Insights

CarbonNet storage site selection and certification

The CarbonNet project is investigating the potential of geological formations in south eastern Australia to store significant volumes of carbon dioxide (CO2), which could form the basis of a multi-user carbon capture and storage (CCS) network. To date, the Global CCS Institute has published three reports from CarbonNet: a summary and historical background, developing a commercial framework for a CCS hub network, and a report on geological characterisation of three potential sites for the project.

Now in a new report released by the Institute, the CarbonNet team discuss the history of the site selection process and the logical steps to choosing potential sites for the project. It also details the certification process undertaken by CarbonNet, following the DNV GL Recommended Practice (DNV-RP-J203). In this Insight, the Institute's Senior Adviser for Storage (Asia Pacific), Chris Consoli, introduces the report and discusses some of the key findings.

The outcomes from the site selection, and the verification and certification process undertaken by CarbonNet when selecting potential geological CO2 storage sites in the offshore Gippsland Basin, are detailed in a new report: "CarbonNet storage site selection & certification: challenges and successes Gippsland Basin". The report discusses in detail the steps CarbonNet completed to identify potential storage sites, procedures followed to prioritise those sites, and the selection and certification of those sites for the project. This new report follows CarbonNet's recently published report on geological characterisation of three potential CO2 storage sites, prepared for the Global CCS Institute.

Site selection process for CarbonNet

Site assessment

From 2013 to 2015 the CarbonNet Project identified and then scrutinised more than twenty-five storage scenarios in the Gippsland Basin. This is a far greater number of potential sites compared with most basins worldwide, and confirms that the Gippsland Basin is a highly prospective location for the geological storage of CO2, with the potential to host multiple CCS projects.

The sites were prioritised based on three key factors: capacity, containment, and injectivity — the fundamental geological factors for any storage site. The prioritisation study was completed through two extensive work programs and finalised after several iterations of geological and dynamic modelling. Three key sites were identified as priority areas, and further dynamic injection modelling was completed at these sites. Dynamic modelling showed that in each of these sites more than 25 million tons (Mt) of CO2 could be injected at rates exceeding 1 Mt per year. More importantly, the modelling showed that after 1,000 years the CO2 plume stabilised and had no adverse impact on aquifers in the area.

International best practice certification

CCS storage sites are more carefully scrutinised than any other type of injection project. Storage projects are engineered, operated and monitored continuously — all with great care. The CarbonNet storage site selection process was endorsed by a series of peer reviews, including an independent scientific review of experts. CarbonNet then undertook an evaluation of best practice for site selection and storage characterisation, which resulted in a global call for the review and appraisal of the CarbonNet site selection process in 2012. Det Norske Veritas (DNV GL) and the DNV GL Recommended Practice (DNV-RP-J203) workflow was selected due to its transparent, risked-based approach and applicability to Australian storage.

DNV-RP-J203 Certification process for CarbonNet. The CarbonNet Project is currently at the position of the red arrow, having verified the Appraisal Plan for the prioritised storage site.

DNV-RP-J203 is a detailed systematic assessment and documentation approach that takes an operator of a potential CO2 storage site through site selection, appraisal, operation and site abandonment. Following a final review and in accordance with Australian regulatory requirements, DNV GL issued a certificate for the three sites in 2013, known as a Statement of Feasibility. The certificate covers a detailed list of geological, risk and accessibility criteria.

Gaining a comprehensive understanding of local communities, stakeholders and the socio-political context of a proposed project site is also an essential first step. In recognition of this the DNV GL certificate also specifies a number of evaluated social, cultural and environmental implications of the sites.

Each of the three sites had to meet all of these criteria to be issued the final certificate. Following on, the report details the next step for the CarbonNet Project according to the DNV-RP-J203 Certification. A Statement of Verification of Appraisal Plan, if issued by DNV GL, means that all the necessary activities to demonstrate safe storage have been completed, and this enables an application for a future Australian Injection Licence.