Environmental impacts of on-board carbon capture on two LNG-fueled ships

Decarbonization targets for the maritime sector until 2050 require greenhouse gas (GHG) mitigation options like alternative fuels and on-board carbon capture (OCC). This study assesses GHG mitigation and side-effects of OCC via Life Cycle Assessment of two LNG-fueled ships, the large crane ship Sleipnir and an LNG carrier, and their distinct operational profiles. A large bandwidth of 32%–55% GHG emissions mitigation is achievable, depending on the ship, operation and design. Non-Climate impacts increase without raising major environmental concerns for the monoethanolamine-solvent OCC systems, based on the measured emissions from pilot operation, despite the limited applicability of current impact pathway modelling on open-sea context. With lower GHG mitigation potential compared to alternative fuels but potentially better availability due to less competition from other sectors, including OCC into the portfolio of intermediate decarbonization options for the marine sector is recommended, emphasizing case-by-case evaluation of life cycle emissions, especially fuel supply and methane slip affected by the operational profile.