Cool Earth Solar: Solar farms on the cheap

Cool Earth Solar is banking on solar power priced more like a bicycle than a Mercedes.

The Livermore, Calif.-based company, which is still officially in stealth mode, has raised $750,000 in capital with a goal of raising a total of $950,000 to build a prototype, according to founder Eric Cummings. Announcements of board members and executives will be coming in June, he said.

Cummings has taken a radically inexpensive approach to solar power generation, taking into account land use issues as well.

His product design calls for hoisting several connected plastic balloons, referred to as "inflatable solar concentrators," to generate electricity on solar farms.

These balloon-shaped solar collectors (see presentation PDF file for diagram) use plastics to reflect light onto photovoltaic panels to generate power.

The technique of concentration is being actively pursued by several companies because it allows solar devices to squeeze more electricity from expensive solar cells.

Cool Earth Solar says its solar collectors, which are about two meters in diameter, will be cheaper than other concentrators because of the inexpensive plastic it will use to magnify light. Typically, concentrators use sophisticated lenses or polished aluminum.

Cummings envisions that these balloons will be cabled together above farmland and would be replaced every year. That's a radical notion in the solar industry where providers typically warranty panels for 20 or 25 years.

By placing the concentrators above farms and other rural areas, the sun can be put to work generating electricity at a large scale without taking up huge tracts of land, according to Cummings. The design calls for the PV "receiver" to be cooled by circulating water.

Cummings says that his "phase 2" design deployed at large-scale farms will be able to generate electricity at 29 cents per watt. That's far below the industry benchmark, usually measured at $5 to $7 per watt.

Cool Earth Solar, like many green technology companies, is trying out new ideas or recycling abandoned ones to build a business. (See stories on Planktos and Magenn Power for other examples of "out of the box" green tech thinking.)

As with many of these early stage companies, investors and potential buyers will be tracking how well Cool Earth Solar's cost-per-watt projections match with initial tests.