World's largest solar installation to use Stirling engine technology

20-year purchase agreement between Southern California Edison and Stirling Energy Systems, Inc. will result in 20,000+ dish array, covering 4,500 acres, and capable of generating 500 MW -- more electricity than all other present U.S. solar projects combined.

    "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."

-- Gil Alexander (Aug. 11, 2005)
Spokesperson, Southern California Edison

by Sterling D. Allan
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.

Artist’s rendering of a large installation of the Stirling dish arrays

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 Laboratories)

Stirling’s 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.

Artist’s rendering of the inside of the Stirling engine

Artist’s rendering #2 of the inside of the Stirling engine

Artist's rendition of solar array.

• Solar dish QuickTime movie (11MB)
• Photo Gallery
• Artist’s Flash animation depicting how the Stirling engine converts solar thermal energy into electricity.

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 projects combined.

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 company’s 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 propulsion. (ref)

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. Each panel tracks azimuth and elevation to keep the sun’s 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 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. 


Additional Applications

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 utility installations.

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.

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 Company.

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, 2005.
Source: http://stirlingenergy.com

Beginnings with Ford Motor Company

Stirling 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."

# # #

SOURCES

• BusinessWire press release, Aug. 9, 2005
• http://www.edisonnews.com
• http://www.stirlingenergy.com
• Phone interview with Gil Alexander, Spokesperson, Southern California Edison; Aug. 11, 2005
• Phone interview with Bruce Osborn, CEO, Stirling Energy Systems; Aug. 11, 2005
• http://usinfo.state.gov/gi/Archive/2005/Aug/09-544662.html?chanlid=globalissues - Bush tours Sandia facility.
• http://www.southbendtribune.com/stories/2005/08/09/nation.20050809... - another photo of President Bush

CONTACTS

Stirling Engine Systems
http://stirlingenergy.com/
602-957-1818
Bruce Osborn, CEO
or Robert Liden, Executive VP, General Manager

Edison International
Corporate Communications, 626-302-2255
www.edisonnews.com

Close Competitor

• IAUS to Push Solar to Within Competitive Range of Grid Power - Thermal solar panels coming into production in September will produce electricity at 3-5 cents per kilowatt-hour. Highly-efficient bladeless turbine has wide range of waste-heat-harnessing applications.  Methanol production technique will draw CO2 out of the environment, reversing global warming. (PESN; August 2, 2005)

Follow-up Coverage

• Stirling Energy Systems Signs New Contract for 300 MW - Stirling engine design company has signed a second contract with a major utility in California.  Newest contract has options to go to 900MW.  Say it is grid competitive. (PESN; October 12, 2005)

Related Coverage

• Start-up sees new dawn for old solar tech - (CNET News.com; Aug. 14) [They errantly state that Southern California Edison turned them down, when in fact SCE signed a purchase agreement last week to install 500 MW.]
• Steampunk Solar Power (WorldChanging; Aug. 11)
• Sandia joins forces with Stirling Energy Systems to build, test mini power plant of six solar dish systems (Sandia.gov; Oct. 29, 2004)
• Солнечные стирлинги дают бой альтернативной энергетике - (Business-Idea.ru;
• July 2005 in Inc. Magazine
  If David Slawson is right about solar power, our days of oil dependency are numbered.
• May 2005 in Fortune Magazine
  Stirling Energy Systems makes Fortune Magazine’s 25 BREAKOUT COMPANIES 2005.
• Feb 2005 in Popular Science Magazine
  Dishing Out Real Power - Costs are down, interest is up, and the Stirling solar system is ready to flick the switch.
• Jan 2005 in US News
  It has been said that solar energy is the future of energy and always will be. But growing concern about climate change and high oil prices is generating new interest in ways to more efficiently capture the power of the sun.
• http://isolenr.free.fr/page_fr/accueil_fr.html

Feedback

• World's Largest Solar Array to use Stirling Engine - Slashdot link to the above story; with hundreds of feedback comments. (Aug. 11, 2005)
  
  • "Sterling engines are pretty cool. They have one huge advantage over silicon solar power: much much less pollution in production. Photovoltaics are basically large chips, they use the same nasty chemicals and lots of electricity. Sterling engines are just machines, and very scalable apparently." (J05H (5625); August 11, @08:57PM)
    
  • "Any solar technology that doesn't use silicon is definitely a good thing these days. The Photovoltaic industry is the "poor cousin of the microchip industry", and so microchips get all the good silicon while PV gets the leftover crap that Intel et al. don't want. For this reason, and a general shortage of poly-silicon, there is a huge shortage of PV panels all over the world. Germany and Japan gobble up all they can and at a fair price too, leaving hardly anything for the rest of the world.  It's good to see the Stirling engine being used like this because in my opinion, the PV industry has some serious problems, especially if they have to compete with the Slashdot crowd for silicon!" (grqb (410789); August 12, @06:07AM)
    
  • "This is the sort of stuff I read Slashdot for. I'm so freaking excited right now. A few days in the past few years I've really sat down and thought about Solar Energy. I thought of ways to make solar powered distillation of pure water by creating heat differentials. I also considered macro heat differential potential of using black tires thrown away into the desert, and harnessing wind. I also thought that if a house has its own batteries, it could last through blackouts, and with solar powers, offset some of the power costs of the house. You could even take battery arrays from your car, and switch them with your house one, so your car gets new power immediately, and the old power pack starts charging. I went through many ideas, but for some reason I never thought Sterling. Now I have a ton to think about. I can't wait to get my hands on some Sterling Engines, and use magnifying glasses and mirrors to harness sunlight. I want to sit down and do the math to figure out what the most optimal configuration you need to have sunlight heat up a material. I want to figure out what the best material to heat up is, and I want to figure out what size and make of sterling engine is best to sit on it. Once you figure out the best way to run a sterling engine, all you need to do is mass produce it and sit it in the desert somewhere for loads of money. To me, this stuff is very exciting, its like an engineering breakthrough." (CrazyJim1 (809850); August 11, @09:29PM)
    
  • "In related news, ants in a 4500-acre area have all mysteriously vanished." (Junior J. Junior III (192702); August 11, @09:08PM)