Determination of optimal volume of temporary storage tanks in a ship-based carbon capture and storage (CCS) chain using life cycle cost (LCC) including unavailability cost

This study estimated the life-cycle cost (LCC) of a ship-based carbon capture and storage (CCS) chain to determine the optimal volume of temporary storage tanks. The temporary storage tanks should be installed in the ship-based CCS chain to enable ship transportation. Concepts of the ship-based CCS chain were suggested with different volumes of the temporary storage tanks. They were analyzed from an economic viewpoint by LCC analysis. Although general LCC is composed of capital expenditure (CAPEX) and operation expenditure (OPEX), this study additionally considered the unavailability cost, which was derived from the availability. The availability indicates the operational effectiveness depending on the volume of the temporary storage tanks. For estimating the availability, factors causing production loss in the chain were defined first. The failure frequency and restoration time of the defined factors were collected and then the chain was modeled. Finally, the unavailability cost was estimated. CAPEX and OPEX were calculated using a commercial tool and relevant literature. The results showed that the unavailability cost decreased with the increment of the volumes of the temporary storage tanks. In contrast, the CAPEX and OPEX increased with the volumes. When the temporary storage tanks had the same volume of a CO2 carrier, the lowest LCC was indicated. A sensitivity analysis was performed to investigate the influence of different design parameters and assumptions: CO2 trade cost, the number of CO2 carriers, cargo volume of a CO2 carrier, and distance from a source to a sink.