NorthWestern Energy submitted an application to the Montana Public Service Commission last week to build a new 175-megawatt natural gas plant and move forward with Montana’s first utility-scale battery project.

NorthWestern’s application asks for commission approval to recover $54 million for the natural gas plant in the supply rates paid by its 700,000-plus customers in Montana. The company argues that the natural gas plant it proposes is the best and cheapest option for a new high-capacity resource that could be online by January 2024.

The total cost of the plant, factoring in land, construction costs, property taxes and capitalized interest incurred during construction, is expected to top $286 million, and NorthWestern is seeking a 10% return on equity for the project, for an overall rate of return of 7%.

The company is also seeking to enter a 20-year agreement with Beartooth Energy Storage, LLC, for a 50-megawatt energy storage project near Billings. Beartooth would build and own the facility, and NorthWestern would control its charging and discharging functions.

The idea behind that project is to direct excess electrons on the grid to the battery when supply is high and demand and energy prices are down, and release electricity back onto transmission lines when demand surges and intermittent energy sources fall off. NorthWestern says this will keep the company from having to make more expensive market purchases for energy.

The company argues the acquisitions are in the public’s best interest because they’ll provide customers with reliable, cost-effective service and protect them from risks associated with volatility and unreliable service when demand for energy peaks. It says the portfolio it landed on through this process is the “least risk, most diverse, and most flexible option at a cost-effective price in comparison to the other evaluated portfolios.”

According to its calculations, the average residential customer in Montana who consumes about 750 kilowatt-hours of electricity per month would see their monthly bill increase by $6.64 if the PSC approves the application.

NorthWestern Energy spokesperson Jo Dee Black said the fuel portion of the equation, the price of natural gas, is evaluated through a different process that’s not reflected in the application before the PSC.

Alan Olson, executive director of the Montana Petroleum Association, said natural gas is plentiful, and that’s part of the reason it’s been so cheap recently. He also said there’s some uncertainty about the country’s energy future that makes natural gas plants like the one NorthWestern is proposing particularly attractive to the oil refineries his group represents.

A natural gas plant will introduce certainty to not just NorthWestern’s portfolio, but to the Pacific Northwest’s energy-thirsty grid more broadly, he said.

“The climate agenda, even before President Biden [entered office], is going to create some serious concerns on the ability to generate electricity,” Olson said. “You look at the recent retirement of Colstrip Units 1 and 2. You look at the closure of the Boardman [coal-fired power plant] in Oregon and the upcoming closure of the Centralia Power Plant in Washington state. That’s going to create a lot of unknowns and potential problems because we’re losing that baseload generation. … We’re going to need natural gas generation to firm up the resource as more and more renewable resources come online.”

According to the U.S. Energy Information Association’s 2021 Annual Energy Outlook, natural gas consumption in the U.S. is expected to fall slightly in the near term and then climb steadily for three more decades. 

A new natural gas plant has been on NorthWestern’s forecast for a while. In its 2019 Electricity Supply Resource Procurement Plan, it indicated its interest in a natural gas plant and outlined the capacity and transmission ceiling it bumps up against when demand on the grid is high. 

The company says the battery storage and natural gas plant are good complements to the wind and solar resources it’s acquired in recent years. It also plans to secure 100 megawatts of capacity from primarily hydroelectric resources per a five-year agreement it signed with Powerex Corp. That agreement is not part of the application before the PSC, but it is referenced in the document as part of the overall portfolio the company is pursuing.

In the application, NorthWestern touched on the electricity challenges Texas faced during an unusually long cold snap this February that wreaked havoc on electricity demand and supply for millions of Texans and led to a fervor of political commentary on the country’s energy dynamics.

“Recent events in Texas have tragically demonstrated the risk and consequences of over-reliance on generation in the market to meet customers’ need for electric capacity especially at times of peak demand,” NorthWestern Energy CEO Robert Rowe said in the application.

Rowe also notes that most of the company’s recent acquisitions and agreements involve  hydro, wind or solar energy, and that its last acquisition of a thermal asset like a coal-fired power plant or a natural gas plant was 10 years ago when it brought the Dave Gates Generating Station online. That facility is a 150-megawatt natural gas plant located near Anaconda that’s owned by NorthWestern.

Several executives supplying testimony in the document echo Olson’s statement that there’s a need for more capacity in the Pacific Northwest generally, and that NorthWestern is an outlier among regional utility companies in its dependence on market purchases for power. While virtually all utility companies purchase energy from the grid at some point, NorthWestern does so more often than most utilities, Black said. During periods of peak demand, about 40-50% of the company’s energy comes from market purchases. 

Colstrip’s coal-fired power plant is by far the company’s largest existing capacity resource, providing up to 222 megawatts of energy. Second is the Dave Gates Generating Station, followed by the Judith Gap Wind Station with 135 megawatts.


