The $1 billion, 400 MW Gordon Butte pumped-storage hydro project proposed for Montana has secured an equity investment from Denmark’s Copenhagen Infrastructure Partners, developer Absaroka Energy announced July 8.

Absaroka did not disclose the size of the investment.

CIP said in a release that it would use its initial investment to “finalize the project development and step into the role of the project’s long-term . . . equity provider,” and would determine the rest of the capital structure prior to start of construction.

The closed-loop Gordon Butte project is planned for a site in Meagher County about 3 miles west of Martinsdale and less than 6 miles from its interconnection to the Colstrip 500 kV transmission lines.

The project will use a quaternary configuration of pump and turbine equipment provided by GE Renewable Energy that Absaroka says allows the plant to “move quickly and seamlessly between pumping and generating” at an estimated rate of more than 20 MW per second.

The quaternary configuration “improves upon” the ternary configuration described in its FERC license through better mode-switching speeds and start and shutdown times at a lower unit cost, according to recent comments Absaroka made on the project.

FERC granted a 50-year operating license to the project in 2016 [P-13642] (WPW No. 1 [14]), and in September 2018 approved a request for an extension of time to commence construction, to Dec. 14, 2020.

Absaroka has delayed asking for an extension of time to complete construction—currently Dec. 14, 2021—but said it would once it has more definitive information on construction scheduling and equipment procurement, and has completed project design.

With the enactment of the America’s Water Infrastructure Act in October 2018, FERC hydroelectric license holders can now request construction deadline extensions of up to eight years.