Environmental techno-economic assessment of CO2 maritime transport and offshore sequestration

초록

Achieving carbon credits and enabling carbon dioxide removal (CDR) require the permanent isolation of CO2 from the atmosphere. Ship-based CO2 transport and injection provide flexible and scalable options for offshore storage. However, these systems are capital-intensive, requiring integrated environmental and economic assessments. This study applies life cycle assessment (LCA) and environmental techno-economic assessment (eTEA) to offshore CO2 ship transport and injection systems in accordance with ISO/TS 14076. The analysis considers injection methods (offshore and onboard) and onboard capture. Results show that systems integrating onboard injection with onboard capture achieve the lowest global warming potential (GWP), approximately 60% lower (8.7 kgCO2/tCO2) than onboard injection systems without capture. Energy and exergy analyses further show that ship propulsion fuel consumption dominates system energy demand and thermodynamic losses. Economically, the minimum CO2 injection price (MCIP) ranges from $68.5/tCO2to$105.6/tCO2 depending on injection infrastructure and onboard capture. Offshore injection configurations exhibit MCIP values approximately 43-49% higher than onboard injection systems, primarily due to higher capital costs. Sensitivity and uncertainty analyses identify capital expenditures-particularly ships and offshore injection facilities-as the dominant cost drivers. These findings highlight the importance of system configuration and capital structure in designing costeffective and environmentally sound CO2 transport and sequestration systems.

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