(Business 2.0) – Most solar panels are bulky, pricey, and difficult to install. But imagine if you could turn windows--or entire skyscrapers--into solar power generators. That's the goal of XsunX, a startup in Aliso Viejo, Calif., that has invented a way to stick semitransparent solar cells on plastic film, which manufacturers can use to transform ordinary windows into PowerGlass. "It's like a power-plant skin on a building," says XsunX CEO and president Tom Djokovich.

XsunX's amorphous silicon solar cells aren't more efficient--they convert just 6 percent of light energy that hits them into electricity, compared with 15 percent for traditional silicon cells. They are, however, more versatile: A 20-story building has about 10 times more space for PowerGlass than it does for roof panels. That puts XsunX on the cutting edge of a trend in the $7 billion solar industry called building-integrated photovoltaics, or BIPV. "We're seeing a revolution where solar is disappearing into the building," says Ron Pernick, co-founder of energy research firm Clean Edge. Next year, XsunX plans to begin selling its manufacturing technology to glass and optical-film makers and collecting licensing fees and royalties. Meanwhile, a firm called Iowa Thin Film Technologies has released solar-film radios and tents, and it's now developing opaque BIPV products for roofs. But as the only company making see-through cells for windows, XsunX can envision a bright future ahead.