OFFSHORE CO2 SALINE STORAGE ASSESSMENT METHODOLOGY

Global Energy Review reported that in 2020 the world emitted 33 gigatons of energy-related CO₂ (International Energy Agency, 2021). Geologic carbon storage is a high-capacity storage strategy to help mitigate and reverse the growth rate of CO₂ emissions. To date, geologic carbon storage in the U.S. has focused almost exclusively on onshore systems. However, given the economic driver of the 45Q tax credit and the 2021 Bipartisan Infrastructure Law granting the Bureau of Ocean Energy Management authority to lease Outer Continental Shelf areas for carbon storage, regional storage hubs in the U.S. waters are now being considered. The National Energy Technology Laboratory, DOE’s Fossil Energy and Carbon Management lab, has tailored the DOE method for estimating storage capacity for offshore systems in the Offshore CO₂ Saline Storage (OCSS) methodology. The OCSS methodology accounts for differences between onshore and offshore systems, including changes in CO₂ density and sedimentary differences that impact permanence and capacity estimates. The OCSS methodology is a screening approach to provide long-term estimates of offshore saline storage potential, filling a niche prior to commercial, site-specific assessments. Through mechanizing the methodology, NETL has developed the Offshore CO₂ Saline Storage Calculator to compute and visualize storage capacity for a saline region of interest. This presentation will provide insights into how the OCSS methodology provides probabilistic assessments and demonstrates applications of the calculator for geologically distinct areas in the northern Gulf of Mexico.