Decarbonization of offshore production: LCA methodology applied on a carbon capture and storage system onboard a floating production storage and offloading (FPSO) unit

Carbon Capture and Storage is increasingly recognized as a crucial technology for reducing greenhouse gas emissions in hard-to-abate sectors, including offshore oil and gas operations. This thesis presents a Life Cycle Assessment of a CO₂ capture and storage system integrated onboard an FPSO unit, as a decarbonizing solution for the offshore production field. In addition to the capture unit secured on board the vessel as part of the topside facilities, particular attention has also been devoted to the design of the subsea infrastructure required for CO₂ transport from the FPSO to the designated injection and storage site. The objective is to evaluate the environmental performance of the CCS system, comprising topside and subsea infrastructures, quantifying the emissions associated with its construction and operation over a 25-years design lifespan. The primary data serving as the foundation for the present work have been sourced from various projects and departments within Saipem. The findings provide a comparative evaluation between the investigated system’s performance before and after the CCS plant implementation. Moreover, considerations are made quantifying CO2-eq emissions generated throughout the plant’s lifecycle in relation with its storage capacity. The results offer key insights into the environmental trade-offs of offshore CCS implementation and support informed decision-making regarding the sustainability and feasibility of large-scale deployment in deep-water contexts.