Developing a roadmap for carbon capture, and storage in Oklahoma by assessing the viability of stacked storage

The Intergovernmental Panel on Climate Change concludes that CO₂ capture and storage (CCS) is critical for climate-stabilizing energy transitions. In CCS, captured CO₂ is sequestered in saline aquifers within sedimentary basins. The CO₂ storage capacity and the rate of injection are functions of the geology of the saline aquifer, which is uncertain. To minimize impacts of this uncertainty, CCS projects could include backup plans, such as co-locating geologic CO₂ storage (GCS) sites with or near existing CO₂-enhanced oil recovery (CO₂-EOR) operations. These “stacked storage” projects could hedge against uncertainty in the saline formation performance because captured CO₂ could be injected into either location in the event of unexpected events (e.g., the injectivity decreases). Here, we investigate the possibility and ramifications of developing CCS networks in Oklahoma that are amendable to stacked storage. We find that stacked storage is possible in Oklahoma but the counties with the lowest-cost saline storage resources do not have existing CO₂-EOR operations. At the systems level, we find it is slightly more expensive (e.g., $1/tCO₂ to $5/tCO₂) to site GCS in counties with CO₂-EOR projects. This increased expense is largely due to increased CO₂ transportation costs because hundreds of km of additional pipeline is required to capture CO₂ from the lowest-cost sources. Overall, our results suggest that it is optimal to build more pipelines and avoid injecting CO₂ in some of the lowest-cost saline storage resources, to enable capturing CO₂ from the least-cost sources. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.