Statistical analysis of incidents on onshore CO2 pipelines based on PHMSA database

The development of an integrated network for the management of carbon dioxide requires knowledge and optimization of all Carbon Capture Utilization and Storage (CCUS) aspects, including pipeline transport. Safety is one of the aspects that should be addressed prior CCUS facilities come in operation; the risk for people should be assessed to ensure it is below an acceptable level. In some cases, a quantitative risk assessment (QRA) is required by the approval authority. Normally the risk assessment is based on the use of statistical/historical data. However, for CO2 handling systems the operating experience is limited compared to hydrocarbon transporting systems and, for this reason, hydrocarbon pipeline statistics are normally used as a proxy. The only database that contains records on CO2 pipelines is the PHMSA since in the U.S. several CO2 pipelines have been constructed since the 1970's, essentially for Enhanced Oil Recovery operations. There is limited statistical data available compared to the hydrocarbon pipelines experience and therefore care should be taken when undertaking the frequency analysis. In this work an analysis of incidents data related to the onshore CO2 pipelines in the U.S. between 1985 and 2021 reported by the Pipeline Hazardous Material Safety Administration (PHMSA) of the U.S. Department of Transportation is presented. The aim of the study is to analyze the records contained in the PHMSA database to provide an estimate of a specific CO2 pipeline failure rate to be used in quantitative risk assessments. Concerns and limitations of the data have been also discussed.