Decentralized CO2 storage in unfavorable conditions: An example from Switzerland

The escalating global temperature necessitates immediate action to mitigate greenhouse gas emissions. Geological Carbon Storage (GCS) technology has emerged as a promising solution, specifically by injecting carbon dioxide (CO2) into geological formations, particularly deep saline aquifers. However, finding ideal geological reservoir conditions, including caprock stability and storage capacity, is a rare occurrence.

This study comprehensively assesses the potential for CO2 storage in the Triemli saline aquifer in Zurich, Switzerland. The goal is not only to demonstrate the feasibility of CO2 storage in Switzerland but also to emphasize the viability of decentralized storage with multiple small injection point, for emitters like medium -sized cities, in regions with geologically challenging subsurface conditions. Through numerical simulations, we explore CO$_2$ injection, migration, and long-term reservoir stability to bridge the gap between theoretical estimates and practical feasibility.  Our findings underscore the potential of deep saline aquifers for CO2 storage in Switzerland, particularly in the Swiss Molasse Basin and the adjacent Folded Jura, identified as crucial regions for effective CO2 storage. Employing advanced methods and strategic injection techniques, such as multiple vertical or horizontal injection points along a single well, could optimize this storage capacity to approximately 3 million tons of CO2 over the same period.