Comparative Assessments of At-Sea and Inland Low- and Medium-Pressure CO₂ Transport

Developing cost-efficient systems for transporting CO₂ is key to accelerating the deployment of carbon capture and storage. The present work explores the impact of reducing the pressure of tank-based inland and at-sea transport on their techno-economic performance. The study uses established techno-economic models for CO₂ transport, adjusted with the most up-to-date knowledge on the costs of low-pressure containment and transport. In particular, the impact of cargo tank material and design on the transport costs show that low-pressure cargo tank systems can be 50% less expensive than medium-pressure systems if materials with similar price and strength can be used. This results in reductions in transport costs as high as 30% for long distances. This is partly driven by the currently suggested size limitation on medium-pressure shipping that limits its economies of scale. If this limitation is alleviated, the cost advantage of low-pressure shipping compared to medium-pressure is more limited (10–20%) although it remains advantageous. The same scaling effects on capacity were not found for truck and barge inland transport, thus yielding 1–10% cost reductions of low-pressure transport relative to medium-pressure transport. These results imply that future systems may combine medium-pressure inland and low-pressure at-sea transport and that efficient solutions connecting the two must be investigated.