banks low margins, and reduces the services which they are able to offer. Mobilisation of savings can be very important in providing a resource base for lending agencies and correspondingly reduce their external dependencies. There are some thoughts that borrowers are more careful when they know that it is their neighbour or relative's savings that they are borrowing.

□ Subsidised credit can also lead to avoided repayment, either through default or cancellation of the debt (e.g. in the run-up to an election).

It is therefore seen as a better policy to combine normal credit with grants rather than subsidising interest rates.

Developing country governments often see credit programmes as an easy way to increase the flow of capital to the rural sector. However, it must be ensured that credit is turned into capital and not simply consumption.

In Sri Lanka, experience has shown that people are willing to pay for PV systems in excess of their current energy expenditures for kerosene and batteries because they value the quality of light, the cleanliness of the system and the ability to power small electronic systems. Over 2500 of the 3000 systems installed in Sri Lanka have been provided on commercial terms, at interest rates of up to 34% per year and substantial down payments. Credit schemes have been tailored to the disposable income of the target customer. Leasing programmes are options, particularly in pre-electrification phases.

Most of these and similar small artisan lending programmes still require collateral (for instance land), and have thus been less successful in reaching the poorer groups. But formal lending systems are possibly the best model for offering credit and savings options to large numbers of people. More effort needs to be taken to educate rural peoples to know how to interact with formal lending institutions, and to encourage lending institutions to experiment with lending systems which will cater for the PV borrowing requirements of larger numbers of people.

Table 7-2 summarises the institutional barriers to the wider dissemination of PV which have been discussed above. It also offers some possible solutions to assist in overcoming these barriers.

99 Table 7-2: Summary of Institutional Barriers and Possible Solutions

BARRIERS POSSIBLE SOLUTIONS Lack of knowledge about P V Major information dissemination, promotion and - decision-makers (government, agencies, demonstration activities, closely targeted to particular types NGOs) of decision-makers. - general public Incorrect project costing Allow adequately for recurrent costs. Structure of donor programmes Untie project lending. Decentralise country activities. Lack of prestige Information dissemination activities. Prestige awards. Prestige events. Disregard of PV option in preference for Raise profile through information dissemination, promotion large-scale centralised projects and demonstration. Information exchange with other organisations who have implemented PV options. Lack of integrated resource planning Facilitate inter-sector discussions through workshops, seminars and informal meetings. Short time horizons Realistic/longer project and time-scales for development of the market, support of industry, R&D activities and economic paybacks Regulations Information activities closely tied to the implementation of regulations in other countries and areas Lack of service infrastructure Specific prograimne objective to set up local infrastructure Quality control of products and services Set up methods of product assessment (not necessarily establish national test centres). Specify product performance in prograimne document/tender specifications. Undertake prograimne/proj ect monitoring Inadequate prograimne structures Clearly define in proj ect/prograimne document what organisational responsibilities will be, especially with regard to training, installation, maintenance and repairs. This includes financial responsibility as well as organisational details. Lack of electric utility involvement Encourage information, promotion and demonstration campaign tailored for utility applications of PV. Exchange of information between utilities with PV prograimnes and those without.

100 Table 7-2 (cont.): Summary of Institutional Barriers and Possible Solutions

BARRIERS POSSIBLE SOLUTIONS R&D versus marketing Assist governments and other institutions (as well as private organisations and NGOs) to compile and undertake well- rounded programmes which include adequate provision for marketing activities. Donor and NGO involvement Facilitate the transfer of up-to-date information to and from these organisations, through workshops, seminars, publications, training sessions. Policy and price distortions Encourage governments and utilities to act to reduce subsidies on fuel. Price constraints Encourage the reduction of import tariffs (as applicable), reduction of subsidies, and the inclusion of life-cycle and enviromnental costings for all energy generation technologies. Financing options Undertake studies into methods of financing, also learning from other sectors. Encourage a variety of financial mechanisms appropriate to users. Improve access of small institutions to sources of funding. Assist training of bank staff with regard to provision of small loans. Operation and maintenance issues Ensure adequate provision for operation and maintenance in project, including installation, maintenance, repairs, supply of equipment and training of local technicians and users. Tariffs Encourage the reduction/removal of tariffs and taxes on PV components, as appropriate. Lack of suitable financing mechanisms Encourage the development of more appropriate financing systems. Assist in training bank/NGO staff. Reduce transaction costs. Charge coimnercial rates of interest. Establish deposit facilities. Target poorer sectors of communities to provide suitable financing mechanisms. Make more funding available to small lending institutions.

101 8. PV ECONOMICS

8.1. Introduction

This section outlines a methodology for determining the cost-effectiveness of stand-alone PV systems relative to alternative power systems. It then applies the methodology to a number of typical examples and includes some sensitivity analysis of variable parameters.

8.1.1. Financial or economic

There are two ways of looking at the value of an electricity generating system: either a financial or an economic approach.

A financial analysis is carried out from the point of view of the owner or private investor. Thus, the investment costs for a household or a company will be based on financial costs, including present market prices, taxes, the private cost of capital and any available financial incentives.

The benefits to the private investor will also be viewed in financial terms, i.e. as revenue created or money saved, although these are not always easy to quantify. There are situations where the power produced by a PV system will transfer directly into a saleable commodity e.g. water pumped or batteries charged. In these cases the monetary returns on the investment in the PV system can be predicted from the demand for the service, the selling price, and the likely system performance.

In other cases, investing in a PV system will create revenues in a more indirect manner, for example a lighting system for a shop or bar may extend opening hours, and therefore probably increase business, but by a less predictable amount.

A private investor usually requires a faster payback, applies a higher discount rate (defined later), is less interested in a lifetime longer than 10 years or so, and is not prepared to invest significantly more in a product which has broader benefits to society.

An economic analysis, on the other hand, considers projects from the point of view of the economy as a whole, so uses costs which are independent of taxes and subsidies. It also recognises that market prices may not reflect the full value to society of using a particular resource. Effects not fully captured by the market place are referred to as 'externalities'. The most important 'externalities' in the context of PV systems are societal factors which include: environmental effects, impacts on health and safety, increased security of electricity supply, and changes in employment patterns.

In an economic appraisal, the broader economic and social benefits of PV systems are often difficult to express in monetary terms. For example, a supply of potable water will help to decrease the incidence of water-borne diseases, which in turn will help to prevent people from losing productive hours of work due to illness. For one individual or business, this amount of work could be estimated and valued in monetary terms. However, it would be far from straightforward to estimate for an entire community how many working hours would be saved and consequently, what would be the total economic benefit to the community. In fact, the provision of potable water is only indirectly related to the health of a community, so

102 averted costs would be even more difficult to calculate than for a pure health initiative (such as a malaria eradication campaign). For these reasons, the benefits in an economic analysis become almost impossible to assess with any degree of accuracy.

It should be apparent from the above discussion, and the summary in Table 8-1, that the nature of PV systems makes them more likely to appear cost-effective in a full economic analysis, taking into account all the externalities, than in a purely financial analysis. Governments and other sponsoring agencies have so far been slow to credit PV systems in monetary terms for their advantageous environmental, health and safety features.

In practice, for small projects it is time-consuming to evaluate all projects in both financial and economic terms. However for larger projects financial and economic costs should be calculated.

Table 8-1: Key differences between financial and economic approaches

Financial Economic Capital costs Include taxes (or subsidies), Use real purchase or import costs import duties, etc. Discount rate 10-15% 5-10% Lifetime <10 years 10-30 years Social value Not relevant Qualitative, and preferably quantitative, credit given for wider environmental, social and economic benefits

8.1.2. Cost-effectiveness

The standard method to assess the economic viability of a project is a cost-benefit analysis. This method consists of placing a monetary value on all costs and benefits over a period of time (e.g. the lifetime of the project). For the project to go ahead, the benefits need to be greater than the costs.

