Rethinking solvent regeneration pathways for maritime carbon capture

Maritime transport is difficult to decarbonize, and onboard carbon capture has emerged as a promising option. However, adapting land-based capture systems may not suit the space, energy, and weight constraints of ships. Here we show that shifting solvent regeneration from ship to shore can improve the practicality and cost-effectiveness of maritime carbon capture. We compare onboard and onshore regeneration across 16 shipping routes using four capture solvents under different onboard load limits. The results show that adopting practical load limits (~20%), rather than fixed capture rates, provides a more reasonable basis for system design. Solvents with low regeneration energy are favored for onboard regeneration, whereas solvents with high carbon dioxide absorption capacity are preferred for onshore regeneration. With carbon tax included, onshore regeneration is generally more cost-effective in 2030 and 2050, and an extended analysis of 357 routes indicates it becomes economically viable by 2040 and broadly applicable by 2050.