Photos: The many faces of solar power

Start-up Konarka is one of several companies using nanotechnology to make photovoltaic material that doesn't require silicon. Konarka says its plastic strips, once commercially available, will be flexible enough for a wide range of applications.

Like other solar companies, Konarka envisions flexible solar material that can be used widely, such as attached to an outdoor awning to generate electricity. The company is developing portable, electricity-generating buildings for the Army.

Energy Innovations, an Idealab company, is developing solar "concentrators" that use mirrors and lenses to intensify the light and generate more electricity from solar panels. The company's Sunflower product is designed specifically for flat-roof buildings such as warehouses and large stores.

A design of Energy Innovation's concentrator shows how light reflects from mirrors close to the ground and shines on a silicon solar cell above, which is cooled by fans. The design concentrates the light 25 times, cutting down on the amount of expensive silicon needed. The mirrors move to follow the sun.

Using its research in optics and manufacturing, Xerox's Palo Alto Research Center is partnering with SolFocus to build glass solar concentrators that rotate during the day to face the sun directly. Over the next two years, about 2 megawatts of power generation from this project are slated to be installed and tested.

Stirling Engine Systems is building large dishes that concentrate the sun's rays to drive a mechanical engine. The company is under contract to build an array of dishes capable of generating 500 megawatts of electricity.

With rising electricity prices, traditional silicon-based solar photovoltaic panels are being used more widely. FedEx recently installed nearly 1 megawatt of local power generation at its Oakland, Calif., airport location.

PowerLight, which manufactures solar panels, is developing roofing tiles that can generate electricity. The company hopes to build partnerships with building companies.

Aided by government incentives, solar electricity in Germany is booming. This installation in the Bavarian town of Guenching is one of three sites that together have been dubbed the largest "solar park," capable of generating 10 megawatts.

The solar panels used at Ridge Vineyards in Healdsburg, Calif., are designed to complement the building's architecture.