As mentioned above, the benefits of a new technology may be social in nature rather than providing the local economy with significant economic returns, as is the case for a potable water pumping project, or a project introducing lighting in domestic or community buildings. Placing monetary values on the social benefits of better health or increased educational opportunities becomes impossibly difficult unless the parameters affecting a specific situation or community are known in great detail.

Therefore, in considering the economic case for PV, only the cost side of the cost-benefit analyses will be detailed here, in what could be called a cost-effectiveness analysis (CEA). The potential social and economic benefits have been mentioned qualitatively in previous sections and these should help economists to perform a full economic cost-benefit analysis if quantitative local information can be obtained.

103 Cost-effectiveness analysis is concerned with determining the least cost method of achieving a particular objective. It does not answer the question of whether all the economic or financial benefits of achieving the objective will exceed the sum of the costs incurred.

Figure 8-1: PV Systems Economic Analysis - Outline Methodology

INPUTS

PERFORMANCE DATA COST DATA ECONOMIC PARAMETERS

System Specification □ Capital costs* □ Period of analysis* * • PV module Performance Model area BOS □ Discount rate* • average insolation power BOS • PV array output design overheads □ Inflation • system efficiency installation * □ Net useful energy production□ O&M costs per year □ Component replacement costs and timescale □ Salvage values

*NOTE: OUTPUT

ECONOMIC INDICATORS For a Financial Analysis: 1. Use local market prices □ Life-cycle project cost 2. Include national taxes / subsidies 3. Use shorter period of analysis □ Annualised project cost 4. Apply higher discount rate □ Levelised unit cost of energy

Figure 8-1 illustrates the outline methodology for conducting either an economic or a financial cost-effectiveness analysis of PV in particular local situations. The parameters are the same whether an economic or financial approach is taken, but their values will differ as explained in the note. The categories of input required are:

□ system performance

□ cost data

□ economic parameters which are combined to give economic indicators describing the cost-effectiveness of the system under analysis.

104 8.1.3. Life-cycle costing

In a life-cycle costing, the initial costs and all future costs for the entire operational life of a system are considered. The period for the analysis is normally the lifetime of the longest lived system being compared.

For instance, a PV array costs more to buy than a diesel generator, but the modules should last over 20 years. The diesel generator might last 10 years, using a certain amount of fuel each year. In this case the analysis period would be 20 years. In addition to the capital cost, the cost of a replacement diesel after 10 years, plus 20 years' worth of fuel must also be included in the cost of the diesel option. The costs of maintenance and repair for the two systems over the whole 20 year cycle must also be included. Depending on the exact figures, either the PV or the diesel system will work out cheaper overall.

To make a meaningful comparison, all future costs and benefits have to be discounted to their equivalent value in today's economy, called their present worth or PW. To do this, each future cost is multiplied by a discount factor calculated from the discount rate. The discount rate expresses how the value of money decreases the further into the future it is received.

For example, a discount rate of 10% per year would mean that in real terms it is equivalent for a customer to receive $100 now or $110 dollars in one year's time. Therefore a cost of $110 dollars one year from now has a present worth of $100. Standard economics texts should be consulted for further detail in this respect.

8.1.3.1. Lifetime of PV modules

A distinction must be made between the lifetime of crystalline silicon modules and amorphous silicon modules.

Crystalline modules

Some crystalline silicon module installations have now been in operation for more than 25 years, including in developing countries under harsh climatic conditions (e.g. in the Sahara desert with great extremes of temperature from day to night and sand storms, on islands and buoys with sea water corrosion, etc.) Hence a period of analysis from 15 to 30 years is acceptable; 20 years is taken as the norm (and is now guaranteed by at least one manufacturer).

It may be suitable in some cases, when comparing with technologies that have shorter lifetimes, to consider a ten year lifetime for crystalline modules. In this case a salvage (or re­ sale) value, should be considered. However, it is difficult to estimate the re-sale value which will depend on the price and availability of new PV modules in ten years' time as much as on the conditions of the module. It is worth noting that 8-year old second-hand PV modules from a dismantled PV power plant in the USA are currently on sale at around 80% of the $/Wp price of new modules.

Amorphous silicon modules

A maximum lifetime of ten years should be considered with no re-sale value. A five-year lifetime can also be considered bearing in mind a re-sale value.

105 8.1.4. Example life-cycle costing : PV lighting kit vs. 2 kerosene lamps

A detailed example calculation is presented in Figure 8-2 in a spreadsheet layout that can be used for other systems. The resulting life-cycle costs are presented in the Economic Indicators box at the bottom of each spreadsheet.

The example calculations have been made for a PV lighting kit and a flame-based lighting system based on two kerosene lamps. Each kerosene lamp has a total light output of 50 lumen and is costed at $8. The lighting kit is composed of an 18Wp PV module, a 70 Ah battery, a regulator and two 8W fluorescent tubes. Each fluorescent light output is 400 lumens (lumens being the standard unit of light ie. each lamp emits 50 lumens per watt). The total initial investment is US$350 for the PV system.

Installation, area-related and indirect costs are taken at zero as the systems are very small. No-salvage values are taken into consideration. The inflation rate has been taken as zero.

The Annualised Life-Cycle Cost (ALCC) - ie. the total life-cycle cost (LCC) expressed in terms of a cost per year - for the kerosene and PV cases are $96.51 and $81.61 per year. Although PV comes out slightly cheaper, the small difference between the costs in this case is not significant as it falls within the margin of error of this type of life-cycle costing estimate. It should therefore be concluded that the annualised costs are comparable in this case. The last line gives the cost per unit of light output, measured in dollars per thousands of lumen-hours or $/klm-hour (i.e. the cost per hour of lighting is divided by the light output in lumen). The PV system has a cost less than one eighth of that of the kerosene lamp system when measured this way. This is because the light output (2 x 400 lm) is so much better than that of the kerosene lamps (2 x 50 lm).

106 Figure 8-2: Example life-cycle costing

NOT AVAILABLE ELECTRONICALLY

107 8.1.5 Example: comparison of portable lighting systems

The life-cycle costing method has been applied in Table 8-2 to various types of portable lanterns popular in rural areas, based on four hours of lighting per day. The table summarises the calculation for candles, kerosene lamps, butane lamps (with rechargeable cylinders) and PV lanterns. Unit costs are expressed in US Dollars per hour of lighting, and US Dollars per kilo-lumen-hour ($/klm-hour).

The PV lantern has the lowest cost per hour, and the lowest cost per klm-hour. This is due to its exceptionally low running costs and its high light output. It means that PV lanterns can give great improvement in lighting while still being cheaper than (or comparable to) other conventional portable lighting devices, on a life-cycle cost basis.

Table 8-2: Economic comparisons of portable lanterns

Type of lantern Candle Hurricane Pressure Gas Lamp PV Lantern Lamp Lamp Energy source Paraffin wax Kerosene Kerosene Butane Solar Fuel consumption 1 per 4 hours 0.03 I/h 0.07 I/h 30 g/h none Fuel price (US$) 0 0.8 $/I 0.8 $/I 1 $/kg 0 Light output (lm) 16 50 700 500 320 Investment cost (US$) 0.12 8 55 25 150 Replacement costs - lamp lamp lamp * No. of lamp replacements - 3 2 3 - Non-fuel running costs (US$/year) 44 10 10 10 0 ALCC (US$) 44 48 109 63 37 Cost US$ / hour 0.03 0.032 0.075 0.043 0.025 Cost US$ / klm-hour 1.88 0.66 0.11 0.09 0.08 * Replacement costs for PV lantern: battery, $40 every 3 years; fluorescent tube, $8 every 3 years; control card $40 every 6 years. Assumptions 4 hours of daily use, period of analysis = 12 years, discount rate = 10%______

8.1.5.1. Sensitivity analysis

The examples are valid for one particular set of circumstances and prices. As most of the LCC of PV lighting systems is in the capital cost, the final annualised cost is insensitive to hours of use. However, for the flame-based lighting systems, the bulk of the life-cycle cost is recurrent fuel costs, so the hours of use and fuel price have a large impact on the annualised cost.

