SunRun, which leases solar panels to homeowners for lower-cost power without the upfront expense, just expanded into its 10th state.

SunRun is now doing business in New York.

“That’s right, the Big Apple,” said SunRun spokeswoman Susan Wise. “The expansion itself demonstrates the growing demand for what we offer.”

SunRun owns, maintains and insures rooftop solar photovoltaic installations for homeowners. The homeowners sign a 20-year fixed-rate agreement to get their power from the panels on their roofs.

The concept saves homeowners from making a big upfront investment, while allowing them to make the environmental choice to go solar and reap the financial benefits of a secure and steady power bill through the next two decades when electricity costs are expected to rise.

SunRun was already doing business in California, Oregon, Colorado, Arizona, Hawaii, Pennsylvania, Maryland, New Jersey and Massachusettes.

“It takes a number of factors for a state to be right for solar, but more particularly right for third-party owned solar,” Wise said.

New York has started to implement policies that make the state a friendly political environment for third-party solar.

“There’s still some work to do,” Wise said. “But they’ve started.”

She said 23 percent of the state’s single-family homes are in the utility territories where SunRun is setting up its business, and the existing utility rates in those territories are among the highest in the state, which makes SunRun’s solar leasing more attractive to homeowners.

Wise said the next step will be to reach out to New York residents and launch education campaigns so people know about the policy changes and how SunRun’s business model works.

The company boasts that one in every eight homeowners that went solar in 2010 did it with SunRun.

Photo: Steve Hargreaves for CNN Money.