Lynn Jurich and Edward Fenster
SunRun, San Francisco

Lynn Jurich has been called a financial genius in an energy-genius costume, and nowhere is her monetary acumen more evident than in her approach to risk. When she married a colleague at an investment firm, the couple agreed to take a portfolio approach to building their future. One of them would land a steady job. The other would go for broke by starting a company. "We both wanted to do the entrepreneur thing, so it was a race as to who would find the better idea first," says Jurich, 31. "I won."

That idea, which became the San Francisco -- based company SunRun, also derives from an insight about risk. Most people recognize the benefits of solar energy, but the necessary rooftop panels can cost as much as $25,000. Jurich and Edward Fenster, her co-founder at SunRun, realized many consumers weren't willing to bet they would remain in their homes long enough to recoup such a large investment through lower energy bills. So the two recast the clean-tech challenge as a financing challenge.

SunRun installs solar panels on residences at nominal or no cost. Homeowners sign 20-year contracts to buy power at a fixed price, around 15 percent less than their current electric bills. The contract is linked to the house; when the homeowner sells, the next resident inherits the panels and the arrangement. Houses that generate more power than they use receive credits.

"People keep telling us, it sounds too good to be true," says Jurich. But in fact, it's a win-win-win-win. Homeowners start saving immediately. SunRun benefits from long-term customers and predictable costs. So do its investors. The environment breathes easier. The company, founded in 2007, is growing at 300 percent a year and has 6,000 customers in seven states.

It's a capital-intensive business. Fortunately, Jurich is also a master of the fundraising domain, which she learned at Summit Partners. She and Fenster have raised $85 million in venture capital and an additional $400 million in project financing to purchase the solar systems, which are installed by regional contractors. "To unlock the residential market, we needed to think differently," says Jurich. "People used to pay $10,000 for a satellite dish. Now, DirecTV owns the dish and you pay a monthly service fee. We thought residential solar would go the same way."