December 21, 2005
SDG&E gets state approval for solar power plan
LOS ANGELES (Reuters) - San Diego Gas & Electric will use
solar energy generated from dishes in the Imperial Valley east
of San Diego that could eventually power more than a half
million homes, the company announced on Tuesday.
SDG&E's contracts to buy 300 megawatts of solar-generated
electricity during peak -- sunny -- hours from Stirling Energy
Systems of Phoenix, Arizona were approved last Thursday by the
California Public Utilities Commission. If two more phases of
the project are completed, it could mean 900 megawatts for
SDG&E during peak hours by 2016.
Four months ago, Southern California Edison signed a deal
with Stirling to buy 500 megawatts of power from solar panels
and Stirling engines on 4,500 acres near Victorville,
California about 70 miles northeast of Los Angeles.
The So Cal Ed deal with Stirling can expand to 850
Both projects would be among the largest solar energy
fields in the world.
Together, the two proposed projects could supply peak-hour
electricity to about 1.1 million homes, based on an estimate of
650 homes per megawatt in Southern California.
In the SDG&E deal, Stirling by 2008 or 2009 will sell power
to the San Diego utility, said SDG&E vice president for
electric and gas procurement, Terry Farrelly.
The sun will shine on three square miles of solar dishes in
the southeastern California's Imperial Valley to turn
generators using updated Stirling engines. The Stirling engine
was first developed in 1816, the utility said in a news
The Stirling engine has four sealed cylinders containing
hydrogen or helium. When a cylinder is heated, the gas expands
and pushes a piston, and when the gas cools, the piston
The action of the piston turns a generator, producing
"The project will provide clean, renewable solar energy and
move us closer to achieving our goal to supply 20 percent of
our customers' needs from renewable resources by 2010," said
SDG&E's vice president for electricity and gas procurement,
The plan is for the power to be transmitted to SDG&E's
customers by 2010 on the proposed 500-kilovolt Sunrise
Powerlink. The line will cost between $1 billion and $1.4
billion to build and will stretch over 100 miles from the
Imperial Valley to San Diego.
It takes 40 Stirling engines to create a megawatt of
electricity and each engine gathers sunlight on
SDG&E is a subsidiary of Sempra Energy.
The So Cal Ed plan near Victorville would need 20,000
dishes that will be built over a four-year span.
So Cal Ed said a six-dish model Stirling power project is
currently operating at the Sandia National Laboratories in
Albuquerque, New Mexico.
So Cal Ed is a subsidiary of Edison International based in
Rosemead, California east of Los Angeles.