Widespread deployment of carbon capture and storage (CCS) is likely necessary to be able to satisfy baseload electricity demand, to maintain diversity in the energy mix, and to achieve climate and other objectives at the lowest cost. If all of the carbon dioxide (CO₂) emissions from stationary sources (such as fossil-fuel burning power plants, and other industrial plants) in the United States needed to be captured and stored, it could be possible to store only a small fraction of this CO₂ in oil and natural gas reservoirs, including as a result of CO₂ utilization for enhanced oil recovery. The vast majority would have to be stored in saline-filled reservoirs (Dahowski et al., 2005). Given a lack of long-term commercial-scale CCS projects, there is considerable uncertainty in the risks, dynamic capacity, and their cost implications for geologic storage of CO₂. Pressure buildup in the storage reservoir is expected to be a primary source of risk associated with CO₂ storage, and could severely limit CO₂ injection rates (dynamic storage capacities). Most cost estimates for commercial-scale deployment of CCS estimate CO₂ storage costs under assumed availability of a theoretical capacity to store tens, hundreds, or even thousands of gigatons of CO₂, without considering geologic heterogeneities, pressure limitations, or the time dimension. This could lead to underestimation of the costs of CO₂ storage (Anderson, 2017). This paper considers the impacts of pressure limitations and geologic heterogeneity on the dynamic CO₂ storage capacity and storage (injection) costs. In the U.S. Geological Survey (USGS)’s National Assessment of Geologic CO₂ Storage Resources (USGS, 2013), the mean estimate of the theoretical storage capacity in the Mount Simon Sandstone was about 94 billion metric tons of CO₂. However, our results suggest that the pressure-limited capacity after 50 years of injection could be only about 4% of the theoretical geologic storage capacity in this formation. Because this is far less than emissions of CO₂ from stationary sources in the region around the Mount Simon Sandstone, the costs to accommodate the potential annual demand for CO₂ storage in this formation could be significantly greater than current estimates. Our results could have implications for how long and to what extent decision makers can expect to be able to deploy CCS before transitioning to other low- or zero-carbon energy technologies.