Professor Jan Emblemsvåg, from the Norwegian University of Science and Technology, delivered a compelling presentation at the Gard Summer Seminar titled “Making Waves – geopolitics, energy, and the future of shipping.” He is an experienced and vocal advocate of nuclear power for vessel propulsion, and during his talk, he made a persuasive argument for incorporating nuclear reactors as part of the array of alternative fuels to drive the shipping industry’s green transition.
Upscaling of green fuels may be unrealistic
Green ammonia is often hailed as a promising solution for decarbonizing shipping and large transporters. However, it faces a challenge concerning volume and energy density.
This issue becomes evident in the case of large container ships, which are typically larger than 10,000 TEUs (Twenty-foot Equivalent Units). In 2020, approximately 580 such large container ships were navigating the seas, consuming around 250 to 350 tons of Heavy Fuel Oil (HFO) daily. To put this in perspective, HFO has a thermal value of 11.2 MWh per tonne, resulting in an average energy requirement of 3,350 MWh per day.
When compared to HFO, green ammonia has a lower thermal value of 5.2 MWh per tonne. Consequently, a ship of this scale would require approximately twice the volume of green ammonia compared to HFO to meet its energy needs. This highlights the significance of addressing volume and energy density challenges to fully leverage the potential of green ammonia as a viable fuel alternative in the shipping industry.
Green ammonia production involves electrolysis, which requires approximately 9 to 15 MWh of electricity per tonne. Taking the midpoint of this range, we find that to replace 1 TWh of thermal energy in shipping, it would necessitate 2.2 TWh of electric energy when utilizing green ammonia.
Considering that the global marine fuel consumption is around 300 million tonnes per year, applying the same calculation shows that an annual electricity supply of 7,778 TWh is needed for green ammonia production, which is almost 2.7 times the total electricity production of the European Union in 2021 (2,888 TWh per year). These figures highlight the substantial electricity demand required to support widespread adoption of green ammonia as a viable and sustainable fuel source for the shipping industry.
To put things into perspective, the marine industry’s total greenhouse gas emissions currently contribute to approximately 3% of the global emissions, which is slightly higher than the emissions of an entire country like Germany. However, without significant countermeasures, it is projected that international shipping could account for 10 to 13% of global emissions within the next few decades.
The task of decarbonizing the shipping sector is undeniably challenging and currently appears highly unrealistic with existing approaches. This calls for innovative and fresh thinking to develop effective solutions that can meet the demanding requirements of decarbonization. It is evident that a radical shift in strategies and technologies is necessary to address the urgent need for sustainable shipping practices.
Shipping going nuclear
The nuclear option becomes a compelling choice due to its remarkable energy density. Natural uranium contains approximately 3 million times more energy than coal, while thorium holds about 3.5 million times more energy than coal. Energy density plays a vital role in the green transition, as noted by Vaclav Smil, and has been a consistent historical trend. However, this time, the key difference is the imperative to avoid emissions. By embracing nuclear power, emissions are entirely eliminated, as the process involves fission rather than combustion.
Another significant advantage of nuclear power is the abundance of materials. A 2020 EU report highlights the risks of the current energy policy, given the limited availability of materials for renewable energy and electric vehicles. In contrast, uranium can be extracted directly from seawater in vast quantities, offering a cost-effective and plentiful resource. The nuclear option presents a promising pathway to address the challenges of the green transition while ensuring a sustainable and emission-free energy future.
Lastly, nuclear power offers a cost advantage. Through my own research, I have demonstrated that for an Aframax tanker operating between Singapore and the Persian Gulf, the nuclear option can lead to cost reductions compared to using Heavy Fuel Oil (HFO). Moreover, nuclear power has the potential to produce synthetic fuel at competitive levels. For instance, at the nuclear power plant Nine-Mile-Point in the USA, the goal is to produce hydrogen at a cost of 1 USD/kg within the next 10 years. This cost is actually cheaper than hydrogen derived from most fossil energy sources today, which typically range from 0.7 to 1.6 USD/kg. Competing technologies are expected to achieve a cost of 1.5 USD/kg at best. The cost-effectiveness of nuclear power makes it a compelling option for the decarbonization of shipping and the broader transition towards sustainable energy sources.
Why it didn’t work before
The historical question regarding nuclear power in commercial shipping is indeed relevant. In the past, three nuclear-powered merchant vessels were constructed, but they faced significant cost challenges that prevented widespread adoption. However, the current situation differs primarily due to advancements in reactor design.
All previous nuclear-powered vessels, both civilian and military, utilized Light-Water Reactors (LWRs) that operated on uranium as fuel and water as a coolant. While LWRs are considered safe, their pressurized nature introduces explosion risks, necessitating additional safety mechanisms that add to the overall cost. Moreover, water’s low thermal density compared to alternative coolants like liquid lead and molten salt makes it challenging to design small LWRs with high output efficiency. Consequently, LWRs are more cost-competitive at a certain size. However, advancements in modularization and industrialization have improved the situation, not only for LWRs but also for other types of reactors.
A crucial aspect to consider is that modern reactor designs are inherently safer compared to their predecessors. This advancement not only makes the idea of having nuclear reactors on merchant ships feasible but also reduces costs by simplifying the complexity of the entire reactor system. The effectiveness of this approach was demonstrated by the research conducted at Oak Ridge National Laboratory in the 1960s and 1970s, where the Molten-Salt Reactor (MSR) outperformed the conventional Light-Water Reactor (LWR) and Pressurized Water Reactor (PWR) types by nearly 20%, with both being less expensive than coal power without carbon tax.
It is important to acknowledge that technological advancements in the last 30 to 50 years have been transformative. Digital technologies now allow for more precise and meticulous design of reactors, as well as enable novel forms of collaboration. In the past, nuclear ships had to be entirely self-sufficient in terms of crew and their expertise, making it challenging to recruit enough nuclear-trained personnel to operate such ships. However, today, remote operation technologies make it possible for a control center on land to manage multiple ships in situations that may exceed the crew’s expertise. Additionally, modern manufacturing techniques improve the efficiency of producing most components, resulting in cost reductions.
Considering these developments, it is evident that the early pioneers of nuclear propulsion in merchant shipping were ahead of their time. However, the present circumstances present an opportune moment for nuclear technology in this industry.
Why nuclear will work today
Given the pressing nature of the climate crisis, I firmly believe that nuclear power must be incorporated into the solution. As Machiavelli once wisely stated, “necessity is the mother of invention.” The urgency is clear, and the present moment calls for action.
The technology is nearly ripe, so why delay cost-cutting measures until tomorrow when we can begin today? Undoubtedly, there are some aspects that require further development, and early adopters are inevitably taking calculated risks – a common occurrence in any industry. The crucial understanding is that establishing a new industry typically spans a generation. Thus, it might take a couple of decades before nuclear propulsion systems replace HFO. Obtaining approvals and operating licenses for nuclear technology demands time, and construction capacity and workforce upskilling will also be time-consuming. Hence, initiating the process now becomes all the more imperative.
Clearly, addressing the fuel challenge in shipping requires time, but it’s not as distant a future as one might think. Accelerating progress is possible with early, informed decisions and sufficient funding to sustain the efforts. Conversely, delays can occur, as is common in innovation work, if mistakes are made and funding becomes scarce. One thing is certain: if we succeed, the benefits are immense, encompassing emissions reduction, energy security solutions, and economic gains. Quoting the late Ray Anderson, Chairman of President Clinton’s Sustainability Council, “I want to do well by doing good.” While subsidies might be necessary initially, ensuring a successful energy transition demands an objectively superior alternative to the old solution, and modern nuclear technology holds this potential.