Skip to content

ULSTEIN THOR ship design solves the zero-emission challenge

The ULSTEIN THOR ship concept uses a thorium molten salt reactor (MSR) to provide clean energy for tomorrow’s all-electric vessels. “THOR may be the missing piece of the zero-emission puzzle for a broad range of maritime and ocean industry applications,” says Øyvind Gjerde Kamsvåg, Chief Designer at Ulstein International.Published 14 Dec 2022 (updated 7 Feb 2024) · 3 min read

The race to decarbonise the shipping industry is on. But a frontrunner has yet to emerge in the industry’s search for low-carbon fuels. Contenders include hydrogen, methanol, ammonia and liquefied natural gas (LNG). Batteries, combined with such fuels, look promising as well.

“We need a long-term, sustainable power source, not an intermediate fix. By taking a whole new approach, we may have found the silver bullet for the maritime sector,” says Kamsvåg.

Clean, mobile power for ships

Ulstein has launched ULSTEIN THOR, a vessel concept capable of making zero-emission cruise operations a reality. The design features a thorium MSR to generate vast amounts of clean, safe electricity. This will enable the vessel to operate as a mobile power station for a new breed of battery-driven cruise ships.

“THOR incorporates our ‘3R design’ – Replenishment, Research and Rescue,” explains Kamsvåg. “First and foremost, THOR is an enabler, providing a clean, continuous, on-site power source for electric cruise vessels. It can replenish supplies as well,” he says.

THOR itself would never need to refuel. As such, the vessel provides a blueprint for entirely self-sufficient vessels of the future.

In addition, THOR has high-tech features to conduct research tasks and facilitate rescue operations. The assets include helicopter pads, rescue booms and autonomous surface vehicles, as well as cranes, laboratories and a lecture lounge.

ULSTEIN THOR can power up to four vessels at a time, such as the ULSTEIN SIF cruise vessel positioned here for recharging.

Ulstein harnesses thorium for clean power

Ulstein is the first shipbuilder to equip an ocean vessel with MSR, an efficient energy solution that works by dissolving thorium in liquid salt.

“MSRs provide an abundant energy source that, with the right approach, can be safe, much more efficient and cheaper, with a smaller environmental footprint, than any existing alternative,” explains Jan Emblemsvåg, professor at the Norwegian University of Science and Technology (NTNU).

The implications of this are enormous. Clean, quiet electric vessels will be able to sail long distances, even in environmentally fragile areas, and recharge at sea.

“There’s a multitude of applications and operational capabilities where THOR’s superpower can be utilised,” says Kamsvåg. “And there are many different vessel types that can either use THOR for recharging or can house integrated MSRs as their primary power source.”

“That’s pretty much all of deep-sea shipping,” he points out.

Urgent need for cleaner marine power

Shipping is on a long voyage towards decarbonisation, driven by rising fuel costs, political and social pressure, and the International Maritime Organization’s (IMO) strict emissions limits.

“Business opportunities abound,” says Kamsvåg. “Owners of a THOR vessel could lease out its energy or research infrastructure. Ecotourism is another potential area of revenue. These are just a few of many ideas.” Potential customers include national governments, large companies, research universities and wealthy, private individuals.

THOR features Ulstein’s innovative X-BOW® hull design. To demonstrate THOR’s feasibility, Ulstein has also developed the ULSTEIN SIF, a zero-emission expedition cruise ship that will use THOR to recharge at sea.

Ulstein Group is a large group of shipbuilding, ship design and supporting companies. Founded in 1917, it is one of Norway’s largest shipbuilders.

Affordable and clean energy

7. Affordable and clean energy

About the goal

ULSTEIN THOR generates clean power from an onboard thorium molten salt reactor and provides this to electric vessels.

Industry, innovation and infrastructure

9. Industry, innovation and infrastructure

About the goal

ULSTEIN THOR increases sustainability in the maritime sector by reducing ship emissions.

Sustainable cities and communities

11. Sustainable cities and communities

About the goal

ULSTEIN THOR is an enabler for fully electric shipping, which contributes to the reduction of air and noise pollution from ships in urban ports.

Contact company



Osnesvegen 118, 6065 ULSTEINVIK, Norway

Lars Ståle Skoge

Commercial Manager, Ulstein Design & Solutions AS

Send an email
Data engineers at work - Origo Solutions is streamlining floating offshore wind with SCADA+, which compiles comprehensive data into a single, user-friendly interface for a total overview of operations, slashing costs and emissions.

Submit a solution

Are you a Norwegian company and want to have your own article on Business Norway? Register your interest and we’ll get in touch.
Find out more