Edison International (NYSE:EIX), subsidiary Southern California
Edison (SCE), and Stirling Energy Systems have entered into an agreement , subject to California Public Utilities Commission
approval, for the development of a 4.500 acre solar generating station 70 miles northeast of Los Angeles. Plans for the facility,
which relate to the 20-year power purchase agreement, are for a 500 megawatt solar project (with an option for 850 megawatts)
capable of generating enough power for 278,000 homes. Central to the clean energy facility, is Stirling dish technology. The
initial phase of the project includes a one megawatt test facility, which employs 40 of Stirling’s 37-foot diameter
dish assemblies. The next phase of the plan would result in a 20,000-dish array at the site, which is expected to be near
VictorVille, California.
Edison International indicated that the Stirling dish technology
has already been successfully tested for 20 years with more than 26,000 hours of solar operation. One such Stirling power
project is in operation at Sandia National Laboratories in Albuquerque, New Mexico., where President George Bush recently
signed one of the United States’ major energy bills.
Alan Fohrer, Chief Executive Officer at SCE, said in a statement
that the contract would not require a state subsidy and offers lower costs than other solar technologies, "We are especially
pleased about the financial benefits of this agreement for our customers and the state. 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."
So how does the Stirling dish technology work? A mirror array is
first used to focus the sun’s light rays onto the Stirling Engine’s receiver. The receiver then heats a container
of hydrogen gas, which expands as a result of the heat. The resultant pressure of the expanding gas, drives a piston, which
in turn is used to generate electricity. Unlike combustion engines however, the hydrogen gas is not ignited. This results
in an engine that is emission free. The complete energy conversion process is contained in a canister the size of an oil barrel,
according to Edison International.
The Stirling dish technology converts thermal energy to electricity
by using a mirror array to focus the sun's rays on the receiver of the 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.
The Stirling dish has been found to offer efficiencies that are
almost twice that of other solar technologies according to tests performed by SCE and Sandia National Laboratories.
