One billion dollars is a lot of money, but that’s what Warren Buffett’s utility holding company PacifiCorp is spending to partially repower most of its wind turbine fleet across the US western states of Washington and Wyoming.

The 11-facility, 898MW initiative is among the largest undertaken nationwide, as owners transition older wind assets to newer and significantly more efficient technology – where it makes economic sense – by extending their useful lives without replacing the full turbine.