So far we have been concentrating on economic aspects of grid-connected systems and the ways in which governments in developed nations encourage the development of PV markets. Passing reference has been made to stand – alone PV systems, noting that the chief competitor for supplying electricity in remote areas is generally the diesel generator. But all this relates to relatively wealthy nations including those that have driven PV’s spectacular growth over the last decade.
There is another important dimension to the terrestrial PV story, and it concerns the provision of relatively small amounts of solar electricity to families and communities in the developing world, who have little prospect of buying and maintaining diesel generators, and no prospect of connection to a conventional electricity grid in the foreseeable future. This challenging yet worthwhile activity is referred to as rural electrification.1,3 A major aspect of rural electrification is the supply of solar home systems (SHSs) to individual families, and we shall concentrate on it here. Other applications include irrigation and water pumping (see Section 5.5.3), refrigeration of vaccines and medicines in remote hospitals, and the supply of PV systems to small businesses and institutions. It is sobering for those of us who live in developed countries to realise just how little electricity is needed to provide valuable services to people who otherwise have none. For example, the average electricity consumption of a household in Western Europe is around 10 kWh/day. The stand-alone system for a holiday home that we designed in Section 5.4.1 (see also Figure 5.15) assumed a consumption of 2.2 kWh/day, sufficient to run a good range of modern electrical appliances if used with care. But when we consider a SHS based on a single PV module, typically rated between 30 and 60Wp, the figure is more likely to be 0.2kWh/day – one-fiftieth of the electricity taken for granted
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Figure 6.7 Pride of ownership: a family in China (EPIA/Shell Solar). |
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by most European families. This modest amount can power a few low- energy lights and a small TV, offering genuine improvements to rural living standards and a contact with the wider world.
Like other PV systems, SHSs have most of their costs up-front. A system comprising a small PV module, charge controller, 12 V battery, cabling, switches, and some low- energy lights may retail for a few hundred US dollars or euros. This may not seem much in America, Australia, or Europe, but to many families engaged in subsistence farming in the developing world it looks like an unattainable fortune. The SHS market – or perhaps we should say ‘markets’, because conditions vary widely from one country to another – therefore needs its own financing arrangements.
Efficient and convenient lighting is arguably the most important service offered by a SHS. Families without electricity often spend a substantial proportion of their disposable monthly income on kerosene lamps, candles, or dry cell batteries, so this money is in principle available to pay for a PV system.
Typical financing schemes for SHS’s include:
■ a short-term loan to cover all or most of the initial cost, paid back with interest over a period between 1 and 3 years.
■ a leasing arrangement whereby a SHS is installed and maintained by an organisation or company in exchange for monthly fee-for- service payments.
A wide variety of official, commercial, and aid organisations are involved in the financing of SHS programmes around the world. In addition to national governments, local banks and leasing companies, the United Nations and the World Bank are actively involved and so are various nongovernment organisations (NGO’s) and aid agencies.
Among the many countries with impressive rural electrification and SHS programs we might mention:
■ In Asia: China, India, Sri Lanka, Bangladesh, Thailand and Nepal.
■ In the Americas: Mexico, Brazil, Argentina, Bolivia and Peru.
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InAfrica: Morocco, South Africa, Kenya and Uganda.
We end this section with a few comments on cultural and social issues surrounding the introduction of high-tech products into developing countries. In many cases a small standtalone PV system represents the only contact of a rural family with 21st-century technology. Proper system maintenance can be a problem and education is a very important part of the package. Although PV modules are normally very reliable, the lead – acid batteries used in SHSs need regular topping-up and occasional replacement, modules must be kept reasonably free of dust and bird droppings, and electrical connections must remain tight and corrosion free. Such tasks are far removed from the experience of many rural communities. When SHSs are financed as part of a community electrification project there may be problems of management and control. A great deal has been learned over the past 30 years about the cultural pitfalls of rural electrification, where failures tend to occur for reasons other than the purely technical.3 But any such difficulties should not detract from the great social benefits of rural electrification, which is surely one of PV’s most admirable achievements.
6.2.1
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