As soon as next month, Washington-based TerraPower will select an aging Wyoming coal plant to build a first-of-its-kind nuclear reactor. It’s an undertaking backed by Bill Gates, who’s said it will revolutionize America’s nuclear industry. If successful, the reactor could have dramatic implications for future energy production across the Rocky Mountain West, and in Colorado, amid a broader push to slash carbon emissions this century.

The Natrium reactor—considered a safer alternative to conventional light-water reactors across the country—will be located at one of four sites in Wyoming and is a joint project among TerraPower (founded by Gates), Berkshire Hathaway Energy’s PacifiCorp, and the United States Department of Energy.

The advanced nuclear energy demonstration plant would produce 345 megawatts at its base level and could offer up to 500 megawatts continuously for nearly six hours when needed. At those times, the plant would generate enough electricity for about 400,000 homes.

The reactor—which TerraPower would build and then hand over to PacifiCorp to operate—could serve as a blueprint for nuclear expansion into states like Colorado, which saw its only nuclear plant close in 1989.

“Wyoming offers an absolutely crucial piece that could help make people feel more certain about nuclear safety and its power-generating capabilities,” says Michael H. Fox, an emeritus professor at Colorado State University who studies global warming and authored Why We Need Nuclear Power: The Environmental Case. “If the Wyoming project does what they say it will do, it could be a game-changer.”

At conventional light-water nuclear plants, water absorbs heat created through fission, which is turned to steam that rotates a turbine and produces electricity. The issue in those reactors, however, is that the steam can also create intense pressure inside the reactor and create a catastrophic failure, like at Three Mile Island in 1979.

In contrast, TerraPower’s Natrium reactor would use liquid sodium as a cooling agent. Liquid sodium has a higher boiling point than water and can absorb more heat, which prevents high-pressure buildups within the reactor.

Rendering of the Natrium reactor and energy storage system. Image courtesy of TerraPower

Wyoming officials have lauded the project. Governor Mark Gordon called the future plant an effective way for the state to follow through on federally mandated clean-energy initiatives while still allowing fossil fuel production. The plant, Gordon said this year, would give Wyoming—among the largest fossil fuel-producing states—the ability to become carbon negative in the future. U.S. Energy Secretary Jennifer Granholm said this summer that the reactor would be a boon “to residents who draw power from it,” adding that the plant would help Wyoming lead the nation into the future of clean energy production.

TerraPower says the Wyoming project would cost about $4 billion and would be split between its company and the federal government. If completed, the plant would open in 2028 and would employ 250 workers by the time it began generating power for PacifiCorp customers in California, Oregon, Utah, Washington, and Wyoming.

“This is an aggressive timeline, but we’re moving at light-speed for nuclear,” TerraPower spokesman Jeff Navin told 5280. He says the company wants to move quickly in order to position itself as a clean energy alternative for other states and utilities that look to meet federal emissions guidelines for 2035 and beyond. “As we build more [nuclear plants], costs will go down. We want to be an option in these places.”

That includes Colorado, where state legislative targets for 2030 mandate dramatically slashing greenhouse emissions and require utilities to reach 80 percent decarbonization. Will Toor, the Colorado Energy Office’s executive director, says state modeling suggests that Colorado can get up to 90 percent reduction through renewable energy, such as solar and wind, by 2050 but needs “firm zero-carbon generation to get us that next 10 percent.”

While the state will look at “all its options,” Toor cautions that nuclear power is just one of several alternatives in Colorado—including green hydrogen and gas plants with carbon capture and storage—and those options won’t be considered for years. “What we do know is that, over the next decade, more expensive coal generation is going to be replaced by wind and solar,” Toor says. “That’s our focus at the moment. We’re all about renewables. No one can pick the other winners yet.”

A proposed “clean energy” site in Pueblo County would have set aside land for a nuclear plant. However, the idea received widespread criticism from environmentalists over water and safety issues, and was killed by county commissioners in 2011 in the wake of Japan’s Fukushima Daiichi Nuclear Power Plant disaster. And in 2020, Carnegie Mellon University researchers reported continued public fears over nuclear power nationwide, even in comparison to much dirtier fossil fuels. In its report, the research team says it would take “a substantial amount of regulatory pressure on fossil fuels” to push the public to nuclear power in the future.

“This project absolutely is designed to provide proof and evidence to future customers in other locations that we can build on time and on budget, and it can operate safely for decades to come,” Navin says. “This is the first of many. This isn’t a science experiment. We will deploy this.”

Colorado hasn’t had a nuclear plant in more than 30 years, when nuclear operations at Fort St. Vrain ended. That plant—which operated for a decade as a high-temperature, gas-cooled site to rival light-water plants—is the only reactor that has been built in the state. Though considered a technical success, it served as a proof-of-concept for advanced technologies and faced extensive maintenance issues as well as expensive corrections.

TerraPower executives think a successful Natrium operation in Wyoming could bring longtime nuclear opponents to the table and create openings in states that want to dramatically alter energy portfolios. CSU’s Fox adds that Gates’ name gives the project an aura of technical muscle and makes the plan “seem far more realistic to complete and operate successfully.”

The Wyoming project isn’t the only proposed nuclear plant in the West. The Department of Energy earlier this year approved a $1.4 billion multi-year cost-share award to the Utah Associated Municipal Power systems for a 720-megawatt NuScale modular plant based out of the Idaho National Laboratory. That project, if successful, could dramatically reduce modular build costs at future sites and give utilities even more options down the line.

“States and utilities are going to have to look at more energy sources to fill gaps,” TerraPower’s Navin says. “Wind comes and goes. Solar comes and goes. People in Denver and Salt Lake City want to know that when they flip a light switch, the power will come on. You need available power 24 hours a day, seven days a week, and nuclear fills that role.”