Figure 0-3 shows how the annualised cost of the flame-based system varies with kerosene price and hours of use. The horizontal line represents the PV system. The LCC has been assumed to be constant for the PV system , although in reality there would be some slight variations due to more frequent tube and battery replacement with longer hours of use. It is interesting to note that there are only a few cases (except at a low kerosene price or low daily use) where kerosene lighting is cheaper than using PV. In general, the greater the lighting demand, the more cost-effective is the PV lighting system.

108 Figure 0-3: PV lighting kit vs kerosene lamp sensitivity analysis

Fig. 8-3 NOT AVAILABLE ELECTRONICALLY

The assumptions used for this analysis are summarised below:

Kerosene lamps Total initial investment (2 lamps: 2 x 8) 16 $ Replacement of both lamps 16 $ Lamp lifetime 3 years Lamp fuel consumption 0.03 litre/hour Total lamp output (2 lamps x 50lm) 100 lumen Maintenance (spares) 20 $/year

PV lighting kit Solar insolation 5 kWh/m 2/day Total initial investment 350 $ Replacement batteries, tubes 86 $ Lifetime of batteries, tubes 3 years Replacement of regulator 100 $ Lifetime of regulator 6 years

109 Life-cycle cost and sensitivity analysis for other PV systems

It is not in the scope of the report to calculate for each system the life-cycle cost along with multiple variations of parameters. This would be of limited relevance when the local project conditions that may affect prices are unknown. However, some more illustrative examples are provided to demonstrate the methodology: PV pumping system vs. diesel motor-pump and PV refrigerator vs. kerosene refrigerator. General assumptions for all the examples discussed below are that the discount rate is 10%, the excess inflation rate for all systems is zero, as it has been assumed that all the various costs will change at the same rate, and that the salvage value is zero.

8.1.7. PV pumping system vs. diesel pumping

Figure 8-4 represents a life-cycle cost analysis over a 20 year period for a PV and diesel pumping systems for a village water supply, where water must be drawn from a borehole of depth 20 metres. The comparison is between a 2.5kW diesel pump set and a PV submersible borehole pump. The analysis considers only the pumping systems; borehole, storage tank and pipe work costs are not included as they are similar for the two systems.

The usual way to compare the economics of water pumping systems is in terms of 'unit water cost', expressed in $/m 3 of water delivered at a particular depth of borehole, and the life-cycle costing example has been presented with these units. It should be noted that this example is specific to site conditions and pumping head, and cannot be generally applied.

From the analysis, it can be seen that the relative economics of PV and diesel powered water pumping is highly dependent on the quantity of water required per day. The comparative costs of PV pumps can be less than diesel, particularly for low water demand. The relative costs depend largely on the price of diesel fuel, the solar insolation and the capital cost of PV in $/Wp.

8.1.7.1. PV pumping for irrigation

Although PV pumping for irrigation can be more cost-effective than diesel pumping, such cases are highly site-specific. For example the economic problems of PV-powered irrigation pumping were studied in Pakistan (World Bank, UNDP, report 103/89). The majority of off- grid irrigation pump-sets there are diesel-powered, the smallest in common use being 5 kW and priced under $1000. (Equivalent PV pumps cost $4000 or more). The diesel pump-sets are often oversized and poorly maintained such that efficiencies are only between 3 and 5% (compared to 10% for an overhauled andwell maintained pump-set).

Despite the poor performance of the diesel units, the World Bank study concluded that with PV module prices at $3/Wp (which has not yet been reached), and based on life cycle costing, PV pumps would only be cost-effective against diesel units on small farms with a daily water demand (volume-head product) less than 120m4. This corresponds to farms of less than 1.1 hectares and solar pumps with array sizes of 400-600 Wp. Although there are more than 1 million farms of less than one hectare in Pakistan, the market is unlikely to materialise in the short term because small farmers lack capital and can rent diesel pumps or buy water from neighbouring farms at marginal cost. In effect the solar pumps have to compete with larger well utilised diesel pumps.

110 Assumption Units

General Borehole depth 20 m Pump operator cost 0.25 $/hour Installation cost as a fraction of capital cost 0.1 Fuel energy content 11 kWh/litre

Diesel pump Motor pump power 2.50 kW System cost 1000 $ Replacement (pump set) 1000 $ Pump set lifetime 10 years Pump efficiency 0.5 Motor-pump overall efficiency 0.06 Maintenance (spares) 200 $/year Operator checking time vs. pumping time 0.5

PV pump Solar insolation 6.00 kWh/m 2/day System unit price 13.00 $/Wp Replacement pump set 700 $ Replacement power control 300 $ Lifetime of pump set and power control 10 years Motor/pump efficiency 0.35 Operator checking time vs. pumping time 0.10 Maintenance (spares) (fraction of installed cost/year) 0.01

8.1.8. PV refrigerator vs. kerosene refrigerator

Figure 8-5 is a life-cycle costing, over a period of 15 years, comparing kerosene and PV refrigerators for a health centre requiring 6000 vaccine doses per year. The ALCC is expressed in $ / potent vaccines doses available which depends on the reliability / availability factor of the refrigeration unit.

PV refrigerators can be more economic to operate than kerosene when examined on the basis of cost per potent vaccine dose. This is because of their greater reliability and lack of fuel supply problems. High reliability of vaccine refrigerators even at a higher cost is crucial because the use of ineffective vaccines leads to mistrust of the population in the worth of immunisation programmes.

111 Figure 8-4: PV pumping system vs diesel pumping

NOT AVAILABLE ELECTRONICALLY

Figure 8-5: PV refrigerator vs kerosene refrigerator

NOT AVAILABLE ELECTRONICALLY

112 Assumption Units

Kerosene Total initial investment 1300 $ refrigerator Replacement burner and misc. 200 $ Burner and misc. lifetime 7 years Fuel consumption 1 litre/day Maintenance (spares) 100 $/year

PV refrigerator Solar insolation >5 kWh/m 2/day Total initial investment 4000 $ Replacement batteries 600 $ Lifetime of batteries 5 years Replacement regulator 100 $ Lifetime of regulator 7 years Annual costs (misc.) 50 $

8.1.9. Critical factors affecting PV system economics

The cost-effectiveness of PV systems when compared with conventional systems depends upon a variety of parameters as illustrated through the above examples. The aim of this section has been to identify the economic factors related to PV systems. It is beyond the scope of this report to look in detail at the factors affecting the economics of alternative energy supply systems, although this would be a necessary part of the decision-making process when considering the viability of a PV programme.

However, it is possible to summarise some of the critical factors which affect PV system economics: the energy costs of PV systems are most sensitive to changes in energy conversion efficiency, capital cost, and lifetime.

8.1.9.1. Energy conversion efficiency

Future improvements in cell efficiency will have a significant impact on the cost of energy from the PV technology. To a first order approximation, increased efficiency results in a proportional reduction in energy costs. Improvements to the efficiency of load equipment also results directly in improved energy costs.

8.1.9.2. Capitalcost

Reduction in capital costs result in approximately proportional improvement in energy costs. This relationship will remain true until operation and maintenance costs become a significant contributor to the cost of electricity from PV systems. Reduction in capital costs will also make financing of PV systems easier.

113 For the majority of stand alone PV applications, electricity has to be stored in batteries to cover periods of low insolation. The high price and poor reliability of batteries are a continuing problem in the effort to reduce the capital (and running) costs of PV systems.

8.1.9.3. System lifetime

Module life for single-crystal silicon technology is a less critical variable because the technology is approaching the goal of a 30-year lifetime. Module lifetime and reliability are much more critical development issues of amorphous silicon modules and other PV technologies and systems. For many stand-alone systems the battery life is the most significant factor affecting system recurrent costs.

