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 With present lower oil prices, the programme has become uneconomical. But it saves the nation hard currency, and it provides the additional benefits of rural development, employment generation, increased self-reliance. and reduced vulnerability to crises in the world oil markets.

80. The use of geothermal energy, from natural underground heat sources, has been increasing at more than 15 per cent per year in both industrial and developing countries. The experience gained during the past decades could provide the basis or a major expansion of geothurmal-capacity. By contrast, technologies for low-grade heat via heat pumps or from solar ponds and ocean thermal gradients are promising but still mostly at the research and development stage.

81. These energy sources are not without their health and environment risks. Although they range from rather trivial to very serious problems, public reactions to them are not necessarily in proportion to the damage sustained. For instance, some or the commonest difficulties with solar energy are, somewhat surprisingly, the injuries from roof falls during solar thermal maintenance and the nuisance of sun-glare off their glass surfaces. Or a modern wind turbine can be a significant noise nuisance to people living nearby. Yet, these apparently small problems often arouse very strong public reactions.

82. But these are still minor issues compared with the ecosystem destruction at hydropower sites or the uprooting of homesteads in the areas to be flooded, as well as the health risks from toxic gases generated by rotting submerged vegetation and soils, or from waterborne diseases such as schistosomiasis (snail fever). Hydrodams also act as an important barrier to fish migration and frequently to the movement of land animals. Perhaps the worst problem they pose is the danger of catastrophic rupture of the dam-wall and the sweeping away or flooding of human settlements downstream – about once a year somewhere in the world. This risk is small but not insignificant.

83. One of the most widespread chronic problems is the eye and lung irritation caused by woodsmoke in developing countries. When agricultural wastes are burned, pesticide residues inhaled from the dusts or smoke of the crop material can be a health problem. Modern biofuel liquids have their own special hazards. Apart from competing with food crops for good agricultural land, their production generates large quantities of organic waste effluent, which if not used as a fertilizer can cause serious water pollution. Such fuels, particularly methanol, may produce irritant or toxic combustion products. All these and many other problems, both large and small, will increase as renewable energy systems are developed.

84. Most renewable energy systems operate best at small to medium scales, ideally suited for rural and suburban applications. They are also generally labour-intensive, which should be an added benefit where there is surplus labour. They are less susceptible than fossil fuels to wild price fluctuations and foreign exchange costs. Most countries have some renewable resources, and their use can help nations move towards self-reliance. /…