Assessing biogenic carbon dioxide resource for synthetic e-fuel production to decarbonise shipping

A high-level assessment of the production potential and costs of three synthetic e-fuels, methane, methanol and Fischer–Tropsch diesel, derived from renewable hydrogen and biogenic carbon dioxide (CO 2 ) was conducted for maritime transport in the EU and Ireland for 2050. Biogenic CO 2 sources included by-products from biomethane production and ethanol fermentation (priced at €30/tonne), and emissions from biomass combustion (€80/tonne). Direct air carbon capture (€400/tonne) was assessed as a supplementary carbon source. The analysis evaluates CO 2 availability, fuel production potential, hydrogen and electrolysis requirements, and levelised fuel costs relative to projected maritime energy demand of 705 TWh in the EU and 3.86 TWh in Ireland. Based on the assumptions used, total theoretical biogenic CO 2 enables methane and methanol production exceeding projected EU maritime energy demand. In contrast, Fischer–Tropsch diesel production potential from biogenic CO 2 yields only 59% of projected demand, requiring supplementary direct air carbon capture. Methanol recorded the lowest modelled levelised production cost at €113/MWh. Fischer–Tropsch diesel was significantly more expensive (€312/MWh) due to higher hydrogen and CO 2 requirements, lower carbon utilisation and broader product distribution. Biogenic CO 2 availability for the maritime sector may decrease due to competition from other sectors, such as aviation, and limited access to point sources. If the biogenic CO 2 resource available to maritime falls to 50% for methanol or 40% for methane, direct air carbon capture becomes necessary to meet EU maritime fuel demand. The findings demonstrate how CO 2 source, cost and availability influence synthetic maritime fuel production potential and costs.