The Kemmerer coal mine (left) and Naughton coal-fired power plant, pictured Jan. 19, 2022. The power plant will be retired in 2028 when TerraPower commences operations for its proposed Natrium nuclear reactor power plant at the same location. (Dustin Bleizeffer/WyoFile)

Having already agreed to take on one nuclear power plant in Wyoming, western utility giant PacifiCorp will now consider adding five more to its electric generation fleet by 2035, by co-locating “small modular reactors” where it plans to retire coal-fired power plants in Wyoming and Utah.

PacifiCorp, which serves customers in six western states and operates as Rocky Mountain Power in Wyoming, will join nuclear energy developer TerraPower to study “the potential for advanced reactors to be located near current fossil-fueled generation sites, enabling the companies to repurpose existing generation and transmission assets for the benefit of [PacifiCorp’s] customers,” the companies announced in a joint statement Oct. 27. 

Before choosing locations, “both companies will engage with local communities.”

“This is just a first step, as advanced nuclear power needs to be evaluated through our resource planning processes as well as receive regulatory approval,” Rocky Mountain Power President and CEO Gary Hoogeveen said in a prepared statement. “But it’s an exciting opportunity that advances us down the path to a net-zero energy future.”

A schematic of TerraPower’s proposed Natrium nuclear power plant. (TerraPower)

PacifiCorp entered into a tentative agreement in 2021 to take ownership of TerraPower’s first-of-its-kind Natrium nuclear power facility slated for construction at the Naughton coal-fired plant site outside Kemmerer. The plant is scheduled to begin operations in 2028. PacifiCorp would take ownership sometime thereafter.

Coal-to-nuclear shift

Nuclear power is emerging as a potential strategy to help PacifiCorp meet low-carbon emission standards — particularly in California, Oregon and Washington — while also meeting continuous power reliability and making use of its existing coal-fired power facilities. 

The utility plans to convert fuel sources or retire at least six coal-burning units in Wyoming by 2035, taking offline about 2,691 megawatts of continuous “baseload” power capacity, or more than 36% of the state’s coal-fired power generating capacity, according to PacifiCorp data and WyoFile calculations. It plans to shut down its entire coal-fired power fleet in the state by 2039, according to its 2021 Integrated Resource Plan.

Aside from potentially replacing coal plants with nuclear reactors, PacifiCorp plans to add more than 3,700 megawatts of new wind power by 2040 throughout its six-state region, including in Wyoming, while adding commercial-scale solar power and battery storage.

“You have to look that far down the road when you’re talking about this sort of technological change if you’re [selling nuclear plants to a utility]. So it makes sense for both TerraPower and PacificCorp.”

Rob Godby, University of Wyoming

Wyoming lawmakers have passed a suite of bills aimed at delaying coal-plant closures in the state by forcing regulated utilities like PacifiCorp to retrofit coal units with carbon capture utilization and sequestration technologies. But so far, the cost-benefit of CCUS retrofits haven’t penciled out for PacifiCorp or Black Hills Energy, according to the companies. 

Legislators and the state’s top energy officials, however, are also enthusiastic about adding nuclear to the state’s power mix. Not only would it provide replacement jobs for coal-plant workers, but some hope it would also help revive Wyoming’s languishing uranium mining sector.

“Wyoming has been working hard to develop a nuclear industry — from the supply chain via our uranium reserves all the way through the value chain to produce zero-emissions electricity that can then be used as feedstock for other net-negative emission products,” Wyoming Energy Authority Executive Director Glen Murrell wrote WyoFile. “The news that [TerraPower and PacifiCorp are] taking on an additional feasibility study to potentially deploy more reactors in the area will strengthen the industry and create jobs and growth for Wyoming’s benefit.”

TerraPower’s Natrium Project Director Tara Neider visits with Wyoming Rep. Scott Heiner (R-Green River) during a Jan. 19, 2022 meeting with officials from TerraPower and PacifiCorp. (Dustin Bleizeffer/WyoFile)

It makes sense to begin analysis and planning for multiple nuclear power reactors now because TerraPower needs to deploy the technology “at scale” if it’s going to prove the Natrium technology commercially viable, University of Wyoming energy economist Rob Godby said.

“You have to look that far down the road when you’re talking about this sort of technological change if you’re [selling nuclear plants to a utility],” Godby said. “So it makes sense for both TerraPower and PacificCorp.”

