First Suncatcher solar dishes to be used in Arizona
By Paul Ridden
September 2, 2009
Tessera Solar and Salt River Project have just announced that they'll partner to construct a 1.5 megawatt solar generation installation in Peoria, Arizona. The proposed output from the Maricopa Solar LLC project might not sound too impressive but when combined with the news that the 60 dish installation represents a template for much bigger operations to come and will be the first commercial plant to use Suncatcher technology - things just got interesting.
Annual electricity usage in your typical US home is around 13,000 kilowatt hours so a 1.5 megawatt power plant isn't going to make much of a dent in an industry relying heavily on fossil fuels. But generating energy from the sun is starting to make inroads. According to a recent report by Austin's DisplaySearch solar cell production is set to increase in 2009 by a whopping 56% and will continue to grow year on year thereafter.
And latest figures available from the US Energy Information Administration show that the US generated some 4166.5 billion kilowatt hours of electricity in 2007, with solar, wave and fuel cell technologies accounting for just 0.6 billion kilowatt hours.
Catch me if you can
Next year Suncatcher technology is to be used to develop two of the world's largest solar installations in Southern California, as well as a large project in Texas. Being the first commercial-scale project, the Peoria facility represents an important first step towards generating some 1600Mw of grid quality solar electricity. The new venture will consist of 60 Stirling Energy Systems Suncatcher solar energy collection dishes and will be sited next to the Agua Fria Generating Station, which is owned by Salt River Project.
Each dish can generate up to 25Kw and starts to generate power as soon as it is constructed. As more units are added, more power is generated until full capacity is reached when the project is fully realized. Work on the first dish is due to start this month aiming for completion in January 2010.
For every square mile of the Earth's surface the sun beats down (on average) some 2.6 gigawatts of energy. Tessera Solar claims that the Suncatcher system provides the most efficient method of harnessing that power and converting it to grid quality electricity. The technology has recently been certified by Sandia National Laboratories as producing the highest efficiency sun-to-grid conversion when compared with peer technologies - 31.25% (the previous best was recorded as 29.4% in 1984).
The concentrating solar-thermal power dish uses precision mirrors (made with a low iron glass with a silver backing that make them highly reflective) attached to a parabolic dish to concentrate as much as 94% of the sun's energy into a high-efficiency Stirling Engine (a sealed system filled with hydrogen, as the gas heats and cools, its pressure rises and falls. The change in pressure drives the pistons inside the engine, producing mechanical power, which in turn drives a generator and makes electricity).
Making sure the dish always points towards the sun is taken care of using sophisticated software which ensures that the maximum amount of solar energy is focused into the power conversion unit.
Water, water everywhere - except here
In addition, unlike most other thermal-powered generating systems Stirling's Suncatcher dish doesn't require any water for heating or cooling. Well that's not strictly true - a small amount of water is used to clean the mirrors and maintain the dish but only a tiny fraction when compared to other systems.
More than 90% of the components in a Suncatcher dish are manufactured in the US and the modular design means that replacement of failing or end of life parts is a relatively quick and easy process. This plug and play functionality also means that the size of an installation can vary considerably, from the 60 units in Peoria up to hundreds or thousands of units and beyond.
The project is set to help Salt River Project, the third biggest public power utility in the US with some 930,000 customers, achieve its 2025 target of having 15% of generated energy produced from sustainable resources.