THE POTENTIAL FOR WIND-POWERED DESALINATION IN WATER-SCARCE COUNTRIES

Master of Arts in Law and Diplomacy Thesis Submitted by Edward Spang 7 February 2006

© 2006 Edward Spang

http://fletcher.tufts.edu

Abstract

This paper explores the global potential for integrating wind power and desalination technologies to increase water supplies. Desalination processes allow for the conversion of abundant salt water to relatively scarce freshwater and therefore represent great potential for water scarcity alleviation. A major limitation of desalination is its high energy requirements, and therefore it is useful to explore how renewable energy sources (such as wind) can be linked into desalination systems for sustainable freshwater production into the future. Desalination and wind technologies are summarized in this paper, including growth trends, costs, and emerging technological advancements. GIS is then used to generate a map of global wind-powered desalination potential “hotspots”, to give a rough idea where the integration of these technologies might be the most applicable. The analysis generated a short list of countries that have the greatest potential for leveraging gains from wind-powered desalination plants, including: Barbados, Cape Verde, Egypt, Haiti, Libya, Madagascar, Mauritania,

Morocco, Saudi Arabia, South Africa and Yemen. While there are significant limitations to the data used for this paper, it is hoped that the results of this analysis will generate discussions and further research on the implementation of wind-powered desalination in the identified countries, as well as other regions of the globe.

i Table of Contents

INTRODUCTION 1

WATER RESOURCES OVERVIEW 2

GLOBAL SUPPLY 2 WATER AND SUSTAINABLE DEVELOPMENT 3

DESALINATION 6

TECHNOLOGY BACKGROUND 6 INTRODUCTION 6 THERMAL DISTILLATION 8 MEMBRANE TECHNOLOGIES 8 COMPARISON OF TECHNOLOGIES 9 GROWTH AND DISTRIBUTION 12 GROWTH 12 DISTRIBUTION 15 COSTS 16 EMERGING TECHNOLOGY 19

WIND POWER 21

INTRODUCTION 21 TECHNOLOGY BACKGROUND 22 GROWTH AND DISTRIBUTION 25 GROWTH 25 DISTRIBUTION 25 COSTS 27 EMERGING TECHNOLOGY 29

DESALINATION & RENEWABLE ENERGY 31

OVERVIEW 31 WIND ENERGY AND REVERSE OSMOSIS 34 EMERGING TECHNOLOGY AND OPPORTUNITIES 38

MAPPING GLOBAL POTENTIAL FOR INTEGRATED WIND & DESALINATION TECHNOLOGY 42

INTRODUCTION 42 GIS DATA 43 POLITICAL BOUNDARIES 43 COASTLINES 43

ii GLOBAL WIND POWER POTENTIAL 43 WATER SCARCITY 44 WATER POVERTY INDEX 45 GIS METHODOLOGY 46 ACCESS TO THE COAST 46 LOW-COST WIND POWER POTENTIAL 47 INSUFFICIENT WATER SUPPLY (1) – WATER SCARCE COUNTRIES 48 INSUFFICIENT WATER SUPPLY (2) – WATER POVERTY INDEX 49 GIS RESULTS 49 RESULTS SUMMARY 49 A BRIEF CASE STUDY: THE POTENTIAL FOR HAITI 50 ANALYSIS 51

CONCLUSION 55

BIBLIOGRAPHY 57

iii Introduction

"If we could ever competitively, at a cheap rate, get freshwater from salt water, that would be in the long-range interest of humanity and would dwarf any other scientific accomplishments" - President John F. Kennedy, April, 19611

Water is life – a critical substance for the survival of all living organisms on the

Earth. For humans, the services provided by fresh water expand beyond physiological

necessity to include other essential uses: hygiene, sanitation, agriculture, energy,

industry, navigation and recreation. As the human population continues to grow

exponentially, we encounter greater scarcities of water around the world. According to

the United Nations Environment Programme (UNEP):

Two hundred scientists in 50 countries have identified water shortage as one of the two most worrying problems for the new millennium (the other was climate change).2

Unprecedented commitment on a global scale to innovate new water technologies and management systems will be required to 1) preserve the quality of our current supplies, 2) reduce the demand for water through gains in efficiency, and 3) increase the overall quantity of freshwater available.

This paper specifically seeks to address the third intervention described above, by exploring the global potential for integrating wind power and desalination technologies to increase water supplies. Desalination processes allow for the conversion of abundant salt water to relatively scarce freshwater and therefore represent great potential for water scarcity alleviation. A major limitation of desalination is its high energy requirements,

1 Gleick 2001 2 United Nations Environment Programme (UNEP) 2003, http://www.unep.org/wed/2003/keyfacts.htm

1 and therefore it is useful to explore how renewable energy sources (such as wind) can be

linked into desalination systems for sustainable freshwater production into the future.

Both desalination and wind technologies are summarized in this paper, including

growth trends, costs, and emerging technological advancements. These brief descriptions

provide snapshots of the current status of these technologies and their markets, as both

independent and integrated technologies. GIS is then used to generate a map of global

wind-powered desalination potential “hotspots”, to give a rough idea where the

integration of these technologies might be the most applicable.

Water Resources Overview

Global Supply

“Water, water, everywhere, nor any drop to drink”3

Only 2.5% of the total amount of water on the planet is freshwater, of which 74% is frozen in ice caps and glaciers, 25.7% is underground or in soils, and only 0.3% is available as surface freshwater.4 Of this available freshwater, it is estimated that humans

withdraw 54% of this water, and water that we are not directly using we are increasingly

polluting as a result of continued economic development and population growth5. As a

result, 40% of the world population is struggling with serious water shortages, with the

majority of this burden falling on people who live in remote rural areas and rapidly

expanding urban areas.6

3 Coleridge, Rhyme of the Ancient Mariner. 4 UNEP 2003 5 Postel 1996 6 UNEP 2003

2 As the global populations and economies steadily expand, the global demand for freshwater resources will continue to grow. Since 1950, global water use has tripled and in the next 20 years, it is estimated that humans will require 40% more water than is currently being used.7 Meanwhile, the existing supply of natural water resources is declining as a result of increasing water pollution (90% of wastewater in developing countries is released directly into rivers and streams without treatment) and overexploitation of groundwater sources (groundwater currently supplies 50% of drinking water, 40% of industrial water and 20% of agricultural water globally.)8 Finally, climate change may disrupt current rainfall patterns and regional water cycles around the globe. These combined pressures suggest increased water scarcity in the future, and a growing need for a proactive response in the spheres of water policy and management.

Reducing water scarcity can take two forms: augmenting supply or reducing demand. Historically, the supply side solutions have been pursued with greater vigor, and although this paper specifically addresses yet another supply-side solution, the author would like to emphasize the importance of exploring water conservation and demand management initiatives in conjunction with supply-side interventions.

Water and Sustainable Development

The link between water and sustainable development represents a nexus for development interventions. Water is intricately related to health, human dignity, gender empowerment, agricultural production, industrial expansion, transport and environmental protection. It is estimated that 470 million people (the majority of whom live in

7 UNEP 2003 8 Ibid.

3 developing countries) currently live in water stressed countries and this number will increase to three billion by 2025.9

At the most basic level of development access to safe water is critical for survival.

In fact, 80% of illnesses and deaths in developing countries are caused by water-borne diseases, which represent a massive burden on both the ill and those who care for sick family members (usually women).10 Finally, in areas where water sources are far from the home, women and children generally shoulder the task of hauling water to the house.

This daily task can often becomes a major obstacle for children to receive adequate schooling and for women to pursue income-generating opportunities.

The first global attempt to improve access to safe water was the UN-declared

Drinking Water and Supply Decade from 1981-1990. While efforts under this program expanded services to 816 million people, the population growth that took place over the same decade meant that there was only a 3% net increase in service.11 The global effort towards improving water supply was renewed in 2000 as part of the UN Millennium

Development Goals (MDGs) and access to improved sanitation was added to the MDGs at the Johannesburg Summit in 2002.12 The final version of Target 10 for water and sanitation under Goal 7 (Ensure Environmental Sustainability) of the MDGs reads as follows, “Halve, by 2015, the proportion of people without sustainable access to safe drinking water and basic sanitation.”13

9 UNEP 2003 10 Ibid. 11 WHO/UNICEF 2000, p7 12 UN 2002 13 Lenton and Wright 2004

4 Of the approximately 6 billion people on the planet, 83% (or 5.2 Billion) have

access to safe water, leaving 1.1 billion people struggling to access safe water on a daily

basis.14 The WHO/UNICEF Joint Monitoring Program (JMP) defines “safe water” as

water that comes from an “improved source” as listed in Table 1 below:

Table 1. Improved and Unimproved Sources of Drinking Water15 Improved Sources Unimproved Sources Household connection Unprotected well Public standpipe Unprotected spring Borehole Rivers or ponds Protected dug well Vendor-provided water Protected spring Bottled water* Rainwater collection Tanker truck water *Bottled water is not considered improved due to limitations in the potential quantity, not quality, of the water.

As the primary agency responsible for monitoring global progress towards the

Millenium Development Goals (MDGs) in Water and Sanitation, the WHO/UNICEF

JMP has the difficult task of aggregating a massive amount of data from around the world

into a limited set of indicators to represent “access to safe water.” While this monitoring

effort is critical for mapping the progress of nations towards the MDGs, it is less useful

as a snapshot understanding of global access to safe water. For example, a house that is connected to a water pipe will be regarded as having “access to safe water” even thought the quality of the water might be poor or the service intermittent. Considering the potential for this kind of misrepresentation, it is likely that the WHO/UNICEF JMP numbers might be overestimating the numbers of people with “access to safe water,” and therefore, the problem may be even more pervasive than the statistics suggest.

Regardless of how the problem is measured, the massive scale of the problem is evident. The real challenge is to increase the water services available to the

14 WHO/UNICEF, 2004 15 Ibid.

5 approximately one billion people currently without adequate access. Real progress in the

realm of water provision will require the coordinated efforts of governments, foreign aid

donors, NGOs, local institutions and target communities. For these groups to

communicate and plan effectively, they will need to have knowledge of a range of

potential solutions for addressing water shortage. This paper explores the role of

desalination technology as one of these potential solutions.

Desalination

Technology Background

Introduction

The process of generating fresh water from seawater, or desalination, has been in

operation for over 50 years.16 The impetus for the development of this technology is clear

as saltwater makes up 97.5% of water resources on the planet, representing an effectively

limitless source of freshwater in the context of desalination.17 In addition, 40% of the

world’s population lives within 60 km (37.3 miles) of the coast18 suggesting that the

benefits of desalination have the potential to reach a large target population.

