Solar Thermal Power May Make Sun-Powered Grid a Reality

 From: World of Solar Thermal - October 30, 2008

Read Full Article: World of Solar Thermal.com - News - Solar Thermal Power May Make Sun-Powered Grid a Reality

It's solar's new dawn. For five decades solar technologies have delivered more promises than power. Now, new Breakthrough Award–winning innovations are exiting the lab and plugging into the grid—turning sunlight into serious energy.

Planted in the New Mexico desert near Albuquerque, the six solar dish engines of the Solar Thermal Test Facility at Sandia National Laboratories look a bit like giant, highly reflective satellite dishes. Each one is a mosaic of 82 mirrors that fit together to form a 38-ft-wide parabola. The mirrors’ precise curvature focuses light onto a 7-in. area. At its most intense spot, the heat is equivalent to a blistering 13,000 suns, producing a flux 13 times greater than the space shuttle experiences during re-entry. “That’ll melt almost anything known to man,” says Sandia engineer Chuck Andraka. “It’s incredibly hot.” 

The heat is used to run a Stirling engine, an elegant 192-year-old technology that creates mechanical energy from an external heat source, as opposed to the internal fuel combustion that powers most auto mobile engines. Hydrogen gas in a Stirling engine’s four 95 cc cylinders expands and contracts as it is heated and cooled, driving pistons to turn a small electric generator.