Some solar cells rely on a thin wafer of single-crystal silicon. Impurities are then added to the silicon wafer enabling it to convert solar radiation into electricity. Silicon is produced from sand. It has been estimated that one tonne of sand can generate as much electricity as burning over half a million tonnes of coal, taking into account the efficiency of the solar cell and its operating lifetime into account.
Since 1984, the South Pacific Commission (SPC) has been operating a photovoltaic solar electrification programme. Following pilot projects in eleven South Pacific countries, SPC coordinated a regional photovoltaic solar electrification programme for the French territories of the South Pacific region. Individual family homes are supplied with four panels allowing a total daily consumption of 433 Wh, or six panels allowing a total daily consumption of 637 Wh. Community buildings are supplied with ten panels, or thirty-two panels allowing for a total daily consumption of 3375 Wh. Each panel costs about US$1,000. Under this programme, 614 of the above systems have been installed. Apart from installing the systems, and keeping the installations operating beyond the warranty period, the SPC and the French territories have undertaken a training programme to teach solar panel maintenance.
An experimental solar power station, the first of its kind using the sun's energy directly to run hot-air turbines to produce electricity, is being built at the Weizmann Institute in Rehovot, Israel. The plant uses a field of mirrors that focus the sun's rays towards a large mirror set atop a nearby tower. This mechanism concentrates the rays 5,000 to 10,000 times their natural concentration before reaching earth. The intense light and heat is then focussed on a group of special solar panels on the ground that contain compressed air. The air heats up and this produces electricity. The invention makes it possible to power state-of-the-art, combined-cycle power plants by both natural gas and solar energy.
Solar energy could have made a far more significant penetration of the energy market had it received subsidies and other support remotely equivalent to that accorded fossil fuels and nuclear power. This argues against a free-market (laissez-faire) approach to development of solar energy (i.e. the argument that it will develop when it is commercially viable).