Cool Earth Solar eyes rural power with balloons

Tag : solar powered light

It's a design that combines cheap building materials, notablyplastics, with expensive high-efficiency solar cells. Light goesthrough the side of the balloon facing the sun, is reflected on analuminum coating on the bottom, and is concentrated onto solarcells in a "receiver."
The method can concentrate light between 300 and 400 times. To keepheat under control, the balloons have an automated water-coolingsystem.
The test installation for Cool Earth Solar, which was founded in 2006 , will be small--on the order of a few dozen suspended balloons,according to a company representative. That's so that the companycan make changes to the second version of its concentrating solarballoon.
Following that test system, which will generate about 100 or 200kilowatts of electricity when done, the company intends to startbuilding a 1.5-megawatt commercial solar power plant this winter,said CEO Rob Lamkin. One and half megawatts is enough power tosupply about 400 or 500 U.S. homes. That installation, expected tobe constructed in Tracy, Calif., will sell electricity to autility.
Following that, Cool Earth Solar hopes to ramp up quickly, Lamkinsaid. It is planning another test facility, sized at 10 megawatts,for next summer, he said.
Unlike the rest
Cool Earth Solar's design is nothing like most concentrating photovoltaic (CPV) systems, which concentrate sunlight onto solar cells to makeelectricity.
Typically, concentrating solar devices use lenses and mirrors todirect and focus light to squeeze more electricity from high-endcells. The lenses, as well as the mounting and cooling systems, addsignificantly to the cost.
Cool Earth Solar's device, too, concentrates light onto expensivesolar cells. But using materials like aluminum-coated plastic--thesame sort of thing you'd find in a Power Bar wrapper--means thecompany can make electricity at $1 per watt, a few dollars per wattcheaper than other companies, Lamkin said.