By Kari Williamson

The storage could further reduce the total cost of energy by increasing the capacity factor of solar thermal power, extending the production of electricity into later parts of the day when it is most needed by utilities.

“With these agreements, we’re demonstrating that power tower technology is not only advancing the solar thermal industry, but that utility-scale solar generation can be both cost effective and reliable,” says John Woolard, President and CEO of BrightSource Energy.

Under the original power purchase agreements with Southern California Edison, BrightSource would provide approximately 4 TWh of electricity annually across 7 power plants. Due to higher efficiencies and capacity factors associated with energy storage, the new set of agreements will provide approximately the same amount of energy annually but with one less plant, reducing the land impacts of delivering this energy and avoiding transactional costs that ultimately impact California’s ratepayers.

The new set of contracts, if approved by the California Public Utilities Commission, consist of two BrightSource solar thermal plants scheduled to deliver electricity in 2015 and three BrightSource plants with energy storage scheduled to deliver electricity in 2016 and 2017.

In addition, BrightSource and its partners – NRG Energy, Google and Bechtel - are currently constructing a 126 MW plant for Southern California Edison at the Ivanpah solar project in south-east California.

California encourages storage

California recently passed Assembly Bill 2514, landmark legislation designed to encourage the adoption of energy storage technologies.

"Energy storage improves the overall efficiency of our electric power system which will lower costs for consumers," says Assembly Member Nancy Skinner (D – Berkeley), author of the bill. "The Assembly's passage of AB 2514 is another step that advances California's clean energy economy and represents a great economic opportunity for the State."