The race to find green propulsion of the future has dominated the yachting industry for the past few years, although it has yet to land on a one-size-fits-all solution. Could nuclear power be the solution? This topic will be discussed at the Superyacht Design Festival 2025 in Kitzbühel, Austria, on 2-4 February 2025. Here, one of the panellists is the chief designer of Norwegian shipbuilder Ulstein Group, Øyvind Gjerde Kamsvåg, who will reveal the thinking behind his innovative nuclear yacht concept.
As yachting searches for the answer to sustainable propulsion, Ulstein Group has led the way in forging a serious discussion on nuclear power. “We started talking about it as far back as 2006,” says Kamsvåg. “And although we could see some positives and negatives, we also recognised that the nuclear option would be an extremely tough sell!”
When it comes to green fuels, Kamsvåg believes there are pros and cons for everything, particularly when it comes to hydrogen and ammonia. “How can you ensure that hydrogen is manufactured in an eco-friendly way? Where do you find green ammonia? How much energy do you need to produce the amount of hydrogen and ammonia necessary to power a marine fleet? When it comes to hydrogen, you will currently need a tank almost the size of the ship to be able to have a certain range... Alternative fuels currently available all have their limitations, but I believe the benefits of nuclear power would far surpass those of the alternatives.”
In 2021, Ulstein Group was involved in building small expedition cruise vessels used to travel from Ushuaia to the Drake Passage and over to the Antarctic Peninsula. The challenges of accessing sustainable fuels such as HVO in such a remote region led them to start looking into nuclear more seriously. “We wanted to see if it was possible to introduce a new energy infrastructure to improve the sustainability in the cruise industry,” says Kamsvåg.
They came up with the idea of the 149-metre nuclear-powered Thor, a vessel that could base itself in remote areas such as the Antarctic and serve as a mobile power and charging station for vessels visiting the area.
“Thor will not only be an enabler for power, but it will have a research, replenishment and rescue capability and be able to travel around the world,” says Kamsvåg. And having just one nuclear-powered boat will encourage the building of more sustainable electric expedition vessels that can recharge from it.
Read More/Is yachting ready for nuclear propulsion?Kamsvåg’s plan would be to equip Thor with a nuclear reactor to generate 20 MW of clean electricity. Nuclear reactors are typically large affairs and, although the technology can be scaled down, the challenge is to find someone prepared to build a small enough reactor to produce megawatts rather than gigawatts.
Thor and Sif could theoretically house any kind of small next-gen reactor (salt, fast neutron, gas-cooled). While they could also use any fuel, they chose thorium in their concepts over the more conventional uranium and plutonium due to the reduced risk of this power source. They also believed that nuclear power and thorium would be “an interesting mix, because we have an abundance of thorium in the Norwegian soil, and it could become a new energy economy".
Along with Thor, Ulstein created a complementary concept they called Sif, a fully electric expedition cruise ship that can be recharged by Thor. Thor is designed to charge one cruise vessel at a time, with a total capacity to charge four vessels per day. “By doing this, we have introduced a different type of infrastructure when it comes to energy availability in these remote areas,” says Kamsvåg. Not only that, but Thor could be the first responder for rescues in the area.
In terms of design, many people have opined that converting yachts to nuclear propulsion could be game-changing as they could save a lot of space and weight by removing diesel tanks. “We don’t know yet,” cautions Kamsvåg. “Although the nuclear industry has tended to over-complicate and overscale some of the reactor systems, we don't yet know the size of reactor we will need or its complexity, as well as the shielding - this may need to be concrete and we don’t yet know how thick the walls need to be.”
Another complexity will be finding crew with the right technical expertise to handle a nuclear yacht. Kamsvåg agrees that there are lots of hoops to jump through. “I think the IMO, class and flag states, port authorities and insurance companies all need to sit down around the table and discuss these issues openly.”
But he is positive about what might happen in the future, saying that he is certain we will see the technology making its way into the shipping industry in the next few years. Perhaps superyacht owners could play a part in leading the way. “If they could start doing the design now, they could always make room for that unknown black box in the future. After all, while alternative fuels will be an intermediate solution, in the long term, I think nuclear power is the viable option for the future, either for power charging, to produce green fuel or to install as a source of energy.”
The Superyacht Design Festival 2025 brings leaders of the superyacht industry and guests from the luxury community together for a thought-provoking and entertaining event that celebrates the world of design. Returning to the alpine town of Kitzbühel, Austria, on 2-4 February, tickets are available now.
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