This year, SunPower installed 70,000 solar panels, producing 15 megawatts over 140 acres, at Nellis Air Force Base in Nevada, the largest installation in North America. About a quarter of those panels will use SunPower's new solar cells to convert the sun's ray into electricity at 22 percent efficiency, the highest of any commercial solar cells yet.
SunPower boosted efficiency by rearraging the circuitry patterns on each cell, creating morecontacts from which to pull current while forming a reflective surface that traps light in the cell to increase electricity production. A single-motor tracking system on each row points dozens of panels at the sun, like venetian blinds.sunpowercorp.com
Source: Popular Science Magazine, December 2007