Causes and financial consequences of geologic CO₂ storage reservoir leakage and interference with other subsurface resources

Leakage from geologic carbon dioxide (CO₂) storage reservoirs used in CO₂ capture, utilization, and storage (CCUS) technologies could trigger costs to a variety of stakeholders, including operators of other subsurface activities, such as oil and gas recovery and groundwater withdrawal. We identify the drivers of these costs and the resulting financial consequences of leakage. Costs could be incurred even in the absence of legal action or if the leakage does not affect other subsurface activities, groundwater resources, or reach the surface. In a case study of leakage potential for CO₂ injection in the Michigan Sedimentary Basin, we find that the majority of leakage costs arise from activities to "Find and Fix a Leak" and from "Injection Interruption". We also found that these costs will be influenced by regulator decisions specific to a leakage event and depend on the developmental state of the CCUS industry. Estimated costs for an Nth-of-a-Kind (NOAK) project range from $2.2MM for a low-cost event with only leakage to $154.7MM for a high-cost event that reaches the surface. Leakage from First-of-a-Kind (FOAK) projects incurs approximately 1.6-3.0× more costs than equivalent leakage from an Nth-of-a-Kind (NOAK) project across all of the storylines we develop. Multiple stakeholders will incur leakage costs, and such externalities must be managed lest they impede the development of the CCUS industry.