Ten Eco-Friendly Companies

The company has scored some minor victories. Sen. Maria Cantwell used the plant in April as a backdrop to introduce legislation to boost the nation's biofuel production. And a few weeks after Hurricane Katrina struck, Tobias drove his diesel VW Beetle to a gas station and noticed that, for the first time in the region, pure biodiesel was cheaper than regular diesel. He hadn't expected the price inversion for two more years, and the company's phones started lighting up. Although the inversion was temporary (indeed, it lasted a month and a half), the company celebrated with six-packs of beer. A few more victories like that, and they'll be upgrading to champagne.

--Brad Stone

2 Soaking Up the Sun

Miasole: Developing new ways, besides silicon, to capture the sun's rays and create energy

Dave Pearce and Dennis Hollars, of Silicon Valley start-up Miasole, can be called many things. They're Southerners, from Texas and Tennessee, respectively. They're serial entrepreneurs who learned "to squeeze every nickel until the buffalo roars," says Pearce. Just don't call them environmentalists. "Heck no," Hollars says. "Environmentalists are insane. We believe you ought to do what is sane.'' Their mission: make solar work without government subsidies.

Pearce and Hollars see a rich opportunity for a technology breakthrough. Here's why: more than 90 percent of panels use crystalline photovoltaic cells derived from silicon. It's a 50-year-old technology, but demand from many industries has created a worldwide shortage. Miasole (in Italian, "My Sun") is building solar cells without silicon. Instead, superthin layers of a semiconducting copper alloy, deposited on stainless-steel foil, convert the sun's rays into electricity. Pearce and Hollars are making prototype solar cells today, and plan to move into commercial production next year. "In a few years we can match the cost of conventionally generated electricity," says Pearce.