MidAmerican announced plans in May 2013 to spend as much as $1.9 billion on wind farms in Iowa. Berkshire’s energy unit is also backing wind power Wyoming and solar projects in California and Arizona. The investments have given Buffett, the company’s chairman and chief executive officer, a way to invest large amounts of money in assets with reliable rates of return.

At a utility-industry conference in June, Buffett said he wants to spend even more on clean power as the U.S. moves away from fossil-fuel power generation. Berkshire had a record $55.5 billion in cash at the end of June.

“There’s another $15 billion ready to go, as far as I’m concerned,” he said then. “It’s where the country’s going.”

By the end of 2015, MidAmerican will have developed about 3.5 gigawatts of wind-power capacity in Iowa, enough to power more than 1 million homes.

Copyright 2014 Bloomberg

Lead image: Wind turbines via Shutterstock