On the test benches of Konarka Technologies in Lowell, MA, a new kind of solar cell is being put through its paces. Strips of flexible plastic all but indistinguishable from photographic film bask under high-intensity lights. These strips, about 10 centimeters long and five centimeters wide, are converting the light into electricity. Wire a few of them together, and they generate enough power to run a small fan.

Solar cells, of course, are nothing new. But until now, solar power has required expensive silicon-based panels that have relegated it, largely, to niche applications like satellites and high-end homes. What's remarkable about Konarka's power-producing films is that they are cheap and easy to make, using a production line of coating machines and rollers. The process is more akin to the quick-and-dirty workings of a modern printing press than to the arcane rituals performed in the clean rooms of silicon solar-panel manufacturing. The company literally has rolls of the stuff; its engineers plan to cut off usable sheets as if it were saran wrap.