At the Flathead County Landfill, one person's trash really is another's treasure — at least for the Flathead Electric Cooperative. 

Since 2009, the member-owned utility has found treasure in the trash that fills the municipal solid waste facility along U.S. Highway 93 between Kalispell and Whitefish. A power generating plant there, developed in partnership with Flathead County, turns methane gas from decomposing waste into electricity that goes into the power grid — a novel use of a harmful greenhouse gas that otherwise would be burned in an outdoor flare without harnessing its combustive energy.

Flathead Electric Cooperative's Ron Catlett inspects a gas skid outside of the Landfill Gas to Energy Plant outside of Kalispell on Tuesday, June 18, 2024.

The facility was the first of its kind in Montana when it went online in 2009 but is one of hundreds nationwide. Every U.S. state but Wyoming has at least one facility using landfill gas to produce electricity or heat. It's still the only landfill gas facility in Montana that primarily generates power for the electrical grid. A newer facility at a landfill in Billings produces a more highly refined methane gas used to power trucks and heat homes. 

This past December, the co-op doubled the Flathead site's capacity with the addition of a second specialized engine and generator that burns methane from decomposing landfill trash to create electricity. The twin 20-cylinder Caterpillar engines and accompanying generators can produce 1.6 megawatts of electricity each for a total facility capacity of 3.2 megawatts — enough to power about 3,200 homes for a year, according to the co-op. 

The facility currently operates below maximum capacity, producing around 2.4 megawatts, meaning the electricity produced at the facility makes up little more than 1% of the co-op's normal 200 megawatt usage at a given time. The co-op, which is growing, is Montana's second-largest electrical utility and its largest electrical co-op. And even at full capacity, powering 3,200 homes would only energize a sliver of the co-op's 58,000 members. 

But for a utility whose power is 97% carbon-free electricity mostly purchased from Bonneville Power's hydroelectric dams, according to Courtney Stone, the co-op's communications and marketing supervisor, the landfill facility's output still matters. 

"It's small," she said during a tour of the facility on June 18, "but it's not insignificant." 

The Landfill Gas to Energy Plant sits outside of Kalispell by the Flathead County Landfill. The plant aims to make energy from items in the landfill.

Power from the landfill's methane gas is available at all hours, she noted, unlike solar installations whose output can vary with sunshine unless bolstered by battery storage. (The co-op is also working on a solar array with batteries to provide power when the sun isn't shining.) 

And the electricity from the landfill facility costs consumers about 6 cents per kilowatt-hour, which is less than half the average electricity price across the Mountain West and only a small fraction of the price elsewhere, according to data from the U.S. Bureau of Labor Statistics. 

Nationally, there were 457 facilities actively turning landfill gas into electricity for the power grid as of March, according to a dataset from the U.S. Environmental Protection Agency. The Flathead facility, with its 3.2-megawatt max capacity, ranks roughly in the middle in terms of rated power output. 

Hundreds of other landfill facilities have been shut down, and hundreds more landfills have forthcoming facilities planned or are candidates for facilities. And other facilities collect and process methane from landfills for other uses than electricity, such as heating buildings or fueling vehicles. About 60% of operational landfill gas facilities in the U.S. are used for electricity generation, according to the EPA. 

Will Tutvedt, the co-op's digital marketing and community outreach specialist, said the Flathead County Landfill could keep generating combustible gas, and thus electricity, for another 30 years with the current amount of trash already there if it were to stop accepting more. 

When solid waste that includes organic materials is deposited in a landfill, he explained, microbes break down the organic material and produce gasses that include methane. Methane production, an anaerobic process, happens once no more oxygen is left in the waste, according to the EPA, usually about a year after waste is deposited in a landfill. 

Meters display input and output of gas and energy levels on the generators at the Landfill Gas to Energy Plant outside of Kalispell on Tuesday, June 18, 2024.

Methane is a particularly harmful greenhouse gas that contributes significantly to global climate change. The United Nations' Intergovernmental Panel on Climate Change found that methane traps heat in the atmosphere at 28-times the rate of carbon-dioxide. And, according to the EPA, about 14.4% of methane emissions in the U.S. in 2022 came from municipal solid waste landfills. Equating the warming power of methane to other greenhouse gasses, the annual methane emissions from U.S. landfills is the equivalent of 24 million passenger vehicles. 

