In 2006, semiconductor-equipment giant Applied Materials got into the solar-power market in a big way. At the company's headquarters in Santa Clara, CA, you can see just how big: a ceiling-mounted crane lifts a piece of glass the size of a garage door onto a table for testing. The glass sheet, covered with a thin orange film of amorphous s­ilicon, ­is destined to become one of the world's largest solar panels.

Applied Materials developed the equipment to produce these extremely large photo­voltaic panels in order to lower the price of solar power--­crucial if solar is to compete on price with fossil-fuel electricity. The value of a solar installation comes down to the cost of each watt of power it can produce over the lifetime of a panel, and Applied Materials' panels bring down costs in two ways. The equipment for manufacturing thin-film solar cells operates more efficiently when the panels are bigger. And larger modules need less hardware and labor to wire them together and support them.