Geological CO2 storage feasibility in Southwestern Ontario: Cost assessment and the role of pressure management

Geological CO₂ storage presents a promising method for controlling CO₂ emissions and mitigating global warming. However, this approach is accompanied by significant uncertainties related to the geology of the storage site. This study employs robust optimization techniques to address geological uncertainties and provide more accurate estimates of storage capacity and associated injection costs for a site in Southwestern Ontario. To achieve this, 500 geological realizations based on available rock data were created and ranked to identify the most probable models. The robust optimization process targeted maximum overall CO₂ trapping, including both dissolution and residual trapping, by involving P10, P50, and P90 geological realizations. The potential storage area was determined through robust optimization, revealing that the estimated cost for operating a 1 Mt/year CO₂ injection is $54.79 per ton, which is considered high due to the limited storage capacity of the area. This research introduces a brine extraction approach to enhance storage capacity. Simulation results indicate that a 60 km² area could accommodate 1 Mt/year CO₂ injection at approximately $30 per ton for offsite re-injection. However, cost assessments suggest that offsite brine re-injection could escalate costs up to $80 per ton of CO₂. This study provides valuable insights into CO₂ storage capacity and cost implications, offering a basis for future research and industrial applications in CO₂ storage.