44. What if there is a leak of CO2 underground?

Storage sites are carefully chosen and studied to ensure that the chance of CO2 escaping from the storage reservoir(s) into surrounding rocks is very low. If any leakage were to occur, researchers have shown that CO2 would almost certainly move along narrow pathways into nearby rocks through faults, fractures or deep wells. In the multiple layers of rock present above storage sites, CO2 would have to pass through several more layers of sealing rocks to reach sensitive areas such as shallow groundwater or ecosystems, which are located a thousand metres or more above the injection zone.

WMP research has shown that significant leakage of CO2 from the reservoir to potable groundwater in the shallow subsurface is very unlikely – even if the worst assumptions are made about the nature of rock layers and the condition of older wells that have been drilled into the oilfield. For the WMP, workshops were held with the local community and environmental experts in order to identify environmental assets of most concern, and assess possible impacts of any leakage. The results of these detailed assessments show that risks are low and can be effectively monitored and managed.