8.1.9.4. Other Factors

PV systems can be costly to install and maintain if they are spread over a large area. Studies have shown that limited implementation of photovoltaics for a single purpose (e.g. a vaccine refrigerator in health centre) results in high installation and repair costs and also infrastructure and overhead costs. Conversely, integration of a number of applications in one location (e.g. PV refrigerators, lighting kits for health centre, staff housing, schools within one location) and many locations in one region can reduce installation and maintenance costs. Furthermore it can act as an incentive to local entrepreneurs to develop the installation and maintenance skills and help to share and reduce costs.

8.1.10. Financing options

In more than twenty developing countries, numerous private or development projects have been implemented to introduce PV systems. There have been minor technical problems, but the major problem is often the same: the high capital costs, and the fact that most people for whom these schemes are designed have no capital.

Although PV systems can be more economical on a life-cycle cost basis than traditional systems, their capital costs remain high. This will hinder their diffusion among the majority of rural people unless some financing mechanisms can be provided to spread the costs over time.

It has been found that a market for the cash purchase of PV systems for domestic use can be successfully stimulated in towns and villages where working PV demonstration systems are well established. The purchasers in these cases tend to be those with higher disposable incomes, such as business people, urban weekend commuters and some government employees.

However, the next tier of people, with income from subsistence earnings and local trade have insufficient cash to make the relatively expensive purchase of a PV system, by which they could increase their standard of living.

Ideally, financial assistance, for example for a modern lighting system, should allow people to pay for the system without exceeding their present weekly or monthly expenditures on lighting (i.e. monthly fuel costs). The rationale is that people already spend money on a weekly or monthly basis to maintain their lighting systems (from $15 up to $200 per household per year according to income level). Most traditional lighting stems however are

114 cheap to buy but comparatively expensive to run, as has been demonstrated in previous sections. Hence, financing mechanisms are needed to convert the capital costs of PV systems into weekly or monthly household expenditures which are seen to be lower than the existing costs for a household, farm or business.

Rural people commonly have limited access to formal credit for various reasons: lack of collateral requirements, high borrower transaction costs, limited education (low level of literacy and numeracy), social and cultural barriers (women may be excluded from local organisations that could provide credit). Investments in PV systems are also seen as high risk and low profit by the banks. However, well-designed and well-implemented saving and credit schemes can be effective to allow rural people to have access to PV technologies, which in turn can help to alleviate their poverty.

The following sections briefly describe various financing schemes. These are not blueprints but can be adapted according to a country's specific technical, economic and social context. Examples are also provided to give ideas for achieving the introduction of modern lighting systems.

8.1.10.1. Co-operative or commercial bank loan schemes

Co-operatives and/or commercial banks may provide individual loans on, say, a PV lighting system for a period ranging from two to five years with or without an advance payment. The maximum duration of the loan usually does not exceed the lifetime of the major system components likely to fail within this period (e.g. three to five years for batteries in a PV lighting system). Ideally for the client, the monthly loan payments should be in the range of the previous monthly lighting expenditure. The interest rate should be as low as possible, if possible subsidised by a development bank. Such schemes are currently in use in Sri-Lanka, Zimbabwe (under financing from the current Global Environment Facility project) and Rwanda. In Sri Lanka there is a 19% annual interest bank scheme which finances up to 80% of the system purchase price, payable over a period of not more than 60 months. A guarantor and/or collateral are required for participation in this programme. The Rwandese project is outlined below.

8.1.10.2. Example: Financing PV lighting systems in Rwanda

In Rwanda, as in many developing countries, 95% of the population lives in rural, non- electrified areas. The government has launched a costly rural electrification programme, but the cost of grid extension is very high: the equivalent of US$3350 for a transformer, US$5600 per kilometre of line, etc. Each individual connection to the grid costs US$400 to the user plus $80 for each lamp installed.

In comparison, PV systems offer a lower cost option. The initial capital and installation costs of a solar lighting kit comprising four 8W lamps is US$560 and there is no bill at the end of each month. Although this may seem promising, it is of course, quite impossible for a Rwandese peasant to find a single payment as large as US$560. Therefore the "Union of Popular Banks" has agreed to provide interested people with appropriate loans in order to cover the expense provided that:

□ there are at least five interested people in the village;

115 □ each person puts up 20% of the cost, i.e. US$110.

When these conditions are met, the bank pays the total cost of the system to the supplying company, who then proceed with the installation. The reimbursement of the loans is spread over 12 to 37 months with instalments ranging from US$14 to $40 per month. As a result, 1450 lighting kits were sold and installed in 1991.

A variation of this financing scheme is an individual loan only for the components of a lighting system that maintain a high resale value, (e.g. photovoltaic modules for a PV lighting system). These components can serve as a form of collateral as they can be repossessed by the lending organisation if payments default. One advantage of this system is to avoid financing a loan on components having a shorter lifetime than the loan (e.g. batteries for PV or Wind-powered lighting systems). As the total loan is smaller, the duration of the loan can be extended (e.g. up to ten years for PV modules) and therefore the monthly payments will be lower and become eventually more affordable and attractive for more people.

8.1.10.3. Renting schemes

Renting Schemes have the advantages of off-setting all capital costs and avoiding the burden of a financial contract (i.e. repayment of a loan). To implement this scheme, the initial capital must be made available, for example by an aid organisation, to purchase all the systems. The main draw-back of this scheme is the lack of ownership of the systems by the users which may eventually lead to premature failures due to mis-use or even theft. Such schemes have been implemented in various west-African countries, for example Senegal. From 1991 in Senegal, 36 systems, comprising a PV recharging station with 5 PV portable lamps each, were being rented. The project was managed at the central level by the Centre d'Etudes et de Recherche sur les Energies Renouvelables de Dakkar, and at the local level by existing local organisations. Between 10 and 15 lamps were rented by villages at a cost of US$0.38 for each recharge. Despite some technical problems due to the poor design of the lamps, the lamps were continually rented 80% of the time (i.e. 24 days per month), (see Further Reading, Les Lampes Portables).

8.1.10.4. Leasing schemes

Leasing schemes allow the users initially to rent and at a later date to buy the lighting systems. In this case, the sense of ownership is much greater, leading to extended lifetime of the system and lower overall cost. Such schemes have been implemented in the Philippines and in Indonesia for the introduction of modern lighting systems in remote areas.

8.1.10.5. Partial or total subsidies

Partial or total subsidy schemes can be applied to reduce or fully off-set the capital costs of any energy efficient lighting system. Total subsidy may also be applied only on the electricity generator (e.g. PV module), so the user pays for the lights, batteries, regulator and cables. Such schemes have been successfully implemented in Martinique, Guadeloupe and French Guyana for example.

116 8.1.10.6. Revolving funds

Revolving credit funds allow individuals to borrow cash and pay it back over time, usually on better terms than are available at commercial banking institutions. Revolving funds are usually used for value-added projects such as land reclamation and improvement, livestock acquisition and more recently PV systems.

With this scheme, some pioneering users pay a monthly amount that is free (or almost free) of interest for a period of time until he or she eventually owns, say, a PV lighting system. The regular payments are collected in a fund used to buy other solar lighting systems to be installed in the community or elsewhere at a later date. For this system to start, it needs a donation of money or equipment by, for example, an aid agency or a private company to install the first systems. The monthly payments usually reflect the monthly expenditure on lighting for conventional lighting systems (e.g. kerosene, candles, battery recharging). Thousands of solar lighting systems have been installed using revolving funds in the Dominican Republic (1500 systems) and in Indonesia, as described below.

8.1.10.7. Example: Revolving fund for PV lighting systems in Lebak, Indonesia

Before this project, villagers of Lebak in Indonesia were mainly using kerosene lamps for lighting, and batteries for radios and TV. The villagers were paying between $0.20 to $0.40 for one litre of kerosene and the expenditure each month was approximately $5.4 to $12.0. This amount is now being used for the loan payments of solar lighting systems.

