Day: May 21, 2007

Technology Review: Solar Power at Half the Cost
“A new mechanism for focusing light on small areas of photovoltaic material could make solar power in residential and commercial applications cheaper than electricity from the grid in most markets in the next few years. Initial systems, which can be made at half the cost of conventional solar panels, are set to start shipping later this year, says Brad Hines, CTO and founder of Soliant Energy, a startup based in Pasadena, CA, that has developed the new modules.

Concentrating sunlight with mirrors or lenses on a small area cuts the costs of solar power in part by reducing the amount of expensive photovoltaic material needed. But while concentrated solar photovoltaic systems are attractive for large-scale, ground-based solar farms for utilities, conventional designs are difficult to mount on rooftops, where most residential and commercial customers have space for solar panels. The systems are typically large and heavy, and they’re mounted on posts so that they can move to track the sun, which makes them more vulnerable to gusts of wind than ordinary flat solar panels are.

Soliant has designed a solar concentrator that tracks the sun throughout the day but is lighter and not pole-mounted. The system fits in a rectangular frame and is mounted to the roof with the same hardware that’s used for conventional flat solar panels. Yet the devices will likely cost half as much as a conventional solar panel, says Hines. A second-generation design, which concentrates light more and uses better photovoltaics, could cost a quarter as much. He says that a more advanced design should be ready by 2010.

The Soliant design combines both lenses and mirrors to create a more compact system. Each module is made of rows of aluminum troughs, each about the width and depth of a gutter. These troughs are mounted inside a rectangular frame and can tilt in unison from side to side to follow the sun. Each trough is enclosed on top with a clear acrylic lid. Inside each trough, a strip of silicon photovoltaic material runs along the bottom. As light enters, some of it reflects off the inside surface of the trough and reaches the strip of silicon. The rest of the incoming light is focused on the strip by a lens incorporated into the acrylic lid.”

Lots more in this article from the MIT Technology review (thanks to Fraser Clarke’s newsletter for the tip). I’m not a big believer in domestic micro-generation from PV unless you live in a hot desert because PV technology is inefficient with poor ROI. Investing in insulation is a MUCH better option – PV is essentially a rich boys toy in most cases, though it’s good for hot water and underfloor heating. But it’s good to see that the technology is moving on. As a cursory look at the red herring will tell you there is VAST VC investment in PV going on right now. We’ll have to see whether it pans out as a domestic solution – unlike wind, which for most people relies on economies of scale (and tall windmills) to be worth doing. I.e., big wind farms.

Nevertheless I would very much like a rich boys toy in the shape of some PV panels (we won’t have room – or sufficient wind speed – for a windmill) and I am tracking this space closely.

See also this and this:.