SolarCity's innovation wasn't technological but financial. Instead of selling solar systems outright, which can cost $20,000 or more, SolarCity would install them for free and then sell the electricity the panels generated to customers at a fixed rate over the life of a 20-year contract.
Given that utility rates are expected to rise, customers taking advantage of so-called power-purchase-agreement contracts are able to avoid the prohibitive up-front cost of solar and save money over the life of their contract. SolarCity also offered solar leases, not unlike car leases, in which customers pay a fixed monthly price for their systems. "With a lease, you immediately start saving, and from Day One you pay less for electricity than you were before," says Shayle Kann, vice president for research at Greentech Media. The model--now used by most solar installers--opened a huge new market.
Of course, subsidies help. The federal government offers a 30% tax credit on solar systems, and states provide additional incentives. Some states also have net-metering laws, which require utilities to pay solar-system owners for any excess electricity they feed back into the grid. That's what has some utilities concerned about distributed solar. If solar can keep growing, a significant percentage of utility customers will begin producing more and more of their own energy--and paying less to utilities. Rhone Resch, the president of the Solar Energy Industries Association, argues that if utilities don't evolve, SolarCity will become a threat.
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