The influence of risk mitigation measures on the risks, costs and routing of CO2 pipelines

Abstract

The aim of this study was to analyze whether, and if so, in what way risks would influence the design, costs and routing of CO2 pipelines. This article assesses locational and societal risks of CO2 pipeline transport and analyses whether rerouting or implementing additional risk mitigation measures is the most cost-effective option. The models EFFECTS and RISKCURVES are used to estimate the dispersion and risk, respectively. The pipeline routes are optimized by using the least cost path function in ArcGIS. This article evaluates three case studies in the Netherlands. The results show that pipelines transporting dense phase CO2 (8–17 MPa) with a minimal amount of risk mitigation measures already meet the 10−6 locational risk required in the Netherlands. 10−6 locational risks of 135 m are calculated for intermediate pumping stations, handling 450 kg CO2/s (about 14 Mt CO2/year). In all the cases, pumping stations could be located along the pipeline route without any problem. For the cases studied transporting gaseous CO2 (1.5–3 MPa) leads to larger 10−6 locational risk distances than transporting dense phase CO2. This is caused by the large momentum behind a dense phase CO2 release, leading to smaller but higher jet and to a higher mixing rate with the surrounding air than for a gaseous CO2 release. Based on our analysis, it can be concluded that dense phase CO2 transport is safe if it is well organized. The risks are manageable and widely accepted under current legislation. In addition, risk mitigation measures, like marker tape and increased surveillance, are available which reduce the risk significantly and increase the costs only slightly. Pipeline routing for gaseous CO2 transport appears more challenging in densely populated areas, because larger safety zones are attached to it.