Clean power from deserts

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Generating electricity in the Sahara

By Hervé Kempf, Le Monde, November 17, 2007

[Comments by Olivier Daniélo]

Nuclear reactors in Libya? Forget it. The future of energy in the countries south of the Mediterranean lies not with the atom, but with the sun. A group of German engineers have persuaded the Berlin government as well as various partners along the Mediterranean coast. Their arguments are also making progress in Brussels, where two MEPs, Rebecca Harms and Anders Wikjman, have organised a symposium on November 28 on the most ambitious technology project of our age.

The idea is powerful yet simple: in the Sahara there's no shortage of sunshine. If we could harness even a fraction of it, it would meet a large part of the energy needs of the Mediterranean countries, not to mention the rest of Europe. Solar technology is now advanced enough for this to be a realistic prospect.

On paper, the reasoning is unanswerable. "The hot deserts cover about 36 million square kilometres of the 149 million square kilometres of land on the planet," says physicist Gerhard Knies, who inspired the TREC (Trans Renewable Energy Cooperation) project. The sunlight falling on 1 square kilometre of desert every year averages 2.2 terawatt-hours (TWh), or 80 million TWh a year. This is a huge amount of energy – so huge that 1% of the surface deserts could produce all the electricity needed by the whole of humanity." Therefore, it should be possible by increasing the number of solar power plants in the desert to supply all the countries around the Mediterranean, let alone other European countries.

The idea has been in the air for a long time, but started to come together in 2002, when Gerhard Knies, an early convert, contacted the German section of the Club of Rome. A meeting of experts was held early in 2003: the government was won over and agreed to fund a study. It was carried out by the German Aerospace Centre (DLR, the equivalent of CNES in France), written up by Franz Trieb, an engineer, and published in 2005 and 2006. It confirms the feasibility of the project using existing technologies.

Specifically, what infrastructure would be required? Energy is produced by using mirrors to concentrate the heat of the sun. The heat produced generates steam which feeds turbines, but it can also be stored in reservoirs of molten salt and released at night. Energy left over from power generation could also be used for the desalination of sea water, a major concern for the countries south of the Mediterranean. The experts also believe that, despite some inevitable losses in transmission, it would still be worth transferring electricity north across the Mediterranean because twice as much sunlight pours down on the Sahara as on Europe. [Comment: High Voltage Direct Current transmission loses about 3% per 1,000 km and there are small losses in AC/DC conversion as well.]

The key test of the project, of course, is its economic viability. According to its advocates, it meets this challenge. "Today, a solar electricity generator can produce power for between 0.14 and 0.18 Euros per kilowatt-hour (kWh). If a capacity of 5,000 megawatts (MW) was installed worldwide, the price could be between 0.08 and 0.12 Euros per kWh, and if we had 100 GW of capacity, between 0.04 and 0.06 Euros per kWh," says Franz Trieb.

"The idea of TREC is a step in the right direction," adds Alain Ferrière, a CNRS solar energy specialist. "If we develop the technology further the cost will fall." At the moment, solar power plants – in Spain, the United States and Germany – can be counted on the fingers of one hand. Besides, they are often built in the countryside or on agricultural land, which is far from satisfactory from an environmental point of view. [Comment: 500 MWe of the CSP installed in the world today is basically in the deserts of the southwestern USA]. The 40 MW generator at Brandis, Germany, has covered 110 acres of good land with solar panels. [These are photovoltaic panels, not solar concentrators.] In the desert, this waste of space is less worrying. [You can grow crops under the mirrors and thus generate an income.] Hence there is growing interest in the concept of TREC from several electricity companies in Egypt, Morocco and, in particular, Algeria.

In June Algeria, potentially the most important solar generator of the whole Mediterranean basin, announced a development plan with a timetable, to be implemented by NEAL (New Energy Algeria). On 3 November, the Minister of Energy, Chakib Khalil, set the official seal on the project by laying the foundation stone of a hybrid power plant, comprising a 150 MW gas generator and a 30 MW solar power plant, in the gas producing area of Hassi R'mel (Sahara). It is due to open in 2010, a first step towards what might, given reduced production costs, become mainly a solar facility.

Another milestone was reached on 13 November: the CEO of NEAL, Toufik Hasni, announced the launch of a 3,000 km [6,000 MW] electrical link-up between Adrar in Algeria, and Aachen in Germany. "This is the beginning of a network between Europe and North Africa. Eventually it will carry 80% solar electricity," Hasni told Le Monde. Europe has set a target of producing 20% of its electricity from renewable sources by the year 2020, so this initiative could have come at just the right time. Funding for the Adrar - Aachen link still has to be finalised; and the adverse effects of a high-voltage Africa-Europe network on the landscape have yet to be addressed.

On the positive side, the use of solar power could help to solve some of the pressing problems faced by the Arab countries. The TREC project is considering building a solar power plant in the Sinai desert to supply the Gaza Strip, which is desperately short of electricity. It is also contemplating the  installation of a seawater desalination plant in Yemen where the capital, Sanaa, faces an emergency when its groundwater reserves run out some time in the next 15 years.

More generally, the development of solar energy, its advocates point out, could serve the cause of peace by becoming a credible alternative to nuclear power which, as shown by developments in Iran, could have military implications.


Last updated: 2009-08-20 (ISO 8601)