The price of wind power is dipping to unheard-of lows in the upper Midwest thanks to bigger turbines, with developer Apex Clean Energy advancing a project in North Dakota that could sell its output for less than $20/MWh.

Apex, among the top US renewables developers, last month received regulatory approval for its 300MW Dakota Range project in South Dakota, to be completed in 2021 and owned by utility group Xcel Energy.