Energy and CO₂ Emissions Penalty Ranges for Geologic Carbon Storage Brine Management

Safe and cost-effective geologic carbon storage will require active CO₂ reservoir management, including brine extraction to minimize subsurface pressure accumulation. While past simulation and experimental efforts have estimated brine extraction volumes, carbon management policies must also assess the energy or emissions penalties of managing and disposing of this brine. We estimate energy and CO₂ emission penalties of extracted brine management on a per tonne of CO₂ stored basis by spatially integrating CO₂ emissions from U.S. coal-fired electric generating units, CO₂ storage reservoirs, and brine salinity data sets under several carbon and water management scenarios. We estimate a median energy penalty of 4.4-35 kWh/tonne CO₂ stored, suggesting that brine management will be the largest post capture and compression energy sink in the carbon storage process. These estimates of energy demand for brine management are useful for evaluating end-uses for treated brine, assessing the cost of CO₂ storage at the reservoir level, and optimizing national CO₂ transport and storage infrastructure.