2025 Spring Meeting and 21st Global Congress on Process Safety
(179d) Northern Ireland/Great Britian Clean Maritime Corridor
Authors
In response, the International Maritime Organization (IMO) introduced its 2023 GHG Strategy, aiming for net-zero emissions by 2050, with interim targets of 40% reduction in carbon intensity by 2030 and 70% by 2040. The IMO's strategy stresses the need for alternative fuels and innovative technologies, such as zero and near-zero GHG fuels, to support these goals. By 2030, at least 5% of international shipping’s energy should come from such fuels, striving for 10%[3].
This study investigates the feasibility of green methanol (e-methanol) as an alternative fuel in the Northern Ireland-Great Britain (NI/GB) Clean Maritime Corridor project. The project evaluates the use of e-methanol for Ro-Ro ferries and container vessels operating between Larne (Northern Ireland) and Birkenhead (England). It proposes a circular carbon economy where hydrogen is produced onboard ships via methanol reforming, CO₂ generated during the process is captured and stored, and the captured CO₂ is later recycled at ports to synthesize e-methanol.
The project has two key objectives:
- Assessing the feasibility of key processes, including onboard hydrogen production via high-temperature methanol reforming, CO₂ capture and liquefaction using the cold energy of methanol tanks, and green methanol synthesis at port facilities.
- Evaluating the costs and scalability of the system, including capital and operational expenses, as well as its potential economic benefits.
The proposed system consists of four key processes:
- Green methanol synthesis on Larne port by combining hydrogen (generated from renewable energy) with captured CO₂ by catalytic hydrogenation process.
- E-methanol is stored in cryogenic ISO tanks (-40°C to -50°C) for stable liquid transport to ships.
- E-methanol is reformed at high temperatures (300°C, 20 bar) to produce hydrogen, which is fed into proton exchange membrane fuel cells (PEMFCs) to produce power for propulsion and auxiliary systems.
- CO₂ generated during reforming is captured exploiting the cold energy of methanol, stored onboard, and returned to ports for reuse in methanol production.
This collaborative project involves following partners: DFDS Seaways, Maritime Power to X, B9 Energy Storage, and Net Zero Industry Innovation Centre from Teesside University, aiming to demonstrate the technical and economic potential of e-methanol as a sustainable fuel for maritime transport.
To conduct the technical feasibility study, thermodynamic process models of vessel and port are developed using Aspen Plus software. The study analyses the required fuel and energy consumption for the round trip, based on voyage details provided by DFDS Seaways, and determines the amount of hydrogen needed for propulsion, the methanol required for hydrogen production, and the CO₂ generated during methanol reforming. The model also evaluates key operational conditions required on board, such as the reformer temperature and pressure conditions, as well as the pressure and temperature needed to liquefy CO₂ for storage in ISO tanks.
The thermodynamic model developed in Aspen Plus for the Larne to Birkenhead round trip reveals promising results for using green methanol as an alternative fuel for ships:
- The model indicates that 53 tons of e-methanol are required onboard to produce 9.2 tons of hydrogen (H₂). This hydrogen is then fed into a PEM fuel cell (PEMFC) to generate 5.67 MW of propulsion power.
- The e-methanol is fed at cryogenic temperatures between -50°C, and the cold energy from the fuel is utilized to liquefy CO₂ at 20 bar, achieving a 99% CO₂ recovery rate. The captured CO₂ is stored in the same cryogenic ISO tanks and unloaded at the port for reuse in the production of green methanol, contributing to a sustainable closed-loop CO₂ economy.
- Of the total methanol requirement, 49.2 tons (83.5%) are reformed onboard to produce hydrogen, while 3.8 tons (6.5%) is burnt indirectly to meet the heat demand of the reformer and the remaining 10% is kept as contingency.
- The methanol reforming reaction also requires 28 tons of water to produce the 9.2 tons of hydrogen necessary for the trip.
- For the round trip, four ISO tanks are required for storage. These four tanks can accommodate the 53 tons of methanol at cryogenic conditions, requiring a volume of 64 m³. Additionally, the same four ISO tanks can store the 72.83 tons of liquid CO₂, occupying 65 m³ of volume.
Comparison with Base Case
In contrast, the base case scenario, where conventional fuels such as HFO (31.69 tons) and MGO (4.75 tons) are consumed, to produce the same 5.67 MW of propulsion power resulting in an engine efficiency of 33%. Moreover, the base case emits 98.40 tons of CO₂ during the voyage, contributing substantially to the carbon footprint. In comparison, the methanol reforming system, coupled with the PEMFC, shows an efficiency of 44%, demonstrating a significant advantage in terms of energy efficiency with on-board CO2 capture and its subsequent utilization on-port.
As part of the ongoing work, a thermodynamic process model for methanol synthesis is being developed to compute the required amount of green hydrogen and renewable energy needed to synthesize methanol required for the round trip. Additionally, efforts are underway to estimate the capital and operational costs for both the vessel and port operations, with a particular focus on the reference route between Larne and Birkenhead.
By demonstrating the feasibility of green methanol as a fuel for greener ship propulsion and closed-loop CO₂ economy, where emissions from maritime transport are captured and reused in a sustainable manner, the project aims to contribute to the global effort to decarbonize the shipping sector which help to meet the ambitious emissions reduction targets set by IMO.
[1] https://unctad.org/topic/transport-and-trade-logistics/review-of-mariti…