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The long-awaited commercial deployment of the world’s most efficient solar technology looks like it will now be near Phoenix, in a 1.5-megawatt, 60-unit deployment of Stirling Energy Systems’ solar thermal collectors.
Announced late last week, the 60-dish Maricopa Solar project will be the first commercial-scale solar facility built using Stirling Energy Systems/Tessera Solar’s SunCatcher concentrating solar technology.
The SunCatcher consists of a solar concentrator in a dish structure that supports an array of curved glass mirrors. Iterations of the SunCatcher have been among the world’s most efficient machines for solar-to-grid electric conversion for twenty years, most recently breaking the record last year with the highest-ever conversion rate of 31.25%.
The project will serve as a precursor to the deployment of much larger commercial projects previously announced in California and Texas that total more than 1,600 MW. “It’s like kicking the tires,” said Sean Gallagher, vice president of marketing and regulatory affairs for Stirling Energy Systems, in an interview earlier this summer. Gallagher added that the credit crunch made a demo project more critical than before to win financial support. “We think that the lenders and investors are going to want to see more of a slice of a system operating and some data before they are willing to finance larger projects.”
Mixing the old with the new
The SunCatcher mixes old technology with new design. By employing a system of mirrors attached to a parabolic dish to concentrate the sun’s energy onto a high‐efficiency Stirling Engine, each dish can generate up to 25,000 watts of power.
At its most intense spot, the heat produced is equivalent to a blistering 13,000 suns, “That’ll melt almost anything known to man,” says Sandia National Laboratories’ engineer Chuck Andraka. “It’s incredibly hot.” Sandia has worked extensively on developing the new iteration of the technology.
The SunCatcher is a 40-foot wide, 25-kilowatt-electrical (kWe) solar dish Stirling system designed to automatically track the sun and collect and focus solar energy onto a Power Conversion Unit (PCU), which then generates electricity.
The PCU converts the focused solar thermal energy into grid-quality electricity with a a closed-cycle, four-cylinder, reciprocating Solar Stirling Engine utilizing an internal working fluid that is recycled through the engine. The hydrogen gas in the PCU’s solar receiver tubes heats up and this gas in turn powers the Solar Stirling Engine
Stirling Engines have been around for over a century-and-a-half and are recognized for their efficiency, reliability, and because they can use almost any external heat source to power the engine.
An additional advantage of the technology is that the SunCatcher requires no water for heating or cooling and a minimal amount of water is required to wash the mirrors. The water component is particularly helpful in the dry climate of the desert southwest, where this and other future projects are currently in development.
Using the North American automotive supply chains for solar deployment
“They have the lowest water use of any thermal electric generating technology, require minimal grading and trenching, require no excavation for foundations, and will not produce greenhouse gas emissions while converting sunlight into electricity,” said Sandia engineer Andraka.
By utilizing the automotive supply chain to manufacture the SunCatcher, Tessera hopes to leverage leverage the talents of an industry that has refined high-volume production through an assembly line process. The forty reflective mirrors needed for the construction of each dish are formed into a parabolic shape using stamped sheet metal similar to the hood of a car. The mirrors are made by using automobile manufacturing techniques.
The company says more than 90 percent of the SunCatcher components will be manufactured in North America. Because of the Maricopa Solar Project’s proximity to existing grid infrastructure—adjacent to the 650-megawatt Agua Fria generating station—project leaders say it should be online in early 2010.
Article from Treehugger
Improved Solar Power Dish with Stirling Engine Made by Car Parts Suppliers
by Michael Graham Richard/Treehugger
New and Improved Solar Thermal Collection Dish
While a lot of people think about photovoltaic panels when "solar power" is mentioned, solar thermal must not be underestimated. One of the players in that field is Stirling Energy Systems (SES), who we've written about before when they set a new world record for "solar-to-grid system conversion efficiency" (31.25 percent, beating the previous record of 29.4 percent). Well, in collaboration with Sandia National Laboratories, SES has refined its SunCatcher design. Read on to find out how the new version compares to the old one.
Not Reinventing the Wheel
The new Suncatcher is evolutionary rather than revolutionary (you can compare it to the older design by looking at the photo below), but according to the specs released by Sandia National Laboratories, it seems like a significant improvement:
The new SunCatcher is about 5,000 pounds lighter than the original, is round instead of rectangular to allow for more efficient use of steel, has improved optics, and consists of 60 percent fewer engine parts. The revised design also has fewer mirrors — 40 instead of 80. The reflective mirrors are formed into a parabolic shape using stamped sheet metal similar to the hood of a car. The mirrors are made by using automobile manufacturing techniques. The improvements will result in high-volume production, cost reductions, and easier maintenance.
90% of the Suncatcher components will be made in the US, and by using automobile suppliers to make the parts, Stirling Energy Systems is leveraging their manufacturing expertise (and I bet that auto suppliers are glad to get the extra work). “By utilizing the automotive supply chain to manufacture the SunCatcher, we’re leveraging the talents of an industry that has refined high-volume production through an assembly line process. More than 90 percent of the SunCatcher components will be manufactured in North America," says Steve Cowman, Stirling Energy Systems CEO. Last year, Tim wrote about how a Suncatcher unit set a solar power conversion efficiency world record. I'll be curious to know if these upgraded versions will do even better.