Katherine Duncker Romanak, University of Texas
Over the past 20 years of its development, carbon capture and geologic storage has been proven robust, safe and effective. Currently some 40 million tonnes of CO₂ are being successfully stored in geologic reservoirs across the world every year. Despite the proven safety of CO₂ storage sites, regulations require significant amounts of environmental monitoring including: acquisition of background measurements, leakage detection and quantification, and assessment of leakage impacts. This synthesis of monitoring protocols illustrates that, under the regulations as written, leakage quantification and impact measurement may be required prematurely, without leakage being actually confirmed. Thus, the importance of “attribution monitoring” to determine whether anomalous CO₂ in the environment actually represents leakage is important for project developers despite the proven safety of storage and the lack of requirements for attribution monitoring in global regulations. Recent CO₂ storage project experience supports the importance of attribution monitoring and further indicates that using baseline measurements for determining leakage can create false positives for leakage and put projects at risk. This is because temperature rise from global climate change is directly causing natural ecosystem CO₂ production rates to rise over time. A rise in CO₂ concentrations in groundwater and seawaters is also occurring. This general trend in CO₂ coupled with an expected increase in ecosystem variability from a changing climate means that “baselines” will not provide a valid comparison over the lifetime of a typical project. Using a baseline approach to attribution when CO₂ in soils, groundwater and seawater is rising will inevitably result in false positives for leakage that could risk project operations, even though a conscientious project follows the regulations. This presentation will give examples of when attribution monitoring became a key factor to project success and outline new cost-effective methods and approaches to attribution to satisfy regulations while retaining project success.