Quantitative risk assessment of CO₂ transport by pipelines-A review of uncertainties and their impacts

A systematic assessment, based on an extensive literature review, of the impact of gaps and uncertainties on the results of quantitative risk assessments (QRAs) for CO₂ pipelines is presented. Sources of uncertainties that have been assessed are: failure rates, pipeline pressure, temperature, section length, diameter, orifice size, type and direction of release, meteorological conditions, jet diameter, vapour mass fraction in the release and the dose-effect relationship for CO₂. A sensitivity analysis with these parameters is performed using release, dispersion and impact models. The results show that the knowledge gaps and uncertainties have a large effect on the accuracy of the assessed risks of CO₂ pipelines. In this study it is found that the individual risk contour can vary between 0 and 204m from the pipeline depending on assumptions made. In existing studies this range is found to be between <1m and 7.2km. Mitigating the relevant risks is part of current practice, making them controllable. It is concluded that QRA for CO₂ pipelines can be improved by validation of release and dispersion models for high-pressure CO₂ releases, definition and adoption of a universal dose-effect relationship and development of a good practice guide for QRAs for CO₂ pipelines.