Nearly three years ago, two Southern California utilities caused a stir when they announced deals to buy up to 1.75 gigawatts of electricity from massive solar farms to be built by Stirling Energy Systems of Phoenix. The company had developed a Stirling solar dish – a 38-foot-high, 40-foot-wide mirrored structure that looks like a big shiny satellite receiver. The dish focuses the sun’s rays on a Stirling engine, heating hydrogen gas to drive pistons that generate electricity.
Plans called for as many as 70,000 solar dishes to carpet the desert. For Southern California Edison (EIX) and San Diego Gas & Electric (SRE) – both facing a state mandate to obtain 20 percent of their electricity from renewable sources by 2010 – it was a big gamble. As the years ticked by and Stirling tinkered with its technology, competitors like Ausra, BrightSource Energy and Solel came out of stealth mode and stole the limelight, signing deals with PG&E (PCG) and filing applications with California regulators to build solar power plants. By the time I visited Stirling’s test site in New Mexico in March 2007 for a Business 2.0 feature story, industry insiders were telling me – privately, of course – that Stirling would never make it; Stirling dishes were just too complex and too expensive to compete against more traditional solar technologies.
That may or may not end up being true, but Stirling has moved to silence the naysayers by filing a license application with the California Energy Commission for its first solar power plant – the world’s largest – a 30,000-dish, 750-megawatt project to be built 100 miles east of San Diego on 6,100 acres of federal land controlled by the U.S. Bureau of Land Management. (A energy commission licence application – an extremely detailed and expensive document; Stirling’s runs 2,600 pages – is considered a sign that a project has the wherewithal to move forward.)
The first phase of the SES Solar Two project will consist of 12,000 SunCatcher dishes generating 300 megawatts for San Diego Gas & Electric. While the Stirling solar dish is more complex and contains more moving parts than other solar thermal technologies – which use mirrors to heat liquids to generate steam to drive a standard electricity-generating turbine – or photovoltaic panels like those found on rooftops, it also offers some distinct advantages. For one thing, it’s the most efficient solar thermal technology, converting sunlight into electricity at a 31.25% rate. Each 25-kilowatt dish is in fact a self-contained mini-power plant that can start generating electricity – and cash – as soon as it is installed. Stirling will build 1.5-megawatt clusters of 60 dishes that will begin paying for themselves as each pod goes online. A conventional solar thermal power plant, of course, must be completely built out – which can take a year or two depending on size – before generating electricity.
The 750-megawatt Stirling project will also use relatively little water – no small matter in the desert – compared to other solar thermal plants. According to Stirling, SES Solar Two will consume 33 acre-feet of water – to wash the dishs’ mirrors – which is equivalent to the annual water use of 33 Southern California households. In contrast, a solar power plant to be built by BrightSource Energy that is nearly half the size is projected to use 100 acre-feet of water annually while a 177-megawatt Ausra plant would use 22 acre-feet, according to the companies’ license applications.
Still, there’s some big hurdles for Stirling to overcome. While it did score a whopping $100 million in funding in April from Irish renewable energy company NTR, the company will need billions in project financing to build Solar Two. And the project’s second 450-megawatt phase is dependent on the utility completing a controversial new transmission line through the desert called the Sunrise Powerlink. Depending on how fast the project is approved, construction is expected to begin in 2009 and last more than three years.
The other big unknown is what environmental opposition may develop. Within 10 miles of the SES Solar Two site are proposals to build solar power plants on an additional 51,457 acres of BLM land. Then there are the wildlife issues. Several California-listed “species of special concern” have been found on the Stirling site, including the burrowing owl, flat-tailed horned lizard and the California horned lark.
Regardless it’s a big step forward for Stirling. As California Governor Arnold Schwarzenegger said in a statement, “This groundbreaking solar energy project is a perfect example of the clean renewable energy California can and will generate to meet our long-term energy and climate change goals.”
Green Wombat 
Well I would guess we may have spoken to some of those same industry insiders. Many feel that these will use far too much land, for the amount of energy they produce and they are vastly underestimating the amount of maintenance these things are going to require. It is one thing to have a few that are hand built but quite another to put 20,000 in the field. About the only advantage I see with the dishes is water use. They can talk efficiency all they want but if they use more land and end up costing more, then it is just smoke and mirrors.
What do you mean by too much land? If they are that efficient, they must use less land per unit of energy than any other technology. Where is your source for this (mis)information?
I think what Steve in Victorville is talking about is that tracking solar units need to be spaced far apart so that their shadow footprints don’t interfere with each other.
I think that part of the problem is that all these huge numbers are being thrown about and there’s no real perspective. So here’s the perspective.
San Diego has 45,000 acres of parkland within it’s city limits (which consequently makes it the #2 city in park to person in the nation). The entire city itself took up 207,360 acres (640 acres per square mile) in 2000.
And keep in mind that there’s not much out there in the desert where these units are being installed. If anything, it is entirely possible that the impact on the fauna in the area will be positive, rather than negative. They are creating shade areas in the desert, after all.
What about dust storms and harsh weather impact on these panels?
Freemarket my source of information is the internet and the fact I work in the solar-thermal industry. If you would have spent the time looking at a couple of websites, you spent with your reply, you may have come off a little more intelligent.
Moekandu as I understand the project they are not going to build it on any of San Diego’s Parks so land use is a very big issue. I believe Todd recently wrote an article about the problems with getting land for solar projects, not sure why it has not been posted on here yet. While I believe solar projects can coexist with the desert, it will definitely change the area they are in. My problems with the efficiency claims is that they are basically only good for press releases. In the end they things that matter most are costs, environmental issues, energy produced and reliability.
In my opinion for solar to ever really be significant we need to have plants that act like conventional power plants. That is be able to adjust load to meet demand. I just don’t see how this type of technology can be adapted for this. Other forms of solar thermal are working on solar storage that will at the very least allow them to adjust load and extend the day. Imagine what stresses the electrical grid will face if clouds move in on these units and they very abruptly stop producing. (Believe me this is very common) More conventional types of solar thermal will slowly start to lose load and they slowly gain it when the sun comes back. These, along with PV, appear to be more lights on, lights off.
Re: Solar Land Rush
Trace the land rush and contract awards through the glad handing good old boy political networks and you then you have a story…
…although an oft repeated one, like, everytime a plans for a new road are finialized…
is it any wonder we spend trillions on new roads and nothing on maintaining old roads…
…there is no profit or collusion to be had in land that’s already expensive, owned, and built upon…
Thats great putting a solar plant in the middle of the desert, but now you’ve got to build transmission lines to get the power to a useful location. At the cost of about a $1,000,000 per mile, I just can’t see how this can be in any way cost effective. It may be somewhat more cost effective to put 10-25 MW solar banks around existing substations and operating power plants where electrical infrastructure already exists. I’ll be willing to bet that all these states with a renewable energy mandates will end up extending their deadline or will include natural gas as a renewable source.