Projects explore the future of ammonia propulsion for OSVs

A UK government-backed project has completed a concept combustion system design and delivered validated injection data for developing a four-stroke ammonia marine engine for the offshore support vessel sector.

Part of the FASTMOVE (Feasibility of Ammonia 4-STroke Marine engines in Offshore VEssels) project, the study results would inform a UK-led design of a next-generation ammonia combustion engine. A consortium including engineering and environmental consultancy Ricardo, Brunel University of London, and the Port of Cromarty Firth completed the study under the UK SHORE programme, with funding from the Department for Transport.

Initial concept work included capturing high-pressure ammonia injection experimental data at 200 bar, developing and validating ammonia spray modelling using CFD simulations, producing high-pressure dual-fuel (HPDF) combustion models, and generating a concept engine combustion system design.

Because it is an excellent hydrogen carrier, contains no carbon and is energy dense by volume, ammonia (NH3) is viewed as a potential alternative fuel for shipping to reduce CO2 and greenhouse gas emissions.

But while it is widely traded globally for use in fertilisers, ammonia is extremely toxic and corrosive, burns poorly compared to traditional marine fuels and yields high levels of NOx emissions during combustion. This has led to the development of new engine technology and fuel supply systems, specialised safety systems, and new guidelines and regulatory frameworks for handling, bunkering and training.

As part of its study, Ricardo said safety ran as a parallel work stream, covering in-port and on-board ammonia storage for OSVs, as well as bunkering operations.

The FASTMOVE consortium developed three HPDF combustion system concepts, selecting the most viable for deeper analysis to optimise injection and combustion conditions and refine emissions predictions. Safety considerations were examined against current regulatory and environmental risk frameworks, and the requirements for fuel storage at the Port of Cromarty Firth, onboard the vessel, and in the bunkering process.

Ricardo global technical expert in Sustainable Engines, Richard Osborne, said the project “will act as a case study to help determine whether ammonia offers a more sustainable solution for the maritime sector.” The next step will be to use the results “to understand the feasibility of developing a single-cylinder engine to further verify combustion processes. We will also consider potential commercialisation of this technology and the use of ammonia in the future, subject to further studies being undertaken,” said Mr Osborne.

Over the last several years, engine makers in Europe and Asia have developed ammonia engines, building on their previous dual-fuel engine technology. This year, Exmar took delivery of Antwerpen, the first oceangoing vessel with a two-stroke, slow-speed ammonia dual-fuel engine.

In the OSV sector, Norway’s Eidesvik Offshore is working with state-owned oil major Equinor to convert a platform supply vessel to operate on ammonia. In May,Viking Energy entered the dry dock at Halsnøy Døkk shipyard for the conversion. Once the conversion is complete, Viking Energy will go on charter with Equinor on the Norwegian continental shelf.