Energy from a Thousand Suns

Old Technology rediscovered
It is not just in the Sahara that the expertise of the DLR is in demand: Climate regulations oblige energy providers to considerable increase their eco-energy proportions in the near future. In sunny Spain, they want to set up solar energy power stations with 800 megawatt (MW) capacity by the end of 2010. In the hot south-west of the United States, 6000 MW are planned. Special subsidy programmes are firing up the building boom: about 0.27 Euro per fed-in kilowatt hour of solar heat energy is paid to power station operators in Spain. In the USA, investors can deduct up to 30 percent of the investment from their taxes. Experts believe solar power stations to be so efficient that they will soon get by without any subsidies. “The cost reduction potential of this technology is enormous,” explains Trieb.

The idea of creating energy using the sun’s heat is not a new one. As early as the times of the oil crisis in the 1980s, the first parabolic trough power station was built on the Californian Mojave desert. Giant fields of parabolically concave reflectors throw their light onto long absorber pipes. The medium circulating within heats up to 400 degrees Celsius as a result, flows through heat exchangers and generates steam which drives a generator using a turbine. However, no matter how reliably these solar strongmen worked – when the oil prices fell again, people lost interest in them. Only at the Plataforma Solar de Almería research centre in Andalusia did Spanish and German engineers continue to deal intensively with the technology. They perfected the parabolic troughs, while developing new power station concepts. In 2007, with the commissioning of the 64 MW power station Nevada Solar One near Las Vegas, solar heat finally got its breakthrough. Spanish construction company Acciona built the plant for 250 million dollars, operating it on the basis of energy transfer contracts with regional energy providers.

Erlangen-based power station builder Solar Millennium is now making even bigger plans: The company wants to build three parabolic troughs in California’s Kern County with a total capacity of 726 MW. Each of these systems is almost four times the size of the Nevada block. The key components for this, the absorber pipes, will be provided by Mainz glass specialist Schott. The company is among the regular exhibitors at the Glasstec, the world’s biggest trade fair of the international glass industry, and will also present its innovations there this coming year (28.09 to 01.10.09). The energy provider Southern California Edison will accept the energy generated in Kern County. Solar Millennium is currently negotiating about further plants in the USA, as company spokesperson Sven Moormann explains, “Providers have selected more than 1,500 MW.”