Review of Technical Challenges, Risks, Path Forward, and Economics of Offshore CO2 Transportation and Infrastructure

Abstract

Offshore storage capacity has been identified as an essential part of long-term Carbon Capture, Utilization, and Storage (CCUS) strategies. Transporting the CO2 from the source onshore to the offshore storage site will be a critical aspect of the technical and economic viability of offshore storage projects. Transport of CO2 will include all processes and equipment from the preparation of CO2 for transport at the source to the wellhead at the offshore storage site. This paper will review the technology required at each step, identify risks/key knowledge gaps specific to the offshore transport process, suggest steps to be taken to advance the technology, and provide an overview of cost/economics for each step in the process. The authors use existing literature, an analysis of analog industries (e.g., offshore natural gas transport), knowledge from CO2 onshore transport, and a technical review of the processes and equipment required for offshore CO2 transportation. This analysis is based on a hypothetical CO2 source and transport process, but will highlight some project and site-specific challenges and decisions for each step. Specific results from the review of offshore transport process include the following: Impact of CO2 source on transport processes, including purification and preparation for transport (e.g., dehydration/compression processes); Comparison of offshore pipeline specifications and costs to comparable onshore applications; Review of scenarios where alternate transportation methods (e.g., ship transport) may be considered; Technical review of wellhead and injection facility in the offshore CO2 application in comparison to onshore analogs; Review of the impact of CO2 utilization (e.g., enhanced oil recovery) of CO2 on transport processes; Tabulation of gaps in data or knowledge to guide further research or industry input. The limited experience with offshore CO2 transport projects leaves significant gaps in available data and information on these projects. By aggregating the available information on offshore CO2 transport projects, supplementing with knowledge and data from related processes (offshore natural gas transport, onshore CO2 transport), and performing a technical review of the offshore transport processes and infrastructure, some specific data needs and risks for offshore CO2 transport projects are identified.