On November 28th, 2011 BrightSource Energy Inc. (Oakland, California, U.S.) announced that it has added thermal storage to three power purchase agreements (PPAs) with Southern California Edison Company (SCE, Rosemead, California, U.S.) for the sale of electricity from concentrating solar power (CSP) plants.

BrightSource notes that by adding storage to its CSP plants, it is able to further reduce the total cost of energy by increasing its capacity factor. Under the new agreements, which will go before the California Public Utilities Commission for approval, the company will supply power from six CSP plants instead of seven, as previously planned.

"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," said BrightSource Energy President and CEO John Woolard.

"We're thrilled to offer Southern California Edison a solution that provides higher value for its customers, while supporting a more reliable and stable grid for all Californians."

Plants to utilize solar power tower design

BrightSource also notes that the addition of thermal storage allows it to extend electricity production into later periods of the day, when utilities have a large need for power.

The PPAs in question cover the sale of electricity which will be produced by BrightSource CSP plants which utilize solar power tower designs. This design involves a field of mirrors (heliostats) which concentrate light onto water vapor in a central receiver, which is used to drive turbines.

With the addition of molten salt thermal storage, a portion of this steam is directed to a heat exchanger, where the heat is transferred to molten salts, storing the energy for later use.

Contracts to cover plants scheduled for commissioning in 2016, 2017

Under the original PPAs with SCE, BrightSource would provide approximately 4 million MWh of electricity across seven power plants. BrightSource states that due to higher efficiencies and capacity factors associated with energy storage, it can now offer the same amount of electricity annually with only six plants.

The new set of contracts will cover two BrightSource CSP plants scheduled to go online in 2015, as well as three plants with energy storage scheduled for commissioning in 2016 and 2017.

Additionally, BrightSource is currently building a 126 MW CSP plant as part of its Ivanpah project in Southern California.

2011-12-01| Courtesy:BrightSource Energy Inc.  | solarserver.com © Heindl Server GmbH

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