Losing hydropower on the Colorado River will not likely increase total greenhouse gas emissions (GHG), according to findings by Save The Colorado, a nonprofit committed to restoring the river and its tributaries. With support from other groups, the organization wishes to restore the river by removing its dams. But there’s pushback from critics who claim it would be impossible to replace what is often described as a carbon-free energy source.

Save the Colorado argues this is a red herring argument because reservoirs created by dams produce large amounts of methane, the second most prevalent GHG in the atmosphere and 86 times more potent. In 2016, a group of Swiss scientists found that GHG emissions from Glen Canyon Dam were roughly half that of natural gas power plants, while emissions from Hoover Dam were roughly equal to a coal-fired power plant producing the same amount of electricity. Advances in methane measurement suggest emissions are likely even higher than the amounts found in 2016.

In 2022, a research and advocacy team led by Patagonia, Save The Colorado, and Earthjustice submitted a petition to the EPA calling for dam and reservoir emissions to be counted in the agency’s Greenhouse Gas Reporting Program.

Why This Matters

Many have long touted hydropower as an integral part of the clean energy transition, but its future is now imperiled by climate change itself. As global warming intensifies the US West’s 20-year megadrought, reservoirs and man-made lakes that provided so-called “clean energy” are drying up. Lake Powell, the country’s second-largest reservoir, uses the Glen Canyon Dam to generate hydroelectric power for 5.8 million homes. But water levels have dropped 100 feet in the last three years, and hydropower production along with it by 16%. In a worst-case scenario, the US Bureau of Reclamation estimates that Glen Canyon Dam could be non-operational by January.

“It’s likely that replacing Glen Canyon and Hoover Dam hydropower with natural gas-fired power plants would not increase GHG emissions,” stated David Wockner, co-founder and executive director of Save The Colorado. “Further, replacing Hoover Dam electricity with natural gas would likely decrease GHG emissions, while replacing both hydropower facilities with wind or solar would almost certainly reduce GHG emissions.”

Damn Dams

Across the West, cries for dam removal are becoming stronger as hydro becomes an increasingly obsolete energy source. States forced to choose between scarce water and electricity are searching for alternative energy, especially as wind and solar become more viable.

“Not only does removing dams help reduce emissions, restore former carbon sinks, and increase climate resilience -- it allows us to spend money once used for costly dam maintenance on truly renewable, clean energy and more sustainable water solutions,” wrote Patagonia CEO Ryan Gellert in Front Lines.

Along the Klamath River Basin, over $450 million has been allocated for the largest dam removal project in US history. The effort is a collaboration between the federal government, California and Oregon state governments, universities, consultants, nonprofits, and indigenous tribes. Another four dams on the Lower Snake River in southeastern Washington have been contentiously debated for decades because of their devastating impact on the river’s salmon populations. Even in light of the very necessary clean energy transition, between greenhouse gas emissions and ecological and cultural impacts, dams have huge downsides.