Under provisions of the federal Clean Air Act, landfills are generally required to capture and burn methane-laden landfill gas to prevent it from entering the atmosphere. This is often accomplished by burning it in an open-air flare. That converts the methane into water and less-harmful carbon dioxide. 

"When people saw that," Tutvedt said, "it was a source of energy." 

The generators at the Landfill Gas to Energy Plant constantly work throughout the year, only being shut off in need of oil changes or other maintenances.

Flathead Electric Cooperative's landfill gas power generation station sits inside a nondescript cinderblock building with a maroon metal roof on the northeast corner of the landfill. A mountain of garbage capped with soil and grass looms behind, dotted with 85 wells that collect landfill gas. The wells come together into a central pipe feeding the building. 

Outside, only a low hum emanates from the building.

Inside the building, in two adjacent engine rooms, nearly identical machines painted in Caterpillar yellow — two 20-cylinder, 5,270-cubic-inch behemoth engines — thunder away as they burn methane and produce more than 2,100 horsepower to turn generators that create electricity. For comparison, a gasoline-powered 2024 Ford F-250 pickup truck has an eight-cylinder, 445-cubic-inch engine producing about 430 horsepower.

Three-ton steel I-beam cranes bridge the ceiling above each engine, and square tanks of lubricant oil fill the back corner of each room. The engines are shut down for six hours every 1,000 hours of operation for an oil change, according to Brian Kratofil, a plant operator, and they take 140 gallons of oil each. (The Ford takes 2 gallons.) 

Outside, two gas blowers powered by electric motors pull a suction on the web of landfill gas well pipes penetrating the landfill. The blowers draw gas from the landfill and send it inside for the engines to burn. A control room monitors operations, and operators have small offices in the building. 

Landfill Gas to Energy Plant operator Brian Kratofil checks on the status of all the parts of the generators at the Landfill Gas to Energy Plant outside of Kalispell on Tuesday, June 18, 2024.

The first engine and generator, manufactured in 2008 and brought online at the landfill in 2009, were paid for primarily with a $3.5 million Clean Renewable Energy Bond from the U.S. Department of Energy, according to the co-op. The latest expansion cost about $4.5 million. 

There are some caveats to electricity generation from landfill gas. The generators need outside power to start up, and 2–4% of the power the engines generate goes back to running the facility. According to the EPA, landfill gas facilities capture about 60–90% of the methane a landfill produces, depending on system design, meaning some still enters the atmosphere. 

Another challenge is that the engines require gas with a relatively high concentration of methane — 45–50% — but gas from landfill wells can range from 5% methane to about 50%, Kratofil said. There's a lot of carbon dioxide already in the gas before it's burned, he said, and some butane, propane and other materials. 

A unique feature of the Flathead facility is that its operators can control the mix of gas coming into the facility by monitoring and turning on or off specific wells based on the gas composition in each one, according to the co-op, and Kratofil and operator Shaun Morgan, both of whom work for SCS Engineers. SCS designs, builds and operates landfill gas facilities such as the Flathead plant on a contract basis. 

The facility is "for the most part pretty simple," Morgan said, but in the gas, "There's a lot of different impurities in there," including water that's removed in a condenser. 

Landfill Gas to Energy Plant operator Brian Kratofil checks on the levels of production in the control room at the Landfill Gas to Energy Plant outside of Kalispell on Tuesday, June 18, 2024.

In more populated areas, landfill gas facilities for electricity are "very, very common because they've got to do something with the gas," Morgan said, but most are forced to burn whatever mix of gas comes out of the landfill. If it's not good enough, they may not run. That's not the case for the Flathead facility. 

Kratofil and Morgan often check all 85 wells by hand daily to tune the plant's intake to gas with 45–50% methane content — they can't afford to waste vacuum power pulling lower-quality gas from the landfill. They monitor gas composition from the control room, along with other operating parameters. The system automatically shuts down if incoming gas contains 2.2% oxygen or more. 

In addition to the ability to manage gas intake, Kratofil and Morgan also appreciated that the facility had its own building, rather than being a modular setup in shipping containers that's common at other landfills. 

"This one is really nice," Morgan said. "A lot of them are really industrial.

"It's more serviceable, you can actually see everything," he continued. "This is probably one of the Taj Mahals of these plants."