BrightSource files for an IPO

A solar company that's building a massive plant in the desert using Federal funds has filed to go public. The documents provide an interesting glimpse at the challenge solar thermal power faces. From Earth2Tech,

Washing the Mirrors: Building solar thermal plants in the desert has at least one major drawback: The mirrors get dirty. BrightSource says each mirror needs to be cleaned every two weeks to get rid of dust and maintain solar performance. The mirrors will be washed at night using a dedicated crew using specialized mobile equipment. But BrightSource says: "If the mirror washing equipment and process are not effective, actual operating costs may be substantially higher than forecasted or total electrical production may fall short of estimates."