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

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.