Promotingurban energy technical Energy note Efficiency in Buildings in East Africa Urban Energy 17 Technical Note

Solar Home Systems and Solar Lanterns

Globally, approximately 1.5 billion lighting, phone charging, computers • 1 Wp of PV provides enough people do not have access to electricity, and water pumps. A solar home system electricity for a small light and a often living far from the electricity is generally designed and sized to supply phone charger. grid. Household solar systems and direct current (DC) and/or alternating lanterns allow those consumers access current (AC) electrical appliances. It How Solar Home to electricity and replace costly, harmful consists of a solar module connected to Systems and Solar kerosene lamps and candles. While a solar charge controller, an inverter and solar lanterns play an important role in a battery. The generated DC power is Lamps Work curbing kerosene usage and providing stored in the battery and converted to AC Solar home systems and lamps use light to students, more sophisticated power for supplying to AC loads. photovoltaic (solar-electric or PV) cells and solar systems have been developed in Solar lanterns and solar home systems rechargeable batteries to provide electrical recent years that provide a range of (SHS) are helping homes in developing power away from the mains grid. Lamps functions to customers – from mobile countries that are not connected to the provide a single light (and sometimes charging to television usage. While main grid (off-grid) to have access to phone charging) and are portable. Solar solar technology has been promoted in electricity for the first time. home systems are fixed in a home and can developing countries since the 1970s, it supply several lights, phone charging and is only recently that falling prices and Key facts other small appliances. innovative business models have led to • Millions of solar home systems and PV cells are made from more widespread adoption. solar lanterns are in use globally. materials, such as silicon, and generate A solar home system is a stand- direct current electricity from sunlight. • High quality lanterns retail for as alone system, suitable for residential A number of cells can be connected little as US$10 each. applications such as home appliances, together and sealed in a weatherproof casing to form a PV module. Fig. 01: Components Solar Home System

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Layout of Solar Fig. 02: Solar Home System Design for Home Applications Home System Description Application Solar PV cells and modules are specified SHS 30Wp 2 bulbs of 9W for 7hr use by their ‘watt-peak’ (Wp) rating, which is the power generated under standard SHS 50Wp 9W compact fluorescent lamp for 12hr use conditions, equivalent to bright sun in SHS 100Wp 2 bulbs of 9W compact fluorescent lamp for 12hr use the tropics although they can still work at lower light levels. Solar home systems use SHS 130Wp 2 tubes of 10W fluorescent lamp + radio or 21” TV. Approximate energy between about 5 and 100Wp of PV, solar produced 400Wh per day lanterns between about 0.5 and 2Wp. SHS 400Wp 3 tubes of 18W fluorescent lamp + radio+ TV + fan, 20L fridge. The rechargeable batteries store Approximate energy produced 1kWh per day (suitable for small size electricity, so that it is available at night home) and on cloudy days, as well as when the SHS 2000Wp Fluorescent lamp + radio+ TV + fan, large size fridge + water pump. sun is bright, and they also provide a Approximate energy produced 6kWh per day (suitable for medium size stable voltage for the appliances that use home) the electricity. Larger solar home systems normally use lead-acid batteries designed SHS 4000Wp Any appliances except air conditioner. Approximate energy produced specifically for solar use – standard car 12kWh per day (suitable for general home) batteries do not last long with the deep or hang from the ceiling. Some have small levels of discharge needed in a solar How solar home plug-in PV modules, like solar home systems, system. Nickel-cadmium and nickel- systems and solar but others have the PV cell mounted on metal-hydride batteries have been used the casing. This cuts the cost, but has the in lanterns and smaller systems because lanterns are used disadvantage that the whole lamp has to be they are easier to make portable and The PV module of a solar home system out in the sun to recharge the battery. in small sizes. But lithium-ion batteries should be fixed in a position that collects are rapidly becoming the most popular as much sunlight as possible, ideally on Solar-home-systems and lamps can be because, with good electronic controllers, an unshaded roof – this also reduces the very reliable and need little maintenance, they last longer. risk of theft. Ideally, how much a surface although in many countries there are should be tilted towards the sun depends cheap, poor quality products on the market An electronic charge-controller protects on the latitude and what time of year most as well. Users must be trained to check the the battery from being overcharged solar collection is required. If a surface is battery, keep the PV module clean and (when it is very sunny) or over- tilted at an angle equal to the latitude, it make sure that connectors are secure. Even discharged (when people try to get will be perpendicular to the sun’s rays at with careful use, batteries deteriorate and too much electricity from the system). midday. The battery is kept indoors with need to be replaced every few years. Other features can also be built into the terminals covered so that they cannot the controller, like different brightness be touched accidentally. The PV, battery, settings for lamps. Benefits of Solar lights and sockets for appliances are wired Appliances that are powered directly to the charge-controller. Home Systems and must operate at the DC voltage of Customers usually buy solar systems Solar Lanterns the battery but an inverter (DC to AC based on the service that they provide The amount of electricity provided converter) can be included in a larger (for example: ‘charge one phone and by solar home systems and lamps is system so that standard mains-voltage run two lights for six hours each day’). surprisingly small: the 20 Wp module equipment can be used. It is up to the supplier to make sure supplies about 50 watt-hours (0.05 kWh) that there is sufficient PV capacity to per day, and the cell on a small lamp provide this service throughout the only about one watt-hour (0.001 kWh). year, and sufficient battery capacity to However, the benefits can be huge. One advantage with keep the supply running even when The main use of a solar home system is technologies is that they are there are several cloudy days in a row. It to provide better lighting. Many homes modular, i.e. they can be tailored pays to use the most efficient lights and without access to grid electricity use to the power needs of individual appliances, so LED lights are now most kerosene lamps, which are dangerous, applications such as electric commonly used, although larger systems producing health-damaging fumes and calculators, small radios, televisions, also use fluorescent lights. computers, lights or electric pumps. a constant risk of fires. Children are Solar electric systems can be In a solar lamp, the LED light, battery and particularly at risk, so Ashden winner expanded easily by adding more charge controller are all in a casing which SolarAid has focused on selling solar study modules and batteries. is easy to carry and can stand on a table, lamps, which can be used on a table for

