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A large, ungainly wind turbine blade sits in the Logan County Landfill in February 2020. (Andy Colwell, Special to The Colorado Sun)

When it comes to greenhouse gases and climate destruction, coal-fired power plants and gasoline cars tend to catch most of the grief. 

But Colorado, like all other states, has another major source of greenhouse gas emissions right under our feet: Garbage. 

Here and all across the country, decomposing trash and organic waste buried in landfills generate large amounts of methane, which is dozens of times more potent in altering the climate than carbon dioxide if the methane is left to leak. 

The nonprofit watchdog Environmental Integrity Project is highlighting the worst landfill offenders across the country in a new report, “Trashing the Climate.” Thankfully, Colorado does not make the top 10, either in the worst individual landfills or the worst overall states for producing free-flying landfill methane. 

The worst alleged offender is a North Carolina landfill near Raleigh, Sampson County Landfill, which according to the EPA’s annual greenhouse gas calculator belches 825,000 metric tons of carbon dioxide equivalent after the methane multiplier is factored in. The second and third largest landfill emitters were in Georgia and Ohio, the report says.

By comparison, the large and soon-to-be-closing Larimer County Landfill in southwest Fort Collins puts out 196,000 tons of carbon dioxide equivalent a year. To put that in perspective, the Comanche power complex in Pueblo emits nearly 8 million tons a year, and the cement kiln at Florence emits 684,000 tons. 

The national report said combined methane emissions from all landfills have the same climate impact as running 66 million gas-powered cars for a year, or 79 coal electric plants. 

The EPA and environmental groups, which know you can’t just stop burying trash all at once in a modern economy, want landfills to capture methane in piping systems and either use it onsite to generate electricity, replacing fossil fuels uncorked from the ground, or use it as a renewable gas fuel in vehicles. The last alternative is to burn off the methane onsite, which is not ideal, but it does convert the climate changing multiples of methane into less-harmful carbon dioxide. 

Methane leaking from landfills remains a large source of greenhouse gases causing climate change, as methane is far more potent than carbon dioxide in trapping heat. (Source: Environmental Integrity Project)

Colorado health officials agree, and had their landfill methane plan approved by the EPA in 2021. Many of the large Front Range landfills have long had systems to collect methane for power generation, and private companies are signing up more landfills in the West to add their methane to existing natural gas pipelines feeding vehicle fueling stations. 

The state “continues evaluating ways to further reduce methane from landfills,” a health department spokesperson wrote in an email response. 

The state Air Pollution Control Division is putting finishing touches on a new credit-trading system for “recovered methane.” Rules passed in late 2022 require utilities distributing natural gas to account for methane leaks and greenhouse gas emissions from their networks, and start reducing them. They can build or acquire credits from new landfill methane collection, agricultural manure collection, or systems that collect biogas from municipal sewage treatment. 

The Colorado Energy Office, which monitors the state’s greenhouse gas reduction plan, mentioned a number of landfill projects they hope will spread around the state. 

At Front Range Landfill in Erie, Aria Energy operates a methane-fueled electrical generator that can power about 3,000 homes, with the United Power cooperative buying the electricity for the grid.

A similar-size methane generator runs from gas produced by the closed Lowry Landfill and the still-open Denver Arapahoe Disposal Site next door, northwest of Aurora Reservoir. 

Larimer County Landfill installed methane-powered generators in 2010, and the 1.6 megawatts of electricity produced is bought by the Poudre Valley Rural Electric Association. One megawatt can serve 400 to 1,000 homes. 

X3CNG operates a collection of methane fueling stations for commercial trucks and government fleets running on the gas up and down the Front Range. The company says it is buying equivalent amounts of landfill and agricultural methane to power nearly 100% of its needs, and is seeking development of more methane sources at western landfills not currently collecting all their leaking methane. 

A break-the-mindset solution does exist, but getting there is metric tons of work. The best way to reduce methane is to put less rotting stuff into those landfills in the first place. Colorado starts from behind in that goal, with waste stream diversions of only about 15% statewide compared with national averages of closer to 30%. 

A series of recent state and local moves gives environmental groups some hope for diversions away from landfills. The Producer Responsibility Law will have packaging producers pay fees into a new statewide recycling support system, bringing more composting and curbside recycling to underserved communities. 

Denver, meanwhile, has voted to expand mandatory recycling to multiunit buildings. 

Americans throw out 40% of their food, the Environmental Integrity Project says in the report. Those wasted calories start producing methane within a year. 

“On a global scale, if wasted food were a country,” the report says, “it would be the third-largest emitter of global greenhouse gases, behind China and the United States.”

Michael Booth is The Sun’s environment writer, and co-author of The Sun’s weekly climate and health newsletter The Temperature. He and John Ingold host the weekly Sun-Up podcast on The Temperature topics every Thursday. He is co-author with...