World wide there is a significant research effort underway to study the capture and storage of CO2. Most of this research is focused on the capture and storage components of the process but the critical linking component, CO2 transmission, is often overlooked. It is likely, for most onshore and near-shore CO2 storage projects in geological reservoirs, that the CO2 will be transmitted by a pipeline network. One of the potential risks for CO2 release during any storage operation would be as a result of a transmission pipeline failure. Carrying CO2 in pipelines onshore is not a new concept. In the USA, there is already an extensive CO2 pipeline infrastructure carrying (mostly) naturally occurring CO2 to oilfields as part of CO2 enhanced oil recovery (CO2-EOR) operations. The aim of this paper is to draw upon the experiences that can be gained from the existing CO2 pipeline networks to derive estimates of the risk of CO2 releases from CO2 transmission pipelines; the results show that such pipelines do not represent a significant risk in terms of potential for release, which should help build confidence that such lines would not represent a significant public hazard. The paper also presents information on costs of onshore and offshore CO2 pipelines and the sensitivity of cost to distance and capacity. (C) 2004 Elsevier Ltd. All rights reserved.