MidAmerican Energy Holdings is to acquire a 49% interest in the Agua Caliente solar project from NRG Energy.

The 290-MW solar photovoltaic (PV) project in Yuma County, Arizona, will generate enough electricity to offset about 5.5 million metric tons of carbon dioxide over 25 years.

The $1.8 billion project, is being constructed by CdTe manufacturer, First Solar and is expected to be complete by 2014. It is supported by a $967 million loan guarantee from the U.S. Department of Energy and a long-term power purchase agreement with Pacific Gas and Electric for all of the project’s generation.

“We are aggressively pursuing opportunities to expand our presence in the renewable energy sector, and the Agua Caliente project is another important step toward that goal," said Greg Abel, Chairman, President and CEO of MidAmerican Energy Holdings Company. “We look forward to partnering with NRG Energy on this exciting project."

NRG first announced in May the company’s intention to bring quality partners into its large-scale solar projects, noting the strength and creditworthiness that credible partners can bring to these projects.

“Partnering with an industry leader like MidAmerican on Agua Caliente, one of the largest PV

projects in the world, enhances the strength and credibility of what was already one of the world’s leading solar projects," said David Crane, NRG President and CEO. “NRG and MidAmerican complement each other in the capabilities and experiences they bring to this project and to solar power more generally."

The deal is subject to certain customary closing conditions, including the U.S. Department of Energy approval.

This is the second solar project announced by MidAmerican this month. On December 7, MidAmerican announced it had purchased the 550-MW Topaz project, being built in San Luis Obispo County, California, from First Solar. The Topaz project is one of the world’s largest solar projects.

The MidAmerican group is one of the largest owners of wind-powered energy among rate regulated utilities and, at year-end 2011, 28% of its total generation capacity will be from renewable and non-carbon sources.