Solar power from mirrors in deserts
ASHLEY SEAGER
SCIENTISTS SAY the global energy crisis can be solved by using desert sun.
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 square kilometre.
Common assumption
Many people think of solar power as a few panels on the roof of a house producing hot water or a bit of electricity. But according to two reports prepared for the German government, Europe, the Middle East and North Africa should be building vast solar farms in North Africa'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 world's hot deserts with a technology called concentrated solar power (CSP) would provide the world's entire electricity needs. Focusing on Europe, North Africa and the Middle East, they say, Europe should build a new high-voltage direct current electricity grid to allow the easy, efficient transport of electricity from a variety of alternative sources.
Britain could 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 emissions 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 sun's rays on a pipe or vessel containing some sort of gas or liquid that heats up to around 400{+o}C and is used to power conventional steam turbines.
Three benefits
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. ``It is this triple use of the energy which really boosts the overall energy efficiency of these kinds of plants up to 80 per cent to 90 per cent,'' says Dr Knies.
Cost of power
The German reports put an approximate cost on power derived from CSP. This is now around $50 per barrel of oil equivalent for the cost of building a plant.
That cost is likely to fall sharply, to about $20, as the production of the mirrors reaches industrial levels.
It is about half the equivalent cost of using the photovoltaic cells that people have on their roofs. So CSP is competitive with oil, currently priced around $60 a barrel.
This is why the reports recommend a collaboration between countries of Europe, the Middle East and Africa to construct a high-voltage direct current (HVDC) grid for the sharing of carbon-free energy.
The DC advantage
Alternating current cables, which now form the main electricity grids in Europe, are not suitable for long distance transport of electricity because too much is lost on the way. Dr Trieb, of the German Air and Space Agency, says the advantage of DC cables is that the loss in transport is only about 3 per cent per 1,000 kilometres, meaning losses between North Africa and Britain of about 10 per cent.
``Contrary to what is commonly supposed, it is entirely feasible and cost-effective to transmit solar electricity over long distances.
Solar electricity imported to Europe would be amongst the cheapest sources of electricity and that includes transporting it,'' he says. ``CSP imports would be much less vulnerable to interruption than are current imports of gas, oil and uranium.''
Algeria already exports huge quantities of oil and gas to Europe via pipelines but has a vast potential resource in sunlight that could make it a complete energy supplier to Europe.
The two reports make it clear that an HVDC grid around Europe and North Africa could provide enough electricity by 2050 to make it possible to phase out nuclear power and hugely reduce use of fossil fuels.
Many members of the Opec oil cartel, which have worried that alternative energies would kill demand for their oil, have hot, sunny deserts that could become a further source of energy income.
Umbrella group
An umbrella group of scientists has been formed across the region called the Trans-Mediterranean Renewable Energy Cooperation (Trec).
Neil Crumpton, renewables specialist at Friends of the Earth, said: "Most politicians on the world stage, particularly Tony Blair and George Bush, appear to have little or no awareness of CSP's potential let alone a strategic vision for using it to help build global energy and climate security.''
Dan Lewis, energy expert at the Economic Research Council, calculates that CSP costs $3-5 million per installed megawatt, one-fifth the cost of fusion.
He says: ``Fusion is basically a job creation scheme for plasma physicists.''
Mr Crumpton agreed: ``Nuclear power accounts for just 3.1 per cent of global energy supply and would be hard pushed to provide more.''— Guardian Newspapers Limited 2006.
Printer friendly
page
Send this article to Friends by
E-Mail
Sci Tech
