"With the addition of this project, we continue to grow our solar footprint in California," said Duke Energy Renewables president Greg Wolf. "As this asset continues to contribute to the state and city's renewable energy goals for years to come, we look forward to being a positive presence in this community."

The solar power system, developed and operated by Recurrent Energy since 2010, consists of nearly 24,000 solar panels mounted on top of the Sunset Reservoir. The facility provides electricity for the city and county of San Francisco's municipal services and facilities.

The San Francisco Public Utilities Commission (SFPUC) is purchasing the energy under a 25-year power purchase agreement. "The Sunset Reservoir solar project more than tripled San Francisco's municipal solar generating capacity," said Harlan L Kelly Jr, general manager of the SFPUC. "The renewable, greenhouse gas-free energy from Sunset Reservoir and all of our other facilities help power public buses, the San Francisco International Airport, health clinics, and other vital city services."

"This agreement with Duke Energy Renewables shows the continued movement of solar into mainstream power," said Recurrent Energy CEO Arno Harris. "Their investment in the Sunset Reservoir project further shows solar's ability to attract capital from conventional energy investors."

In April, Duke Energy Renewables acquired the 21-megawatt Highlander solar power projects in Twentynine Palms, California. The Sunset Reservoir project adds to Duke Energy Renewables' more than 100 megawatts of generating capacity at 16 US solar farms. Since 2007, Duke Energy has invested more than US$3 billion to grow its commercial wind and solar business.