However, it is important to state that desalination should not be viewed as the

panacea for the world’s water problems. The utility of desalination is generally

recognized as being limited by its costs, energy requirements and geography. Therefore, desalination processes should be viewed as a supplement to existing water supplies, and should only be implemented in conjunction with pollution prevention and demand

16 Wagnick 1998 by Semiat 2000 17 UNEP 2003 18 UNEP 2003

6 management programs to protect and improve the efficiency of use of current water

supplies.

Many desalination technologies currently exist and are in operation at various

scales around the globe, allowing human populations and industries to grow and thrive in

previously inhospitable locations. Two basic technologies are utilized to remove the salts

from ocean water: thermal distillation and membrane separation. See Figure 1 below for a

categorization of desalination technologies. This section addresses only those technologies identified by the large red boxes, as these are the most widely adopted desalination technologies. Eventually, the potential of using indirect solar through a wind

energy converter will be discussed.

Figure 1. Categories of Desalination Processes19

19 Oldach 2001

7 Thermal Distillation

Thermal distillation technologies in their various forms all depend on the same

concept: converting saltwater to steam and then condensing and collecting the freshwater

distillate. Thermal distillation units began to be installed in the 1960s at a commercial scale, or up to 8,000 cubic meters per day.20 The three basic technologies for thermal

distillation include: Multi-Stage Flash (MSF) Distillation, Multi-Effect Distillation and

Vapor Compression.

All three of these distillation technologies are based on converting salt water to

steam in a series of chambers of progressively reduced pressure. The reduced pressure

allows the saltwater to boil at lower temperatures, thereby requiring less thermal energy

input. MSF and MED processes tend to be on a larger scale than VC, although VC units

are sometimes used in combination with the other processes. For schematic drawings of

these three types of thermal distillation, see Appendix I.

Membrane Technologies

Membrane technologies rely on the basic process of using selective membranes to

separate salts from water molecules. Membrane technologies began to be commercially

viable in the 1970s, and include two basic processes: Reverse Osmosis (RO) and

Electrodialysis (ED). See Figure 2 below for a basic illustration of how these two

technologies use membranes to separate salt from water.

20 Buros 2000

8 Figure 2. Selective Membrane Processes: Electrodialysis and Reverse Osmosis21

Both processes require energy inputs to overcome the existing osmotic pressure

between fresh water and saltwater. ED technology is usually limited to brackish feed

water, while RO technologies can be used with brackish waters (BWRO) or seawater

(SWRO). Electrodialysis (ED) was developed about 10 years before RO and uses electric

currents to draw salts through a selective membrane, leaving behind a freshwater effluent.

Reverse Osmosis (RO) relies on forcing salt water against membranes (usually made of

cellulose acetate or aromatic polyamide) at high pressure, so that water molecules can

pass through membranes and the salts are left behind as a briny concentrate.22 For schematic representations of these two types of membrane technologies see Appendix II.

Comparison of Technologies

The selection of an appropriate desalination technology depends on a range of

variables, including: type of feed water, energy source, quality of freshwater output and

plant size. Table 2 below compares the major technologies based on these variables.

21 USAID by Buros 2000 22 Oldach 2001

9 Table 2. Characteristics of the Major Desalination Processes23 Typical Max Typical Energy Product Water Plant Capacities Requirements 3 3 Feed Water Energy Quality (ppm (m /day) (kWhel/m ) Process Type Source TDS) Multi-Stage Flash Distillation (MSF) Seawater Steam ~10 5,000-60,000 10-14.5 Multiple-Effect Distillation (MED) Seawater Steam ~10 5,000-20,000 6-9 Vapor Compression (VC) Seawater Electricity ~10 2,400 7-15 Sea Water Reverse 4-6* Osmosis (SWRO) Seawater Electricity ~350-500 128,000 7-13** Brackish Water Reverse Osmosis (BWRO) Brackish Electricity ~350-500 98,000 .5-2.5 Electrodialysis (ED) Brackish Electricity ~350-500 45,000 .7-2.5 Note: *with energy recovery **without energy recovery

As shown in Table 2 above, all processes work well with seawater except ED, which is limited to treating brackish waters. RO is capable of treating either seawater or brackish waters. Using RO, brackish waters require significantly less energy to process and allow for a higher recovery rate than seawater (25-40% recovery for SWRO and 65-

85% recovery for BWRO)24, so operational costs for SWRO systems tend to be 3 to 5 times greater than BWRO systems.25

Energy sources vary across the technologies, with MSF and MED technologies relying upon thermal energy and VC, RO and ED processes requiring electricity. The use of steam for thermal distillation processes allow for the efficient integration of these technologies with power plants or other industrial processes that produce waste heat.

Alternatively, the electrical input for VC, RO and ED technologies make theses processes more suitable for integration with electrical generators, including renewable sources such as wind turbines and solar photovoltaics.

23 Adapted from Loupasis 2002 24 Oldach 2001 25 Loupasis 2002

10 The different processes do not produce the same quality of water. Distillation

processes produce higher quality freshwater, with total dissolved solids averaging about

10 parts per million of total dissolved solids (ppm TDS) in comparison to membrane

processes which produce freshwater with approximately 350-500 ppm TDS (see Table 2

above). The WHO standards for potable water allow for a maximum value of 1500 ppm

TDS.26 So even though the freshwater produced by membrane processes is of lower

quality than distilled water, it is still well below WHO maximum standard for TDS. Some

RO plants include a secondary treatment process to further improve water quality and

remove the taste of salt residue, but this process is not required for health reasons.

Finally, Table 2 shows the typical maximum production capacities for each

desalination technology. SWRO plants demonstrate the greatest maximum capacity with

128,000 cubic meters per day (m3/d) followed by BWRO (98,000 m3/d), MSF (60,000 m3/d), ED (45,000 m3/d), MED (20,000 m3/d), and lowest capacity represented by VC

(2,400 m3/d). It is important to note that these numbers represent typical maximum capacities, and do not represent actual production limits of each technology. Additionally, while RO is capable of high capacity production, it is also well suited for small and even micro-installations (such as individual sailboats at 0.1 m3/d). The RO systems are

modular, so membranes and pumps can be successively added to increase the capacity of

RO installations.

Figure 3 below shows results from a 1998 inventory of desalination plants,

illustrating that MSF technology is the most widely adopted process around the world at

(44% of desalination technology) with RO technology close behind (42%).

26 Ibid.

11 Figure 3. Distribution of Global Desalination Operations by Technology27

This distribution suggests that of the currently available technologies, MSF and RO have

historically been the most preferred technologies for desalination. As the current

technologies continue to be refined and new technologies are developed, it is likely that this distribution will change in relation to the relative costs of the technologies.

Growth and Distribution

Growth

The installation of desalination technology has grown steadily around the world.

Figure 4 below shows that capacity has increased from essentially 0 to over 22.5 million cubic meters per day (~6,500 million gallons per day) between 1965 and 1998.

27 IDA 1998 by Buros 2000

12 Figure 4. Total Installed Capacity of Desalting Facilities28

As global demand for freshwater increases and global supplies decrease (as a result of pollution, saltwater intrusion and groundwater overexploitation), it seems that this growth trend in the desalination market will continue well into the future.

Additionally, advances in desalination technology and increasingly competitive production costs will likely add to the potential for future growth.

Among the various technologies for desalination, Reverse Osmosis (RO) seems to be growing at the fastest rate (approximately 12% annual increase or 200% overall increase between 1988 and 1997) as evidenced by Figure 5 below. The rapid growth potentially signifies technological advancements and reduced energy requirements that have lowered the cost of RO relative to the other methods for desalination (see section on

Costs below.)

28 IDA 1998 by Buros 2000

13 Figure 5. Distribution of Desalination Capacity by Type of Technology29

Membrane-based desalination plants generally require less time for construction

than thermal plants. Large MSF installations can take between three to five years, while

large RO plants can be constructed in 18 to 24 months.30 Meanwhile, small-scale RO

operations can be installed in four to five weeks.31 The rapid construction of small RO

plants is especially interesting for development and relief efforts, where freshwater

supplies must be delivered to needy populations (such as displaced refugee) on relatively

short notice.

Appendix III shows a table comparing RO technology to MSF and MED

distillation technologies. According to this source, RO technology has a comparative

advantage to the other methods relating to: total energy requirements, low capital costs, and high potential for further improvement. As discussed earlier, the modularity of RO

29 IDA 1998 by Buros 2000 30 Loupasis 2002 31 Loupasis 2002

14 system designs allows for this technology to be applied flexibly to match the demand requirements for various sites. For these reasons, in addition to the appropriateness of linking RO to wind power (discussed later), RO technology will be the focus of this paper. For a more detailed comparison of desalination technologies, see Appendix IV.

Distribution

The International Desalination Agency publishes an inventory of all existing desalination plants with pertinent information relating to location, type of process used, feed water characteristics, cost of production, quality of water produced, type of energy input and other pertinent variables. However, due to financial constraints, this author could not afford to purchase the data set, so the distribution information below is an incomplete set of installations around the world. Table 3 below shows desalination installations in seven countries. Of these countries, Saudi Arabia has 48.8% of the total installed capacity and the US has the second greatest capacity at 26.8%. It is also important to note that 48.5% of the capacity in these countries is covered by MSF technology, followed by RO technology at 39.8%.

Table 3. Installed Desalination Plants Capacity (in thousands of m3/d)32 Country MSF MED VC RO ED Total % Saudi Arabia 2700 50 1000 94 3844 48.8 USA 50 50 130 1600 280 2110 26.8 Kuwait 350 50 400 5.1 Libya 400 130 67 597 7.6 Spain 56 40 230 45 371 4.7 Italy 200 75 40 50 365 4.6 Algeria 60 30 80 16 186 2.4 Total 3816 50 325 3130 552 7873 100 Percent (%) 48.5 0.6 4.1 39.8 7.0 100

32 Adapted from Loupasis 2002

15 Table 4 below shows the composition of the current water supply in a set of ten

water scarce countries. As evidenced by the data, Kuwait and Qatar are 100% dependent on desalination for municipal and domestic water supply. Additionally, the water scarce countries of Barbados, Jordan and Yemen are 100% dependent on groundwater sources, suggesting a future need for desalination plants to replace the supplies from depleted aquifers.

