carbon emissions uk

Effectiveness of carbon capture facilities routinely overestimated, say researchers

Image credit: reuters

Governments are routinely overestimating the amount of carbon that has been sequestered from carbon capture efforts, a report from Imperial College London (ICL) has found.

Carbon capture and storage (CCS) is a worldwide initiative to reduce the amount of carbon dioxide (CO2) in the atmosphere by capturing the greenhouse gas at its source and storing it underground. The Intergovernmental Panel on Climate Change (IPCC) has said that CCS is key to reaching the goal of net-zero emissions by mid-century to mitigate climate change.

The researchers compared estimations of stored carbon with official reports, and found that the reports lead to overestimates of actual carbon stored by 19-30 per cent.

They calculated 197 million tonnes of carbon were captured and stored between 1996 and 2020, but a lack of consistent reporting frameworks means the current rates of carbon capture are overestimated.

The report suggests this disempowers climate mitigation strategies like the Paris Agreement and risks hiding issues that could otherwise be easily solved, such as inefficiencies in facility technology and transport.

Lead author Yuting Zhang, PhD candidate at the Department of Earth Science and Engineering, said: “Carbon capture and storage (CCS) is rightly a cornerstone of climate change mitigation, but without a centralised reporting framework we approach climate change on the back foot when we need to be more proactively tackling the issue with robust and accurate reporting.

“Policymakers should embrace a centralised reporting database that includes rates of carbon capture, transport, and storage, including quality assurance measures like independent auditing.”

As of 2021, the global capture capacity was estimated at 40 million tonnes per year across 26 operational CCS facilities.

No centralised framework exists globally to compel the reporting of precise amounts of carbon captured, so actual rates of capture, transport, and storage are not centrally reported.

However, this information is needed for accurately tracking the climate change mitigation impact of existing operations. Variations in the performance of industry-scale CCS plants may also help us to understand and mitigate any issues affecting the performance of individual facilities.

Senior author Dr Samuel Krevor said: “Carbon capture has the potential to significantly alter the planet’s fate, but unclear guidance means there’s no international consensus on how much has been stored so far, save for academic calculations. We urgently need clearly defined parameters so we know exactly where we stand.

“The nearly 200m tonnes of climate-warming carbon removed from the atmosphere is significant, but reaching this figure should not have relied on academic research.”

To carry out the study, the researchers looked at the capture and storage rates of 20 of the 26 CCS plants worldwide from a variety of publicly available sources recorded between 1996 and 2020.

They calculated the carbon capture rate to be 29 million tonnes of CO2 in 2019 and the total storage over the study period (1996 –2020) to be 197 million tonnes. At these rates, underground storage provided CO2 mitigation of around half of the emissions avoided by solar panels in the USA in 2019.

They then compared these figures with those currently reported by think tanks – currently the most authoritative source of information on CCS achievements, which report carbon capture capacity.

The researchers found that reporting only capacity means storage rates are overestimated by between 19 and 30 per cent. They argue that requiring facilities to report actual capture rates would tell us more precisely how well CCS is working and put us in a much better position to address the climate crisis.

Sign up to the E&T News e-mail to get great stories like this delivered to your inbox every day.

Recent articles