Insights and Commentaries
CO2 Pipeline Design – an Australian perspective
15th September 2015
Topic(s): Carbon capture, Engineering and project delivery, use and storage (CCUS)
A new report published by Brown Coal Innovation Australia examines the applicability of Australian Standard 2885, the current Australian Standard (Standard/s) relating to pipelines, in the context of carbon dioxide (CO2) pipeline transportation. Appropriate policies and regulation, including design Standards, are critical for carbon capture and storage (CCS) to fulfill its vital role in tackling climate change at least-cost to the world economy. Standards for natural gas pipelines can be applied with minimal modification to CO2 transport, ensuring safety and the application of international best practice. In this Insight the Institute's Senior Adviser for Storage (Asia Pacific), Chris Consoli, discusses the report and implications for CCS in Australia.
Australian Standards for gas pipelines can be applied to carbon dioxide transport with minimal modification. Picture courtesy of Province of British Columbia via flickr CC BY-NC-SA 2.0
The Australian government has recently announced a target of reducing national greenhouse gas emissions 26 per cent below 2005 levels by 2030. According to modelling conducted by the United Nations Intergovernmental Panel on Climate Change (IPCC), to meet this target at least-cost to the world economy will require deployment of the full range of low emissions technologies, including carbon capture and storage (CCS). Today, there are 14 large-scale CCS projects in operation around the world already reducing carbon emissions. For this number to grow to the scale necessary to achieve global emissions reduction goals will require technology-neutral policies and appropriate regulation.
One of the key areas where development is needed is Standards for CCS infrastructure, including transport from capture facilities to storage sites. According to the National Carbon Mapping and Infrastructure Plan, Australia needs more than 5,000 kilometres (km) of large-diameter CO2 pipelines to meet stated emissions reduction goals. This is a significant expansion, as Australia currently has only 50 km of CO2 pipelines.
Despite the requirement for massive scale-up of pipe infrastructure, preparation for wide-scale CCS deployment in Australia has largely been focused on capture and storage, yet transport is just as critical a component for successful CCS projects. Although pipeline technology and deployment is mature with over 7,000 km of pipelines worldwide, individual countries will still need to prepare for local conditions, Standards and regulations.
Australian Standards for CO2 pipelines
The Australian requirements for pipeline design Standards and regulation is the focus of a comprehensive report recently published to guide future CO2 pipeline infrastructure development. The report reviews the current status of CO2 pipeline design, implementation and operation, as well as relevant pipeline regulations. The report then discusses if pipeline Standards can address risk management procedures when applied to future large-capacity pipelines for CCS projects, with a focus on CO2 dispersion.
The report authors found that the current pipeline Standard, Australian Standard 2885 is an appropriate guide for the design of CO2 pipelines in Australia. This Standard is widely used for gas and liquid petroleum despite not being currently mandatory. The guidelines in the Standard apply to natural gas and can be applied to CO2 as long as a gap analysis is completed to identify differences between CO2 and natural gas, which this report has done, detailing a number of differences and recommending consequent modifications to AS 2885 in the case of CO2.
One major difference between natural gas and CO2 transport in pipelines is the potential for harm resulting from pipeline rupture. Natural gas is flammable, and a rupture could affect people and property as far as several hundred metres away. A sudden CO2 release would create different challenges, with any release likely to affect only a small, localised area. The potential for harm would be influenced by the terrain, wind speed and direction – all factors that can be effectively modelled through comprehensive computer simulation.
Dispersion modelling
This report is clear that while the AS 2885 is suitable for planning and early design phases, it is not applicable for detailed design and operation as the Standard omits an important area of risk management for CO2: dispersion modelling. Modelling the movement of CO2 after accidental release or rupture must be completed using computer-based modelling tools used to simulate the dispersion of CO2 gas away from the pipeline. The modelling simulations must be completed on a project per project basis.
The report reviewed most available modelling tools for their applicability to individual projects, and found that most models are suitable to meet Australian regulations. Only two models include the ability to simulate pipeline depressurisation: the DNV-GL model PHAST and the TNO model EFFECTS. These modelling tools are the only two that have also been field tested in major research projects including CO2 PipeTrans, CO2 PipeHaz and COOLTRANS. These three European-based research projects all sought to understand what happens when dense-phase CO2 is released to atmospheric conditions. Both the DNV GL and TNO models assisted in the research for this report which concluded the appropriate modelling tool should match the requirements of the pipeline and the local conditions.
Summary
This report provides guidance on best practice in CO2 pipeline design, particularly to match risk assessment requirements during early design phase. It serves as a manual to reduce the risk as low as is reasonably practical, namely to meet regulatory and social requirements comparable to natural gas pipelines. There is a significant knowledge gap on CO2 pipeline research and development in Australia, not just for general technical expertise in building and operating such pipelines, but importantly to develop assurance for the Australian regulators and community that pipeline leaks can be avoided, and operational venting and ruptures can be safely managed. The first step would be a nationally consistent approach to CO2 pipeline regulation, followed by R&D and field trials to address Australian-specific risks.
The report was prepared for Brown Coal Innovation by Sherpa Consulting and funded by the Australian National Low Emissions Coal Research and Development Ltd (ANLEC R&D) and the Department of Economic Development, Jobs, Transport, and Resources of the State of Victoria, administered through Brown Coal Innovation Australia Limited and is part of the series of reports focusing on CCS in Victoria.