Table 4. Current of Municipal, Domestic, Water Supply in Water Scarce Countries33

Costs

It is difficult to compare the costs of desalination installations at an aggregated

level because the actual costs depend on a range of variables specific to each site. The

type of feed water, desalination technology, production capacity, water quality standards,

local construction costs (materials and labor), and energy costs all strongly influence the

final cost. However, energy requirements necessary to separate salt from water tends to

be the greatest contributor to costs, whether through thermal processes or high-pressure

membrane separation. According to Table 2 (pg. 9) RO technologies with energy

recovery systems require the least amount of energy to process seawater (at 4-6 kilowatt

33 FAO Aquastat 1997 by Bremere, et. al., 2001

16 hours per cubic meter, kWh/m3,) compared to all other technologies. Even without energy recovery systems, RO remains competitive with the other technologies in terms of energy usage. Finally, if brackish water is included as a potential input, then the energy requirements for RO drop significantly and are basically equivalent to using ED treatment for brackish water (0.5-2.5 kWh/m3).

See Appendix V for more detailed cost comparisons between the different desalination technologies. The data show that the costs of RO systems ranging from approximately 0.90 cents per gallon (US$2.37/m3) for a plant with capacity of .03 million gallons per day (mgd) to 0.21 cents/gallon (US$0.55/m3) for a 30 mgd capacity system.

RO remains the cheaper option at both low and high production capacities in comparison to the other technologies. However, it is important to restate that desalination cost data is extremely site specific, so the comparison of costs across the different technologies is not as straightforward as it may appear in the Appendix V table.

Figure 6 below shows the cost composition for a standard SWRO installation.

While energy clearly represents a significant portion of the total cost (26%), the greatest cost influence actually arises from the fixed costs (mostly capital costs at 31%).

However, it is important to note that RO technology has the lowest fixed capital costs in comparison to MSF and MED technologies (see Appendix III). Regardless of this fact, the importance of fixed capital costs to the overall cost composition once again demonstrates the importance of economic parameters, such as the interest rate and discount rate, to determining overall installation costs.

17 Figure 6. Cost Composition for a Typical34 Seawater RO Plant35

The development of cheaper and more effective membranes, improved energy

efficiency systems, and other technological advancements has allowed the cost of SWRO

to decline significantly. Figure 7 below illustrates the dramatic reduction in costs (66%

reduction) across a set of actual SWRO installations around the world.

Figure 7. Cost Evolution of the SWRO Process36

34 Based on SWRO plant Sabha A, Israel. 35 Ebensperger and Isley 2005 36 Ibid p15. *Projected estimate

18

Costs might be further reduced through the implementation of subsidies

specifically for desalination projects. The subsidies can be viewed as investments in

research or as a catalyst to help bring the sector to scale so that further cost savings can

be realized. In the US, the “2004 Desalination Energy Assistance Act” was implemented

to provide incentive payments to selected desalination installations to reduce the actual

electricity costs.37 Finally, local costs for desalination installations in developing

countries might be further reduced through development assistance programs and NGO

projects.

Emerging Technology38

Reverse osmosis technologies have continuously improved over the years,

resulting in the fastest growth of this desalination technology relative to all the others (see

Figure 5 on p. 14). RO systems can be made more efficient by advancements in various

components of the process, including: pump design, energy recovery, membrane

thickness, the chemical sensitivity of membrane materials, and pretreatment.

High-pressure pumps drive the RO process by forcing the seawater against the

selective membranes at a pressure sufficient to overcome osmotic pressure, thereby

allowing the freshwater to separate from the salty feed water. These pumps represent the

majority of energy required for the RO process, so the development of more energy

efficient pumps would save maintenance by producing more fresh water per unit of

energy.

37 Ebensperger and Isley 2005 38 This paper focuses specifically on RO desalination, so while there have been technological advances in all types of desalination technologies, this section only addresses technological advances relating to RO.

19 Similarly, the recovery of energy from the pressurized brine concentrate saves

energy costs and increases efficiency. In a typical RO plant 40% of the feed water is

converted to freshwater, leaving 60% of the pressurized water as effluent.39 In other words, the leftover salty water is still pressurized and the energy of this pressurized wastewater can be recaptured within the system. Some advances have already been made in this area through the installation of energy recovery turbines and piston systems in RO plants. See Appendix IIB for a schematic drawing of an RO plant with an energy recovery turbine as compared to a plant without this technology in Appendix IIA.

The quantity of freshwater produced by pushing salt water through a membrane is inversely related the thickness of the selective membrane.40 Therefore, thinner

membranes allow for a more efficient production of freshwater. While current membrane

“skins” are already quite thin, ranging from 50-300 nanometers (nm) thick, any

advancement in creating even thinner membranes will increase the economic efficiency

of the system.41

As mentioned previously, most RO membranes are made of either cellulose

acetate (CA) or aromatic polyamide (PA). While these membrane materials function

similarly as selective membranes, they both have particular chemical sensitivities that

threaten the longevity of the membranes. The quality of CA membranes are compromised

when exposed to pH levels outside the range of 3.5 to 6.5, while PA membranes

deteriorate as a result of exposure to chlorine.42 Therefore, if new membranes are

39 Oldach 2001 40 Ibid. 41 Ibid. 42 Ibid.

20 developed that have greater resilience to variable chemical conditions, it will reduce costs

by increasing the longevity of RO membranes.

Membranes are also sensitive to other chemical factors, temperature, pressure and

biological agents.43 To prevent membrane fouling or rupture, feed water is generally

pretreated, which can include adjusting pH and various filtration processes. Costs can be

reduced and efficiency of freshwater production increased by any advances in

pretreatment technologies or the development of membranes that require less intensive pretreatment processes.

Wind Power

Introduction

The operating principle behind wind generators is the conversion of the kinetic energy of wind into electricity. The blades of a wind turbine capture this kinetic energy from wind to spin a rotor that can be used to generate electricity. The power of the wind

(P) is determined by three variables: the density of air (
, in kilograms per cubic meter),

the area of the windmill blades (A, in square meters), and the wind velocity (V, in meters

per second). The relationship between wind power and these variables is given in the

following formula:

As evidenced by this formula, wind speed has the greatest influence on

determining potential wind power (wind power determined by the wind speed cubed -

doubling the wind speed increases potential wind power by a factor of eight.)

43 Oldach 2001

21 Considering wind speeds (and directions) can be highly variable on differing time scales,

designing wind generators that can withstand periodic gusts of high velocity winds is a

critical aspect for the feasibility of wind power systems. Additionally, intermittent winds

mean variable power production based on exogenous factors, which is a general criticism

of the potential for expanding wind power generation.

Furthermore, it is important to note that while the formula above does provide a

value for wind power, this is not the value of the wind power captured by the wind

generator because the blades do not stop the wind completely (a necessary result of

complete conversion of kinetic energy to electricity.) In 1919, Albert Betz, a German

physicist, calculated the maximum wind power conversion potential of wind turbines to

be 59.3%, known as the Betz limit.44 However, a recent study has shown that the Betz limit may have been an overestimation because Betz neglected to incorporate the curvature of fluid streams (such as air currents) into his calculations. This same study suggests that the practical conversion rate at maximum efficiency is closer to 30% for typical, horizontal-axis wind turbines.45

Technology Background

Humans have harnessed the power of wind for production purposes for thousands

of years. The earliest evidence showing the use of wind-powered mills in China around

3000 BC and wind-powered water pumps in Babylon around 1600 BC.46 Large-scale use in Europe began in the 12th century for milling and irrigation, and in the case of the

44 Gorban et. al. 2001 45 Ibid. 46 Oldach 2001

22 Netherlands, for massive drainage of land areas below sea level.47 Despite the broad application and development of this technology over thousands of years, it largely dropped out of favor during industrialization as fickle winds were replaced with more reliable fossil fuels.

In the 1970s, American engineers experimented with large, lightweight wind

turbine designs, but their attempts generally failed as the machines were commonly

destroyed by heavy winds.48 In the mid-80s, Danish wind companies (such as Vestas

Wind Systems) began to build heavier, more rugged models that have become the global

standard for turbine designs.49 A typical modern turbine has three blades on a horizontal

axis, spanning 77 meters in diameter and capable of producing 1500 kW.50 Further

technological advances have included computer systems that automatically adjust blade

position and speed to produce electricity as efficiently as possible and also protect the

turbine during high winds.51

As mentioned above, the majority of modern wind turbines operate on a

horizontal axis, but vertical-axis turbines can also be used. An advantage of vertical-axis

turbines is that they do not have to be manually or digitally oriented towards the wind,

but rather can utilize wind from any direction without adjustments. Additionally, some

studies suggest that vertical-axis turbines have the potential to more efficiently convert wind power into electrical energy (35% conversion rate as opposed to 30% maximum for

47 Oldach 2001 48 Fairley 2002 49 Ibid. 50 Archer and Jacobson 2005 51 Ibid.

23 horizontal–axis turbines).52 See Figure 8 below for a representation of both horizontal

and vertical axis wind turbine designs.

Figure 8. Schematic Representation of Horizontal and Vertical Axis Wind Turbines53

Site selection plays a critical role in the viability of wind power production. The importance of wind speed was discussed as a critical determinant of wind power potential in a region. Not only does the local wind velocity need to be high, but it also needs to be somewhat consistent for a wind generator to be economically efficient. Therefore, having wind speed measurements throughout the year for many years is important data necessary for determining the viability of a wind power site.

In addition to consistent, high velocity winds, proper sites need to be relatively free of obstructions, such as: large buildings, forests, rocky cliffs, etc. A large obstruction can create a 200-300m “wake” that can reduce wind speeds at a downwind turbine by up

52 Gorban et. al. 2001 53 AWEA 2005, www.awea.org/faq/basiccf.html

24 to 10%.54 Consequently, the potential for offshore wind farms becomes obvious as the

coastal shelves provide a massive resource of relatively uninterrupted wind space.

Growth and Distribution

Growth

Despite some of the difficulties associated with wind power mentioned above the global wind capacity has increased steadily over the decade. Figure 9 below shows that capacity increased from approximately 5,000 megawatts (MW) in 1995 to nearly 50,000

MW in 2004. This tenfold increase in ten years represents an annual growth rate of approximately 26%. From 2003 to 2004, total capacity increased by approximately 8,000

MW.

Figure 9. World Wind Capacity55

Distribution

The use of wind power is not evenly distributed around the world. In fact, nearly

three quarters (72%) of all installed wind power capacity is in Europe as shown in Figure

10 below.

54 Oldach 2001 55 AWEA 2004

25 Figure 10. Regional Distribution – Installed Wind Power Capacity in 2004 (in %)56

Appendix VI provides more detailed information about the global distribution of wind

power, including data on how many MW of wind power were added in each region in

2004. Note that India and China, which collectively represent a significant proportion of

the developing world, seem to be aggressively installing wind power systems. China

added 197 MW in 2004 for a 35% increase over previous capacity and India added 875

MW in 2004 for 41% increase over previous capacity.

