Carbon capture on the agenda again

Carbon capture from the air and removal or storage is on the agenda at COP28 at the end of November, with the UN climate change conference to showcase technologies that might limit global warming to well below 2 degrees Celsius.

The Intergovernmental Panel on Climate Change has stressed carbon dioxide removal as a key component of the global strategy.

The International Energy Agency says it hopes to remove 85 million metric tonnes of carbon dioxide by the end of the decade through direct air capture. By 2050, that number skyrockets to 980 million metric tonnes.

Authors Deanna D’Alessandro and Sam Wenger from University of Sydney writing in 360 Info say there are two main ways to remove carbon dioxide: “By enhancing natural carbon sinks (storing carbon in soils, planting more trees or enhancing ocean-based carbon sinks) and directly remove carbon dioxide from the atmosphere.

“In direct air capture, air is pushed through filters that remove carbon dioxide from atmospheric gases like nitrogen, oxygen, argon and water vapour.

“Direct air capture is different from carbon capture and storage.

“Carbon capture and storage focuses on directly capturing emissions from large industrial sources like power plants before they are released into the atmosphere.

“Upon capture, the carbon dioxide is transported and kept underground in geological formations, preventing it from contributing to greenhouse gas accumulation.

“Direct air capture is difficult because of the extremely dilute nature of carbon dioxide in natural air. It comprises just 0.04 percent of molecules in the atmosphere, compared with the relatively higher concentration in carbon capture storage applications — typically 10-15 percent.

“The most conventional early processes rely on temperature and pressure swings— or a combination of both—for filters to react with dilute carbon dioxide at ambient temperatures and pressures. Once the filters are saturated, heat and a vacuum, or both, are applied to the filters, releasing the carbon dioxide-rich gas.

“The energy required to capture and release carbon dioxide now limits the technology and should be a focus for improvement.”

The International Energy Agency says it hopes to remove 85 million metric tonnes of carbon dioxide by the end of the decade through direct air capture. By 2050, that number skyrockets to 980 million metric tonnes.

Carbon capture – what’s needed

There are 18 operational direct air capture facilities, with Iceland housing the biggest. There are several megaton-scale facilities planned in the United States.

While commercial direct air capture plants have started operating over the past few years, they are relatively expensive to operate, costing between USD$600 and USD$1000 for each tonne of carbon dioxide.

Funding isn’t the only barrier to CCS/DAC projects.

Addressing an APEC symposium in Kobe, Japan, this month, CO2CRC CEO Dr Matthias Raab said regulatory delay is limiting Australian carbon capture projects.

The CO2CRC has been operating since 2003. It owns and operates the Otway International Test Centre in South West Victoria where it has seven purpose drilled CO₂ storage wells (>1.5km deep), within a 1km area, for CO₂ injection and monitoring.

Raab told the conference the current project approval cycle takes up to nine years due to “cumbersome State and Federal regulatory processes.”

“We need to rollout multiple CCS projects with large-scale storage around and across Australia – and this needs to be done quickly to meet emissions reduction targets.

“The CCS industry can move faster than governments can approve projects. Legislated targets are at odds with the industry’s ability to get project approvals.

“Delays are deadly – a lack of urgency will deter investment and entrench the status quo in emissions.”

“Industry accepts environmental approval processes must be robust, but to deliver CCS at scale, we need a faster, more efficient approach to regulatory approvals.

“Australia has the world’s largest carbon storage project at Chevron’s Gorgon facility in Western Australia, with Santos having taken a final investment decision to develop the Moomba CCS project in South Australia. Another 17 projects are in feasibility.”

CO2CRC identifies four of those projects as “high potential”: the SEA CCS and CarbonNet projects offshore Victoria and the Bonaparte and Bayu-Undan projects of offshore NT.

Raab says if all were delivered by 2032, along with Gorgon and Moomba, between 31 and 35 million tonnes of CO₂ a year could be stored – reducing Australia’s emissions by 8%: ”…but that was an optimistic target given current approval timelines.”

CO2CRC announced at the beginning of October it had secured an additional $10.2 million to advance its Otway Stage 4 program, a multinational program with researchers from Australia, the United Kingdom, the United States, South Korea and Japan.

The research program aims to provide research organisations with data to conduct commercially relevant trials to help accelerate technical development required to support CCS projects.