Cheaper Solar Concentrators  

Technology Review has an article on making solar power cheaper using concentrators combined with PV panels - Cheaper Solar Concentrators.

Skyline Solar, a startup that today announced its existence to the world, has developed a cheaper way to harvest energy from the sun. The company's solar panels concentrate sunlight onto a small area, reducing the amount of expensive semiconductor material needed to generate electricity.

The technology will bring the cost of solar power in line with the average cost of electricity, at least in sunny areas, says Ben Eiref, Skyline Solar's director of product management. Currently, solar power can be far more expensive than electricity from conventional sources; many governments have resorted to subsidies to increase its use.

Skyline Solar has raised $24.6 million to date and has been awarded $3 million by the Department of Energy to speed up production. It has also installed a pilot power plant that can produce 24 kilowatts of electricity, and has started production of its solar panels with the goal of selling them later this year. They are designed for commercial installations in the 1-to-10-megawatt range, such as on food-processing and water-treatment facilities at the edges of cities or in rural areas.

The startup isn't the first company to attempt to reduce costs by concentrating sunlight onto smaller solar cells. But Skyline Solar says that it can better compete with other energy sources by combining two technologies that can be produced in high volume using existing equipment and that have been demonstrated in the field for decades: conventional silicon solar cells and reflective parabolic troughs, which are used now in solar thermal plants. In these thermal plants, the long, curved troughs concentrate light on tubes, heating up a fluid inside them that, in turn, is used to drive power-generating turbines. Skyline Solar has replaced those tubes with narrow solar panels, adding a heat sink to keep them from getting too hot. The troughs concentrate the light by about a factor of 10, increasing the power output of the panels by about the same amount as conventional solar panels without concentrators. (To compensate for the increased power output, the company has incorporated larger electrical contacts into the panels.)