2 urban energy technical note homework. Even these smallest solar Dissemination of (ventilation and air conditioners, lamps give more light than a kerosene Solar Home Systems calculators, watches, path lights, lamp. And it is not just studying that emergency power and battery There are probably more than ten is easier and safer with better light. chargers). million solar home systems in use. Housework is faster, midwives can deliver Over three million homes have been babies more safely, shopkeepers can Financing Options supplied through the IDCOL programme display goods, cattle can be tended and in Bangladesh, in which Ashden for Solar Home farm produce sorted and packed. Award-winners Grameen Shakti and Systems Mobile phones keep people in touch with Rahimafrooz are family and friends, and give access to major partners. The work of the REDP The solar home system market is a fast information, entertainment and mobile led to the installation of over 400,000 developing area of the energy access money. Being able to charge a mobile systems in rural China. Kenya is the sector, and companies in this sector have phone at home with enables largest market for solar home systems pioneered some of most innovative people in off-grid homes to stay connected in Africa, with a large number of financing mechanisms and distribution to the world, without the cost and effort independent businesses involved and strategies. M-KOPA Solar in Kenya has of sending phones to be charged in town. about 350,000 systems in use. partnered with Safaricom, the country’s Solar systems can also power radios, largest mobile network provider; to providing entertainment and information, The Lighting Africa and Lighting Global launch mobile payment enabled pay-as- and larger systems run televisions as well. initiatives have helped to improve the you-go solar service using technology quality of solar lamps and small plug- from d.light design. and-play systems, and sales have grown Cost Off.Grid Electric in Tanzania allows its rapidly over the past five years. Ashden Costs of solar home systems and lamps customers to prepay for energy generated winner d.light has sold over 6 million vary between countries, and have come from their solar systems using a mobile solar lamps, helped by SolarAid in Africa. down rapidly over the past decade. payment-enabled subscription service, In 2014, it would cost approximately reducing the up-front cost burden Important applications of solar home US$150 to buy a 20 Wp Barefoot Power M-KOPA’s systems. Systems developed by systems include: kit including five LED lights and a phone Azuri Technologies allow customers to • Rural electrification (lighting and charger in East Africa, or to have a 20 top-up by purchasing scratch-cards. power supply for buildings, power Wp system with three lights and phone supply to remote locations, potable Each of these business models has the charger installed on your home by water for nomadic herdsmen); potential to unlock vast segments of the Grameen Shakti in Bangladesh. Even • Water pumping and treatment; market that were previously without though many families spend more than • Health care (for storing vaccines and electricity due to the high up-front US$150 on kerosene and phone charging medicines in PV refrigerators); costs of the systems themselves. The in a year, it is a large amount to pay in one • Communication (PV-powered remote development of leapfrog technologies in instalment and the up-front cost can be radio telephones or repeaters); these countries, such as mobile money, prohibitive. In South Asia, micro finance • Agriculture (solar pumps for water have allowed businesses to access has been used successfully for many years pumping); hundreds of thousands of customers by to make solar home systems affordable. • Transport and navigation aids (PV- reducing the burden of up-front costs More recently there has been growing powered navigation and signal lights); and transitioning to “energy as a service” interest in providing systems on a ‘pay-as- • Security (PV-powered security lights); rather than selling products whose full you-go’ basis, with businesses like Off Grid • Corrosion protection; cost remains out-of-reach. Electric in Tanzania encouraging customers • Household and office appliances to pay with their mobile phones.

