All done by mirrors

Using solar power to drive turbines could become much more affordable following the development of a solar energy system with cheaper components by Germany's Fraunhofer Institute.

The prototype system, set up for testing in Almeria, Spain, last week, will be trialled until the end of next year. Designed to be more cost-effective than traditional solar energy systems, it uses linear Fresnel mirrors to collect the sun's radiation, and water instead of thermal oil is heated to produce the steam to power turbines.

The solar platform comprises a primary mirror field, an absorber tube and a secondary mirror. The primary mirror field has 25 rows of flat mirrors on the ground, each 100m long by 60cm wide, which reflect the sun's rays on to a 100m-long absorber tube hanging several metres above the primary field. Above the absorber tube is a secondary mirror that concentrates any remaining reflected light on to the linear tube.