Targeting Wyoming

TerraPower, backed by Microsoft billionaire Bill Gates, selected PacifiCorp’s Naughton power plant at Kemmerer for its demonstration Natrium nuclear power plant in November 2021. Engineering and geologic sampling work is ongoing at the Kemmerer location. Construction is slated to begin in 2024 and bring 2,000 workers to the tiny community.

The company is looking to the U.S. Department of Energy to cover about half of the estimated $4 billion cost of the Kemmerer plant, contingent on a 2028 in-service date.

That schedule, however, was thrown into question after Russia invaded Ukraine earlier this year. TerraPower cut ties with the Russian state-owned Tenex — the only facility in the world with the capacity to supply commercial volumes of high-assay, low-enriched uranium fuel. The company is working with DOE and Congress to speed up the development of a domestic HALEU supply chain, including the potential to “downblend” weapons-grade uranium to meet initial fuel needs at Kemmerer by end of 2025, according to TerraPower.

TerraPower Founder and Chairman Bill Gates speaks in a recorded video message during the June 2, 2021 press conference announcing efforts to advance a Natrium reactor demonstration project in Wyoming. (Michael Cummo/Wyoming Tribune Eagle/Wyoming News Exchange)

Yet some doubt the viability of adding new nuclear power to the grid under such a time constraint. The Oregon Public Utility Commission in March declined to formally acknowledge PacifiCorp’s plans for Natrium to be a part of its future electrical generation portfolio.

TerraPower is confident of a speedy federal permitting process and that a domestic HALEU supply will come into play, however, and is moving forward with the project as scheduled, a company official told WyoFile.

Kemmerer and PacifiCorp’s Naughton power plant make an ideal location for TerraPower’s demonstration Natrium plant due to “local community support, the physical characteristics of the site, the ability to obtain a license from the U.S. Nuclear Regulatory Commission for the site, access to existing infrastructure, and the needs of the grid,” the company said.

Those same factors make other locations in Wyoming a prime target for Natrium facilities, according to the company.

In its initial analysis to choose a location for its demonstration plant now slated for Kemmerer, TerraPower had also considered the Jim Bridger plant near Rock Springs, the Dave Johnston plant in Glenrock and the Wyodak plant near Gillette — all owned by PacifiCorp.

“We have been impressed and humbled by our work with the Kemmerer community and PacifiCorp,” TerraPower President and CEO Chris Levesque said in a prepared statement. “We look forward to evaluating new potential sites for Natrium plants that have the same energy expertise and capabilities as our demonstration site.”

Dustin Bleizeffer is a Report for America Corps member covering energy and climate at WyoFile. He has worked as a coal miner, an oilfield mechanic, and for 25 years as a statewide reporter and editor primarily...

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  1. $4B for 350MW for Kemmerer! How much for these additional boondoggles? That’s nuts. $4B would buy 4000MW of utility scale solar, more than 10x what’s being planned here using “shovel ready” technology with virtually no maintenance, safety hazard, security risk, or hazardous waste compared to nuclear. Existing hydro, only run at night, can keep the lights on until pump storage and aluminum – sulfur batteries come on-line. Nuclear just doesn’t add up unless your salary depends on a huge government handout.

  2. C’mon – Natrium technology is simply a smaller plant utilizing sodium as primary coolant rather than water, or for that matter salt. The idea has been around for over 50 years and never been tested. Not once. Its a theory. No Sodium plant has ever been hooked up to a commercial electrical supply grid. I challenge Bill Gates, Gov. Mark Gordon and U.S. Sen. John Barrasso RIGHT HERE on WyoFile to outline the “….much-needed economic boon…..”. Show us the numbers boys. Also, please explain how and where they will store the expended radioactive fuels that must be changed out twice as often as those in conventional reactors. And, why we should support this never-before-used “technology” when a moderate wind farm will produce twice as much megawatts without the highly toxic waste associated with nuclear power.

    1. The technology has been previously deployed in EBR 1, EBR 2 and Fermi 1 outside of Detroit. A moderate wind farm has a third of the capacity factor and needs to be replaced approximately every 20 years. Nuclear plants are currently licensed for 60 years with additional licensing up to 80 to 100 years. So in the short run, you need to overbuild the wind and eventually you need to replace it several times over the life expectancy of a nuclear plant.

  3. If we are going to be hosting more nuclear facilites, Wyoming should look for a viable location for a nuclear waste repository within the state. Not sure there is one, geologically, but we are pretty good at building underground mines and we have lots of empty space. That would also pump billions of dollars into the economy. The new waste is going to sit at these facilities and will need a more secure and long-term home at some point.

