Putting the "Clean" in Clean Energy

Work crews recently took to the rooftops of Caltech's buildings and parking structures to wash clean the thousands of solar panels that provide the campus with as much as 1.4 megawatts of electricity.

Tom Shaffer, energy & LEED-existing buildings program manager, said that the Institute has so many of the panels—almost 5,000 on 11 structures across campus—it takes a four-man crew more than four days to clean them all. The cleaning, performed as often as twice a year, restores the panels to peak performance, which can degrade by as much as 20 percent when the they are dirty. The panels provide about 2 percent of the campus's power annually.