A mainland company is offering an option to local homeowners who want to generate their own electricity with rooftop solar panels but can’t afford the upfront costs.

San Francisco-based SunRun Inc. is expanding to Hawaii with a business model in which it installs photovoltaic systems at no cost and sells the electricity back to the homeowner at a fixed rate over 20 years.

Until now, so-called purchase power agreements like SunRun’s have been available in Hawaii only on a commercial scale. SunRun will partner with local PV installers Sunetric and RevoluSun in the venture.

SunRun said the rate it charges for the electricity varies depending on the market, but "is generally lower than what you’re paying your utility today."

In its marketing materials SunRun also notes that by locking in at current rates customers are protecting themselves from future utility rate increases.

After 20 years, SunRun customers would have the option of buying the system from the company or renegotiating their fixed rate.

SunRun’s entry to the Hawaii market follows a failed attempt by the Legislature this year to authorize a similar, government-sponsored program.

The initiative, which lawmakers plan to bring up again next year, calls for using state bonds to finance loans to cover the upfront cost of solar installation.

Under the bond-financing program, homeowners would be given loans that would be repaid through assessments on their county property tax bills.

Upfront costs can be a barrier for many homeowners interested in solar, despite federal and state tax incentives. Prices for PV systems vary depending on size, but one large enough to power a typical Hawaii home using 600 kilowatt hours per month of electricity could cost $15,000 or more after state and federal tax credits.

In addition to Hawaii, SunRun operates in Arizona, California, Colorado, Massachusetts, New Jersey and Pennsylvania.

Mark Duda, founder of RevoluSun and president of the Hawaii Solar Energy Association, welcomed SunRun’s entry into the local market.

"Our partnership with SunRun is a major shift in the market that will make solar affordable to as many Hawaii homeowners as possible," he said.

Alex Tiller, chief executive officer of Sunetric, said the structure of the SunRun program eliminates the financing issue that had been preventing many homeowners from installing PV systems.