Cheap solar energy

The world’s largest solar dish has the potential to generate energy for about 5 cents (U.S.) per kilowatt-hour (kWh), according to David Faiman, director of Ben-Gurion University of the Negev's National Solar Energy Center in Israel, where the dish has been built. In comparison, solar electricity generally costs around 30 cents per kWh, according to Solarbuzz, Inc., an international solar energy research and consulting company.

The 400-square-meter (m2) dish, which is known as the Photon Energy Transformer and Astrophysics Laboratory (PETAL), can generate approximately 400 kW of thermal energy at intensities up to 10,000 times stronger than noontime sunshine.

To generate solar energy at a price that “no other solar energy can come anywhere near,” Faiman says, the dish must be used in conjunction with solar photovoltaic (PV) cells. He plans to use the dish to illuminate 1 m2 of PV cells, which will be actively cooled to 60 °C. “Under such conditions, the cells should have a peak power of about 100 kW and produce about 150,000 kWh,” he explains.

Faiman’s calculations are based on using 23% efficient solar cells; the economics would be proportionately better if he used 40% efficient solar cells, which are expected to be available soon, he says. He also notes that the 60 °C cooling water could be reused for other purposes, such as refrigeration or water desalinization projects.