CONTROVERSES
ENERG...ETHIQUES !
| The power needs of Europe, the
Middle Eastand North Africa could be met by an ambitious idea to network
renewable energies across the region. The cornerstone of the plan, developed
by a group of scientists, economists and businessmen,involves peppering
the Sahara Desert with solar thermal power plants, then transmitting the
electricity through massive grids.
Prince Hassan bin Talal of Jordan was scheduled to present this green-energy idea, dubbed DESERTEC, to members of the European Parliament in Brussels on 28 November. The vision is ambitious: it would require roughly 1,000 100-megawatt power plants, using mirrors to concentrate energy from the Sun's rays, throughout the Middle East and North Africa to meet the region's projected energy needs. A high-efficiency electricity grid, yet to be built, would then ferry the power around and across the Mediterranean Sea and northern Europe. "The technology for the DESERTEC concept is available and can offer unlimited, cheap and carbon-dioxide-free energy to Europe," says Gerhard Knies, a retired physicist based in Hamburg, Germany. Knies is co-founder of the Trans-Mediterranean Renewable Energy Cooperation (TREC), which came up with the DESERTEC idea. The European Union has a binding target to get 20% of its energy from renewable sources by 2020, so the idea is gaining support in some areas. "It makes a lot of sense to profit from the high amount of solar radiation in the deserts," says Robert Pitz-Paal, head of the solar research department at the German aerospace agency DLR. But with a price tag of almost €400 billion (US$595 billion), it remains to be seen if DESERTEC will be adopted politically. "Unless it's extremely cheap, it won't stop people using easy-to-get fossil fuels," says Jon Gibbins, an energy engineer at Imperial College London. "We didn't stop using coal in the last century because of oil." Nationalistic concerns may also be a stumbling block, with European politicians reluctant to be dependent on Africa. For instance, Hermann Scheer, a member of the German parliament, is in favour of renewable-energy approaches, but is pushing for European energy autonomy through small, decentralized power plants on European soil. The vision of covering the Sahara with solar panels to generate electricity for Europe goes back to Frank Shuman, a Philadelphia-based inventor who built a prototype solar thermal plant in Egypt in 1913. But the idea never took off, and today solar power in the region comes from relatively small solar-cell installations on houses and other individual buildings. |
In 2003, Knies co-founded TREC and began presenting
the idea at conferences. He eventually got the attention of the German
environment ministry, which has commissioned three technical studies to
evaluate the concept. Germany aims to get 50% of its energy from renewable
sources by 2050, and is a leader in developing solar thermal power. "The
ministry was interested in knowing if it's feasible to import solar energy
from North Africa and to penetrate the market there," says Ralf Christmann,
an officer at the ministry.
The DESERTEC scenario foresees a mix of renewable energies, from wind to geothermal to biomass power (see map). But the core is solar thermal power, which uses solar energy stored in a special heat-retaining fluid to drive a turbine and create power. First demonstrated in 1982 with a 10-megawatt plant in California's Mojave Desert, solar thermal plants can now produce electricity at a cost of about 15-20 eurocents per kilowatt-hour. According to the DLR, further improvements in technology and scale could bring that down to less than 10 eurocents per kilowatt-hour, making it more competitive with coal. Initial solar thermal plants are being planned in Algeria, Egypt and Morocco, with more under construction in Spain and Italy. Bringing electricity from Africa to Europe presents another challenge. The DLR says that €45 billion of the overall budget should be invested by 2050 to place high-voltage d.c. transmission cables throughout the region. Such a line already exists between Norway and the Netherlands. The DESERTEC group is asking parliamentarians to set up a €10-billion fund to finance the development of solar thermal plants over the next 7 years, and to establish a political framework for the idea. But although the project may not take off on the scale its supporters hope for soon, solar thermal power could still pick up elsewhere. "Right now, 1,000 megawatts of solar thermal energy are being built in California and Nevada deserts, and we are planning an additional 5,000 megawatts," says Dan Kammen, director of the Renewable and Appropriate Energy Laboratory at the University of California, Berkeley. "Exploiting solar energy from deserts is a good idea worldwide." http://www.nature.com/news/2007/071127/full/450595a/box/1.html
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