FleetMon in Research: Techno-Economic Feasibility of Green Ammonia as a Fuel for the Maritime Fleet

Transparency and greener shipping are two of our most important goals at FleetMon. Therefore we support students, universities and institutions in their maritime research projects with AIS data. More than 120 universities are part of our cooperation partners – one is Oxford University. In 2022, Daniel Bundred, a MEng student from the Department of Engineering, contacted us and requested AIS data for his project on decarbonizing global shipping.

Exploring Green Ammonia’s Feasibility as a Fuel for Bulk Carriers and Reefer Vessels

The IMO has targeted a 70 % reduction in CO2 emissions intensity by 2050, which can only be achieved by using a fuel with fewer well-to-propeller emissions than the heavy fuel oil (HFO) used presently. Green ammonia, produced from water, air, and renewable electricity, has the potential to meet this target and has been shortlisted as a potential replacement for HFO due to its favourable energy density and cost compared with batteries and other green fuels. Despite this, more space is required for an ammonia engine room and fuel storage than have previously been needed for HFO in the past. Along with this, there are extra costs associated with building an ammonia-fuelled powertrain, and at the time of the study green ammonia was more expensive than HFO per unit of energy delivered. 

Use of AIS Data by FleetMon

Using AIS data provided by FleetMon, a year of operation was modelled for a variety of ships, including Ultra Large Container Vessels, small bulk carriers, and LNG carriers. The model inputs the ship’s engine characteristics and route data provided at an hourly resolution for 2019. This data is used to calculate the ship’s fuel consumption by modelling the power required for the vessel to overcome resistive forces such as skin friction. Energy consumed over the year was used to calculate fuel consumption and the most energy-intensive trips to size fuel tanks and thus estimate cargo capacity. Economic revenue was also modelled, so each ship’s total lifetime profits were assessed and compared with a HFO baseline. Green ammonia prices are expected to fall significantly over the next 30 years (and fossil fuels have increased their cost during 2022), so another model was developed to explore the effect of varying fuel prices and freight rates over the ship’s lifetime. It incorporates the operator’s reaction to varying economic conditions by optimising the vessel’s operating velocity for that year to maximise profit.

Results

Results confirm ammonia’s technical feasibility as a maritime fuel, with cargo capacity being reduced by less than 5% for all ships. This is despite variability in size, average journey length, operating speed and auxiliary power demand observed between different ships. The results highlight that cost is the main barrier to introducing green ammonia as a maritime fuel.

Capital costs were found to be higher due to the extra equipment needed to run an ammonia engine and the extra material needed for fuel storage. By operating at lower speeds when fuel costs are high, the ships were able to reduce the extra operating costs associated with a more expensive fuel over the ship’s lifetime. However, these extra costs are still a significant barrier to the use of green ammonia as a zero-carbon fuel.

Overall, ships powered by green ammonia achieved total lifetime profits in the range of 30 to 80% of what would be achieved by an equivalent HFO powered ship. Some economic measure will therefore be required to incentivise investors to back zero-carbon ships.

The study also confirmed that utilising green ammonia as a maritime fuel can lead to a significant emissions reduction. Ships running on green ammonia had lifetime scope 2 emissions reduction in the range of 94.8-96.7% compared with conventional ships, which is enough to meet the IMO’s 2030 target for reductions in emissions intensity.

Yet the research highlights the importance of future work to better understand the N2O emissions of ammonia-fuelled ICEs. The study estimates that the majority of GHG emissions from ammonia-fuelled ships could come from the emission of N2O, and the uncertainty in this figure leads to significant uncertainty in the global warming potential (GWP) reduction of green ammonia as a maritime fuel.

The table below shows the eight ships considered, along with the relative NPV achieved by the ammonia-fuelled ship and the reduction in emissions relative to the original (HFO-fuelled) ship. A range is given for the NPV of   the ammonia-fuelled ships corresponding to the range of predicted green ammonia prices used in the model.

Author: Daniel Bundred, Supervisor: Prof. Rene Banares-Alcantara, University of Oxford

Are you also in the process of writing a thesis, or is your university working on a research project that needs maritime data? You are welcome to send us an inquiry. We look forward to hearing from you!