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Feb 022009
 

By Catherine Girardeau
Green Right Now

Renewable energy companies are no doubt pleased that the proposed economic stimulus plan being considered by Congress could double the nation’s clean energy capacity — enough to power six million American homes.

The White House agenda calls for even more progress: The administration wants incentives to increase private sector spending in renewable energy; a cap-and-trade system that would make heavy industries like coal-burning power plants pay for carbon pollution and a declared goal that America reduce greenhouse gases 80 percent by 2050.

It’s shaping up to be a perfect storm for companies that can figure out how to generate renewable energy, including solar thermal companies which intend to compete with wind and direct solar as large-scale energy providers, despite the cool economy.

“You’ve got all the market drivers. You’ve got climate change, you’ve got the broader awareness of policy makers that we’ve got to do something, you’ve got countries seeking energy independence,” said Keely Wachs, senior director of corporate communications at Oakland, CA-based BrightSource Energy.

“The Energy Information Administration predicts that electricity demand will double by 2030,” Wachs said. “Is it best for us to meet that demand with fossil fuels, or should we meet that demand with clean energy?”

Solar thermal, also called “Concentrating Solar Power (CSP)”, uses sunlight to produce steam, which is then used to generate electricity. Solar thermal systems concentrate the sunlight, in much the same way that a magnifying glass does, to harness its heat.  The sunlight heats water, which makes steam, which drives an electricity-generation engine.

By contrast, photo-voltaic (PV) systems convert sunlight (photons) into heat energy (electrons) to generate electricity directly.

Purveyors of solar thermal energy are not making solar arrays you can put on your roof. Solar thermal is large-scale, and solar thermal companies are positioning themselves to make a much bigger impact by selling solar energy to industrial users and utilities.

Why solar thermal?

For one, solar thermal plants are cheaper to build on a large scale. Steel and glass are the main ingredients of a solar thermal system, whereas photovoltaic (PV) systems require specialized and more expensive materials like poly-silicone. Solar thermal is also more efficient than PV systems. PV systems can typically utilize about 20% of the sunlight that hits them, whereas BrightSource claims its solar thermal systems can turn 60% of the available sunlight into energy.