This post has been contributed by Dr Jacqui Robertson, Lecturer in the Griffith Law School and a member of the Law Futures Centre.
Dramatically reducing global green-house gas emissions is clearly imperative (see the latest Intergovernmental Panel on Climate Change (IPCC) report). Australia is now committed to achieving net-zero carbon emissions by 2050 through a range of ‘low emissions’ technologies, such as carbon capture and storage (CCS). However, ensuring that CCS does not have unintended consequences will not be easy.
In summary, CCS captures green-house gasses that are released from a particular activity or project, such as a coal-fired power station, and permanently stores the gasses deep underground. CCS can be seen as a key defensive technology for Australia given our existing reliance on fossil fuels for base-load electricity. For example, CCS could reduce the risk that the power station would become a stranded asset in a net-zero world. Six companies have now been awarded a share of the federal government’s Carbon Capture, Use and Storage Development Fund.
In Queensland, Glencore’s Carbon Transport and Storage Company Pty Ltd (CTSCo) has been awarded $5 million for its demonstration project near Millmerran. That project proposes to capture the exhaust from the existing coal-fired power station at Millmerran, convert the gasses to a liquid substance and transport the liquid CO2 by truck 260kms to Moonie. At Moonie, the liquid CO2 will be injected more than 2000m deep into a sandstone aquifer. Not all CCS projects require an aquifer to store the CO2 stream. In a 2009 report detailing an assessment of Australia’s potential for CCS, the National Carbon Storage taskforce noted that the simplest form of CCS involves depleted oil or gas fields. But for this project, injection of the CO2 stream will use a very deep part of the Precipice Sandstone aquifer. Once the CO2 is injected, this makes the actual injection zone unusable as a water source. The whole idea is that the CO2 is injected where it will never see the light of day again. This means that the area of injection effectively becomes unusable as an aquifer.
The target location in the aquifer has been described by some as ‘salty’ and ‘unviable for livestock’. The Initial Advice Statement (IAS) for the project sets out key water quality parameters of the aquifer in the target injection area and argues that the target zone water quality is generally unsuitable for water supply. The IAS cites elevated alkalinity, salinity, chloride and fluoride as the key characteristics that make it unsuitable for irrigation, stock or domestic use (p 36). (Industrial or commercial uses for the water are not considered.)
Nevertheless, the Precipice Sandstone aquifer is in fact a Great Artesian Basin (GAB) aquifer, and many of our GAB aquifers have variable qualities of groundwater. In the GAB, a lot of groundwater is saline to some extent. Many landholders currently extract and rely on groundwater which then requires treatment, such as reverse osmosis. For example, the bore assessment report available on Queensland Globe for the Miles town water supply (Registered Number 58410) shows similar values for electrical conductivity and total solids (indicators of water quality) as the CTSCo target injection area water quality results. I am not a hydrogeologist and am no expert in water quality or treatment costs. However, before accepting that the water is unsuitable for any use, details about comparative water quality in the GAB, demand, usual treatment, and costs of treatment would assist in testing this claim.
It was certainly a relief that Australia was able to promise net-zero emissions by 2050 on the world stage at COP26 late last year. But when heralding these innovative technologies, what is missing seems to be any discussion or acknowledgement about costs of these activities on water resources. I can’t find any real acknowledgement in the mainstream reporting of the project that CCS in the Surat Basin in Queensland would affect water resources. Indeed, it seems that there has been no open acknowledgement that it would affect something as precious as our GAB, the life blood of our rural communities.
When one contemplates the expected effects of a drying climate on an arid country like Australia, can we afford to relinquish any quantum of water resource (whatever its apparent water quality) including parts of the storage capacity of a GAB aquifer? Areas of the Precipice Sandstone aquifer are already showing signs of overextraction. In addition, the quantum of unallocated water in the GAB has been steadily reduced by the Queensland Government over previous years. Put simply, this means we already know there is more demand than there is a sustainable supply of groundwater in some areas of the GAB.
The IPCC report predictions for Australia mean that this situation is likely to become much worse. Predicted impacts of climate change for Australia are generally: higher evaporation of surface water, increasing droughts, variable rainfall, increasing flood events and severe storms. These predictions mean an increasing need for not just reliable groundwater resources but also to be able to store water where it won’t evaporate or flood. The recent impacts of the flood events in South-East Queensland and our management of dams are a case in point.
Admittedly, there are a few arguments relating to the project’s impacts on water resources that would support the CTSCo project in this location, apart from the argument that the groundwater directly impacted is unsuitable for any use without treatment. These include that the depth of the Precipice Sandstone aquifer in the target injection zone is too deep to provide an affordable source of water for landholders. Most Precipice Sandstone aquifer bores are currently in the shallower parts of the aquifer.
Another argument for adoption of CCS in the Surat Basin is that injecting the CO2 in the deeper regions of the aquifer can increase the hydraulic pressure for the surrounding shallower water bores. This is because the Precipice Sandstone aquifer is relatively transmissive: it readily allows for water movement. Thus, CCS in this location could result in a more reliable, cheaper, and easier to access source of water in the short-term to landholders. However, it also may mean that landholders end up with free-flowing bores when once they were not. This could result in non-compliances with current water licences which require GAB bores to be controlled. It may also result in costs to upgrade existing bore construction. Thus, details about how the project may affect hydraulic pressures will be important.
