Opportunities for underground geological storage of CO2 in New Zealand : report CCS-08/10, risk assessment methodologies

Risk assessment is likely to be an important part of future CO2 sequestration projects in New Zealand. Although the global CO2 sequestration risk assessment community may be moving towards a common best-practice, neither a standard approach nor consistent views have yet been reached for risk assessment of carbon, capture and storage projects. This diversity of opinion arises in part because for many storage projects presently under consideration the risk assessment is focussed on containment where the probability of catastrophic leakage has been determined to be extremely low. These low probabilities, together with a general acceptance that appropriate uncertainties are not always well constrained (particularly for reservoir and seal flow properties), has lead some to question the utility of risk assessment. The purpose of this report is to outline the risk assessment methods best suited to potential future CO2 sequestration projects in New Zealand and to recommend tasks that, if completed, would either reduce the risk or enable the likelihood of these risks to be constrained better. To achieve these primary objectives we assembled a team from multiple organisations (GNS Science, Monitor Scientific, CRL Energy and University of NSW) with expertise in risk assessment, CO2 sequestration, geology, engineering, social science and economics. This report is the culmination of a review of existing methods, two risk workshops and a series of meeting between members of the team. The report sets the foundation for risk assessment of potential future carbon, capture and storage projects in New Zealand, outlining a series of practical steps that we believe are necessary to maximise the utility of risk assessment. (auth/DG)