I recently had the opportunity to attend a workshop in London where the global marine community was beginning to think about the possibility of nuclear power for ships. Various governments, companies and marine classification societies have recognised that the technology for nuclear power in commercial ships both viable and visible in the medium term, even while there is no short-term prospect of such ships coming into service. But these same organisations also recognise that creating a safe marine regulatory environment for nuclear powered ships could take many years, so starting now is a prudent step to at least allow for the possibility of this technology to emerge.
But under what conditions might such a development take place? Is there any pathway to nuclear powered shipping?
Scenarios are the ideal tool for addressing such questions and the recently released 2025 Energy Security Scenarios are well placed for this purpose with one of the scenarios featuring nuclear powered commercial shipping. Just to be clear, these story-lines are exploratory in nature, as is the case with all the scenarios that Shell produce (including those with normative outcomes – see Horizon below). There is no intent to forecast the emergence of nuclear shipping but rather to awaken people to the possibility that it could happen and the circumstances required.
The 2025 Energy Security Scenarios are comprised of three scenario story-lines:
Surge – an era of robust economic growth is ushered in by artificial intelligence technologies that are welcomed and not overly challenged, with economic growth and AI infrastructure driving up energy demand. The geopolitical landscape offers a spur for change as China and the USA compete for AI dominance. A new technocratic era emerges.
Archipelagos – self-interest is deeply rooted in national psyches. The world is still mindful of the energy system disruption in 2022 following Russia’s invasion of Ukraine, but also a world that reacts to the pressures of increasing migration across multiple borders and uneven global trade patterns. Trade friction and geopolitics impinge on the speed of the energy transition, but this is countered somewhat by growing societal pressure to address climate change, which forces action.
Horizon – illustrative of a rapid acceleration of the energy transition and introduction of carbon management practices to sharply reduce emissions, both in response to a comprehensive policy framework with strong societal and political support. The scenario takes a normative approach aimed at a world that achieves two key things: net-zero emissions by 2050 and global warming limited to 1.5°C by the end of the century.
The three stories also illustrate three very different pathways that could be taken by the marine sector, but all three scenarios indicate that change is coming.
In Horizon, the urgent need to get to net-zero emissions in the near term drives the sector to quickly rally around hydrogen fuel cell technology (or the use of hydrogen could also be interpreted as ammonia for marine fuel) as a solution that can be delivered in the near term. While biofuels do help lower the carbon footprint of marine bunkers for a period, the singular early push towards hydrogen dominates the storyline. By 2050 the technology is very well established and by 2075 most ships are using fuel cell technology and hydrogen as the energy source. By late in the century the marine sector is back to a single fuel, as has been the case for many decades up to now. While the scenario sees an end to fossil fuel use in the sector, this isn’t the case by 2050, the current year for a net-zero emissions goal as adopted by the International Maritime Organization (IMO) in July 2023. This means that in 2050 the sector will need to make considerable use of carbon removal offsets, which the Horizon scenario makes available in abundance by mid-century.
In Archipelagos, a broadly slower transition means that by 2050 the situation is little changed from today. Biofuels are in use and hydrogen fuel cell technology has been established, but deployment remains limited within the global shipping fleet. However, as pressure mounts on the sector with the world heading towards 2°C of warming and the first 2°C year already on the record books in a warm El Niño year in the early 2050s, fuel cell technology starts to gain momentum. By 2075 hydrogen fuel cell propulsion is ordered for the majority of new ships, but it still takes a further 30-40 years for the global fleet to completely change. The end of fossil fuel use in shipping isn’t seen until about 2120.
In Surge, a very different pathway emerges in a world of technology achievements and broad societal acceptance of science and technology. In the period up to the early 2040s a number of different marine technologies appear, including hydrogen fuel cells, ammonia, biofuels, green methanol and drop-in synthetic fuels. But the array of technology choices becomes a problem in itself, with the sector that traditionally prefers a single fuel not seeing significant investment in any one option.
In a parallel development in Surge, the small modular reactor (SMR) comes into the picture in the 2030s as major AI technology companies fund development, seeking new secure energy solutions for very large data centres. The technology matures quickly, and AI itself helps solve early issues. SMR use becomes much broader than data centres, with assembly-line style production bringing down costs, leading to a near plug-and-play nuclear customer experience in the 2040s. A handful of marine companies adopt the SMR developments and form a consortium to build a medium sized SMR powered container ship which undergoes successful trials and multiple port visits in the late 2030s and early 2040s.
Finally, in the mid-2040s in Surge, after years of stop‒start progress in alternative marine fuels but pressure still building on the sector to reduce emissions, a major Chinese shipping company places an order for five large SMR container ships, each with twin 30 megawatt reactors. These are put into service in 2050 on well-established routes from Shanghai to the US West Coast and to Rotterdam in the Netherlands. Following a successful start, the technology becomes established throughout the industry, to the extent that by 2090, all large vessels have SMR propulsion.
The nuclear story in Surge only comes about for several very specific reasons. These are all challenging to imagine.
Nuclear is not immediate, so its emergence depends on no other early single emissions solution for the marine sector becoming locked in (as is the case in Horizon). This is both a technology issue and an issue with society not fully addressing CO2 emissions in the near term in alignment with the Paris Agreement.
Broad societal acceptance of nuclear power, which aligns with the techno-optimism of Surge.
A global security situation that can accept the wider use of nuclear technology (problematic in Archipelagos).
Changes in the commercial nuclear regulatory environment, which tends to licence specific fixed sites for nuclear power, rather than considering the reactor as a mobile entity.
A marine regulatory environment that can classify and set high standards for commercial nuclear vessels.
None of the above is to argue that commercial nuclear shipping will happen, it may never appear, but it is nevertheless interesting to think about the problem in a structured way and consider the alternatives for the sector. Scenarios, – such as Shell’s 2025 Energy Security Scenarios are an excellent tool for doing this.
Note: With the release of new scenarios from Shell, please read here what scenarios are, and what they are not.
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