This research investigates the value of transport mode flexibility in OCCUS supply chains, particularly under uncertain CO2 supply during the early phases of CCUS development. This study aims to develop a strategic decision support model that quantifies the economic and environmental benefits of transport flexibility within the supply chain.
The literature review provides two key insights. First, it identifies the essential steps in the CO2 sup- ply chain: CO2 is captured onboard ships, temporarily stored onboard in solvent, and transported to onshore facilities for regeneration and liquefaction, after which the liquefied CO2 is transported to per- manent underground storage. Second, the review reveals that no comprehensive studies currently model the full OCCUS supply chain while incorporating uncertainty in CO2 supply. Consequently, no established approaches exist to address transport flexibility under such uncertainty within this context. However, real options analysis has been successfully applied in land-based CCUS projects to value in- vestment and operational flexibility under uncertainty. Building on this proven methodology, the present research adopts a real options approach to quantify the value of the option to switch between transport modes.

This research applies the developed real options model to a case study centered on the Port of Rotter- dam. The supply chain model follows the Value Maritime approach: CO2 is captured onboard ships, stored in CO2 -rich solvent and offloaded at the Maasvlakte terminal. Transport from the port to the re- generation and liquefaction facility is done with containerized trucks, with the option to switch to barges. Two barge types are considered: the smaller CEMT-IVa and the larger CEMT-Va or a combination of the two. The LCO2 is subsequently transported by truck to an underground storage site. The model evaluates scenarios under both a fixed average CO2 price (€136/t) and a variable CO2 price increasing over time based on market forecasts.

The results indicate that while the average CO2 price is insufficient to achieve economic viability at any time and outcome, incorporating the option to switch from truck to barge transport adds value if CO2 supply grows. The option to switch to the smaller CEMT-IVa (€630345) barge shows greater economic benefits compared to the larger CEMT-Va (€131555), mainly due to its better alignment with expected supply volumes during the early implementation phase. The combined switching option (€632010) only yields a marginal additional value, as the larger barge is only required at the highest and least probable supply scenario.

Under the variable CO2 price scenario, the truck-only strategy reaches a positive total value by 2031 with a 30% probability. Introducing the option to switch to the smaller CEMT-IVa barge accelerates this to 2029 with a 55% probability, reflecting earlier and more frequent switching. The larger CEMT-Va barge lags behind, with switching and positive value only occurring from 2030 onward and at a lower 11% probability, indicating less frequent and delayed use.

The break-even price for the truck-only transport strategy is €184.21/tCO2 . The inclusion of switch- ing options reduces this threshold across all configurations: the CEMT-IVa barge option achieves a 4.35% reduction to €176.19/tCO2 , while the CEMT-Va barge provides a modest 0.92% reduction to €182.52/tCO2 . The combined strategy yields the largest reduction of 4.36%, lowering the break-even price to €176.17/tCO2 .