  4. Fascinating piece. How do they keep these “small modular reactors” cool? is my only real question. I think the answer is a totally new technology, but am not sure. Worth exploring in a future column?

    1. The sodium is at atmospheric pressure so there is no potential for a rupture and loss of coolant accident. Due to this if the reactor shuts down the sodium has the ability to absorb more heat and transfer it to the atmosphere without human interaction. Term that is applied is inherently safe.

  5. So now that “they” are looking at building these ‘experimental’ nuclear plants in other parts of Wyoming you guys seem to have questions and worries? Now that it looks like it could be in ‘YOUR’ back yard it matters to you? Welcome to the club??? Now you are worried about where the waste goes? Now you are worried about the environment? Now you are worried that it is experimental technology that we don’t understand or haven’t been educated about? Wow, Go Figure! Basically those of us who live near Kemmerer are now officially a part of this “experiment”. No choice, no voice. It just happened to us. No reason to worry. What could possibly go wrong? Hey, but we all trust that the people behind this have our best interest in mind, right? Couldn’t be money that is in their best interest? Be aware, I have not heard of ‘any’ meetings in my community where we were educated or informed or even asked if we wanted this grand experiment near us. Nothing to help ease our worries about having an ‘experimental nuclear plant’ less than an hour away from our home. I don’t know, maybe they did meet with and inform the people in Kemmerer maybe they all got to vote and say ‘Yes, we want this.’ Maybe, but I haven’t heard my family that live there mention these meeting or their ability to have a voice in it coming or not coming there. Maybe ‘YOU’ and ‘YOUR COMMUNITY’ will have a different experience with this but I doubt it. They have decided that we are a sparsely populated state, that has no value especially since they have taken away the oil, gas and coal industries and now that they are after ranching and farming, our agriculture. What left? So what else can we as a state offer for our economy? Tourism. People will come to see our natural wonders and now they can come to see our experinental nuclear plant built by Bill Gates! That great! We will all become rich. Oh, but people require gasoline or electricity to drive vehicles right, and money and food in order to travel on a vacation. I’m guessing when it comes to heating the house, buying food to feed themselves or having fuel to drive to work that those things just might have priority over doing a vacation in Wyoming. They will most likely pick the vacation last. So I’m thinking that’s going to be out the door, also. So what do we have as an economy? Nothing, so guess now we have to become the Nuclear state. To them, we are a waste land much like Nevada used to be considered and what did they do in Nevada? They did nuclear tests and exposed all the people in southern Utah to it. They considered all those small farmer and ranchers and small town hicks expendable because there wasn’t a huge population living there. That is our future and you seem to welcome it. I don’t know, I hope I’m wrong. I hope I’m just a ‘Debbie Downer’, and that I don’t actually be come a ‘Down Winder’. Anyway, have a good day.

  6. Thanks Dustin, great article. What they are really saying is that 2035 is the earliest any of these plants will like be ready, including Kemmerer. 2028 operational for Kemmerer is a PR talking point, designed to shake off the pesky Legislature.

  7. If we want to keep the lights on, we only have a few choices. We could, do what China is doing and build a hundred new coal fired power plants. Or, we can ramp up fracking and build a bunch of new gas fired power plants. Or we can embrace the latest modern nuclear technology and build new zero carbon nuclear power plants. Wind and solar sound nice, but there is no way they can produce the power the nation needs. Especially if we hope to go all electric in our transportation needs. Anyone who says different hasn’t looked at the data, or doesn’t want to be confused with the facts.

  8. I think more explanation of how the system works needs to be produced. The way I understand it, the federal government is basically footing the bill for the development of these reactors as one has never been built before. Why are we so quick to embrace a technology that produces waste products that remain toxic for thousands of years after the useful life has expired. We still have tons of used heating rods and spent nuclear waste stored on a fault line at Yucca Mountain, Utah we haven’t figured out what to do with. Why so hastily jump into an agreement to a technology that’s not only unproven, but actually doesn’t exist?

  9. Could anyone please tell me what happens with the nuclear waste? This is a question no one seems to tackle.

    1. Nothing happens to it, it is stored on site, just like all the nuclear waste in the country is on site at the plants.

      1. Eventually, reactors that are considered Gen IV reactors will utilize the nuclear waste as their fuel. The government is working on allowing reprocessing. Once the fuel is reprocessed, the unused Uranium and trans-Uranium elements are put back in the core and used as fuel. Teh Lantinides and Actinides are then vitrified (turn to glass) and only need stored for <300 years until they are below the natural back ground radiation levels.