PERSPECTIVES ON A CARBON STORAGE ECOSYSTEM BUILT FROM DISTRIBUTED CO2 SEQUESTRATION RESOURCES IN ARIZONA

Permanent subsurface carbon storage has traditionally focused on geologic sites that have large potential storage volumes near CO₂ point sources and existing pipeline infrastructure. The Arizona Geological Survey (AZGS) has been investigating these types of carbon capture and storage (CCS) sites in Arizona since the early 2010s as part of U.S. Department of Energy (DOE) programs and regional initiatives, most recently the Carbon Utilization and Storage Partnership (CUSP). Carbon storage in Arizona has low risk because the state has minimal seismicity and is largely rural. However, CCS advancement in Arizona remains relatively new, due to the lack of deep, high quality subsurface data needed to identify seals and address challenges related to water salinity and availability. Arizona has abundant carbon storage potential throughout the state, including in 57 sufficiently deep (>800 m) Cenozoic sedimentary basins in the Basin and Range/Transition Zone and in Paleozoic & Mesozoic strata within the Colorado Plateau. Basin and Range CO₂ storage is untested, but individual basins contain 100s km³ of porous & permeable clastic rocks, many with interbedded evaporite deposits and mafic volcanic rocks. More recently, AZGS has begun investigating carbon storage in non-traditional geologic resources to make CCS more accessible and distributed throughout the state. We envision a carbon storage ecosystem that includes multiple facets of carbon capture, carbon storage, and economic or industrial carbon use that will facilitate America’s energy transition and benefit disadvantaged communities in the region. Potential CCS in Arizona can include: (1) long-term CO₂ storage in stacked saline and mafic rock reservoirs, (2) blue, green, and/or pink hydrogen production with CO₂ capture and storage in stacked saline and mafic rock reservoirs near point sources, (3) combining Direct Air Capture (DAC) technology with in-situ and ex-situ mafic rock mineralization at a local-distributed scale, (4) using CO₂ for enhanced gas recovery, and (5) sequestration via geothermal utilization. Early public outreach to address perceived and real costs/benefits of a carbon storage ecosystem will be essential to gain public support for these efforts.