SolarCity

Foster City, Calif.

To avoid the headaches and expense of buying and installing their own panels, homeowners or businesses can instead sign a 15-year lease with SolarCity, for no money down. The company designs the system, processes permits and tax incentives, and monitors electricity use. SolarCity has a new deal with U.S. Bank to finance solar systems for small businesses. The company designs the system, processes permits and tax incentives, and also monitors electricity use, even guaranteeing that customers save money on utility bills.

Key investors: Draper Fisher, Elon Musk, FirstSolar