New IEAGHG Report: IEAGHG Monitoring Network – Webinar & Virtual Discussion: Monitoring Expertise Showcase for Post-Closure Monitoring, 2021-TR03

This new report from IEAGHG details a webinar held in January 2021 by the IEAGHG Monitoring Network; an expertise showcase for post-closure monitoring. This was an interactive and informal experience for the audience using a scenario-based exercise; various experts in the area of post-closure monitoring proposed how they would approach a post-closure monitoring plan for a given hypothetical CO₂ storage site. The webinar audience acted as the site developer for this hypothetical site and following questions and discussion from the IEAGHG Monitoring Network Steering Committee, the audience was invited to vote on which of the seven approaches they would be likely to choose if they were the developer for this hypothetical site.

Many topics were looked into around the area of post-closure monitoring for CO₂ storage sites, and several key messages were drawn from the discussions:

• There is a wide range of available technologies that can be deployed for post-closure monitoring programmes, all of which have different merits,
• Post-closure monitoring is very site specific,
• Effective and proper post-closure monitoring requires a full and detailed site characterisation, baseline knowledge and a lot of data from the area before a site can be approved,
• It’s important to do both operational and post-closure monitoring,
• Leakage is defined as CO₂ that fluxes across the ground surface and not out of the reservoir; greenhouse gas emissions accounting is concerned with the CO₂ reaching the air or water column,
• More work is needed on deep monitoring methods informing the near surface methods in real time,
• The subsurface is known well but operators need to be prepared for any changes,
• It is likely and recommended that monitoring programmes will use a variety of technologies that complement one another,
• Shallow and surface monitoring may be needed as assurance monitoring,
• Responding to stakeholder concerns is an important facet of monitoring programmes,
• Environmental liability differs in different regions,
• False positives are an important factor to consider when choosing technologies,
• Understanding of post-closure monitoring approaches is still immature,
• Geologic CO₂ storage is safe by design, and is designed to be safe

For a copy of this report, please email tom.billcliff@ieaghg.org quoting reference number 2021-TR03.