Within the last two decades, the aviation sector’s global energy-related carbon emissions have grown faster than rail, road, or shipping emissions. Amid an urgent need to transition this industry to clean energy sources, Denver International Airport (DEN) has proposed a bold solution: nuclear power.

On Wednesday, August 6, airport chief Phil Washington and Denver Mayor Mike Johnston announced they were seeking proposals for a $1.25 million feasibility study of a small, on-site nuclear reactor to support Denver International’s rapid growth. The small modular reactor would provide clean energy to fuel the rising demand placed on airport assets while meeting safety and customer experience goals, Washington said in a DEN statement. Following pushback from a member of Denver City Council, however, the airport has paused its plans.

“There had been no conversation with myself, the council office, none of the [registered neighborhood organizations], no one in the community about even the idea of a feasibility study, and nothing said about the natural resources that might be affected by that feasibility study,” said Councilmember Stacy Gilmore during a Council meeting on Monday, August 11, according to Denverite. Gilmore represents District 11, which includes DEN.

Effective Friday, August 8, the airport delayed its request for proposals to allow the community time to consider an overview of the potential project, an unnamed DEN spokesperson told Denverite in an email. “Our goal is to present this idea to the community, listen to their feedback, and understand what they would like to see included in the feasibility study,” they stated.

DEN was the third-busiest airport in North America in 2024, serving more than 80 million passengers that year. The airport expects that figure to climb to 120 million by 2045. According to Wednesday’s announcement, DEN has already installed 100 acres (40 hectares) of solar arrays, increased its electric vehicle fleet, and constructed the largest energy performance contract in Colorado. These are important steps toward the airport’s goal of achieving net-zero carbon emissions by 2040, “but we must plan now and explore all possible options so that we are prepared for the future,” Washington said.

He believes a small modular reactor would help DEN meet its future clean energy demands. This compact, scalable technology offers reliable power around the clock—a significant advantage over intermittent renewable energy sources such as solar and wind. It can generate up to 300 megawatts of power per unit, which is about one-third the capacity of traditional nuclear reactors, according to the International Atomic Energy Agency. Washington said small modular reactors can be “stackable” and “scalable” to increase capacity as the airport expands, AVWeb reports.

Not everyone is convinced. According to The Colorado Sun, critics immediately raised concerns about the airport’s nuclear project, pointing out the absence of a U.S. repository for spent nuclear fuel, high cost overruns typically associated with nuclear power plants, and the fact that no modular reactors have yet been completed in the U.S. In light of these and other issues, detractors argue that DEN should instead focus on expanding its solar and wind capacity.

In Wednesday’s announcement, Washington acknowledged that small modular reactors are a relatively new technology and emphasized the importance of the feasibility study. “We know that anything we would do would require significant investment and that SMRs are complex. So, we are keeping an open mind, learning more and continuing to responsibly plan for the airport’s future,” he said.

Amid strong opposition from many community members, it’s unclear whether DEN’s feasibility study will get off the ground. Mayor Johnston hopes the airport at least has the opportunity to explore nuclear power as an emissions-cutting option. “We are in no way slowing down on all of our other ambitious climate goals around renewable energy,” Johnston said during a Wednesday press conference, according to The Colorado Sun. “This is an investigation, it’s a study as to whether or not we think nuclear can be one part of that puzzle.”