SolFocus launches a new concentrating solar system that ups sunlight-to-electricity efficiency to 25 percent, up from 18 percent in its last system

SolFocus unwrapped its new concentrating solar energy system Thursday. Its second commercial product can now convert 25 percent of the sunlight that hits its cells into electricity.

The Mountain View, Calif.-based startup improved the efficiency – a leap from the 18 percent reached by its first commercial system launched a year ago – largely by redesigning the optical components, said Nancy Hartsoch, vice president of marketing for SolFocus.

A SolFocus system is composed of a giant panel mounted on a tracker that tilts the panel to follow the sun's movement. On the panel are rows of curved mirrors that can concentrate 500 times the sunlight onto optical rods, which then lead the light into solar cells made with germanium substrate and gallium-arsenide and other compounds in the same class of semiconductors