BrightSource’s 370-megawatt facility near Las Vegas is taking shape, but the future of solar thermal is much more fuzzy.
By Kevin Bullis
Why: It efficiently produces solar thermal power, which focuses sunlight to heat water into steam.
Key innovation: A boiler is heated directly with sunlight that bounces off mirrors.
BrightSource is cutting the cost of solar thermal power by using sunlight directed from thousands of sun-tracking mirrors to heat a boiler placed atop a tower at the center of the installation. While other concentrating solar systems heat tubes of oil that then circulate to the boiler, BrightSource's tower design allows the mirrors to concentrate light directly onto the boiler, where it heats the water to 538 °C, creating superheated steam that is then piped to a conventional turbine to generate electricity. To conserve water in the desert, where the systems will be installed, the steam is cooled and recirculated back into the boiler.
The company has signed purchase agreements with Pacific Gas & Electric and Southern California Edison for 2.6 gigawatts of power. It plans to build over a dozen plants by 2017 to fulfill those contracts.
To finance its first large-scale project in California, a 370-megawatt installation now under construction in the Mojave Desert, BrightSource secured a $1.4 billion loan guarantee from the U.S. Department of Energy. The plant, which will double the amount of solar thermal power capacity in the United States, is scheduled to begin generating electricity in 2013. BrightSource's pilot facility in Israel has already demonstrated the viability of the approach on a smaller scale.
Challenges and Next Steps:
The federal loan-guarantee program expires in September, so once BrightSource’s first full-scale project in California is completed, it will have to deliver power with the efficiency and reliability its technology promises in order to secure private funding for expansion.