Mount Diablo Unified School District and SunPower Corp have completed installation of 40 SunPower solar power systems planned for district schools and facilities in the US.

Upon completion of the total number of 51 systems with a total capacity of 12.1MW later this year, the systems are expected to reduce the district’s electricity costs by about $3m per year, and save $220m over the next 30 years.

SunPower is installing the system on rooftops and shade structures in parking lots and hard court areas.

The systems use high efficiency SunPower solar panels, the most efficient panels on the market today, which are manufactured locally in Milpitas, California.

SunPower regions president Howard Wenger said the completion of the largest solar school project in the U.S., delivering electric bill savings of more than 90% at 51 schools.

"The Mount Diablo Unified School District selected SunPower to deliver the world’s highest performing solar systems for its schools, in partnership with great local firms," Wenger said.

"The district has established a high standard for clean energy investments on school facilities. As a California company, with roots firmly in California education, it is extremely rewarding to deliver needed savings to our public schools."

The school district’s systems were financed through Clean Renewable Energy Bonds (CREBs) secured under the American Recovery and Reinvestment Act of 2009, paid through a local, voter approved general obligation bond.