The uneven global distribution of wind power availability is partially determined

by the availability of sufficient wind sources, but more importantly, it seems that the

political and economic landscapes of the region influence the adoption of the technology.

For example, the countries in Europe have made a stronger political commitment to

environmental agreements as evidenced by participation in the Kyoto Protocol, whereas

the North American region (and more specifically the U.S.) have erred on the side of

56 adapted from GWEC in AWEA 2004

26 protecting the economy over the environment by relying on conventional fuels for power production.

It is also important to note that the relatively undeveloped regions of the Pacific,

Latin America & the Caribbean, and Africa have the lowest installed capacities for wind

power generation, totaling only 6% of world capacity. It seems logical that the greater

initial capital costs of wind power might be a barrier for adoption of this technology in

less developed countries. Of course, these regions also have less total energy available

per capita than the developed countries. This suggests that there is great potential to

expand wind power in these countries, not only as a supplement energy structure, but also

as a primary source for areas that are currently without any access to an electricity network.

Costs

The cost effectiveness of wind generators is primarily influenced by the wind

resource availability of a proposed site and the economic parameters that influence

capital costs.57 As mentioned above, available wind power depends mainly on the local

wind speed – more electricity can be produced in areas with consistent, high-velocity

winds. Wind generators tend to have high initial capital costs, but low operating costs

because of the lack of fuel costs. Therefore, the economic parameters related to the cost

of capital and interest/discount rates are significant variables in the cost calculations.

Costs less than US $0.05 per kWh have been achieved for some grid-connected

wind generators, and costs of approximately $0.03 per kWh are projected for a wind

57 Oldach 2001

27 installation in Scotland in a region that has consistent, high-speed winds.58 Neither of

these cost estimates includes the cost of power storage, which would significantly

increase the estimates.

These costs continue to decrease as advancements are made in the design

technology and the sector continues to grow and gain from economies of scale. By one

estimate, manufacturers of heavy-duty wind turbines have reduced costs fourfold since

1980.59

Appendix VII provides cost estimates of wind power and other renewable energy

sources as compared to nuclear energy and fossil fuels. Onshore wind systems cost about

3 to 5 cents per kilowatt hour (kWh) and offshore wind systems are double the cost at 6

to 10 cents/kWh. However, these costs are projected to drop by 2020 to approximately 2

to 3 cents/kWh. Fossil fuel costs are estimated at 2 to 4 cents/kWh for natural gas and 3

to 5 cents/kwh for coal. It is likely these costs are underestimated considering the costs of

fossil fuels rose dramatically in the last year (the price of a barrel of oil hit an all-time

high of $70.85 in August 2005).

Furthermore, these estimates for fossil fuels most likely do not include externality

costs associated with fossil fuel dependent systems, which may include the health costs

from particulate air pollution and costs associated with greenhouse gas emissions and climate change. Additionally, countries without oil reserves are forced to import oil, thereby spending valuable foreign exchange for ongoing energy costs. With an operational wind sector, it is possible for a country to not only reduce dependence on foreign oil, but also export wind-generated electricity to neighboring countries.

58 Oldach 2001 59 Fairley 2002

28 Considering the burden of costs for wind power fall primarily in the early capital costs, one-time capital-related subsidies might be an effective policy mechanism for governments attempting to reduce their carbon emissions. Specifically, under the Kyoto

Protocol there are opportunities for development assistance in developing countries for renewable energies under the Clean Development Mechanism (CDM), described below:

Under the CDM, an industrialised country with a GHG [Greenhouse Gas] reduction target (an Annex B country) can invest in a project in a developing country without a target (non-Annex B), and claim credit for the emissions that the project achieves. For example, an industrialised country may invest in a wind power project in a developing country that replaces electricity that would otherwise have been produced from coal. The industrialised country can then claim credit for the emissions that have been avoided, and use these credits to meet its own target. For industrialised countries, this greatly reduces the cost of meeting the reduction commitments that they agreed to under the Kyoto Protocol.60

If national government subsidies were to be successfully implemented, then the costs of installing wind power are further reduced in relation to fossil fuel energy production.

Furthermore, according to the Worldwatch Institute, nearly half a billion dollars of development assistance is transferred annually to developing countries for renewable energy programs (with $151 million delivered specifically for wind programs in 2003).61

With this scale of support, there is clearly great potential for wind power in the context of global development.

Emerging Technology

Wind energy technologies continue to advance and new prototypes may contribute to reduced costs of wind energy production. Strategies for improving

60 CDM Watch 2005, www.cdmwatch.org/about-cdm.php 61 REN21 2005

29 performance include making the turbine blades lighter, further developing vertical access

technologies and improving power storage systems.

A company in Washington State, Wind Turbine, designed a wind generator with

blades that are approximately 40% lighter than standard turbine blades and it is estimated

that these lighter blades could reduce capital costs by up to 20-25%.62 Lighter wind blade

designs have historically failed in strong winds. The Wind Turbine design team sought to

avoid potential damage by making to adjustments to the conventional wind generator

design. First, they placed the blades on hinges to allow flexibility for reduced drag during

high winds.63 Second, the blades face downwind, rather than upwind, so they have room

to flex backwards without striking the turbine tower and they are able to adjust

automatically to changing wind directions.64 Further prototypes for lighter turbine design

include the use of only two blades per turbine, rather than the conventional three blades.

As mentioned previously, wind generators with vertical axis turbines (see Figure

8 on pg. 23) might be able to convert wind energy into electrical energy at a greater

efficiency than horizontal axis turbines (35% conversion potential for vertical axis systems as compared 30% for horizontal axis systems).65 An increase in 5% of energy production would significantly reduce the investment cost per kWh.

A drawback to wind energy production is the variable electrical production rates based on changing wind speeds. For wind power to become a more viable option on a global scale, better power storage systems will need to be developed to create a more consistent supply of wind energy. The development of advanced batteries will allow for

62 Fairley 2002 63 Ibid. 64 Ibid. 65 Gorban, et. al. 2001

30 efficient power storage in the future, but these technologies have not yet matured and require further development.

Desalination & Renewable Energy

Overview

The coupling of wind energy and desalination systems holds great promise for increasing water supplies in water scarce regions. An effective integration of these technologies will allow countries to address water shortage problems with a domestic energy source that does not produce air pollution or contribute to the global problem of climate change. Meanwhile the costs of desalination and renewable energy systems are steadily decreasing, while fuel prices are rising and fuel supplies are decreasing.66

Finally, the desalination units powered by renewable energy systems are uniquely suited to provide water and electricity in remote areas where water and electricity infrastructure is currently lacking.

The study of the potential interface between desalination and renewable energy technologies has increased significantly in the last five years. Considering that the energy requirements for desalination continues to be a highly influential factor in system costs, the integration of renewable energy systems with desalination seems to be a natural and strategic coupling of technologies.

Renewable energies can power desalination plants through three types of energy media: thermal (heat), physical (shaft) and electrical. Figure 11 below shows the types of desalination technologies most appropriate for the various sources of renewable energy.

66 Tzen 2005

31 The red box outlines the integration of wind power and desalination systems, which is the focus of this paper.

Figure 11. Desalination Technologies Available for Renewable Energy Sources67

PV = Photovoltaic Solar, RO = Reverse Osmosis, ED = Electrodialysis, MVC = Mechanical Vapor Compression, MED = Muti-Effect Distillation, Multi-Stage Flash Distillation, TVC = Thermal Vapor Compression

Considering the costs and effectiveness of both desalination and wind energy

technologies are highly site specific, when these technologies are integrated the site

location becomes even more critical for a successful installation. The quote below

summarizes the variables that influence a renewable energy-based desalination plant:

The viability of any RES [Renewable Energy Systems] desalination combination will mainly depend on: • the renewable energy potential at the particular site and the form of useful energy which is available after conversion from renewable sources, be it thermal, mechanical, electrical. • the required production capacity from the desalination plant; this capacity somehow determines the size of the energy collection subsystem. • the availability of maintenance and experienced personnel for plant operation at the particular site. • the total system cost.68

Table 5 below shows the relationship between various energy inputs and criteria

for desalination technologies. This analysis suggests that while wind is well suited for

desalination process requiring electrical power, wind energy can be problematic as an

energy source because it is highly location dependent and has intermittent power output.

67 Adapted from Tzen 2005 68 Loupasis 2002, p21

32 Table 5. Evaluation of renewable energy technologies69

Note: 3 = excellent compliance with criterion; 2 = good compliance with criterion; 1 = poor compliance with criterion.

However, Table 5 seems to overestimate the problem of wind predictability. While wind

is intermittent, it is somewhat predictable as long as there is sufficient historical wind

data. Given thirty years of wind speed data, it is reasonable to assume an average annual

wind velocity, and therefore calculate potential annual energy output.

As a result of these many influential criteria for determining the best combination

of renewable energy (RES) and desalination technologies, there is a broad range of

existing installations of RES desalination facilities. As evidenced by Figure 12 below,

wind-powered RO systems make up approximately 19% of total RES desalination

facilities, second only to photovoltaic-powered RO units (32%).

69 Oldach 2001

33 Figure 12. Distribution of Renewable-Powered Desalination Technologies70

Wind Energy and Reverse Osmosis

An important consideration for wind-powered desalination project design is whether to have an autonomous (off-grid) or grid-connected system. This decision will be heavily based on the local context, such that sites close to larger population centers can use grid energy as a backup to the renewable energy source. Alternatively, remote communities might not have any substantial electrical infrastructure, so a standalone system would be better suited for this type of environment.

An advantage of grid connection is that the desalination system can continue to operate in low winds, and can provide a more dependable supply of energy in general.

Additionally, the system could be set up so that any residual wind energy not used for desalination can be sold back to the grid, thereby lowering operational costs by generating operational revenue.

70 Adapted from Tzen

34 For autonomous wind-powered desalination, a power storage or backup generator

may be required to continue operations in periods of reduced wind. This additional

system is required because wind power varies with available winds, but most current

desalination systems are currently designed to operate with consistent energy input.71 An

affordable and effective power storage system would be more desirable than a backup

generator because residual wind energy could be conserved and used rather than

introducing a system that requires fuel sources.

In some cases, fossil fuel systems have been avoided by coupling wind energy

with photovoltaic (PV) systems as an energy backup, but PV systems are also subject

variable energy output.72 In other words, in periods of low wind and low solar energy availability (nighttime) the desalination system would lack sufficient energy input.

