Rocky Mountain Power (RMP), part of billionaire Warren Buffett’s Berkshire Hathaway conglomerate, has filed for regulatory approval in Wyoming for its multi-billion-dollar wind generation capacity expansion plan through the end of 2020.

The scheme would include about 1GW of new capacity, and repowering or upgrading nine existing facilities totaling 634.8MW in the state that the electric utility fully owns (it controls 32.1MW