Solar Bubbles

Tuesday, November 25th, 2008

Kerry A. Dolan of Forbes calls them Solar Bubbles — 8-foot shiny plastic balloons with solar cells inside:

Eric Cummings, the brainy scientist who dreamed up the balloon idea, dismisses flat solar panels as expensive to install and difficult to deploy. The curvature of his balloon concentrates more sunlight onto fewer photovoltaic cells. He envisions vast farms of his 1-kilowatt balloons strung on wires and producing gigawatts of power.

Cummings has no deals yet with a utility, but his company, Cool Earth Solar, raised $21 million from Quercus Trust, a Los Angeles private equity firm, and other investors to build a 1.5 megawatt installation in California’s Central Valley. Construction of a test project in a field of brown weeds across the street from its offices is just beginning. “This is scalable in a way that dwarfs other options,” he boasts. “The goal is to be the 100% solution” to the energy crisis.

Cool Earth Chief Executive Robert Lamkin, who previously oversaw the development and construction of power plants at Calpine and managed plants at Mirant, says rather boldly that next year the company will have its costs down to $1 per watt, installed—at which point it can compete with natural gas and beat other kinds of solar technologies. Typical photovoltaic panels on rooftops cost up to $8 per watt installed. Solar thermal power, which concentrates heat to make steam, is aiming for $4 per watt. (These costs are all in terms of peak watts. Nights and clouds included, solar’s average cost per watt is four times as much.)
Concentrating the reflected light into a receiver produces 300 to 400 times as much electricity out of each solar cell as a system without a concentrator, the company claims. A water-cooled jacket on the back side of the receiver keeps it from overheating. The balloon can add or bleed air to maintain its shape.

Cool Earth’s balloons can last five years but are so cheap it plans to replace them once a year. Or more frequently. It has yet to test against BB guns.

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