Fig. 03: Solar Home Systems LEFT: M-KOPA Solar Home System comprise: 2 LED lights with switches and multiple brightness settings; 1 LED portable solar torch light; Phone charging USB with 5 standard connections; Portable solar radio; 8W high quality . (Source: m-kopa.com)

RIGHT: Students using a solar portable light (Source: offgrid-electric.com).

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While much of the entrepreneurial Future of Solar lighting, communications and mobile activity in East Africa has been focused Home Systems & money. System costs will decrease as the on delivering solar kits and solar home global PV market continues to grow, and systems, many companies continue to Solar Lanterns the improving efficiency of lights and make strides developing distribution As earlier stated, approximately 1.5 appliances will provide increasing better channels to sell solar lights which reduce billion people in the world do not have services (Fig. 04). the need for kerosene and improve access to electricity, most of them in the ability to charge mobile phones. developing countries. For example, in Projections indicate that by the year SunnyMoney, the social enterprise owned Tanzania less than 15% of the population 2030, Africa will still have a non- by United Kingdom charity SolarAid, are connected to the mains electric grid. electrified population of 698 million, has recently sold its millionth light in Even in India where three quarters of the compared to around 809 million sub-Saharan Africa. The company sells population have grid power within reach, people in Asia without electricity. the a range of lights through promotions the supply is unreliable with frequent and UN Millenium Development Project in partnership with schools in a number lengthy power cuts in many places. Solar has set out targets for providing clean of countries, including market leading home systems do not provide the level of efficient energy for reading light and for products such as Greenlight Planet’s power that the grid offers i.e. they cannot illuminating schools and health facilities. SunKing Pro, d.light design’s S2, and run a refrigerator or power tools on 50Wp The target for household lighting Barefoot Power’s Firefly. of PV – but they have huge potential consumption is a minimum requirement. to provide reliable access to electric

Fig. 04: Solar Home Systems Learning Curve

REFERENCES 1. Breyer, C. and A. Gerlach (2010), “Global Overview on Grid-Parity Event Dynamics”, presentation at 25th EU PVSEC/WCPEC-5 (25th European Photovoltaic Solar Energy Conference and Exhibition/World Conference on Photovoltaic Energy Conversion), Valencia, Spain, 6-10 September. 2. Karekezi, S. & Ranja, T., 1997. Renewable Energy Technologies in Africa. Zed Books, London. 3. Powering Households. GVEP International. http://www.gvepinternational.org/en/business/powering-households?gclid=Cj0KEQiAiamlBRCgj83PiYm6--gBEiQArnojD0UgqYO-hX5gRRWV Q46Y7kAVSGoS7UcmN8uBvNMdNIoaArDn8P8HAQ 4. M-KOPA Solar - http://www.m-kopa.com/ 5. Off-grid Electric - http://offgrid-electric.com/what-we-do/ 6. Wheldon, A. Solar lanterns and solar home systems. Ashden Award. http://www.ashden.org/solar

Executed by UN-Habitat with the support of GEF and UNEP

For more information, please contact: The Urban Energy Unit Urban Basic Services Branch United Nations Human Settlements Programme (UN-HABITAT) P. O. BOX 30030 - 00100 Nairobi, Kenya The purpose of this Technical Note is to call reader’s attention to new technical issues [email protected] in the field of sustainable human settlements development. They are not meant to be www.unhabitat.org/urban-themes/energy/ final or exhaustive. For more information, contact the Urban Energy Unit. Prepared by Vincent Kitio and Kennedy Muzee www.unhabitat.org 4