In Wales, Shell Solar set up the CIGS-based panels shown in the photo at left. At right, CIGS cells are printed at Nanosolar, a solar-power company based in Palo Alto, Calif.
What's with the darkened roof tiles? They are silicon solar panels, which can provide up to 65 percent of a home's electricity needs. Earlier this year, California builders began to incorporate them into new homes.
These solar tiles are darker because dark absorbs light better. Grupe Homes has installed these silicon solar tiles on some new homes in a development in Rocklin, Calif.