MidAmerican Energy Holdings Co., an Iowa-based company controlled by billionaire investor Warren Buffett’s Berkshire Hathaway, made it’s first real buy into solar on Dec. 7, and it’s a whopper. The company purchased the 550-megawatt Topaz Solar Farm in California that’s being developed by First Solar, Inc. (NASDAQ: FSLR).

The deal was completed without a loan guarantee from the U.S. Department of Energy. First Solar had applied for one but couldn’t meet the deadlines under its Conditional Commitment.

Until recently the loan guarantee program helped many other utility-scale renewable energy projects, including others being developed by First Solar—like the 550-megawatt Desert Sunlight project, and the much criticized Solyndra loan guarantee.

“The Topaz project also demonstrates that solar energy is a commercially viable technology without the support of governmental loan guarantees and reflects the type of solar and other renewable generation that MidAmerican will continue to seek to add to its unregulated portfolio,” said MidAmerican spokesperson Ann Thelen.

While this is the first major PV project purchase for MidAmerican, it’s not the company’s first foray into renewables. The company is the largest owner of wind-powered generation among rate-regulated utilities in the U.S., CEO Greg Abel said in a press release.

The company will invest in other solar projects as well.

“The projects don’t necessarily need to be as large as this one,” Thelen said. “We are looking at various sizes of utility-scale projects.”

First Solar began construction on the project in November and completion is expected in 2015.

“Power is expected to be delivered beginning in 2012 (likely later in the year), as phases of the project are completed and interconnection is established,” Thelen said.

The project is valued at more than $2 billion, according to MidAmerican. It’s expected to inject $417 million into San Luis Obispo County, Calif., where it’s being developed. Most of that will be created during the project’s development and the rest will accrue over the 25-year life of the contract.

It’s the second such project to move ahead despite failing to secure a loan guarantee before the program expired.

SolarStrong, which will put solar on the homes of on-base military homes across the country, recently secured financing from Bank of American Merrill Lynch to move ahead with that project.