These systems were sold to the inhabitants by the local co-operative by means of interest-free loans. Over ten years, the villagers are paying approximately $4 per month, after which the system is theirs. A small amount is being reserved for maintenance and repair costs. Through this system a financial fund has accumulated which is being used to finance other systems in the village, or elsewhere, on the same basis. 500 houses have been equipped since 1991.

117 9. TECHNICAL REGULATIONS AND STANDARDS

9.1. Introduction

PV power systems will be an important source of energy in the future, particularly for many of the estimated 2 billion people - most of whom live in the developing world - who currently have no access to electricity. As with any other potentially hazardous item of equipment, an awareness of standards and recommendations for the installation and connection of PV systems is vital in order to ensure that new PV systems are set up correctly and safely. This not only helps to ensure that PV system installers, operators and users are not endangered and that equipment is not damaged due to faulty or incorrect installation, but for developers it is essential that they are able to refer to best practice guidlines so that they may take all necessary precautions to avoid dangerous and/or costly problems at a later date.

Due to the very wide application range of PV technology, the technical regulations potentially applicable to PV technology embrace a large variety of subjects in addition to the specific regulations applicable to each envisaged application. Additionally, there are various “site-specific” regulations (regional, national, or local) that continue to be developed as experience with PV systems increases.

Generally speaking the following regulations may be expected to be somehow correlated and applicable to PV technology:

□ specific PV technology standards;

□ general safety and specifically electrical safety;

□ technical quality standards;

□ building standards;

As with any conventional technology, it is growing market demand which usually generates the need for norms, reference standards and regulations allowing the evaluation of the technical quality and performance of a device.

As regards PV technology, related developments of standards and regulations have concentrated, until today, on the following issues: a) Module Qualification Testing b) PV System Monitoring.

There are, however, still other subjects requiring the development of reference standards and regulations, such as:

□ PV system design quality, configuration selection and sizing appropriate for application;

□ PV BOS (= Balance Of System) component quality standards

118 There are several organisations involved in the development of international standards applicable to PV installations. These organisations and the major recommendations that have emerged from them to date in respect of PV installations are covered in the following sections.

9.2. IEC - International Electrotechnical Commission

IEC as the ultimate international body responsible for norms and standards concerning electrical components and systems, in its meeting in Tokyo 1992, decided to create a special Technical Committee denominated TC82, to deal with all aspects of Photovoltaics. As a result, TC82 immediately set up the following three Working Groups:

□ WG1 for PV technology,

□ WG2 for PV cells and modules,

□ WG3 for PV systems.

The Working Groups produce draft standards, which are circulated by the TC82 Secretariat to National Standard Committees for comment. On the basis of these comments, TC82 (which meets every 18 months) either approves the draft for final voting by the National Committees or returns it to the WG for further elaboration.

If the final voting (for which there is a 6 month period) is favourable, the draft is released for publication. Due to this lengthy procedure, it is often necessary that a draft is used as a de- facto standard in the mean time.

At present such TC82 draft releases address specifically two fields within PV technology: a) Module Qualification Testing b) PV System Monitoring.

9.3. European Community - ESTI- JRC Ispra

In 1978, well before TC82 was created by the IEC, module testing activities began at the ESTI (European Solar Test Installation) at the JRC (Joint Research Centre) Ispra.

At first, procedures developed by the Jet Propulsion Laboratory (JPL) in Pasadena (USA) for space applications were adopted. However ESTI very soon identified the need for qualification standards appropriate for terrestrial applications. Since then ESTI has made a substantial contribution to PV standardisation, specifically PV module qualification testing and PV system monitoring as described below.

9.4. PV module qualification testing

Several important official documents and draft standards have been developed for the purpose of PV module qualification testing. These include (in order of publication):

□ "Jet Propulsion Laboratory, Block V"-USA.

119 □ "Norme frangaise NFC 57-101,102,103, relative aux modules photovoltaiques au silicium cristallin pour applications terrestres" (1982).

□ "Qualification test procedures for crystalline silicon photovoltaic modules", specification n° 503 CEC-JRC- Ispra.

□ "IEC 1215", The International Electrotechnical Commission, Technical Committee 82, Working Group 2: joint efforts from USA, Canada, France, Germany and Japan have allowed to issue this document, very similar to spec. 503 CEC-JRC.

□ "Interim qualification tests and procedures for terrestrial Photovoltaic thin film flat- plate modules" NREL, USA.

Apart from the last of these reference standards, all refer specifically to crystalline silicon photovoltaic modules. The NREL standard refers for the first time to thin film flat-plate PV modules. As mentioned above, in the early eighties, ESTI - JRC Ispra identified the need for a PV module qualification standard appropriate for terrestrial uses and started therefore to develop a procedure and a related document (Specification 501) for the testing of crystalline- Si flat-plate modules. Spec. 501 was then accepted by the CEC as the official test procedure for modules to be used in EC financed projects. All module qualification work up to 1984 (in particular, for the first PV Pilot Programme of DG XII) was performed using Spec. 50l.

In 1984 IEC/TC82/WG2 took over the work for the drafting of an international standard on module testing, and this resulted in some modifications of the original ESTI Spec. 501, which was substituted by Spec. 502 and finally (in 1989) by Spec. 503. This latest version became at the same time the IEC/TC82 draft, which was officially accepted in 1993 as IEC Standard 1215 for the qualification testing of flat-plate crystalline Si-Modules.

Other new drafts are expected to be introduced as a result of the development of new module technologies, such as concentrator devices, new thin film materials, etc. ESTI has already proposed its Spec. 701 for the qualification testing of thin-film modules (a-Si) to be circulated as IEC draft. However, it has to be emphasised here that amorphous silicon modules have caused serious problems to standardisation Committees, due to their tendency to degrade under natural sunlight conditions. Special groups of researchers are therefore presently investigating the subject throughout the world, to stimulate experiments and to co-ordinate interpretations, such as SMART in the US, SESAME in Germany, and EMMA in France.

9.5. PV system monitoring

The importance of PV system monitoring was already recognised during the first EC PV Pilot Programme. The main objectives of this first programme were:

□ to demonstrate that PV systems are a reliable energy source,

□ to identify weak system components,

□ to improve system design methods (optimising a PV plant for given site and application),

120 □ to identify operational procedures (such as battery and load management) that optimise the efficiency of an existing installation, and

□ to establish evaluation methods for comparing PV systems with other energy sources in economic terms.

To facilitate the implementation of PV monitoring and to produce sets of comparable data, ESTI founded (under EC financing) the European Working Group for PV Plant Monitoring, consisting of a group of selected PV experts.

This group has developed (and updated) a set of Guidelines for the Assessment of Photovoltaic Plant performance consisting of two documents:

□ Document A: Photovoltaic System Monitoring, which specifies the technical requirements to be followed for: • the type of data recording to be implemented on site (analytical or global), • the set of parameters and measurement procedures, and • the modalities for data transfer to the collecting centre (medium and format);

□ Document B: Analysis and Presentation of Monitoring Data, which gives recommendations for the analysis and evaluation of recorded data, defining 'Figures of Merit' and specifying a standard format for periodic summary reports.

In 1990 Working Group WG3 on PV-systems of IEC/TC82 circulated a draft on PV Monitoring guidelines. This has been revised several times since then. However, as this draft has not yet been accepted as a definite standard, the European Working Group for PV Plant Monitoring has updated its Guidelines by including the generally accepted parts of the IEC- draft.

Thus until the final version of the IEC document becomes available, Documents A and B of the European Guidelines continue to be used as a de-facto standard within the EU, as well as by many research groups outside the European Union.

9.6. Missing Standards for PV systems, typical application designs and BOS components

Unfortunately, since Photovoltaics is still a relatively young technology branch, and most commonly used conventional (non-PV) norms and standards have been developed prior to the development of this new technology, they usually do not take into account the specific requirements of PV applications and particularly those addressing appropriate system design, configuration and BOS (Balance of System) components.

