Repurposed gas infrastructure, dense-phase carbon dioxide transport and a purpose-built compression facility have turned Moomba into a global-scale hub for carbon capture and storage.
When Santos’s Moomba carbon capture and storage (CCS) project began its first injections of carbon dioxide into depleted gas reservoirs in South Australia’s Cooper Basin in September 2024, it signalled an important shift in Australia’s engineering landscape.
What had been one of the country’s longest-running gas processing centres became one of its most significant pieces of decarbonisation infrastructure.
For commissioning engineer April Travis, who helped bring the facility in the state’s north-east online, the transformation marks a significant development in the pursuit of net zero.
“The startup went really well,” she told create. “We went straight to full rates, or at least until we ran out of carbon dioxide from the actual plant, which was amazing.”
The early results are remarkable not only for the engineering achievement, but for the regulatory milestone. Early in November 2025, Santos received 614,133 Australian Carbon Credit Units (ACCUs) for the first six months of Moomba CCS operations, which is the largest single issuance ever made by the Clean Energy Regulator. Each ACCU represents one tonne of carbon dioxide equivalent that would otherwise have entered the atmosphere.
The numbers behind the project illuminate the scale. By mid-2025, Moomba CCS had stored one million tonnes of carbon dioxide equivalent, a climate impact equivalent to removing all electricity-related emissions from every household in Adelaide for a full year.
Clever repurposing
As Australia’s first large-scale onshore hub for the capture and geological storage of carbon dioxide, Moomba can store more emissions every four days than 10,000 electric vehicles avoid in an entire year. Its first-year total of 1.3 million t (achieved despite historic flooding of the Cooper Basin that temporarily disrupted operations) is comparable to taking approximately 530,000 petrol-fuelled cars off South Australian roads.
For engineers, the core of Moomba’s achievement lies in its clever use of existing infrastructure and well-established process technologies. Travis explained that the site has been separating carbon dioxide from natural gas for decades through the Benfield process.
“One of the really cool things about CCS is that it doesn’t use a lot of brand-new technology,” she said. “It’s using what we already use in processing facilities, but with a different fluid in the pipes.”
What’s new is the purpose-built compression and dehydration facility that receives this separated carbon dioxide and prepares it for geologic storage. The system’s design leans on fundamentals while pushing them towards new performance boundaries. The carbon dioxide is passed through multi-stage compression, with precise temperature management due to the sharp thermal swings gas undergoes during pressure changes.
“Carbon dioxide gets really hot and really cold when you change pressure. A lot of the process is managing that.”
After compression, the gas is dehydrated to avoid carbonic acid corrosion in pipelines. From there, it is transported in dense phase, allowing high mass transfer efficiency and stable behaviour under pressure fluctuations. “Dense phase behaves like a gas, but is dense like a liquid.”
The dehydrated carbon dioxide then travels along a dedicated 50 km pipeline, mostly underground, to former hydrocarbon reservoirs in the Cooper Basin. These reservoirs, which held natural gas securely for millions of years, are now being repurposed as long-term storage formations.
“We know our reservoirs really well,” Travis said. “We’ve been operating in the basin for decades. We have monitoring wells outside our injection wells so we can see where the carbon dioxide is going and make sure it’s not leaking.”
For engineers, this subsurface aspect is often the most technically complex. “Selecting the right reservoir and proving it’s suitable for long-term storage takes real technical expertise.”
The facility uses a 30 MW compressor, and the emissions associated with its operation are included when calculating the net carbon dioxide stored. The compressor is also part of a broader innovation: its gas turbine exhaust heat is recovered to generate high-pressure steam, which is then reintegrated into the existing Moomba gas plant for use in heating and power generation.
“Having the CCS facility so close to the gas plant means we can generate steam from waste heat and give it straight back to Moomba. It makes the whole site more efficient.”
This interplay between old and new infrastructure is a defining feature of the project. Repurposing decades-old separation systems, leveraging existing basin knowledge and adding new compression and storage capacity has reduced both Moomba’s and Santos’s overall emissions intensity. “It’s a significant drop,” Travis said.
Moomba CCS will also help Santos meet its obligations under the Safeguard Mechanism. Projects such as Moomba are expected to supply surplus ACCUs that the company can use to offset high-emitting operations elsewhere as it transitions its portfolio.
Capability uplift
Looking ahead, the scale potential is enormous. Moomba CCS and its potential future phases have a future storage capacity estimated at around 20 million t of carbon dioxide per year. This figure puts it among the world’s most substantial CCS hubs.
Since 2024, operational CCS facilities worldwide have increased from 50 to 77 and the total number of facilities in the development pipeline has increased from 628 to 734, according to the 2025 report of the Global CCS Institute.
Santos is now evaluating additional project stages and the possibility of accepting carbon dioxide from third parties in Australia and Asia. The transport mode, whether via pipeline, shipping or by truck, will depend on the location of future hubs.
“It will be different for different areas,” Travis said. “It depends where the hub is and where the carbon dioxide is coming from.”
This evolution turns CCS from a waste-management strategy into a business strategy. “CCS becomes another strand of the company. It becomes a commercial opportunity.”
The Western Australia CCS hub, meanwhile, is in early-stage front-end engineering design, in parallel with ongoing customer negotiations for carbon management services.
For Travis, one of the project’s biggest successes is the capability uplift across Santos’s engineering teams. “We used a lot of our people in-house. We gained a lot of experience in how to operate and troubleshoot a CCS facility. And we’ve learned a lot about the potential and what doors this opens in carbon markets, too.”
As Australia works towards a net-zero future, Moomba CCS stands out as an example of what’s possible, demonstrating how engineering innovation is often less about invention and more about intelligent integration, bringing together proven technologies, trusted infrastructure and deep domain knowledge to craft something new.
“Carbon capture is definitely viable. A lot of the pathways to net zero need CCS. There are technologies where we just can’t use renewables. CCS lets us manage the energy transition responsibly.”
This story was originally published in the February 2026 edition of create with the headline “Refilling the basin”.
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