There are no assurances at this stage that CCS will actually occur in the Surat Basin. At the time of writing, Glencore is yet to make a final investment decision for the project. Moreover, an amendment to CTSCo’s environmental authority is first necessary which requires the preparation of an Environmental Impact Statement (EIS). The EIS will set out more detail about the project, such as, the existing environment including social and cultural aspects, a risk assessment, and mitigating controls and monitoring plans. The draft Terms of Reference (TOR) for the EIS are available now for public review and comment until 23 May 2022. Once the TOR are finalised, CTSCo will prepare the EIS which will be available for public comment in the future.
Any activity that affects the environment needs to be considered holistically, considering both local and global impacts as well as short and longer-term impacts. Thus, when assessing the local impacts of the CTSCo project, it’s not just the current economic value of the water in the target injection zone, and the current economic value of the storage capacity, that are relevant. We must be also considering the future value of the water and the storage capacity.
Groundwater moves extremely slowly, and the bigger the system the larger the response time. For the GAB, response times to changes in volume could be in thousands of years. This means that the cumulative impacts to the GAB by climate change and activities such as CCS, and other activities affecting groundwater, may not be known for an extremely long time.
Calculating the future economic value of the target injection zone in terms of quantum of water, water quality and storage capacity is likely to be based on some key assumptions. For example, with increasing demand and a reduced supply, this will inevitably affect the assumption that the water at over 2000m depth is uncommercial for landholders or other users. We must also assess assumptions about the target zone water quality against future needs, the capacity to access other aquifers, such as the shallower Gubberamunda Sandstone aquifer, and the future capacity to treat water to an acceptable quality. These assumptions will also depend on the future value of the activities for which the water is being used. Potential improvements in drilling technologies ought to also be considered.
It also should not be forgotten that the project is a pilot project. The purpose of the project is that if successful, we would then look to inject larger quantities of CO2 from the coal fired power plant at Millmerran to reduce its ongoing emissions. CTSCo highlights in a technical factsheet that this project could be the first step in developing ‘a large CO2 Storage Hub in Queensland suitable for multiple industrial users, including future CO2 from hydrogen production.’
The TOR for the EIS requires CTSCo to provide detail about the cumulative impacts on environmental values of the proposed project and other major projects or developments of which CTSCo is reasonably aware. Thus, the EIS should also be considering the future impacts of the future operational project alongside other current and future projects. Incidentally, this should include managed aquifer recharge projects which involve the Precipice Sandstone aquifer, such as the ones operated by Origin Energy. These projects reinject treated CSG associated water replacing 88% of the groundwater extracted by non-CSG users from that same aquifer.
Considering all of these factors is an important part of the decision-making process in terms of approving a CCS in the Surat Basin.
In addition, in my view, a water licence for interfering with the Precipice Sandstone aquifer by injecting a CO2 stream will also be needed, in addition to the environmental authority amendment. The IAS states that in relation to the Water Act 2000 (Water Act), the project does not propose to extract or take groundwater or affect recharge to aquifers of the GAB (p45). This may give the impression that the proposal is mostly outside the scope of regulated activities under that Act.
However, the Water Act also regulates interference with groundwater, particularly the GAB. For example, this has been a key issue for the Galilee Basin coal mines and for New Hope’s New Acland mine west of Toowoomba. Surely, increasing the pressure throughout the groundwater system resulting in movement of different quality groundwater away from the injection zone falls within the meaning of ‘interfere’? Controlling interference with groundwater is extremely important where the groundwater system is large. Taking groundwater may not in fact have as much of an impact as interfering with it.
The Water Act does not generally regulate water quality. But injecting CO2 into an aquifer such that it changes the quality of the receiving groundwater to something that is unusable forever would also seem to meet the ordinary meaning of ‘interfere’. Thus, it is appropriate and necessary that both the water regulator (the Department of Regional Development, Manufacture and Water) and the environmental regulator (the Department of Environment and Science) have their say with regards to this project.
CTSCo has also stated in its IAS that there has been limited media coverage and limited interest from members of the public about the project. This seems a shame, as the question whether we should allow injection of captured CO2 into a GAB aquifer is an extremely important question for all Queenslanders. One may assume from CTSCo’s statement that few are interested in the groundwater at this location. Maybe it is assumed that the impact to the Precipice Sandstone aquifer is so minor, relatively, that it is outweighed by the benefits of the project? Or maybe it is assumed that a project that results in making a portion of an important GAB aquifer unusable couldn’t possibly go ahead? Alternatively, perhaps reducing greenhouse gasses is all that matters right now. Each of these assumptions are extremely dangerous.
The balancing exercise between global effects of green-house gas emissions, and local short-term and long-term effects of climate change as well as CCS in the area, is an extremely complicated exercise. Either way, it’s important to not jump to conclusions before the thorough analysis has been presented. I am sure CCS has its place. On balance, it may well be appropriate to use the Precipice Sandstone aquifer in this way, in the location proposed, to reduce our current and perhaps future greenhouse gas emissions.
The future EIS (to be prepared in accordance with the finalised TOR) should provide a thorough analysis of all the likely short-term and longer-term impacts, not ignoring issues about current and future water security. Without this further detail, it is difficult to prudently decide one way or another.
If CCS using a GAB aquifer is to go ahead, the question to be answered is what impact to the Precipice Sandstone aquifer should we allow to reduce our carbon footprint? How to achieve these reductions requires pause for thought and a thorough analysis and assessment, especially when the steps we take may permanently impact something as precious as water.