London, November 27:
In the desert of North Africa is a vast source of energy that holds the promise of a carbon-free, nuclear-free electrical future for the whole of Europe, if not the world.
We are not talking about the vast oil and gas deposits underneath Algeria and Libya, or uranium for nuclear plants, but something far simpler - the sun. And in vast quantities: every year it pours down the equivalent of 1.5 million barrels of oil of energy for every sq kilometre. Many people think of solar power as a few panels on the roof of a house producin-g hot water or a bit of el-ectricity. But according to two reports prepa-red for the German government, Europe, the Middle East and North Africa should be building vast solar farms in North Afr-icaâ€™s deserts using a simple technology that more resembles using a magnifying glass to burn a hole in a piece of paper than any space age technology.
Two German scientists, Dr Gerhard Knies and Dr Franz Trieb, calculate that covering just 0.5 per cent of the worldâ€™s hot deserts with a technology called concentrated solar power (CSP) would provide the wor-ldâ€™s entire electricity nee-ds, with the technology also providing desalinated water to desert regio-ns as a valuable byproduct, as well as air conditioning for nearby cities.
â€œFocusing on Europe, North Africa and the Middle East,â€ they say, â€œEurope should build a new high-voltage direct current electricity grid to allow the easy, efficient transport of electricity from a variety of alternative sources.â€ Britain co-uld put in wind power, Norway hydro, and central Europe biomass and geo-thermal. Together the region could provide all its electricity needs by 2050 with barely any fossil fuels and no nuclear power. This would allow a 70 per cent reduction in carbon dioxide emissio-ns from electricity production over the period.
CSP technology is not new. There has been a plant in the Mojave desert in California for the past 15 years. Others are being built in Nevada, southern Spain and Australia. There are different forms of CSP but all share in common
the use of mirrors to concentrate the sunâ€™s rays on a pipe or vessel containing some sort of gas or liquid that heats up to around 400C and is used to power conventional steam turbines.
The mirrors are very large and create shaded areas underneath which can be used for horticulture irrigated by desalinated water generated by the plants. The cold water that can also be produced for air conditioning means there are three benefits. â€œIt is this triple use of the energy which really boost the overall energy efficiency of these kinds of plants up to 80 per cent to 90 per cent,â€ says Dr Knies. This form of solar power is also attractive because the hot liquid can be stored in la-rge vessels which can ke-ep turbines running for hours after sun has gone down, avoiding the problems association with ot-her forms of solar power.