The National Engineering Policy Centre has today published new analysis to support the UK maritime sector’s transition to low-carbon fuels, coinciding with a new maritime net zero framework expected by the International Maritime Organisation this week. The new report on Low-carbon maritime fuelling provides detailed comparisons on four alternative, low-carbon fuel sources that could power UK shipping in the future. The analysis aims to support policymakers to decide the most appropriate combination of these cleaner fuels to reduce emissions across the sector by the targets outlined in the UK’s Maritime Decarbonisation Strategy. This comparison of low-carbon fuel sources could also help other countries to decide how to decarbonise their own maritime sectors.
Four options for different low-carbon fuels generated by renewable electricity – hydrogen, ammonia, methanol and synthetic hydrocarbons – could be used to power ships in a way that does not produce any direct carbon emissions when combined with direct air capture technology. Further analysis is needed to determine exactly what role each of these low-carbon fuelling options will play in the maritime sector. However, the report’s evaluation of each of the individual fuels indicates that renewable sources are economically competitive with traditional fossil fuel-based sources used in maritime.
Producing renewable maritime fuels is generally more energy-intensive and expensive than traditional fossil fuels, however, the additional cost is found to be reduced once the wider costs of carbon are considered. Advances in renewable energy technologies and production processes may also help to decrease costs and increase efficiency over time.
Trade-offs between each of the four low-carbon fuels examined will need to be carefully considered. Hydrogen is found to be the cheapest low-carbon fuel to produce, but it would require significant overhauls in existing fuel infrastructure and ship engines. Using synthetic hydrocarbons can rely on existing infrastructure, vessels and engines, however, it is the most expensive fuel to produce. Ammonia and methanol are practical to store on a large scale and easier to transport using existing infrastructure, but additional costs would be required to convert a shipping fleet to operate using these fuels.
Producing alternative maritime fuels will also require identifying suitable locations within the UK that are close to sources of renewable electricity and close to regions linked to the shipping industry where there is high demand for maritime fuels. There are significant demands for maritime fuel in the south and south-east of England, but northern Britain has greater access to wind power for generating renewable electricity. Using hydrogen in these regions may also require significant additional investment in transport or electricity transmission infrastructure.
Professor Sarah Sharples FREng, Chief Scientific Adviser for the Department for Transport, said:
“Switching to cleaner fuels presents a significant opportunity for the maritime sector to achieve deep reductions in its greenhouse gas emissions as outlined in the UK Government’s Maritime Decarbonisation Strategy. This report helps to clarify the opportunities and challenges that different low-carbon fuels present and where we need to seek further answers to best make use of the full range of maritime fuels that we will need for a clean maritime future that delivers benefits to the UK economy and the environment.”
Professor Nilay Shah OBE FREng CEng FIChemE, one of the lead authors of the report, said:
“Maritime creates around 3% of global greenhouse gas emissions and is crucial for transporting over 95% of UK imports and exports according to analysis by the Department for Transport, making it an important sector to decarbonise for a net zero economy. The decisions that UK maritime takes towards a low-carbon future need to be considered holistically, with other parts of the energy system in mind. Maritime won’t be the only sector to use these fuels and different low-carbon options each require different types of investment in energy production or new infrastructure. We hope that this report, combined with further analysis of operational costs, will help policymakers to choose the energy mix of alternative fuels that will deliver the most impact to reduce emissions.”
Claudia Flavell-While, Director, Learned Society, at the Institution of Chemical Engineers, said:
“This new report represents a significant leap forwards in the conversation about clean maritime fuel for the UK. It will play a crucial role in helping policymakers navigate the decisions they will have to make in shifting to a cleaner maritime sector and we are delighted to see the expertise of chemical engineers leading this important debate.”
Notes for editors
- Low-carbon maritime fuelling was scoped by the National Engineering Policy Centre and Institution of Chemical Engineers in collaboration with the Department for Transport. The National Engineering Policy Centre commissioned the Sargent Centre for Process Systems Engineering, a Multi-Institutional Research Centre of departments at Imperial College London and University College London to develop the report. This analysis was initially compiled for submitting to the Department for Transport in July 2023 and published in this report in April 2025.
- The National Engineering Policy Centre brings engineering thinking to the heart of policymaking, creating positive impacts for society. We are a partnership of 42 professional engineering organisations that cover the breadth and depth of our profession, led by the Royal Academy of Engineering. Together we provide insights, advice, and practical policy recommendations on complex national and global challenges.