However, as mentioned in the Emerging Technologies section below, there are currently

designs that allow for variable energy input for desalination operation, thereby precluding

the need for back-up generators and energy storage.

Regardless of the difficulties associated with intermittent power production, it

seems that wind-power desalination represents a promising coupling of innovative

technologies (see quote below).

However, the prospects of this combination [wind-powered desalination] are high mainly due to the low cost of wind energy. The operational experience from early demonstration units is expected to contribute to improved designs and a large number commercial systems are expected to appear in the market place soon.73

71 Loupasis 2002 72 Tzen 2005 73 Loupasis 2002, p26

35 In fact, the intermittent nature of wind energy is uniquely suited for water-based applications (such as desalination and pumping) because the water can be processed and stored in periods of high winds and the water stored in reserve can be used during periods of low winds. Effectively, the water storage system acts as a battery, but with an efficiency of nearly 100%.

An additional study explores the relationship between renewable energy systems and desalination plants based on plant capacities. Table 6 below suggests that wind- powered RO installations are recommended for small (1-50 m3/d) and medium (50-250 m3/d) capacities, but for larger capacities wind-powered vapor compression (VC) systems are recommended.

Table 6. Recommended Renewable Energy–Desalination Combinations74

These results are somewhat puzzling given that VC units were identified as having significantly lower maximum production capacities (2,400 m3/d) than RO

74 Oldach 2001

36 systems (128,000 m3/d).75 Table 6 above classifies anything greater than 250 m3/d as

“large”, so VC technologies can be considered as having a “large” capacity in this analysis. This suggests that the intermittent availability of wind production imposes a greater limit on RO units than VC units, and this makes sense considering that membranes are designed to work at a specific, optimal capacity.76

However, given the flexible, modular structure of both technologies (membranes can be added to increase desalination capacity and turbines can be added to increase power capacity), it seems that there might be a greater potential for large-scale wind- powered facilities than Table 6 suggests, especially in the context of any technological advances that address the intermittent availability of wind speed.

An interesting synergy exists between the technologies in relation to coastal geographies. Clearly desalination plants processing seawater gain from being situated close to the water, both for easy access to feed water as well as easier disposal of the briny concentrate. While wind systems certainly gain from relatively consistent coastal winds, the real advantage comes from the recent development of offshore wind technologies. As mentioned previously, wind energy can be significantly reduced by the presence of large obstructions near a site. Offshore technologies allow the turbines to be located miles offshore, thereby reducing dramatically the presence of any potential wind dampening obstructions. A project in Denmark completed in 2002, involved the

75 See Table 2 p. 10 76 Oldach, 2001

37 installation of 80 wind turbines (160 MW total)77 between 14 and 20 km offshore and able to power approximately 150,000 Danish households.78

Emerging Technology and Opportunities

The disconnect between the variable power production of wind and the need for consistent energy input for most desalination systems was mentioned earlier. This relationship is important to address to improve the efficiency of wind-powered RO units.

If RO units could be designed to respond effectively to variable energy input, then the need for backup energy storage or generators could be replaced by water storage systems at a significantly reduced cost. In other words, the desalination units would operate at variable capacities based on the available wind. During times of high wind, excess water could be stored in a tank for use when winds fail. Therefore, the water storage system effectively becomes an energy storage system (a battery) and access to water becomes more consistent, no longer relying on the immediate availability of winds.

In fact, a company based in Germany, ENERCON GmbH, has addressed this specific limitation of RO technology. As a company focused primarily on wind energy products, ENERCON’s operations have expanded to include desalination technologies.

They have developed an RO technology that involves a piston system used for energy recovery that also enables variable levels of energy input. See Figure 13 below for a brief description and a graph illustrating ENERCON’s “flexible operation range” desalination technology (note: the y-axis units should be cubic meters per day, m3/d).

77 REN21 2005 78 Fairley 2002

38 Figure 13. ENERCON: Flexibility in Power Supply79

This technological development for energy recovery and flexible energy input allows for cost savings and an easy integration with a wind generator. Additional developments by ENERCON include readymade modular RO installations that substantially reduce initial capital costs, automated operation for reduced labor costs, pretreatment systems that do not require input chemicals and remote monitoring. The collection of these technological innovations has the potential to dramatically improve the integration of wind power and RO technologies if it is able to perform as well as the company claims.

In addition, in the context of international development, the ENERCON modular concept and automated operation create potential for these units to be installed quickly in

79 ENERCON 2005, www.enercon.de

39 remote and underdeveloped coastal areas (see Table 7 below). If coupled with wind

power, the installation of these units could represent long-term investments in

development in areas previously burdened by scarce water supplies. See Appendix VIII

for an entire brochure on ENERCON’s desalination program.

Table 7. ENERCON Modular Installation Options80

Technological advancements aside, it is also important to examine institutional developments for the support of RES desalination systems. Institutions can expedite the adoption of innovative technologies through efforts in research and development, knowledge sharing, political pressure and seed funding. In relation to RES desalination programs, two institutions have surfaced since 2003: ADIRA and ADU-RES.

Project ADIRA (Autonomous Desalination system concepts for seawater and

brackish water In Rural Areas with renewable energy - Potential, Technology, Field

Experience, Socio-technical and Socio-economic impacts) was formed in conjunction

80 ENERCON 2005

40 with MEDAWARE81 and co-funded by the European Commission.82 Led by Fraunhofer-

ISE of Germany and in collaboration with Turkey, Spain, Greece, Jordan, Egypt,

Morocco and Cyprus, the intention of the five-year project (August 2003 – August 2007) is to install a series of small autonomous desalination units in the partner countries using existing technology. While final reports on the project are not yet available, the project demonstrates significant commitment by the partner countries and the European

Commission to RES desalination technology.

The Coordination Action for Autonomous Desalination Units based on

Renewable Energy Systems (ADU-RES), a consortium of 8 Mediterranean countries and various desalination and renewable energy institutes and enterprises, was also formed through a contract with the European Commission.83 In just over two years of duration

(April 2004 – October 2006), the project has four primary goals: Further Development of

R&D, Cost Analysis, Formulation of Policy Initiatives, and Political Dialogue and

Dissemination.84 This project represents another promising effort towards elevating knowledge of RES desalination units. However, it is important to note that both organizations are heavily based in the Mediterranean region, and there seems to be little discussion for the potential of these technologies in the developing countries. See

Appendix IX for the flyer from an ADU-RES-sponsored 2005 conference in Tunisia.

81 MEDAWARE - Development of tools and guidelines for the promotion of the sustainable urban wastewater treatment and reuse in the agricultural production in the Mediterranean countries 82 Project ADIRA 2005, www.adira.info 83 Project ADU-RES 2005, www.adu-res.org 84 ADU-RES 2005

41 Mapping Global Potential for Integrated Wind & Desalination Technology

Introduction

As mentioned above, the use of both wind power and desalination technologies are growing in absolute terms, as well as geographically. Meanwhile, the cost of implementing both of these technologies is decreasing. Additionally, the global

population continues to grow, creating increased demand for both energy and water

resources. Assuming all of these trends continue, it is likely that the integration of these

two technologies will become an attractive option for increasing regional water supplies

by producing freshwater from seawater.

However, the potential for these technologies is not evenly spread across the

globe. Regions that are not located close to the coast will not have an easily available

supply of seawater for conversion to freshwater (the conversion of brackish groundwater

in interior regions is beyond the scope of this paper.) Furthermore, the availability of powerful winds is clearly necessary for a wind power station to be economically effective. Finally, countries that already have sufficient per capita water supplies will not

require alternative technologies for further supply augmentation.

Potential “hotspots” for the implementation of wind-powered desalination can be

determined by identifying regions that meet all the restrictions mentioned above: access

to the coast, sufficient wind power and scarce water supply. Geographic Information

Systems (GIS) is the ideal tool for identifying these wind-powered desalination (WPD)

hotspots because it allows the user to perform analyses based on spatial reference data.

The GIS methodology for performing this type of analysis is outlined below.

42 GIS Data

GIS analysis involves the integration of data as georeferenced map layers to

determine spatial trends in the data. In this study, there are four critical map layers

required to determine WPD hotspots:

1. A map of the political boundaries of all countries in the world. 2. A map of all the coastlines in the world. 3. A map of global wind power potential. 4. A map indicating countries with insufficient water supply.

Political Boundaries

The political boundaries map simply shows the borders of all countries of the

world. The data for this map layer comes from the GIS software company, (ESRI) as part

of the basic MapInfo software package.85 This map serves as the base map to which all

other data is georeferenced, so that there is a common spatial coordinate system across all

data sets. Each data set will is overlaid or applied to this map for the final spatial analysis.

Coastlines

The coastline map also comes from the data set included with the ESRI MapInfo

software.86 This map shows all the coastlines of the world, including both continental and island coasts.

Global Wind Power Potential

A team of researchers at Stanford University collected surface wind speed data

from 7,753 surface wind measurement stations located around the world and calculated the estimated wind speed at 80 meters altitude at the same locations.87 The researchers

85 ESRI 2005 86 Ibid. 87 Archer and Jacobson 2005

43 adjusted the wind speed estimates specifically to 80 meters to get a more accurate understanding of global wind power potential because this is the hub height of a typical,

77-meter diameter, 1500 kilowatt wind turbine.88 (See Figure 8 on pg. 24 for a diagram of a horizontal–axis wind turbine.)

The global wind power potential map shows the location of these 7,753 surface wind measurement stations and includes the wind speed calculations for 80 meters of altitude. While this map does not show the wind power potential for every location around the world, it does provide some indication of the wind power potential for certain regions of the globe.

Water Scarcity

In 1997, Population Action International (an international NGO) published a report on global water scarcity for the years 1955, 1995, and 2025.89 They calculated natural water scarcity by dividing the quantity of available fresh water by the national population to determine per capita water availability. Countries that have per capita water availability less than 1,000 cubic meters are considered “water scarce”, while nations that have less than 1,700 cubic meters of water available per capita are considered “water stressed.” See Table 8 below that identifies water scarce nations in the past, present and future.

