August 9, 2005

ROSEMEAD, Calif., Aug. 9, 2005—Edison International (NYSE:EIX) subsidiary Southern California Edison (SCE), the nation’s leading purchaser of renewable energy, and Stirling Energy Systems today announced an agreement that could result in construction of a massive, 4,500-acre solar generating station in Southern California.  When completed, the proposed power station would be the world’s largest solar facility, capable of producing more electricity than all other U.S. solar projects combined.

The 20-year power purchase agreement signed today, which is subject to California Public Utilities Commission approval, calls for development of a 500-megawatt (MW) solar project 70 miles northeast of Los Angeles using innovative Stirling dish technology.  The agreement includes an option to expand the project to 850 MW.  Initially, Stirling would build a one-MW test facility using 40 of the company’s 37-foot-diameter dish assemblies.  Subsequently, a 20,000-dish array would be constructed near Victorville, Calif., during a four-year period. 

“At a time of rising fossil-fuel costs and increased concern about greenhouse-gas emissions, the Stirling project would provide enough clean power to serve 278,000 homes for an entire year,” said SCE Chairman John Bryson.  “Edison is committed to facilitating development of new, environmentally sensitive, renewable energy technologies to meet the growing demand for electricity here and throughout the U.S.”

Although Stirling dish technology has been successfully tested for 20 years, the SCE-Stirling project represents its first major application in the commercial electricity generation field.  Experimental models of the Stirling dish technology have undergone more than 26,000 hours of successful solar operation.  A six-dish model Stirling power project is currently operating at the Sandia National Laboratories in Albuquerque, New Mexico.

“We are especially pleased about the financial benefits of this agreement for our customers and the state,” said Alan Fohrer, SCE chief executive officer.  “The contract requires no state subsidy and provides favorable pricing for ratepayers because tests have shown the Stirling dish technology can produce electricity at significantly lower costs than other solar technologies.”

How It Works

The Stirling dish technology converts thermal energy to electricity by using a mirror array to focus the sun’s rays on the receiver end of a Stirling engine.  The internal side of the receiver then heats hydrogen gas which expands.  The pressure created by the expanding gas drives a piston, crank shaft, and drive shaft assembly much like those found in internal combustion engines but without igniting the gas.  The drive shaft turns a small electricity generator.  The entire energy conversion process takes place within a canister the size of an oil barrel.  The process requires no water and the engine is emission-free.

Comparison to Other Solar Technologies

Tests conducted by SCE and the Sandia National Laboratories have shown that the Stirling dish technology is almost twice as efficient as other solar technologies.  These include parabolic troughs which use the sun’s heat to create steam that drives turbines similar to those found in conventional power plants, and photovoltaic cells which convert sunlight directly into electricity by means of semiconducting materials like those found in computer chips. 

Related Facts

  • SCE procured more than 13,000 gigawatt-hours* of renewable energy in 2004, more than any U.S. utility and enough to power almost two million homes for an entire year.
  • In 2004, more than 18% of the power SCE delivered to the 13 million Californians it serves came from renewable energy sources.
  • SCE’s current renewable portfolio can deliver 2,588 MW of electricity, including
    - 1,021 MW from wind
    - 892 MW from geothermal
    - 354 MW from solar
    - 226 MW from biomass
    - 95 MW from small hydro.
  • Within the next several weeks, SCE will launch its ninth request for offers by independent power producers in the past three years and the third exclusively for proposals by renewable energy providers.  These open, competitive solicitations have resulted in 12 new renewable contracts with a maximum potential capacity of 1,630 MW.

*A gigawatt equals one billion watts.

Visuals available at
Under “Press Kits”, “Edison, America’s Leading Purchaser of Renewable Energy”

  • Two 300 dpi photos of Stirling dish
  • Two artists renderings, one of the inside of a Stirling engine, the other of a large installation of Stirling dishes
  • An animated clip of how the Stirling engine generates electricity
  • Time-lapse photography of a Stirling dish tracking the sun from dawn to dusk

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An Edison International (NYSE:EIX) company, Southern California Edison is one of the nation’s largest electric utilities, serving a population of more than 13 million via 4.6 million customer accounts in a 50,000-square-mile service area within central, coastal and Southern California.