Energy from a Thousand Suns

In the Focus of Energy Giants
Solar Millennium is also doing well in Spain: It developed the 150 MW project Andasol, which is currently being built near Granada. The first of three sub-sections of the plant is already up and running. Its dimensions are impressive: On a surface of 510,000 square metres or 70 football pitches, reflectors catch the Andalusian sun. However, the special feature of Andasol 1 is that it is using large-scale storage technology for the first time: In two large tanks, excess heat is stored in liquid salt in the afternoons. In this way, the power station can also produce energy in the dark. “The power stations can be calculated in the base load as a result,” says Manuel Silva, professor at the school of engineering at Seville University. In addition to a decentralised, fluctuating energy production through photovoltaics and wind power, large central power stations could also be operated with it.

This makes the technology interesting for the energy economy: Seven plants are now up and running in Spain. Construction is taking place in more than 20 power station sites. The fact that Madrid officially only wants to support 500 MW solar capacity is apparently leaving the industry cold: According to industry association Protermosolar, 800 MW should exist by 2010. There are even plans for 13,000 MW.

Decreasing investment costs could further accelerate the growth of solar heat. The learning curve, the reduction of costs for technology with a doubling of capacity, is very good with about twelve percent for reflector power stations, explains Trieb. Innovations also promote cost reductions. In a new trial power station in Jülich, engineers from the DLR and FH Aachen are researching the technology of tomorrow: Reflectors throw their light onto a receiver, which is located at the peak of a 60 metre high tower. As a result, air is heated to 700 degrees and generates steam for energy production. In the future, researchers want to create temperatures of 1,000 degrees, thus increasing efficiency to more than 25 percent. The conventional troughs only achieve 15 percent. The technical progress feeds the hope that the Desertec project will not just remain a bold vision.

Sascha Rentzing