The result is that, since reference standards are missing, in many cases, it is difficult for non- PV-experts to evaluate the technical appropriateness of solutions being proposed for a PV application.

Specifically, the evaluation of alternative bids offered by different competing suppliers requires the evaluator to examine also, whether the technical quality of the offered system configuration, and specifically of BOS components, satisfies the envisaged needs.

121 In fact, in the large majority of cases, poor performance of PV systems is not caused by PV module failure, but rather by cheaper (and, correspondingly, lower quality) BOS components. Once installed, such lower quality BOS components become, during operation, the weakest link of the chain, but their failure leads people to believe that PV technology is not yet mature.

Since non-expert purchasers are frequently unaware of the implications of selecting low quality BOS components, they do not define sufficiently severe requirement specification for these, tending instead to focus only on the PV modules.

The result is that, during tender stages, in an attempt to undercut their competitors, suppliers tend to offer BOS components of the cheapest and lowest possible quality, barely sufficient to satisfy the purchasers' requirements.

Once the relatively short guarantee period for the BOS components has expired (typically 1 year or even less, whereas PV modules are usually guaranteed for several years), if there is a BOS component failure the purchaser is frequently left without assistance with a disabled PV system, even though the high cost PV modules may still be operating perfectly.

Norms and reference standards addressing this specific problem area of PV technology are presently still missing.

9.7. Electrical safety standards applicable to PV technology

Electrical safety standards govern the erection of electric installations in buildings with respect to electric safety. Most related national standards comply and are harmonised with the international standard IEC 364, the most important issues of which are the following:

□ protection against electric shock;

□ protection of equipment and immediate surroundings from fire hazard due to overload and short-circuit conditions;

□ protection from overvoltage;

□ requirements for equipment and components;

Electrical safety standards generally distinguish between installations accessible to laymen, and electrical facilities accessible only to technically qualified personnel. For the latter (e.g. utility owned plants) less stringent requirements apply. However, since PV technology is intended to reach widespread and diffused application in locations accessible to the public, more stringent requirements are necessarily to be applied.

9.7.1. Protection of human beings against electric shock

There are various standards designed to ensure general safety under normal operation and to ensure personnel safety in case of faulty equipment or installation. Safe operation under normal conditions requires protection from direct contact, as well as (in case of an insulation failure) protection against indirect contact. Details may be found in IEC 364-4-41 or the German VDE 0100 Section 410. According to these standards, any electrical equipment and

122 appliance must be marked with a label stating clearly the protection class of the device and, accordingly, which protective measures are to be applied. The protection classes of interest to PV technology are the following:

□ Extra-low voltages (SELV/PELV - protection class III)

Defines the voltage limits within which it is possible to touch a life circuit part without risk to human life (50 Vac or 120 Vdc maximum voltage level). Accordingly, for equipment and electrical systems operating within such voltage limits, no protection means are required to protect human life against shock hazard.

□ Protective insulation (protection class II)

Under this class, electric safety relies on a double or reinforced insulation. Generally electric equipment and components classified under safety class II have to withstand a high test voltage (approximately 4000 V for equipment rated for 230 V design voltage) and their mechanical ruggedness must be appropriate for the intended use. Most household appliances having a plastic casing or enclosure fall under this category (hairdryer, razor, power drill, etc.).

□ Automatic disconnection or warning (protection class I)

Equipment classified hereunder relies for safety on a grounded, metallic enclosure which, even in case of an insulation failure, ensures voltage levels near to ground potential. Additionally, the resulting short-circuit current trips a fuse or other protective switching device. All equipment for this protection class needs a metallic enclosure and a terminal to connect the PE (grounding) conductor. Larger household appliances with a metal housing (e.g. washing machines) fall under this category.

9.7.2. Protection against overload and short-circuit conditions

To prevent fires caused by overloads or short-circuits, appropriate protective measures are defined by IEC 364-4-43 and IEC 374-4-473 (German VDE 0100 Section 430). They essentially require suitable fuse or circuit breakers to be installed on each circuit to be protected. In some applications, disruption of current under normal operation is not desirable or feasible, e.g. excitation circuits of electric motors, current transformers, connections from batteries to control boards. In such cases the installation has to virtually eliminate the possibility of an overload or short-circuit condition. Standards explicitly define permitted wiring concepts called ground-fault-proof and short-circuit-proof wiring by means of:

□ Rigid conductors, where mutual contact and contact to grounded conductive parts is excluded e.g. by sufficient distances or by mechanical fixtures.

□ Single-conductor cables, where a mutual contact and contact to grounded conductive parts is excluded e.g.:

□ Single-conductor cables built for higher insulation capabilities (e.g. H07RN-F).

□ Accessible cables placed apart from combustible materials, where the hazard of mechanical damage is excluded by appropriate measures (e.g. installation in locked electric facilities).

123 □ Cables and wires which may burn without presenting a hazard to their surroundings are considered to be equivalent to ground-fault-and short-circuit-proof installation (e.g. underground cables).

9.7.3. Lightning and overvoltage protection

General requirements for lightning protection are also usually defined by standards, intended to limit damage to electric installations due to lightning strikes by reducing surge voltage across the cable insulation. This is achieved by a through potential equalisation bar, to which all active parts are electrically connected

9.8. Conflict areas between electrical safety standards and PV technology

9.8.1. Peculiarities of PV technology

The main peculiarities and differences between a PV generator and common practices resulting from the power supply characteristics of the public utility grid (mains) are as follows:

□ A PV generator acts like a current source, while the public grid mains provides a voltage source. As a result, a PV generator is intrinsically short-circuit-proof and cannot overload its connection wires. Furthermore, since its nominal short-circuit current (Isc) is only 1.2 time higher than its nominal operating current (Impp), it cannot trip common overcurrent protection devices like fuses or circuit breakers.

□ During daylight conditions, a PV generator cannot be switched off. If a PV generator is disconnected from its load (apparently switched off), full open circuit voltage will be present during daylight. For this same reason, leakage currents due to insulation failure are very difficult to disrupt.

□ A PV generator is a DC source. There is no zero crossing of current (like in AC- systems), which supports all interrupting actions and helps to extinguish electric arcs. In combination with the aforementioned current source characteristics PV systems present a specific risk of stable arc development (which usually causes fire), if an insulation fault develops.

□ According to interpretations adopted in some countries PV modules do not comply with the double or reinforced insulation requirements of protection class II since the front glass layer is considered a single, not reinforced, insulation means.

Accordingly, the latest standard developments in Germany, and specifically VDE 0100 Part 7xx, address these issues as follows:

9.8.2. Protective measures for Personal safety

□ In case of very small PV systems (below 1 kWp) protection by low voltages (protection class III), i.e. maximum voltage limit of 50 Vdc and 120Vac is preferably to be applied to the generator’s Voc at standard reporting conditions (SRC).

124 □ Protection by automatic disconnection (e.g. in case of an insulation fault) is difficult to achieve since, as mentioned above, a PV generator cannot be switched off during daylight.

□ In all cases where SELV and PELV low voltages according to class III are not achievable as the resulting current ratings are too high (i.e. PV generators of more than 1-2kWp power rating), protection class II appears to be most reasonable and convenient for categorising PV systems and components. PV module manufacturers are therefore discussing with standardisation authorities how to develop PV modules in compliance with protection class II, and how to interpret the relevant requirements.

□ The combination of ground-fault and short-circuit-proof wiring allows the virtual exclusion of ground faults and shorts in the PV generator, thereby permitting simplifications in overload and short-circuit protections.

□ Protection against indirect contact may be considered unnecessary (regardless of operating voltage) if a PV generator is placed out of reach. In Germany, this criterion is interpreted as applicable to rooftop installations where “out of reach” is considered fulfilled for systems installed at least 2.50 m above the plane of access. People who have access to the roof must however be cautioned by warning signs.

