Renewable energy: winds of change

UNESCO Courier, May, 1998 by France Bequette

Geothermal energy makes use of underground heat, which increases with depth (a drill can go down to a maximum of 5,000 metres), allowing a turbine to be driven by water or steam and produce electricity. Another technique consists in injecting water into fissures in rock, and retrieving it when it has been naturally heated. Heating for 85% of the population in Iceland comes from geothermal sources. A score of countries, mostly developing, use geothermal energy, and there are 250 geothermal power stations in operation in various parts of the world, but cost restricts their further development.

Wind power is the most promising of all the renewable energies and the one that has undergone the most spectacular development. Germany, India and Denmark are the three countries best equipped in this respect. Spain, which comes fourth, is the first country in the European Union to enact legislation incorporating the recommendations made in the European Commission's White Paper on renewable energy sources; wind generators are in wide use in the Canaries, for sea-water desalination among other purposes. Over a hundred wind pumps are already operating in Mauritania, where a non-governmental organization, the Groupement de recherches et d'echanges technologiques (Technological Research and Exchanges Group), working in partnership with the Mauritanian energy authority, has installed wind-powered battery-charging stations in fifteen villages in the Tzarza region, a south-eastern area where there is plenty of wind. These batteries supply electricity to houses or nomads' tents. A $5-a-month subscription buys the use of an individual battery that can be recharged when flat by the wind generator. Wind generators power pumps supplying villages with drinking water in the remotest regions of the Adrar.

THE WORLD SOLAR PROGRAMME

The sun is an immense renewable energy source equivalent to about 10,000 times the total world demand for power. It is ever-present - albeit varying in intensity - throughout the world. It can be harnessed directly, in the form of heat, or converted into electricity. In the former case, all that is needed in the developing countries is a black-backed sheet of glass or plastic to make a cheap drying rack for fruit, vegetables or fish. The latter method - the photovoltaic system - requires panels, a battery and a device for converting direct current to alternating but also needs an operator who has to be trained to use and maintain it.

"Solar technology", explains French researcher Michel Rodot, "represents a major potential, but development runs up against real financial problems, firstly because installation costs are fairly high but mainly because village people and rural extension workers need to be committed to the idea of solar power. It also requires political will on the part of the State and support from the banks. Consumers will have to learn that the supply of solar electricity is a service they must pay for, however modest the price."

Conscious of the part renewable energies can play, UNESCO has devised a ten-year (1996-2005) World Solar Programme, which aims "to develop and implement 300-odd top-priority renewable energy projects of national, regional and international value . . . in order to demonstrate the technical feasibility, economic viability and social and political acceptability of solar energy." The Organization is also offering an extremely well-stocked database, available both in printed form and on computer, and a summer school for French-speaking engineers, instructors, academics, researchers and economists.