If the application is approved by the PSC, the Laurel Generating Station natural gas plant would be built by Burns & McDonnell Engineering Company, operated by Caterpillar Power Generation Systems, LLC, and owned by NorthWestern Energy. At peak construction, between  250 and 300 jobs would be created, Black said. Once built, about 10 workers would be required to run the plant.

The plant itself would use 18 reciprocating internal combustion engine, or RICE, units. Black said there’s a fair bit of flexibility created by this model: the units could be turned off when wind and solar energy production is up and toggled back on as those resources fall off and demand spikes.

The company said it landed on the Laurel location due to its proximity to both natural gas and uncongested transmission lines. It anticipates using a similar process it already employs to acquire natural gas for customers to procure supply for the plant. It will use a combination of daily, monthly and fixed-price natural gas purchases to mitigate market volatility. If the plant is approved, a new pipeline to service the Laurel Generating Station would need to be constructed. 

The application also includes plans for carbon offsets, as required by a law passed by the Montana Legislature in 2007. To meet that need, NorthWestern would make a one-time investment of $327,000 in a carbon offset plan focused on carbon reduction and absorption to be implemented by nonprofit The Climate Trust, which acquires and manages carbon offset programs. Investment preference would be given to Montana-based projects. 


As part of the request-for-proposal process the company launched last January, 21 bidders offered more than 180 proposals to contribute capacity to NorthWestern. Most of those proposals were for energy storage systems — batteries — or a battery storage system paired with a solar project.

Monica Tranel, a former staff attorney for the PSC and Montana Consumer Counsel who has worked in the energy industry for 20 years, said she’s glad that NorthWestern is pursuing energy storage, but doesn’t think a natural gas plant is in Montana’s best interest.

“I think those resources have significant risk in terms of carbon emission pricing, cost of gas and stranded costs,” she said. “I would hope that … careful thought is given to long-term ownership and the potential stranded costs [so] those risks aren’t offloaded to customers.”

She said she’d rather see more investment in renewable energy projects like wind, solar and hydroelectric — “not just the typical run-of-the-mill hydro, but both pumped hydro at the large level like the Gordon Butte project, but also micro pumped storage all over Montana.”

The Gordon Butte project was first proposed more than a decade ago. If built, it would create a large energy storage system in Meagher County. It would pull energy from the grid when supply exceeds demand to pump water to a reservoir on Gordon Butte, a geographic feature near Martinsdale. When demand for energy trends upward, the water would be released through turbines into a lower reservoir, generating up to 400 megawatts of electricity.

Black said NorthWestern couldn’t offer comment on the project proposals it received that it decided not to move forward with, but said that the RFP did give the company a good sampling of the proposals that are out there and the technology that’s being developed.

Even if all three projects it’s planning to move forward with are given a green light, she said, NorthWestern anticipates that it will need to secure additional capacity in the not-too-distant future.

“Now we have an idea what’s out there. It’s exciting. The energy industry is transitioning,” she said, “We’re looking forward to working with some technology we haven’t worked with before and meeting our customers’ desires and needs while continuing to provide service that’s reliable and affordable.”

In addition to Gordon Butte, bids came in for several other high-capacity projects, according to reporting by the Billings Gazette. Those include proposals from NextEra, which is developing a 750-megawatt wind farm for a three-county area in eastern Montana; Broadview Solar II, a 300-megawatt solar farm planned west of Billings; and Mitsubishi Power America, which proposed building a green hydrogen production and storage facility that would incorporate solar power, a gas-fired peaking power plant and a combined cycle gas generator. 

The future of Colstrip is still one of the big unknowns hanging over the company’s future. In a recent call with NorthWestern shareholders Rowe said that without some key pieces of legislation passing this session, the company doesn’t plan to acquire additional shares in Colstrip. 

There’s also some question as to whether renewable energy advocates will intervene on the application and ask for a more careful consideration of projects that NorthWestern opted not to pursue.

“The application certainly brings up questions about resource selection,” NW Energy Coalition senior policy associate Diego Rivas wrote in an email to Montana Free Press. “The NW Energy Coalition will be digging through the filing to determine if a 175 MW gas plant is the right option to meet customers’ needs. Serious questions remain regarding the risk of gas, including price spikes of the volatile commodity, the ability to transport gas to the plant during critical peak times due to lack of pipeline transmission availability, and potential carbon regulation. While NorthWestern may have some capacity needs, the utility has not been aggressive at addressing demand through energy efficiency and conservation, or looking to demand response, all of which address capacity issues at a fraction of the cost.”

The Public Service Commission has 270 days to evaluate the application. That process includes opportunities for public comment.