88 Ibid 89 Gardner-Outlaw and Engelman 1997

44 Table 8. Countries Experiencing Water Scarcity in 1955, 1990 and 2025 (projected), Based on Availability of Less than 1,000 cubic meters of Renewable Water Per Person Per Year90 Countries added to Countries added to scarcity category by scarcity category by Countries added to 2025 under all UN 2025 only if they Water-scare scarcity category by population growth follow UN medium countries in 1955 1990 projections or high projections* Malta Qatar Libya Cyprus Djibouti Saudi Arabia Oman Zimbabwe Barbados United Arab Emirates Morocco Tanzania Singapore Yemen Egypt Peru Bahrain Israel Comoros Kuwait Tunisia South Africa Jordan Cape Verde Syria Kenya Iran Burundi Ethiopia Algeria Haiti Rwanda Malawi Somalia *Cyprus will have more than 1,000 cubic meters of renewable fresh water annually per person in 2025 if it follows either the UN low or medium population growth projection. Zimbabwe, Tanzania and Peru can avoid falling below 1,000 cubic meters per capita only if they follow the UN low projection.

Water Poverty Index

An alternative to the water scarcity index described above, the Water Poverty

Index (WPI) can be used to determine countries with insufficient distribution of water supplies. As mentioned above, water scarcity is not necessarily caused by natural scarcity alone. While a country might have abundant available freshwater at the national level, their may be regional areas or marginalized populations that experience water scarcity.

The Water Poverty Index (WPI) is a metric used to link “physical estimates of water availability with socioeconomic variables that reflect poverty.”91 The WPI is an aggregate indicator (values range from 0 to 100 with low numbers representing poor access to

90 National Council for Science and the Environment 2005 (http://www.cnie.org/pop/pai/water-14.html) 91 Sullivan 2002

45 water) constructed from five indicators representing proxy values for: resources, access, capacity, use and environment. The potential value for creating a WPI is captured in the quote below:

The development of a Water Poverty Index is intended to help this process of identifying those areas and communities where water is most needed, enabling a more equitable distribution of water to be achieved.92

Unfortunately, the WPI is still in the process of development, and many countries of the world have not been assigned a WPI value. Therefore the data set used in this analysis is incomplete, but useful for a comparative analysis of countries with unmet demand for water resources.

GIS Methodology

As mentioned above, the spatial analysis for this paper involves isolating WPD hotspots by applying a set of spatial and attribute restrictions to all the regions of the world. These restrictions included: access to the coast, sufficient available wind power and insufficient water supply. These restrictions can be applied to the data set one after another until the hotspot regions with the desired characteristics are revealed.

Access to the Coast

As mentioned above, the wind power potential data set does not include measurements for all regions of the world. Therefore, we will only be able to analyze wind power potential for the regions where we do have measurements. However, we need to further restrict the data set to wind power measurement locations that are close to the coast to ensure sufficient and easy access to a supply of salt water. To achieve this

92 Sullivan 2002

46 end, the coastline data set and the global wind power potential data sets will need to be integrated for a simple spatial selection calculation.

The first step of the analysis was to choose an appropriate limit for the distance a wind power site could be from the coast. It is assumed that the wind power station and the desalination unit will be sited at the same location so that the efficiencies of energy transfer can be realized. Therefore the location of the wind power unit is limited by the geographic restrictions of the desalination plant. Seawater desalination plants are more efficient when located close the coast for two reasons: input sea water needs to pumped from the ocean into the plant and output disposal brine needs to pumped back out to the ocean (disposing of output brine on land carries greater actual and environmental costs).

For the purposes of this study, potential sites for wind-powered desalination were limited to within 25 kilometers of the coast. This restriction was applied to the spatial data by selecting all the wind power sites that fell within a 25 kilometer buffer area around the coastline data layer. This simple calculation allows for the creation of a new map that shows only the potential wind sites that are close (within 25 km) to the ocean.

Low-Cost Wind Power Potential

Wind speed, and subsequently potential for wind power production, is not evenly spread around the world. Wind turbines can only be cost effective in areas where there is sufficient wind speed to produce significant electrical or physical (shaft) power. It is understood that wind speeds of Class 3 and above (greater than 6.9 meters per second, m/s) at 80 meters of altitude are sufficient for the low-cost production of wind power.93

93 Archer and Jacobson 2005

47 Therefore, the next restriction will be to remove potential wind sites that have wind speed estimations of less than 7 m/s.

This indicator of the global wind power potential data layer is not determined spatially, so a simple selection by data attribute can remove all data points with wind speed measurements less than 7 m/s. This operation can be accomplished using the data attribute table in MapInfo, so that data points can be selected to create a new map that will show only the wind measurement sites within 25 km of the coast and demonstrating wind speeds greater than or equal to 7 m/s.

Insufficient Water Supply (1) – Water Scarce Countries

The final restriction is to identify the remaining potential wind sites that are

located in countries with insufficient water supplies. This final restriction is based on the

spatial relationships between the “sufficient global wind power close to the coast” data

layer and the “water scarce countries” data layer. All countries identified as water scarce, both presently and in the future (2025 calculations), are included in this data layer to create a more robust understanding of where these technologies might be appropriately utilized now and in the future.

This particular spatial selection will identify the final set of wind measurement sites that can be classified as WPD hotspots. A new map is created representing all the wind potential sites that are within 25 km of the coast, show wind speed estimations greater than or equal to 7 m/s at 80 m, and are located within countries that are currently water scarce or show potential for water scarcity in 2025. A final spatial selection can be used to identify the water scarce countries that contain WPD hotspots and shows where

48 the hotspots are within each country. Appendix X is the map of “Wind-Powered

Desalination Potential in Water-Scarce Countries.”

Insufficient Water Supply (2) – Water Poverty Index

In addition to selecting the final hotspots using the Water Scarcity index, I also used the Water Poverty Index to generate an alternate set of hotspots as a comparative study. As outlined in the previous section, the set of wind stations with measurements greater than 7 m/s and within 25 km of the coast was further restricted by identifying only those stations that fell within the bottom third of the WPI (values ranging from 35-50.)

The results of this alternative measure of insufficient water supply on selecting sites for wind-powered desalination in Appendix XI, “Wind-Powered Desalination Potential in

Countries with WPI less than 50.”

GIS Results

Results Summary

Through the use of GIS, I was able to apply a set of spatial and attribute restrictions on the global data set of wind power potential to identify potential sites or hotspots for wind-powered desalination, shown in Appendices X and XI. Using two different sets of data as proxies for insufficient water supplies at the national level, I was able to identify two sets of results for countries with potential for wind-powered desalination, shown in Table 9 below:

49 Table 9. Countries Identified as Containing Hotspots for Wind-powered Desalination Countries Water Scarce Data Water Poverty Index Data Barbados X Cape Verde X X Egypt X Haiti X X Libya X Madagascar X Mauritania X Morocco X X Saudi Arabia X South Africa X Yemen X X *Countries in bold to show that they contain WPDP hotspots using either data set to signify insufficient water supply.

A Brief Case Study: The Potential for Haiti

Haiti is a water scarce country and it also happens to be the poorest country in the

Western Hemisphere.94 In 2003, approximately 74% of energy consumed in Haiti came

from combined renewable and waste sources95, largely represented by fuelwood combustion.96 As a result of this dependence on fuelwood, much of the land in Haiti has

become deforested, which has further exacerbated water quality problems as increased

quantities of eroded sediments runoff into the rivers.97

While the situation in Haiti is certainly dire, the country does have an untapped

reserve of energy in the form of strong winds. If this wind energy could be effectively

harnessed, then its current water shortage could be at least partially alleviated through

desalination. Meanwhile the production of electricity from wind could stimulate

development while simultaneously reducing the previous household dependence on

94 CIA 2005 95 IEA Energy Statistics 2003 96 Earthtrends 1999 97 CIA 2005

50 fuelwoods, which could subsequently reducing the rate of deforestation. While this is

certainly an optimistic view of the power of integrated renewable energy-desalination

systems, it is an important alternative to explore for countries (such as Haiti) that might

be overlooking important resources that are available for their development.

Analysis

The resultsgiven in Table 9 (pg. 50) present a useful understanding of where

wind-powered desalination might be an effective technology for increased water

technology. On first glance it seems that the countries that contain hotspots using either the Water Scarcity or WPI measures (Cape Verde, Haiti, Morocco and Yemen) might represent more robust opportunities for WPD installation. However, this was not the objective behind using both Water Scarcity and WPI as indicators, but rather it was to determine hotspots using two imperfect proxies for insufficient water supply. It is more interesting to view the results as a set of countries that might want to incorporate WPD technologies into their national water planning strategies and policies.

As discussed earlier in the paper, the installation of both of these technologies requires a detailed understanding of the potential sites. However, the data sets utilized for

GIS sets are not sufficiently detailed for any actual site planning for this technology.

Even on a relatively broad scale the data is limited by a variety of characteristics, including aggregated national level data, wind potential point data, type of water scarcity data, lack of brackish water data, lack of production capacity estimates and lack of knowledge about existing WPD facilities.

51 Regional Data – Water Supply For a more realistic analysis of hotspots for WPD, it would be necessary to use

spatial data sets that have more detailed regional information. For example the data sets

used to represent insufficient water supply are national level aggregates that do not take into account regional variations in access to water. For instance, the Northeast region of

Brazil has scarce water resources, but the overall country is not considered water scarce because at the national level there is more than 1000 m3 per capita. This limitation in the

data set becomes particularly evident since there has already been an application of WPD

in NE Brazil and studies have been published to expand the use of this technology in the

region.98

Point Data – Wind Potential Furthermore, the data for global wind power potential is limited to the locations of

existing wind measurement stations. If this data could be interpolated to represent a

continuous surface of data, it might be possible that wind potential exists in more water

scarce countries than were identified in this limited analysis. For example, high wind

power was identified in the interior of Tanzania, however the coastal measurements

showed only medium potential. A continuous surface of wind data may have allowed for

the identification of hotspots within 25 km of the coast that lay between the medium

potential coastal sites and the high potential interior sites.

Water Scarcity vs. WPI Of the two data sets used as proxies for determining insufficient water supply, the

Water Scarcity data set is a more appropriate measurement for this analysis. The indicator

98 Corvalho and Riffel 2003

52 for determining water scarcity is strictly a measure of total water resources available

divided by the population. Therefore an increase in water supply through wind-powered

desalination plant would directly influence this indicator regardless of all other variables

except population.

Conversely, the Water Poverty Index is based on the aggregation of five

indicators, only one of which is based on absolute supply of water. Therefore, an increase

in supply from a wind-powered desalination unit might have only a marginal impact in

improving this indicator. Additionally, the WPI indicators is still being refined and a

value has not been assigned to all the countries of world, so that the analysis using WPI

in this paper is an incomplete estimate of WPD hotspots in the world.

While the Water Poverty Index potentially provides a more holistic assessment of access to water within a country, the issues of access to water relating to access, capacity, use and environment are beyond the scope of the intervention addressed in this paper. Of course, if a country moves towards implementing WPD technology, the success of the implementation will depend on the successful integration of the project into a National

Water Plan that addresses issues such as equity, poverty, appropriate use and environmental protection.

