CO₂ cannot be injected just anywhere underground; firstly suitable host rock formations must be identified. Potential reservoirs for CO₂ geological storage exist throughout the world and offer sufficient storage capacity to make a significant contribution to mitigating climate change. 

After its capture at the industrial facility, the CO₂ is compressed, transported, and then injected into the reservoir formation through one or several wells. The whole chain has to be optimized to enable the storage of several millions of tons of CO₂ per year.

Once the CO₂ is injected in the reservoir, the CO₂ will rise buoyantly filling the pore spaces below the caprock. Over time, part of the CO₂ will dissolve and eventually be transformed into minerals. These processes take place at different time scales and contribute to permanent trapping.

Based on the study of natural systems, carefully chosen storage sites are not expected to show any significant leakage. Natural reservoirs containing gas help us to understand the conditions under which gas is trapped or released. In addition, natural seepage sites help us recognise what the possible impacts of CO₂ leakage could be.

All CO₂ storage sites will need to be monitored for operational, safety, environmental, societal and economic reasons. A strategy has to be drawn up to define what exactly will be monitored and how.

In order to ensure storage security and efficiency, conditions for project design and operation must be imposed by the regulating authorities and respected by the operators.