Published on August 25th, 2009 | by Timothy B. Hurst45
World’s Most Efficient Solar Technology Coming Soon
August 25th, 2009 by Timothy B. Hurst
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%.
“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.
via: Clean Edge