????BY Patricia Sellers

????Lynn Jurich was flying from Hong Kong to Shanghai when a flight attendant told passengers to “look outside at the clear skies.” What Jurich saw disturbed her greatly: a blanket of gray smog. “It kind of hit me right then and there that this is a real issue. This is our Earth,” she says, adding that she decided that it’s “my responsibility as a business person to try to solve these problems.”

????When she was at Stanford pursuing her MBA, Jurich and a classmate founded SunRun. The start-up pays homeowners to have solar panels installed and then signs the customers up for long-term contracts to buy solar power at fixed prices. “So they get benefits for the environment, benefit on a monthly savings, and they get to lock that rate in for the next 20 years,” Jurich explains. Her big goal: Displace half of the $150 billion annual residential electricity market with solar power over the next two years.

????For her innovation and impressive success so far, Fortune selected Jurich to be one of 10 Most Powerful Women Entrepreneurs–a program recently launched in partnership with American Express (AXP). Since its creation in 2007, SunRun has raised $30 million from Accel Partners and Foundation Capital. This week, the company secured $90 million in tax-equity financing from U.S. Bancorp (USB), following an earlier commitment of $105 million in project financing. Jurich’s idea also bought her a ticket to the White House: In early December, she attended a roundtable with President Obama to discuss renewable energy and ways to expand solar adoption in 2010.