An early phase risk and uncertainty assessment method for CO2 geological storage sites

Early phase risk assessments of prospective CO2 storage sites are frequently characterized by a lack of knowledge, or high degree of uncertainty, in the relevant geological characteristics. The methodology presented here attempts to address this challenge by using facilitated expert workshops to rank key knowledge gaps and risks in order to form the basis for future site characterization work. Taken in the context of the CO2QUALSTORE guideline, the goal of such characterization work should be to provide the evidence required to pass the next decision gate in the project. The degree of involvement from national or regional authorities in this process is likely to be greater where performance based regulations are in place and the current methodology is designed to facilitate this interaction if required. In one of the two European case studies discussed here, Vattenfall have actively engaged the relevant authorities in Germany in the risk assessment process, thus laying the groundwork for future dialogue around characterization requirements and storage site risk management. (C) 2011 Published by Elsevier Ltd.