Deciding Whether to Fund Either CCS or CCUS Offshore Projects: Are we comparing apples and pears in the North Sea?

Recent years have seen significant funding competitions launched in Europe and in the UK that call for bidders to propose commercial demonstration projects which will bring innovation across the carbon capture and sequestration (CCS) technology chain to reduce energy system costs. The primary carbon dioxide (CO2) storage site candidates that are targeting funds are the saline aquifers and depleted oil and gas fields in the North Sea. At the time of writing, no outright winners have been announced. These programs are open to CCS projects as well as carbon capture, utilization and storage (CCUS) projects. The former deals exclusively with greenhouse gas storage, but the latter differs by using the injected CO2 for enhanced oil recovery (EOR) before eventually being stored. Hence, there are considerable technical and commercial differences between CCS and CCUS projects, in much the same way as onshore projects face less challenges and constraints than if they were being implemented offshore. The evaluation and selection of which offshore carbon storage projects should be funded is a tough exercise to undertake, but it becomes much more difficult if the competing projects under consideration are allowed to be CCS or CCUS, full chain or part chain, or a mixture of all of the aforementioned. Bias may arise via reliance on selection criterion such as volume of stored CO2 per unit of expenditure, which is likely to favor saline aquifer storage projects over other types, no matter how innovative or compelling they are. The authors believe that selection committees in Brussels and London would greatly simplify their decision of which bid should be funded, and in what proportion, by separating competing projects into straightforward storage types and CO2-EOR types. Offshore experience of either project type is scarce and their relative merits are difficult to reconcile as the subsurface understanding, timeframe, economics, performance and goals of each project type are quite different. The paper recognizes that CCS-type projects can be further subdivided into saline aquifers, with open and closed systems, and abandoned gas fields, as each have different storage limitations. Also, CCUS-type projects, which realistically only include abandoned oil fields, can be further subdivided to reflect the operational and commercial characteristics of different EOR schemes. It is hoped that the discussion outlined in this paper will lead to easier and fairer screening criteria for offshore CCS and CCUS projects for use by governments, operators and investors alike