The 8,000-mile voyage from Busan, South Korea to the European cargo hub of Amsterdam takes about a month and can burn hundreds of thousands of gallons of fuel. Ships can usually make the trip without stopping, but they have to refuel before turning around for the voyage home.
That need for fuel is one of the limits on how far —and for how long— cargo ships can operate, especially on remote routes like the Northwest Passage.
A Seattle-based company, Emerald Nuclear(opens in new tab), believes nuclear power could change that.
Instead of refueling after every long voyage, a nuclear-powered cargo ship could potentially operate for years without refueling. Emerald is betting that kind of endurance could make Arctic shipping routes more practical, while cutting the emissions and fuel demands that come with conventional ships.
“That environment has some very specific constraints that we need to design and develop to,” Emerald’s CEO, Wesley Deason said. “Most of my career I've spent developing nuclear reactors for space applications, so reactors small enough and compact enough that you could put on a rocket to go to the moon or go to Mars.”
Deason’s specialty is microreactors. Don’t think The Simpsons-style powerplants with giant cooling towers, think more like the size of a shipping container.
All nuclear reactors follow the same basic principle, though. They produce energy through a chain reaction of splitting atoms, a process called fission. The process creates huge amounts of heat, which is used to boil water –or in the case of Emerald’s design to heat a gas– which then turns turbines that convert that energy into electricity.
With a warming Arctic, the prospect of putting a floating heater in the water is cause for concern. But Deason said the efficiency of the microreactor is comparable to its diesel counterpart, with both converting about 40% of its total energy into electricity.
“The amount of heat that's being rejected into the environment is very low relative to the environment,” Deason explained. “We're not putting any more or any less heat into the environment that a standard diesel engine would when it operates.”
Deason said the company’s five megawatt Emerald GEM microreactor is still in a “preconceptual design phase”, but that the technology itself is fairly fleshed out.
“We thankfully stand on the shoulders of giants with the developers of TRISO nuclear fuel, which is this very safe, high-temperature form of nuclear fuel,” he said. “And then we have to go through a rather expensive development process to test our system in a non-nuclear means in order to prove its safety.”
The company envisions building modular microreactors that can be swapped in and out when it's time for refueling and maintenance. Emerald plans to lease the microreactors, shifting some of the regulatory burden of owning a nuclear power plant away from the operator.
That leasing model could also apply to floating nuclear power plants serving remote coastal communities. The company reached out to Nome Joint Utility System this spring to learn more about its rate structure and power usage. Deason said a feasibility study using the Nome data will be released this fall.
One potential advantage, Deason said, is that spent nuclear fuel would never need to remain in the community. Instead, the entire floating plant would return to the company’s facility for refueling and maintenance before returning to operation.
Arctic communities face some of the nation’s highest energy costs because of their dependence on imported fuel. And with volatile fuel prices caused by international conflict, it can be hard for utility companies to set a budget. Deason believes this is where the lease model could bring big benefits to rural communities.
“By leasing the reactor at an annual fee, we're able to essentially fit within their current budgeting for how they budget for fuel every year,” Deason said. “In fact, we can provide a more consistent price for energy every year because we simply lease it to them.”
At 5 MW of production, the Emerald GEM microreactor could provide enough power to keep the lights on in Nome. Last year, the utility averaged about 3.7 MW of system load, with more power being drawn in the winter and less in the summer.
Ken Morton with NJUS said a microreactor, paired with Nome’s two wind turbines and new Battery Energy Storage System (BESS), could provide a clean and stable solution for Nome’s power needs.
“I would envision a microreactor becoming a major source of relatively steady energy for the Nome grid, with wind continuing to provide low-cost energy when available, the BESS providing rapid-response capability, and diesel generation remaining available as a dispatchable and redundant resource,” Morton said.
A more mature, land-based microreactor design by Pennsylvania-based Westinghouse Electric Company is expected to cost between $90 million and $120 million. Such an investment in Nome would likely require federal or state funding. Representatives from Westinghouse, along with the Alaska Center for Energy and Power visited Nome in 2024 to discuss the prospects of microreactors in the Arctic.
It’s not known if Westinghouse will offer a similar leasing model for its eVinci microreactor model. Morton said how viable putting a microreactor from any manufacturer in Nome will depend a lot on the numbers.
“The economics will obviously be an important part of this equation,” he said. “For a microreactor to displace a significant amount of diesel generation, I would expect the cost of electricity supplied by the microreactor to be competitive with the marginal cost of diesel generation. The actual dispatch strategy would ultimately depend on the commercial arrangement, the microreactor’s operating characteristics, and NJUS's system requirements.”
Emerald Nuclear plans to develop a research and training reactor with the Norwegian University of Science and Technology, where future marine reactor operators could train. It’s also announced a partnership with Norwegian shipping company Island Offshore as its first commercial customer. The feasibility study with NJUS will be published later this year.
