Life cycle assessment of methanol and dimethyl ether (DME) as marine fuels
The combined effort of reducing the emissions of sulphur dioxide, nitrogen oxides and greenhouse gases to comply with future regulations and reduce impact on climate change will require a significant change in ship propulsion. One alternative is to change fuels. In this study the environmental performance of two potential future marine fuels, methanol and dimethyl ether (DME), are evaluated and compared to present and possible future marine fuels.
Methanol and DME produced from natural gas was shown to be associated with a larger energy use and slightly more emissions of greenhouse gases in the life cycle when compared to HFO, MGO and LNG. Use of methanol and DME results in significantly lower impact when considering the impact categories particulate matter, photochemical ozone formation, acidification and eutrophication compared to HFO and MGO without any exhaust abatement technologies and of the same order of magnitude as for LNG. Methanol and DME produced from willow or forest residues have the lowest life cycle global warming potential (GWP) of all fuels compared in this study and could contribute to reduce the emissions of greenhouse gases from shipping significantly.