Billings Gazette: Bill would build power plant on Montana's Gibson Reservoir

by Tom Lutey

Asmall power plant proposed for Gibson Reservoir 70 miles west of Great Falls is getting attention from Montana’s congressional delegation.

Sens. Steve Daines and Jon Tester, along with Rep. Matt Rosendale, introduced a bill Monday to authorize the Department of Interior to build a power plant at the mountain reservoir. Gibson Dam was plumbed for generation at the recommendation of the now defunct Montana Power Co. when the dam was built in 1926, but a generator was never added.

The reservoir is part Sun River Project, which provides irrigation water to Cascade, Lewis and Clark and Teton counties and is in need of repair, according to a report by the dam’s main stakeholder, Greenfields Irrigation District.

Greenfields has worked for years to get the generation approved and built. The district would like to sell the power to NorthWestern Energy and use the profits for maintenance and repairs on the Sun River Project. Greenfields estimates it could gross more than $2 million a year selling Gibson Dam electricity.

The next 50 years of maintenance on the Sun River System is expected to cost $75 million.

The planned generation capacity is 20 megawatts, said Erling Juel, Greenfields manager. The irrigation district intends to sell the power on contract.

Gibson Dam isn’t the irrigation district’s only hydropower development. Greenfields is also developing two small projects on its system, both three megawatts in capacity, for which it hopes to secure contracts with NorthWestern Energy through a federal law requiring predetermined rates and long-term contracts for small qualifying facilities.

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The federal Public Utilities Regulatory Policies Act, or PURPA, requires utilities to buy power from small qualifying facilities under terms decided by state regulators, meaning the Public Service Commission in Montana. Transmission costs would remain a challenge.

Additionally, there is the 13-megawatt Turnbull seasonal hydroelectric project on the irrigation system near Fairfield in Teton County. Turnbull was certified as a community renewable energy project in 2010.

This isn’t the first time Montana’s congressional delegation has written bills for Gibson Dam. In 2018, Tester, a Democrat, joined Republicans Daines and then U.S. Rep. Greg Gianforte in securing a 6-year licensing extension for the power project. That extra time for approval from the Federal Energy Regulatory Commission expires in 2024. The 2018 extension was signed by then-President Donald Trump.