NorthWestern Energy shows off new power plant near Laurel

The Yellowstone County Generating Station is powered by 18 reciprocating internal combustion engines that were manufactured by Caterpillar in Germany. The 181-ton engines are fueled by methane, which comes to the plant through a pipeline from Colorado.

“This is a very simple plant, it’s gas in, power out,” said Josh Follman, a project manager for NorthWestern Energy. “It’s just like a car engine.”

Montana’s largest public utility pushed ahead with the $310 million development, despite uncertainties with local land-use regulations and ongoing legal challenges from neighbors. The electricity it generates is now expected to help keep up when energy demands peak, typically during the hottest summer days and the coldest winter nights.

“The beauty of this plant is that once we hit the start button, within eight minutes we can have 175 megawatts on the grid,” Follman said.

Each engine has its own motor control center and can be fired up together or individually as needed when hydro, wind and solar power are not available or cannot keep up with demand, Follman said.

“This now is going to allow NorthWestern Energy to do more research into some of these renewable fuel supplies because now we have a backstop,” Follman said. “The worst thing would be relying on something that isn’t reliable.”

Follman, an Anaconda native, said he learned about power plants in the Navy and has helped build dozens of other natural gas plants around the world, including a smaller one for NorthWestern in Huron, South Dakota.

The monopoly utility purchased 33 acres of land to build the Laurel plant between Interstate 90 and the Yellowstone River from the CHS Refinery in 2021. At the peak of the two-year construction along South Strauch Road, about 300 workers were employed. Joe Janecek, of Columbus, will now manage the plant, overseeing a regular operations crew of about 20.

While the plant will have to provide annual reporting to the U.S. Environmental Protection Agency, Follman said, the federal regulators do not require it to have a continuous emissions monitoring system. Instead, the plant is equipped with selective catalytic reduction systems designed by Hug Engineering to mitigate emissions. Follman said the technology shuts down the engines immediately if they are out of compliance.

The EPA defines a major source of toxic air pollutants as plant sites that emit or have the potential to emit 10 tons a year or more of a single hazardous air pollutant, or 25 tons a year or more of a combination of hazardous pollutants.

According to NorthWestern’s air quality permit for the Laurel plant, it is expected to emit a number of hazardous pollutants, including 49.9 tons of formaldehyde, 103.8 tons of particulate matter, 14.1 tons of sulfur dioxide and 165.4 tons of volatile organic compounds annually. That worries some neighbors, local healthcare professionals and nonprofit groups, such as the Northern Plains Resource Council.

In addition to concerns about pollution from the plant, some who live nearby have also cited concerns about noise and light.

The noise inside the plant is “ripping loud,” Follman said. But outside, from about 200 yards away the sound is no more than about 45 decibels, which is quieter than running a typical household dishwasher.

Follman is so confident in the measures the utility took to reduce the noise, including insulating the building with sound-muffling materials and adding them to the top of each exhaust stack, he jokes that he’ll bet anyone who can tell which engines are running from outside the plant a beer.

NorthWestern spokeswoman Jo Dee Black said the generating station is also equipped with “dark-sky friendly” lighting that points downward and is designed to have a minimal impact on the surrounding area.

Neighbors have also taken issue with the plant’s proximity to the Yellowstone River and agricultural land that is used for grazing cattle and growing sugar beets. A lawsuit filed in Yellowstone County District Court challenging the validity of land-use regulations and growth planning policies made for the area around Laurel and the public’s right to meaningful participation in the process, is scheduled for a hearing on Dec. 19.