□ In Germany, if the above requirement (Out of reach) is fulfilled, PV modules having only basic insulation (not corresponding to protection class II) may be used for PV generators rated above 120 Voc. However, since some older PV module types presented non-negligible risks of ground faults during normal service, at present this concept is not recommended without further safety devices - specifically continuous isolation monitoring.

□ In comparison to conventional electric installations, a PV generator presents special hazards for maintenance workers, since it cannot be switched off. Therefore, if the nominal open-circuit voltage of the system is above 120 Vdc, during cabling as well as during maintenance, measures must necessarily be taken to reduce this risk as follows: • Working at night • Effective covering of the PV generator (complete and reliable darkening of PV cells must be achieved) to reduce significantly the open-circuit voltage; • Splitting strings into sections of individual Voc below 120 Vdc. This is achievable by providing disconnectable terminal blocks at the envisaged string intervals.

Protection class II defines certain insulation test voltage levels depending on maximum permissible system voltages according to the formula presented below. Both these parameters must therefore be clearly stated on module labels.

Vtest = 4 * Voc, max + 2000 V

Another important requirement for protection class II modules is a sufficient mechanical ruggedness. While glass-glass-modules are usually considered to be in compliance with this

125 requirement, PV modules with Tedlar backsheet are more prone to incidental damage. To assess their susceptibility to cutting, the cut test specified in the US standard UL 1703 i is adopted as a protection class II test specification.

Class II equipment must not have a PE (grounding) connection. Nevertheless, a protection class II module may have a metallic frame, if it is considered not to be a part of the active module, but simply an external mounting facility. In such cases the protection class II requirement of having no ground connection is not infringed. The issue of class II requirements for PV modules have therefore been brought to the concern of the IEC Committee TC 82.

9.8.3. Overcurrent and short-circuit protection

Conventional overcurrent protection measures (fuses or circuit breakers) do not work in PV systems, since the PV generator is inherently current-limiting. Accordingly, if correct sizing of all source conductors is assumed, it is not possible to overload a wire under normal operating conditions. Proper sizing means: string cables must be rated for the module Isc (at RSC), and the main PV generator connection to the inverter must be rated for the Isc of the entire PV generator.

Only in the case of an insulation fault in a string cable, which shorts the current generated by more than one string of the same PV generator, will the involved string cable be overloaded. Ground-fault-proof and short-circuit-proof wiring, together with a string fuse allow guard the system from this kind of risk. Accordingly, ground-fault and/or short-circuit proof wiring according to VDE 0100 Section 520 are to be employed, which means that “+” and “- ” wires are to be kept separate, either by an appropriate spatial arrangement or by mechanical barriers along cableways as well as inside junction boxes and electrical cabinets.

String blocking diodes are commonly used in battery buffered stand-alone PV systems, since they avoid reverse current flows from the battery through the PV generator during the night, and thereby prevent the battery from undesired discharge. In the case of grid connected PV systems without battery, there are doubts regarding the need For string blocking diodes. If ground-fault and short-circuit-proof installation wiring are applied, under normal operating conditions the blocking diodes are useless. Only in the case of a multiple ground-fault will a blocking diode prevent reverse current flow into this partially shorted string. As a consequence the draft code permits the omission of string diodes under certain defined conditions.

9.8.4. Overvoltage protection

According to German regulations, a PV generator installed on the roof of a building does not increase the risk of that building suffering a lightning strike. The additional installation of an external lightning protection system is therefore considered unnecessary. However, as for any other metallic structure, the mounting structures of a PV generator on a roof must be included into the potential equalisation (grounding) system of the building.

Although a direct lightning strike is very unlikely for most PV installations (this is therefore not a stringent requirement), a protection against induced overvoltages should be foreseen by installing Varistors towards ground in every leg of the PV generator

126 It should be noted, however, that Varistors may change their characteristics under overload conditions. In the long-term, this may result in a permanent loss of current through the Varistor, which again may lead to overheating and fire. This hazard should be accounted for by regularly monitoring the leakage current or by adopting Varistors with an internal overheating protection.

127 10. CONCLUSIONS AND RECOMMENDATIONS

Millions of PV systems are currently in use around the world, yet this number is insignificant compared to the overall potential. It is expected that rural electrification, health care and water pumping projects will increasingly use PV systems as an economic and effective means of supplying electricity to those rural areas which will never be connected to the grid.

In the last 15 years, sunlight-to-electricity conversion efficiencies of PV modules have been increasing steadily, while costs have fallen dramatically. Improvements in the manufacturing technology and production volumes have resulted in a 1994 international price of US$4.5 - 5.5 per peak Watt. Module shipments reached almost 70 MWp in 1994 and the world growth rate is expected to be sustained at 10-15% in the coming years.

10.1. Experiences

Although PV electrification activities are ongoing in a large number of developing countries, detailed information about them is inadequately researched because of the diversity of organisations involved and the thousands of isolated locations. There is a clear need for research which will update current knowledge on system experiences in developing countries.

Efforts to address this need have begun through Task III of the International Energy Agency’s PV Power Systems Programme. A survey of system experiences has been undertaken in ten Member Countries. The findings and recommendations resulting from this survey offer important insights for PV manufacturers, installers etc. who can attempt to address the barriers and problems identified within the “domestic” markets and ensure that they are not replicated elsewhere. A follow-up survey has been devised and distributed to developing countries in order to identify region-specific problems and provide a more complete picture of the actions to be taken in such areas.

Despite the fact that multilateral and bilateral aid projects still duplicate each other's efforts and mistakes, it does appear that progress is being made in world-wide programmes as the number of PV installations increases and as local people take over marketing, installation and service.

10.2. Applications

In developing countries, the market for PV systems is derived either from country aid programmes or from private initiatives. Usually the types of system installed reflect the immediate needs of the population: lighting, drinking water and medical vaccines.

However in principle there are few limitations on the equipment that can be powered by PV because the output can normally be adjusted to meet any kind of requirement.

In health facilities, PV systems can supply energy for lighting, vaccine storage, blood and drug refrigeration, sterilisation, radio and telecommunications. In larger hospitals, it can also supply energy for radiology, laboratory equipment, water pumping, water treatment and passive ventilation.

128 Solar pumps can reliably pump water from boreholes, open wells, rivers and canals to provide safe water. They can be combined with water treatment systems according to the quality of the water required.

PV systems for household use already contribute significantly to the energy requirements and improved quality of life of a growing number of people in rural areas by providing energy for lighting, refrigeration and battery charging.

PV systems also provide power for many of the processes of agricultural production; for example, water pumping for livestock watering, irrigation schemes and fish-farms, and power for food processing activities such as crop drying or milling.

In schools and other educational institutions, PV systems are being used to power lighting, overhead fans, radio and television, and items of science equipment.

In the industrial sector in developing countries, PV systems are used for remote telecommunications equipment, data acquisition systems, and navigational aids.

10.3. Environmental impact

Silicon-based photovoltaic modules are environmentally benign. The most significant environmental problem associated with PV systems is that they are likely to increase the overall use of batteries in the developing world. Battery materials, in particular heavy metals such as lead and cadmium, pose potential environmental and safety hazards and all types of batteries need to be disposed of safely, preferably by recycling.

For most developing country environments the energy ratio of PV modules (lifetime energy produced vs. energy for manufacture) is typically in the region of 10 to 25 according to the type of PV cells, and this will continue to rise as efficiencies improve.

10.4. Installation, operation and maintenance

Remote stand-alone PV systems are most successful and reliable when designed and sized to perform a certain small and well-defined task, such as provide lighting for 6 hours per day, or pump a certain amount of water per week.

The installation of a PV system does not normally involve any major technical problems but does require trained people (technicians with a basic training in electricity), adequate tools and logistic support. Similarly, the operation of a PV system is basically straightforward but to ensure reliable running, users need to be taught clearly how to carry out the minimal but essential maintenance.