Finally, it would be useful to incorporate data from the International Desalination

Association (IDA) inventory of existing desalination facilities as an additional indicator of water scarce regions. After all, if desalination plants have already been constructed in a particular location, it is likely that there is insufficient water supply. For instance, many of the Pacific Island nations (and many small island regions in general) rely on desalination technology to augment the natural water supply, because it is cheaper than

53 transporting water to these remote areas. However, since none of these regions are identified as Water Scarce and many of these regions were not assigned WPI values, none of these nations were identified as having potential WPD hotspots.

Seawater vs. Brackish Water This analysis focused only on the use of seawater for potential desalination feed water. Another analysis could include data relating to brackish water supplies, and subsequently inland wind sources, since the desalination facilities would no longer be limited to the coast.

Scale of Production This analysis does not address the distinction between large- and small-scale potential for WPD. Clearly different scales WPD production will be appropriate depending on a hotspot’s proximity to population centers of different magnitudes. In certain circumstances, micro-scale WPD might be appropriate for small, isolated communities on the coast or small islands, while industrial-scale WPD will be required to meet the needs of large cities.

Current WPD Locations An additional limitation of this study includes a survey of the existing implementation of WPD. Appendix XII shows places where the author was able to find evidence of existing or planned WPD projects. (A complete inventory of worldwide desalination plants was carried out in 2004 by the International Desalination Association

(IDA), but the author was unable to access this data for financial reasons.)

54 As evidenced by Appendix XII, there is no overlap between countries identified

as WPD hotspots in this GIS analysis and existing WPD production. It is likely that the

gap arises from greater access to financial and institutional resources in the countries with

current WPD projects, as compared to the hotspot countries identified in this paper’s

analysis. In fact, this gap may represent great potential for technological exchange from

the industrialized North to the developing South relating specifically to water resource

management and development.

Conclusion

This paper begins with a quote from President John F. Kennedy that is as salient in 2006 as it was over forty years ago in 1961. Indeed, the ability to cheaply produce freshwater from seawater is a powerful tool to improve the lives of millions of people around the world who are in dire need of safe and accessible water supplies. However, this technology should not be viewed in the present context as a band-aid that can solve the world’s water shortage. Rather, it needs to be viewed as an ongoing and long-term technological supplement to appropriate management of existing water resources.

Since desalination is an energy intensive process, the widespread application of desalination technology for increasing regional water supplies is intricately linked to global energy issues. As such, the current and long-term potential for desalination is significantly limited by the availability of cheap energy. While renewable energy sources are not currently considered “cheap”, their costs are decreasing steadily, especially in the context of increasing fuel prices and growing awareness of the environmental externalities of traditional fossil fuel combustion (air pollution and climate change).

55 Therefore, the realization of JFK’s vision of cheap freshwater produced from the oceans may in fact be driven by wind turbines, solar panels and other emerging renewable energy technologies. The successful development of these technologies will be especially important for developing countries that are currently experiencing water scarcity and do not have access (geographically or economically) to sufficient conventional energy resources to implement desalination systems (the case of Haiti).

This last point was the purpose of the GIS analysis for this paper – to identify countries that have existing water shortages, access to the coast and wind energy potential. This analysis generated a short list of countries that have the greatest potential for leveraging gains from wind-powered desalination plants. While there are significant limitations to the data used for this paper, it is hoped that the results of this analysis will generate discussions and further research on the implementation of wind-powered desalination in the identified countries, as well as other regions of the globe.

While it is interesting to look at the potential for these technologies on the global scale, in many ways, it seems the most useful research will come from national and regional level studies that seek to answer the same question: what is the potential for renewable energy-powered desalination in alleviating water stress in the region? It is at this level where the issues of regional water management, local population sizes, existing infrastructure, available funds, and physical site characteristics can be more accurately incorporated into analyses for specific water policy and development program recommendations. After all, the sooner these technologies are transferred from ideas on paper to projects in the field, the sooner that target populations can start to benefit from improved access to water.

56

Bibliography

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58 2005> REN21 Renewable Energy Policy Network (2005) Renewables 2005 Global Status Report (Washington, DC: Worldwatch Institute). Semiat, R., (2000) Desalination: Present and Future (International Water Resources Association, Water International, Volume 25, Number 1, Pages 54-65, March 2000) Sullivan, C. (2002) Calculating a Water Poverty Index (World Development, Vol. 30, No. 7, pp. 1195-1210; Great Britain). Texas State Energy Conservation Organization – SECO (2005) Integrated Wind-Water System, http://www.seco.cpa.state.tx.us/re_wind_news.htm Tzen, E. (2005) Successful Desalination RES Plants Worldwide (Hammamet, Tunisia: Centre for Renewable Energy Sources) < www.adu-res.org/pdf/CRES.pdf> UNCSD (United Nations Commission on Sustainable Development) (2002a) The Johannesburg Declaration on Sustainable Development (Johannesburg: United Nations) UNCSD (2002b) Plan of Implementation of the World Summit on Sustainable Development (Johannesburg: UNCSD) UNEP (United Nations Environment Programme) (2003) Key Facts about Water www.unep.org/wed/2003/keyfacts United Nations (2000) Millennium Declaration (New York: United Nations) WBSCD (World Business Council for Sustainable Development), J. Dormann and C. Holliday (2002) Innovation, Technology, Sustainability and Society (Geneva: WBSCD). WCED (World Commission on Environment and Development) (1987) Our Common Future (Oxford, UK: Oxford University Press). Weaver, P., L. Jansen, G. van Grootveld, E. van Spiegel and P. Vergragt (2000) Sustainable Technology Development (Sheffield, UK: Greenleaf Publishing). WHO (World Health Organization) and UNICEF (United Nations Children’s Fund) (2000) Global Water Supply and Sanitation Assessment Report (Geneva: WHO/UNICEF). WHO/UNICEF (2004) Meeting the MDG drinking-water and sanitation target: A mid- term assessment of progress (Geneva: WHO/UNICEF) WRI (World Resources Institute) (2001) Facts and Figures: Environmental Data Tables (www.wri.org). UN/WWAP (United Nations/World Water Assessment Programme). 2003. 1st UN World Water Development Report: Water for People, Water for Life. Paris, New York and Oxford. UNESCO (United Nations Educational, Scientific and Cultural Organization) and Berghahn Books.

59 Appendix I.

Thermal Distillation Desalination Technologies: Schematic Representations

Appendix IA. Schematic Representation of Multi-Stage Flash Desalination (MSF) Plant99

Appendix IB. Alternate Representation of MSF Plant100

99 Semiat 2000 100 USAID by Buros 2000

60 Appendix IC. Schematic Presentation of Horizontal Tubes Multi-Effect Distillation (MED) Plant101

Appendix ID. Alternative Representation of MED Plant102

101 Semiat 2000 102 USAID by Buros 2000

61 Appendix IE. Schematic Representation of Vapor Compression (VC) System103

Appendix IF. Schematic Presentation of a Horizontal Tube, Vapor Compression Desalination Unit104

103 USAID by Buros 2000 104 Semiat 2000

62 Appendix II.

Selective Membrane Desalination Technologies: Schematic Representations

Appendix IIA. Diagram of Basic Reverse Osmosis (RO) Plant105

Appendix IIB. Diagram of RO Desalination Plant w/ Energy Recovery106

105 USAID by Buros 2000 106 Semiat 2000

63 Appendix IIC. Hollow Fiber Membrane107

107 Buros 2000

64 Appendix IIE. Diagram of Electro-dialysis (ED) System108

Appendix IIF. Alternate Diagram of ED System109

108 USAID by Buros 2000 109 Ibid.

65 Appendix III.

Summary Comparison of RO, MSF and MED Desalination Technologies110

110 Al-Mutaz 2000

66 Appendix IV.

Detailed Comparison of Desalination Technologies111

Appendix IVA. Evaluation of Distillation Processes

Note: 3 = excellent compliance with criterion; 2 = good compliance with criterion; 1 = poor compliance with criterion.

111 Oldach 2001

67

Appendix IVB. Evaluation of Other Desalination Processes

Note: 3 = excellent compliance with criterion; 2 = good compliance with criterion; 1 = poor compliance with criterion.

68 Appendix V.

Unit Product Costs for Conventional and Novel Desalination Processes by Capacity, Plants Operating in 2001112

112 Ettouney 2002 by Ebensperger and Isley 2005

69 Appendix VI.113

113 AWEA 2004

70 Appendix VII. Costs of Renewable Energy Compared with Fossil Fuels and Nuclear Power114

114 ICCEPT 2002 by REN21 2005

71 Appendix XII.

Locations of Existing and Planned WPD Projects Country City/State Year Notes Australia Perth 2005 Planned115 Cost: AU$387 million (US$287.39 million) Wind Capacity: 80 MW (48 turbines) Desalination Capacity: 45 Gigaliters/yr France Lastours 2002 Existing116 Wind Capacity: 5kW Desalination Energy Consumption: 20kWh/m3 Germany Northern 2005 Planned117 Region Desalination Technology: Mechanical Vapor Compression (MVC) Wind Power: 75% shaft, 25% electrical Greece Lavrio 2001 Existing118 Capacity: 0.13 m3/hr, (3.12 m3/day) Desalination Technology: RO Feed water: seawater Power Supply: 900 W (wind), 3.96 kWp (Photovoltaic solar) Battery Capacity: 1800 Ah/100h Unit Water Cost: 23
/m3 (US$27.53/m3) Greece Patras 2002 Out of Commission119 (lack of wind) Wind Capacity: 35 kW Desalination Capacity: 1) 5m3/d 2) 22m3/d Israel Maagan 1999 Existing120 Capacity: 0.125 m3/hr, (3 m3/day) Feed water: brackish Power Supply: 600 W (wind), 3.5 kWp (PV) Battery Capacity: 1500 Ah Unit Water Cost: 7.53
/ m3 (US$9.01/m3) Middle East NA 2002 Existing121 Wind Capacity: 11 kW Desalination Capacity: 25m3/d Desalination Technology: RO w/ energy recovery

115 Kneebone 2005 116 Loupasis 2002 117 Innovation Relay Centre (IRC) – Northern Germany 2005 118 Tzen 2005 119 Loupasis 2002 120 Tzen 2005 121 Loupasis 2002

