Low-cost Solar Thermal Plants at Heart of Algerian-German Research Push

The end of a Luz system two (LS-2) parabolic trough system collector assembly in operation. Credit: Henry Price

The development of a new generation of large-scale, low-cost solar thermal power plants is the focus of a joint research agreement signed between Algeria and Germany.

Researchers will be sharing data and expertise to speed up the market introduction of large-scale solar thermal plants. The plants could supply up to 200 megawatts (MW) of electricity and desalinate water for 50,000 people.

Electricity from solar thermal plants could cost as little as €0.04/kilowatt hour (kWh) [US $0.06/kWh] by 2015 to 2020, Bernhard Milow from the German Aerospace Center (DLR) said. And using solar thermal power to desalinate seawater could cost the same.

"The technology and science is all there. It's just a question of transferring that knowledge to those who have the sunshine and optimizing the technology to make it competitive," Milow said.

Electricity from solar thermal plants currently costs €0.20 to 0.30/kWh [US $0.31 to 0.47/kWh], depending on the location of the plant and the amount of sunshine it receives. But with improvements in the performance of plants and better sites, solar thermal electricity could soon be cheaper than coal, and so generate huge amounts of reliable, clean electricity in hot desert regions, Milow said.

Even factoring in high steel prices and other costs, a kWh of electricity could still be as low as €0.06-0.07/kWh [US $0.09-0.11/kWh] if the power plants are in prime locations, Milow said.

By 2050, he estimated that 10 - 25 percent of Europe's electricity needs could be supplied by North African solar thermal plants.

The agreement between the DLR in Germany and the New Energy Algeria (NEAL) in Algeria will allow German researchers access to data from the 150 MW hybrid solar-gas plant at Hassi R'mel, 420 kilometers south of Algiers. The plant is due to go into operation in 2009 and has a 25 MW solar energy capacity with a parabola trough design. The DLR researchers will look at ways of optimizing the design and manufacture of the component parts and the efficiency of the collectors and absorbers.

Another area for research will be thermal storage technology.

"The DLR has 30 years of experience in solar thermal power technology while Algeria has the right sites for these plants, and has committed itself developing the technology for its own use and for export to Europe, so we can help each other out," Milow said.

Algeria has introduced a feed-in tariff for electricity from solar thermal plants to boost the use of the technology, and NEAL plans to build pure solar thermal plants without gas as soon as the technology allows it. The typical solar thermal plant of the future could be as large 200 MW and supply electricity to 250,000 people and fresh water to 50,000 people.

In fact, solar thermal desalination plants could turn as much as 100,000 m³ / day of sea water into fresh, clean water — and so help boost agriculture and secure the supply of drinking water in a region increasingly hit by drought. According to a German study, there is already a shortfall of 50 billion cubic meters of fresh water in the region and that shortfall is set to grow to 150 billion by 2050. Algeria is particularly rich in sites suitable for solar thermal desalination plants.

The DLR has identified the best locations for plants using satellite images to encourage investment.

"80 percent of the finance for solar thermal projects will come from private investors who will be looking for the best return. That means finding places where there are as few clouds as possible," said Milow.

The DLR has used weather data going back for decades to identity locations with the most sunshine. An average of 2200 kWh of solar radiation falls on each square meter of Algeria with 2650 kWh falling on the Sahara desert region; this compares to just 1000 kWh falling on a square meter in Germany. One study estimated that solar energy harnessed just from Algeria could supply 60 times the electricity needs of Europe.

To transport the electricity to Europe, a 1,875 mile high voltage direct current cable is to be built between Algeria and Germany, running through Sardinia, Italy and Switzerland.

"Getting permission from all these countries to build this cable could slow down the project for years because of all the red tape. But the cable will be able to carry electricity to Europe with only about a 10 percent loss," Milow said. He said small quantities of electricity could be imported into Germany as early as 2010.

The DLR is also carrying out parallel research on a pilot 1.5 MW solar tower power plant in Julich in northern Germany.

"We need to do research on several solar thermal technologies to find the best one," Milow said.

He said that the same model could be used in Australia for electricity and water desalination.

"Plants in Australia could even supply enough fresh water to ensure good, reliable harvests in key crop growing areas that have seen yields drop dramatically because of drought. Israel already successfully uses desalinated water for agriculture, so it has been shown to work in practice, " said Milow.

The southern states of America could also expand their solar thermal plants and eventually export electricity to the northern states, Milow said. Solar thermal power plants have been in commercial use in southern California since 1985. Last year, the 64 MW parabola trough Nevada Solar One plant went into operation.

In Spain, 10 new solar thermal plants are being planned. Spain, which introduced a 25-year guaranteed feed-in tariff of €0.26/kWh [US $0.40/kWh] for solar thermal electricity, is building Europe's two biggest parabola trough solar power plants, Andasol I and II, in Andalusia. The 11 MW PS10 solar power tower has also started operating close to Seville in southern Spain.

New plants are also being planned in Abu Dhabi, Eygpt, Iran, Israel, Mexico, and Morocco. Milow said Morocco and the Red Sea region could also tap wind power in addition to the sunshine to generate clean energy.

"Energy in the future will come from many different sources, including biomass and geothermal, but solar thermal power plants can definitely play a big part when they become cost competitive," he said.

Looking into the future, networks of decentralized and overlapping renewable energy technologies complemented by irrigation networks and water desalination plants could power economies — and large-scale solar thermal power plants could be playing a key role in the energy supply of many regions.

Jane Burgermeister is a RenewableEnergyWorld.com European Correspondent based in Austria.