Development of a CO2 specification for a CCS hub network

The CarbonNet Project (CarbonNet) has developed a preliminary CO2 specification for its carbon capture and storage (CCS) hub based network as part of its feasibility studies. This paper provides a summary of the approach CarbonNet used to develop the CO2 specification, focusing on the main elements of the specification and the trade-offs required between the capture, transport and storage components of the CCS project chain. CarbonNet is exploring the feasibility of a commercial scale CCS network delivering CO2 captured from a range of source projects in the Latrobe Valley of Victoria, Australia, which contains one of the world's largest brown coal deposits, to storage sites in the offshore Gippsland Basin, which has greater than 31 gigatonnes of CO2 storage potential. The CO2 captured from potential source projects will contain minor components which may affect the physical properties and phase envelope of the stream, impact environmental and regulatory requirements, set the transportation and storage design and influence the storage site capacity and geochemistry. The philosophy adopted by CarbonNet for the CO2 specification was a risk based approach to not discourage or prevent potential sources connecting to the network and to allow whole of project CCS costs to be minimised, not just the transport and storage elements. The CO2 specification developed from consideration of limitations imposed by the subsurface, pipeline design and health and safety, reviewing business as usual and technically achievable limits of potential source proponents and considering future acceptance of the proposed specification by targeted assessments. Trade-off studies were completed on the water content, operating pressure and purity requirements. Commercial considerations were reviewed for cost recovery of increased transport and storage costs associated with lower purity CO2 and/or high levels of specific minor components. The CarbonNet CO2 specification has a lower and upper bound for many components and the specification will be further refined to meet the requirements of regulators, design limitations and/or commercial arrangements between source proponents and the transport and storage owner during the next stage of the project. (C) 2017 The Authors. Published by Elsevier Ltd.