Life-Cycle Assessment and Costing of Fuels and Propulsion Systems in Future Fossil-Free Shipping

Future ships need to operate with low or possibly zero greenhouse gas (GHG) emissions while ensuring low influence on other environmental impacts and that the operation is economically feasible. This study conducts a life-cycle evaluation of potential decarbonization solutions involving selected energy carriers (electrolytic hydrogen, electro-ammonia, electro-methanol, and electricity) in different propulsion system setups (engines, fuel cells, and carbon capture technologies) in terms of environmental impact and costs. The results of the study show that the assessed decarbonization options are promising measures to reduce maritime GHG emissions with low-carbon-intensive electricity. The same order of GHG reduction is shown to be possible independent of the propulsion system and energy carrier used onboard, However, the carbon abatement cost ranges from 300 to 550 (sic)/tCO(2)eq, and there is a trade-off with environmental impacts such as human toxicity (cancer and non-cancer effects) and freshwater ecotoxicity mainly linked with the wind infrastructure used for electricity production, Electro-ammonia in fuel cells is indicated to be effective in terms of the carbon abatement cost followed by the so-called HyMethShip concept. The higher abatement cost of all options compared to current options indicates that major incentives and policy measures are required to promote the introduction of alternative fuel and propulsion systems.

Automated summary

Future ships need to achieve low or zero greenhouse gas emissions, minimize environmental impacts, and be economically feasible. This study evaluates different decarbonization solutions involving various energy carriers and propulsion systems in terms of environmental impact and costs. The results show that these options can effectively reduce maritime GHG emissions when low-carbon-intensive electricity is used. However, there is a trade-off between carbon abatement cost and environmental impacts, such as human toxicity and freshwater ecotoxicity linked to wind infrastructure. Electro-ammonia in fuel cells and the HyMethShip concept are indicated as effective solutions. The higher abatement cost compared to current options suggests the need for incentives and policy measures to promote alternative fuel and propulsion system adoption.