80 Desalination Energy Consumption: 11kWh/m3 Country City/State Year Notes Puerto Rico NA 1998 Existing122 Sardinia NA 2002 Planned123 Wind Capacity: 15 kW Spain Gran Canaria 2002 Existing124 Wind Capacity: two 230 kW turbines Desalination Technology: Reverse Osmosis (RO), Electrodialysis (ED) and Distillation Spain Pozo 2004 Existing125 Izquierdo, Capacity: 0.8 m3/h (19.2 m3/day) Gran Canaria Feed water: seawater Nominal power: 15 kW Battery Capacity: 190 Ah Unit Water Cost: 3-5
/m3 (US$3.59-5.99/m3) Spain Tenerife 2002 Planned126 Wind Capacity: 200 kW Desalination Capacity: 200 m3/d Project: PRODESAL Local Wind Speed: 7.5 m/s UK Loughborough 2003 Existing127 Capacity: 0.5 m3/h (12 m3/day) Feed water: seawater Nominal power: 2.5 kW Battery Capacity: no battery Unit Water Cost: 1.78
/m3 (US$2.13/m3) USA Hull, MA 2005 Planned128 USA Lubbock, TX 2005 Planned129 USA Oahu, HI 2002 Existing130 Desalination Capacity: 4000L/d (4m3/d) Local Wind Speed: 8.5 m/s

122 Point Reyes Light 1998 123 Loupasis 2002 124 Ibid. 125 Tzen 2005 126 Loupasis 2002 127 Tzen 2005 128 Johnson 2005 129 Texas State Energy Conservation Organization (SECO) 2005 130 Liu, Migita and Park 2002

81 ENERCON DESALINATION SYSTEMS - Sustainable solutions for drinking water production -

ENERCON GmbH · Desalination Dept. · Dreekamp 5 · D-26605 Aurich Phone +49 4941 9794 620 · Fax +49 4941 9794 629 E-mail: [email protected] · www.enercon.de WATER, THE ELIXIR OF LIFE ENERCON’S SEAWATER DESALINATION SYSTEM

One of today's main problems is providing sufficient drinking water for the world's growing population. ENERCON’S ENERGY RECOVERY SYSTEM About three billion people have no direct access to clean potable water. Water is not only fundamental for human life, but is also essential for social development and prosperity. Global water shortage is already a ENERCON’s seawater and brackish water desalination systems are based on the principle of reverse osmosis source of great social tension and ecological problems. (RO). In this process pressurised seawater flows over a membrane. The structure of the membrane retains the dissolved salts – water is able to permeate. The result is pure drinking water.

After passing the membrane, a three-piston system recycles the energy of the remaining seawater pressure with virtually no loss. endangered areas Thus desalination and energy recovery occur in a continuous complementary process, forming a cycle.

very dry areas

dry areas drinking

semi-dry areas water Piston 1 Piston 2 Piston 3

THE ENERCON COMPANY RO-module

brine As drinking water becomes ever more precious, seawater desalination and water purification are becoming more important. Even in regions where drinking water supplies are now adequate, it won’t be long before new solutions are needed to secure them.

As the leading manufacturer of wind power turbines, ENERCON sees a major challenge to accelerate supply using regenerative solutions. Hence, besides the development, manufacture and optimisation of wind power plants, ENERCON’s product portfolio includes research into and implementation of drinking water production systems.

ENERCON has been active in drinking water production since the mid-1990s. The modular and energy-efficient desalination systems developed by ENERCON have reached series maturity and represent a sustainable concept for the world’s drinking water and energy supply. seawater intake BASIC FUNCTIONALITY OF ENERCON’S SEAWATER DESALINATION PLANT FLEXIBILITY IN POWER SUPPLY

> ENERCON plants have no fixed operating point. The water m /d production can range between max. 12.5% and 100% of 500 Feedwater Drinking Water the nominal capacity by adjusting the piston speed according Reverse Osmosis Intake Filtration (0 bar) to demand. This has two main advantages: Firstly, operation Membranes (RO) is possible with a fluctuating energy supply, and secondly, 400 output can be adjusted flexibly to water demand without shutting down the plant. 300

Only about 25% of the energy in the reverse osmosis process 200 is used to produce drinking water, so without a recovery method, about 75% would go to waste. ENERCON’s energy 100 recovery system comprises a low-pressure pump (max. 20 UV Feedwater Brine 0 400 800 1200 1600 2000 (Seawater: ~ 56bar) bar) and a three-piston system, which raises the pressure (Seawater: ~ 54bar) kW/d Desinfection (Brackish water: ~28bar) (Brackish water: ~26bar) up to 70 bar and simultaneously re-uses the remaining 0

energy. There is no need for a second (high-pressure) pump. ENERCON Desalination Plants So this system consumes very little power and works with a flexible operation range extremely energy efficient. Conventional Desalination Plant with a fixed operation point

ENERCON Energy Pump Brine Recovery System (20bar) (0 bar) MODULAR CONTAINER DESIGN

ENERCON’s seawater desalination plant is modular, comprising various containers. Each 20-foot container contains a separate part of the plant. This design enables easy worldwide transport and set-up logistics and also guarantees optimal protection of the plant from climatic influences.

1. Power and control container The feedwater flows through filters and an UV-disinfection system to the ENERCON Energy Recovery System. The pump pressure of 20bar is transferred to ~ 56bar/seawater or ~28bar/brackish water and flows to the RO-membranes. At the RO-membranes, feedwater separates into drinking water and brine. Drinking water 2. Desalination/RO container leaves the system and brine, still under pressure, flows back to the energy recovery system to support the process. 3. Water storage container

4. Pretreatment container 1 2 3 4 APPLICATIONS

DIRECT CONNECTION OF ENERCON’S SEAWATER DESALINATION PLANT TO THE PUBLIC GRID

Connecting the ENERCON seawater desalination plant directly to a stable grid poses no problem. The sea water is extracted from the open sea with a suction pipe or through a well and fed to the plant.

ENERCON’S SEAWATER DESALINATION PLANT IN COMBINATION WITH AN ENERCON WIND ENERGY CONVERTER AND LINKED TO THE PUBLIC GRID

The seawater desalination plant’s primary power supply is generated by an ENERCON wind turbine. Costal locations present excellent conditions for wind power, especially on islands. During strong winds, the surplus energy can be fed directly into the public grid. When there is insufficient wind the desalination plant can be powered from the grid. CHARACTERISTICS OF ENERCON’S SEAWATER DESALINATION SYSTEM

ENERCON’S SEAWATER DESALINATION PLANT AS A STAND-ALONE GRID SYSTEM Very low energy consumption: The ENERCON recovery system saves 30% energy ENERCON has developed a stand-alone grid system to guarantee a continuous, stable supply of energy and No need for chemicals: Physical control processes eliminate the need for chemicals water to consumers in remote areas far away from the public grid. The seawater desalination plant’s primary power supply is generated by an ENERCON wind energy converter. In combination with other system Energy-efficient output adjustment: Without reducing efficiency, water production can be components, such as a synchronous machine, flywheel, battery and diesel generator, the system supplies adjusted to demand and energy availability within a range of 12.5 % to 100% and stores energy and water precisely according to demand. ENERCON’s energy management system ensures ideal utilisation of the wind and water supply, while guaranteeing exceptionally high quality of the island grid. Based on the power and output variability, ENERCON seawater desalination plants can also be applied in weak power grid areas or as stand-alone systems DIFFERENT OPTIONS Fully automatic operation, including re-start after a power failure, cleansing cycles, control depending on energy and feedwater availability TYPE TYPE CAPACITY NUMBER OF NUMBER OF PUMPS PER OF WATER IN m3/DAY RO UNITS 20’’ CONTAINERS RO UNIT Low operating costs; due to very low power consumption per m3 of drinking water produced EDS SW 300 Seawater 175 - 350 1 4 1 Low noise emission EDS SW 600 Seawater 175 - 700 2 4 1 EDS SW 900 Seawater 175 - 1050 3 5 1 Remote plant monitoring with ENERCON’s SCADA system: Monitoring regardless of location EDS SW 1200 Seawater 175 - 1400 4 5 1 enables online viewing of all operating data. The data can be generated in tabulated or graphic form, statistical assessments can be calculated, etc. EDS BW 600 Brackish 350 - 700 1 4 1 No 24 hour personnel necessary EDS BW 1200 Brackish 350 - 1400 2 4 1 EDS BW 1800 Brackish 350 - 2100 3 5 1 Combination with renewable energy systems, such as wind turbines EDS BW 2400 Brackish 350 - 2800 4 5 1

Desalination Units powered by Renewable Energy Systems

Opportunities and Challenges

26 September 2005 Hotel Savana, Hammamet, Tunisia

Organised in the framework of the project ADU-RES and supported by the EC under the 6th Framework Programme

Participation free of charge - registration required For registration and more information contact: Chaibi M.Thameur: +216 - 71 709 033/719 630 [email protected]

Michael Papapetrou: + 49-89-72012 792 [email protected]

English – French interpretation will be available

www.adu-res.org

Programme of the Seminar

09:30 Introduction Welcome Mohamed Nejib Rejeb, INRGREF 09:50 Project ADU-RES Christian Epp, WIP 10:10 Water supply Water Supply situation in the Taoufic Brahem, DGGR situation in rural areas of Tunisia 10:30 Tunisia On-Site situation in Central Abedeljellil Afli, CRDA Tunisia Kairawan 10:50 Questions and discussion 11:00 Coffee break 11:30 Pilot Description and performance of Aref Maalej, ENIS Sfax Installations the pilot plant in Sfax, Tunisia 11:50 Using geothermal and solar Karim Bourouni, ENIT energy for autonomous water Thameur Chaibi, INRGREF desalination 12:10 Spanish Cooperation project in Penelope Ramirez, ITC Southern Tunisia: PV-RO desalination unit in the village of Ksar Ghilène 12:30 Successful plants worldwide Eftihia Tzen, CRES 12:50 Questions and discussion 13:00 Lunch break 14:00 Research Improvements in energy MurrayThomson, and efficiency Loughborough University 14:20 Development Development of an autonomous Dimitris Manolakos, AUA solar rankine cycle system for RO desalination 14:40 Solar desalination for water Hammami Naceur, ANME supply in Southern Tunisia 15:00 Questions and discussion 15:10 Coffee break 15:30 Market Solar thermal desalination for Stefan Thiesen, available rural applications ZONNEWATER 15:50 technologies The Solco PV-RO system Duncan Stone, SOLCO 16:10 The ENERCON Wind - RO Frank Hensel, ENERCON System 16:30 Questions and discussion 16:40 Closing Conclusions and next steps Panel Discussion 17:00 session End

Organised jointly by:

INRGREF