10.5. Critical factors

PV programmes have been most successful when equal consideration has been given to the technical, social, economical and institutional factors affecting the implementation of the technology.

129 In particular PV should be viewed as a technology with the potential to achieve a number of different objectives, including improving quality of life, generating income, maintaining environmental quality, improving health care, improving regional development and local self-reliance, and alleviating poverty.

To ensure the long-term success of a PV project, it is important to:

□ investigate the needs, preferences, and abilities of the local people who will use, maintain, guard and take pride in the system - the system must be wanted and at least partially owned by the user or community

□ have an affordable capital cost, or capital costs offset by financing mechanisms and with a recurrent cost affordable by the user or community

□ assess in advance the indirect social effects, positive and negative, of implanting new PV technology within a community or institution,

□ organise appropriate local management of the PV system(s)

□ obtain accurate solar irradiation data in advance of sizing the system

□ specify and select PV systems of adequate quality, preferably approved systems, with modules offering a long warranty

□ ensure systems are installed correctly

□ set up an adequate after-sales service

□ provide educational programmes for those who will use, maintain and benefit from the technology

10.6. Economics

The economics of PV systems are different to those of other small power systems, in that:

□ the capital cost of the equipment is high

□ there are no fuel costs

□ maintenance costs are low

□ reliability is high - so replacement costs are low

□ the output of the system depends on its location (i.e. the solar resource available)

Cost-effectiveness analysis, which determines the least cost method of achieving a particular objective, can be used to compare the life-cycle costs of PV systems either with other renewable energy technologies, or with conventional energy systems such as diesel generators, grid-extension, flame-based lighting systems, etc.

130 The energy costs of PV systems are most sensitive to changes in energy conversion efficiency, capital cost, and lifetime. Future improvements in cell efficiency will have a significant impact on the cost of energy from the PV technology. Reduction in capital costs will result in approximately proportional improvement in energy costs. However the high price and poor reliability of batteries are a continuing problem in the effort to reduce the capital (and running) costs of PV systems.

The unit cost of PV electricity is also sensitive to local conditions, in particular the correlation between demand and available sunlight. The decision on whether PV is the best option is also strongly affected by the nature of the load (constant or intermittent, and how important it is to have an uninterrupted supply) and the cost and performance of alternative power supply equipment.

The unit cost of electricity generated by modern PV systems can appear to be prohibitively high - typically US$ 1.0/kWh or more depending on local conditions and the precise calculation used to estimate capital cost. Nevertheless there are many situations in which PV has been found to make economic sense.

At 1995 prices, PV systems are generally economic for small loads where connection to a utility grid is impractical. On a life-cycle cost basis, PV is already a cost-competitive power supply for a number of low-power stand-alone applications, particularly where energy demand is under 3 kWh/day. These applications include lighting, vaccine refrigeration, village and livestock water supply, telecommunications and many others.

Figure 10-1 summarises the typical power ranges within which PV is the least-cost option for five major remote applications. The potential market for these applications is enormous; in the field of waterpumping alone two million diesel pumping systems are sold each year. For village electrification, the UN have estimated that two million villages within 20° of the equator have no access to grid electricity or fossil fuels.

For these smaller applications, economic viability is not the barrier to dissemination; it is the lack of appropriate financial mechanisms to introduce them into the market. As the costs of PV modules fall, the economic range of application will increase. However the overall market is sensitive to more than just price reductions in PV modules because the PV component represents only half of the cost of many systems.

131 Figure 10-1: Economic Ranges for Photovoltaic Systems

Multi-use system

Lighting & home power

Vaccine refrigeration

Communications

Water pumping

0.01 0.1 1 10 100 PV Array kWp

□ PV least cost□ Break-even□ PV not cost-effective

10.7. Institutional barriers

Many institutional barriers are still hindering the widespread impementation of PV systems.

Often these relate to:

□ the bureaucratic nature of funding and implementing institutions

□ lack of technical knowledge within the organisation

□ centralised rather than localised operations

□ a tendency to 'tie' aid

□ the generally short-term nature of many projects

PV-powered systems are still perceived by the majority of decision-makers as 'high risk' technologies and systems, not suitable for use in developing countries, and in most countries national and/or regional governments have not yet made PV an integral part of their energy strategies.

Problems have also arisen with incorrect costing of projects. Too often a project which includes PV equipment has omitted budget allocations for training of local maintenance engineers and end-users.

132 PV is also discriminated against in the market place. Subsidies to conventional energy generators, or alternatively tariffs on renewable energy system components, are critical financial barriers which can hinder the wider dissemination of PV applications. For unbiased decisions to be made by both end-users and institutions, the real costs of all types of energy generation must be available and comparable. All short and long term externalities of energy use should be included (e.g. environmental degradation, resource depletion, wealth creation). New methodologies need to be developed and initiated to facilitate this.

One of the main barriers to increased application of PV is financial, with the lack of adequate financing mechanisms to spread the high capital cost of a PV system over a number of years. Financial mechanisms which could assist in this process include revolving credit funds, local financial co-operatives, tax relief, special grants, and increased appropriate banking services. Subsidised credit is excluded from this list because after some adverse experiences it is now considered a better policy to combine normal levels of credit with grants, rather than subsidising interest rates.

10.8. Future needs

Some general needs have been identified to help achieve the overall aim of creating sustainable commercial markets for PV systems in developing countries and thereby bringing affordable electricity to many more thousands of people in remote rural areas.

In areas where there is no commercial market, the initial need is for more PV programmes to be implemented on a large scale and organised with appropriate financial and technical support.

In particular, new PV initiatives should:

□ encourage greater local production, and include the up-grading of local industries and training of technicians.

□ assist with the technology transfer of PV manufacturing technologies

□ provide assistance with setting up institutional and market infrastructures

□ implement financing schemes to remove the obstacle of high capital investment, thereby helping to stimulate a commercial market.

More broadly, there is a continuing need for international research to optimise the introduction, local production and market development of low-cost PV technologies which are affordable to a wider range of the population (for example there is a need for small portable PV lanterns with light output slightly greater than that of a kerosene lamp, as an addition to existing more powerful but more expensive PV lanterns). Research and development is also needed to further improve the performance and reliability of existing products.

New initiatives along these lines would contribute not only to the wider dissemination of PV systems in the short term, but more particularly to the development of a sustainable commercial market in the long term.

133 11. SOURCES OF FURTHER INFORMATION

Technical papers, books & product guides

Photovoltaics in 2010 - PV2010, EPIA report to DGXVII of the EC, 1995.

Flat-Plate Photovoltaic Modules and Panels, (UL 1703) Underwriters Laboratories Inc.

Solar Electricity. A PracticalGuide to Designing and Installing Small Photovoltaic Systems, Simon Roberts, Pergamon Press, 1992.

Solar Photovoltaic Products: A Guide for Development Workers, A.Derrick et al, IT Power Ltd, and SEI Stockholm, IT Publications, London, 1991.

The Power Guide, Edited by P L Fraenkel and W Hulscher, University of Twente/I T Publications, PO Box 217, 7500 AE Enschede, The Netherlands.

Rural lighting: a Guide for Development worker, J-P.Louineau, M.Dicko, P.L. Fraenkel, R.Barlow, V.Bokalders, IT Power Ltd and SEI Stockholm, IT Publications, London, 1994.

Sale of Excess Solar Energy, WHO Logistics for Health, (WHO/EPI/LHIS/90.1), Expanded Programme on Immunisation, World Health Organisation, Geneva.

Les lampes portables, Solar for Health, A Farcot, J Efforsat, Solar For Health, WHO/EPI/SOL/WP.1, World Solar Summit, July 5-9, 1993.

Leasing Solar Energy, JDD Ngabonziza, Best of Systemes Solaires, No 1, CAS, Paris, April 1993.

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