Copyright © 2005
Pure Energy Systems News
ROSEMEAD, CA, USA -- A Stirling engine is commonly referred to as an
"external combustion engine" in contrast to the "internal
combustion engines" found in most vehicles. Combine a Stirling engine
with solar as the source of heat, and you have a highly efficient means of
converting solar power into usable energy.
That is what Stirling Energy Systems has been perfecting for the past 20 years.
Artists rendering of a large installation of the Stirling dish
On Aug. 8, 2005, President Bush toured
the DOE's National Solar Thermal Test Facility at the Sandia
National Laboratories complex, situated on Kirtland Air Force Base
in Albuquerque, N.M., where he signed the energy bill.
L to R: NM Senator Jeff Bingaman, Sandia's President Dr. Tom
Hunter, Sec of Energy Samuel Bodman, President Bush, NM Senator Pete
Domenici. (Photo Courtesy of Randy J. Montoya, Sandia National
Stirlings six-dish model installation at Sandia National
Laboratories in Albuquerque, NM. Note size of person in
relation to 37-foot-diameter dishes.
Vantage point from the ground.
Artists rendering of the inside of the Stirling engine
Artists rendering #2 of the inside of the Stirling engine
Artist's rendition of solar array.
Now they are ready to go big-time, with an agreement signed Tuesday with
Edison International (NYSE:EIX) a subsidiary of Southern California Edison (SCE),
the nation's leading purchaser of renewable energy.
On Tuesday they announced an agreement that could result in construction of a
massive, 4,500-acre solar generating station in Southern California. This comes
to around seven square miles, with a perimeter of nearly 30 miles. The
completed power station would be the world's largest solar facility, capable of
producing more electricity than all other currently-operating U.S. solar
This signing was a day after President George W. Bush visited their Sandia
National Laboratories installation where they have six prototypes in operation,
having chosen this location as his backdrop for the signing of the Energy bill.
Signed Tuesday, the 20-year power purchase agreement, 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-engine/solar-dish technology. This is enough power to run
approximately half a million homes.
According to the California Energy Commission, there are 966 power plants in
California that generate more than 0.1 MW. Of those, a 500 MW plant would
be in the top 3% for size.
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 companys
37-foot-diameter dish assemblies. (Each dish generates 25 kilowatts.) This phase
is slated to be completed in the first quarter of 2007. One of the 40-unit
arrays capable of a 1 MW output, will be dubbed a "solar power group"
and will be the basis of modular calculations for future installations.
Subsequently, the 20,000-dish array is to be constructed near Victorville,
California, during a four-year period, starting in early 2008. If Edison
opts for the additional 350 MW installation, that will take two more years, and
will bring the total number of panels to 34,000.
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.
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.
Gil Alexander, spokesperson for Southern California Edison said, "We
operate in a competitive marketplace. While [for confidentiality reasons]
we cannot give out precise dollar amounts for how much these installations will
cost, we believe the final agreement is very beneficial to our customers.
We do not need any subsidies to make this work."
Pioneering Stirling-solar to be Commercially Viable
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.
However, this isn't the first commercial application of Stirling engine
technology. For instance, Swedish submarines use Stirling engines for
How It Works
The Stirling dish technology converts thermal energy to electricity by using
a mirror array to focus the suns rays on the receiver end of a Stirling
engine. Each panel tracks azimuth and elevation to keep the suns rays focused
at greatest intensity possible.
The internal side of the receiver then heats hydrogen gas which expands. The
pressure created by the expanding gas drives a piston, crankshaft, 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 suns 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
While the number of potential applications for this technology is huge, in
the near term Stirling Energy Systems will be keeping their focus on these
- 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.
- SCEs current renewable portfolio can deliver 2,588 MW of electricity,
- 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.
About Southern California Edison
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. That includes 4.6
million customer accounts in a 50,000-square-mile service area within central,
coastal and Southern California.
About Stirling Energy Systems
According to their website,
Stirling Energy Systems (SES) is a systems integration and project management
company that is developing equipment for utility-scale renewable energy power
plants and distributed electric generating systems ("gensets"). For
establishing solar power plants, SES is teamed with Kockums Submarine Systems,
NASA-Glenn Laboratories, the U.S. Department of Energy (DOE), and The Boeing
SES is positioned to become a premier worldwide renewable-energy-technology
company, serving the global demand for renewable electric generating
technologies through the commercialization of its own Stirling cycle engine
technology for solar and genset applications. In the future, SES will also be
participating in the biogas, biogas, and hydrogen markets.
Besides the Sandia location, SES solar units are installed in Huntington Beach;
UNLV, Nevada; and near Johannesburg, South Africa, which is the largest power
plant in Africa. Stirling solar generator arrays had been installed in
Washington state, but are not there any longer. The company is in discussion
with parties from a number of other locations.
Installations, actual and potential, as of August,
Beginnings with Ford Motor Company
Energy Systems CEO, Bruce Osborn, said that this technology using the Stirling
engine actually had its beginning 25 years ago when he worked for the Ford Motor
Company. They were investigating the technology, and he was part of that
project. In the interim, the technology changed hands several times until
it came under Stirling Engine Systems.
The support system for each 37-foot-diameter Stirling-solar unit is very similar
to the chassis of an automobile. Other similarities can be found as well.
"The system is very conducive to mass production," said Osborn.
"We're looking at this as a historic event for solar energy -- a
milestone," he said. This will be the first large-scale, grid-level
installation of solar technology anywhere in the world.
"We're happy to be the first ones to do this."
Osborn also noted that SES holds the world's record for efficiently converting
sunlight to usable energy.
Their biggest problem will be to keep from growing too fast, he said.
There will be many metamorphoses as they transform from a small company into a
large one. "It is very tempting" to chase after some of the
other myriad of applications, "but we have to keep our focus."
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Stirling Engine Systems602-957-1818