ONLINE search and advertising giant Google is teaming with investment firm Kohlberg Kravis Roberts & Co to develop four solar energy farms serving the Sacramento Municipal Utility District in California.

Google said yesterday on its Green Blog that it will spend US$94 million ($8 billion) on the projects. They also will receive equity from SunTap Energy RE LLC, a venture formed by KKR to invest in US solar projects.

The projects are expected to provide electricity to power more than 13,000 average US homes. Electricity produced by three of the projects is contracted for 20 years with the utility district, Google said.

Construction on three of the four projects will be complete early next year, and the fourth will come on line later in the year.

KKR said SunTap represents its first US renewable energy investment. It also has invested in a French wind farm operator and a Spanish solar energy company.

Google said it has invested more than US$915 million in clean energy projects, including US$800 million this year.

Google has invested in wind farms in North Dakota, California and Oregon, solar projects in California and Germany, and a project off the East coast of the US meant to help make offshore wind farms possible.

Google has said it is disappointed that it can’t buy renewable electricity for its power-hungry data centres so it is investing to help renewable power expand in scale.

Reducing the environmental impact of its business has long been a focus of co-founder and CEO Larry Page. The company says that since 2007, it has completely offset its emissions of greenhouse gases by paying for projects that remove those gases from the atmosphere.