Challenges for offshore transport of anthropogenic carbon dioxide

Carbon Capture and Storage (CCS) is recognised as having a significant role to play in reducing carbon dioxide emissions and tackling climate change. In CCS schemes, carbon dioxide is captured from anthropogenic sources and transported to suitable sites either for EOR (Enhanced Oil Recovery) or storage. Globally, the largest source of CO2 is from power generation, therefore the initial projects proposed for CCS in the UK are from power plant. There are various technologies for capturing CO2 from power stations, however the captured CO2 can contain significant amounts of impurities. The presence of the impurities in the CO2 stream has an effect on the requirements for pipeline transportation and can change such factors as the flow properties, the decompression characteristics and the solubility of water in the mixture. Although transport of CO2 by pipeline is not new technology, and has been implemented in the USA for over 30 years, the effect of these impurities is not fully understood. The UK is in the advantageous position of having natural sinks for CO2 available offshore in the North and Irish Sea, which can be used for either EOR or storage. Therefore CCS implementation in the UK will involve transport of anthropogenic carbon dioxide from power stations to offshore sinks. All of the current experience with CO2 pipeline transport has been onshore, predominantly from near pure natural sources and therefore this is also a new challenge. This state-of the-art review paper will: • discuss the key technical factors presented by the transport of CO2 from power plant, including the effects of impurities on the design and operation of pipelines, • compare and contrast the current experience of transporting CO2 onshore with the proposed transport onshore and offshore in the UK and identify the technical and regulatory challenges, • present the results of initial modelling work to demonstrate the effects of the key variables on the development of a CO2 transport system in the UK