It is generally accepted that changing the energy carrier is the only way to reduce shipping emissions after implementing all possible efficiency and optimization measures. However, the ideal energy carrier for the future has not been defined yet. To meet at least some of the reduction targets, part of the sector is switching to LNG from marine fuel oil. LNG substantially lowers sulphur, nitrogen oxides, CO2 and particulate matter emissions, but it also has one major drawback: LNG mostly consists of methane.