Solar future: not quite present

Eager-beavers Gizmodo.com just can�t wait to bring us the good news. Such was their excitement over a new type of solar panel from US company Solient that they may have indicated the product will be widely available a year before it actually comes on the market. We covered the next generation of concentrated solar panels last month in “Now Concentrate” .

Gizmodo, a consumer site, said the Heliotube will be available in 2007. Solient say companies may be able to buy the new technology by the end of the year, but residential customers will have to wait until late 2008 to get hold of one. See the article here. The neat thing about the Heliotube is that it contains a new mechanism for focusing light on small areas of PV material, which means you can use considerably less of the silicon which makes solar cells so expensive. Solar energy could finally become cheaper than electricity from the grid in most markets in the next few years.

Traditional concentrated solar PV systems are, typically, difficult to mount onto roofs in residential areas because they�re large and heavy; while mounting them on posts instead makes them vulnerable to gusts of wind.

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.

Each frame 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.

For more information check out the Solient website.

According to Technology Review, the design does have a few drawbacks. Because the troughs are mounted close together, they shade each other during parts of the day, decreasing the total amount of electricity produced. They can also only track from side to side, which makes it impossible for them to follow exactly the arc of the sun across the sky.

This second problem will be addressed in the second-generation design, in which each trough will be divided into sections, each of which can pivot from side to side and also up and down. Best of all, it will use even less PV material � and could cost a quarter as much. The design should be ready by 2010.

Tags: off-the-grid