Screening of Austrian geological carbon and hydrogen storage options. Part I: Hydrocarbon fields

The carbon capture and storage (CCS) potential in Austria remains to be elucidated as the country plans to lift its CO 2 storage ban and permit geologic storage for hard-to-abate emitters. This study presents a static screening and assessment of Austria’s CCS and underground hydrogen storage (UHS) potential in hydrocarbon reservoirs. Using reported ultimate recoveries from oil and gas fields, CO 2 storage capacities were estimated across 73 reservoirs. The results indicate a total static CCS capacity of 263 Mt (183–357 Mt, depending on efficiency factor variation) for pure CO 2 , which decreases to 151–293 Mt when high levels of impurities are considered. The five largest gas fields, with individual storage capacities exceeding 10 Mt, account for approximately 100 Mt of CCS capacity. Site-specific challenges in Austria’s largest hydrocarbon fields may include numerous abandoned boreholes, strong aquifer support, and competition with UHS. Storage efficiency factors and CO 2 density variations significantly impact capacity estimates, particularly in reservoirs near the supercritical threshold. For UHS, the total theoretical storage capacity across suitable fields was calculated to be 55 TWh, with 21 TWh identified in operational underground gas storage sites. Competition between CCS and UHS technologies is anticipated in relatively large gas fields with overlapping suitability. While individual CO 2 storage capacities in hydrocarbon fields are small compared to offshore saline aquifers, they offer advantages such as existing infrastructure, detailed reservoir characterization, and proximity to major emission sources. The identified CCS capacity could bridge crucial periods before CO 2 export or saline aquifer storage becomes viable.