MidAmerican Energy, the regulated Iowa utility owned by billionaire Warren Buffett’s Berkshire Hathaway conglomerate, has formally completed the first two wind farms under its historic 2GW Wind XI programme.

Most construction at the 170MW Beaver Creek and 168MW Prairie wind farms was finished in 2017, but MidAmerican announced their completion this week, having continued adding turbines at the Prairie project in Mahaska County into early 2018.