Friday, July 11, 2008

A Better Solar Collector

A wildcard in renewable energy investing that scares me almost as much as political risk is technology risk. You don't want to be the last investor to get the memo that one of your portfolio names' technology just became obsolete. Yesterday we had "Nano-Etching Breakthrough Could Deliver Cheaper Solar". Today MIT's Technology Review brings us this news:

A more efficient way to concentrate sunlight could reduce the cost of producing solar power.

Looking to make solar panels cheaper, MIT researchers have created sheets of glass coated with advanced organic dyes that more efficiently concentrate sunlight. The researchers, whose results appear in this week's issue of Science, say that the coated glass sheets could eventually make solar power as cheap as electricity from fossil fuels.

The researchers show that the glass sheets can reduce the amount of expensive semiconducting material needed in solar panels and provide a cheap way to extract more energy from high-energy photons, such as those at the blue end of the spectrum. "This could be the cheapest solar technology," says Marc Baldo, a professor of electrical engineering at MIT. "And I think one day, it could be competitive with coal."

The simple, flat sheets of glass have a number of advantages over previous solar concentrators, devices that gather sunlight over a large area and focus it onto a small solar cell that converts the light into electricity. Solar concentrators in use now employ mirrors or lenses to focus the light. Because the new glass sheets are lighter and flat, they can easily be incorporated into solar panels on roofs or building facades. They could also be used as windows, which, connected to solar cells, could generate electricity. What's more, mirrors and lenses require mechanical systems for tracking the sun to keep the light focused on a small solar cell. These tracking systems add cost and can break down over the decades that solar panels are made to be in service. The flat glass concentrators don't require a tracking system....MORE, including video.