A new study finds that the potential for carbon capture and storage is much more limited, by a factor of five or six, than the capacity projected by the United Nations to fight climate change.
The U.N.’s Intergovernmental Panel on Climate Change estimates a maximum of 30 gigatons of carbon dioxide can be trapped underground by 2050. But the study by researchers at Imperial College London finds a best-case scenario of just 5-6 gigatons. The study says the IPCC estimates are unfeasible and argues that projections, particularly regarding China’s future carbon capture, are greatly inflated.
“The existing models assess the use of CO2 storage based on very loosely constrained limitations,” lead author Yuting Zhang told Mongabay by phone, adding that some of these models simply evaluated how much CO2 the Earth’s subsurface was able to hold.
“[Our study] provides a clearer pathway for policymakers, as well as the business sector and modeling community, to start organizing and aligning their actions around this benchmark,” Zhang said.
To date, more than $83 billion has been invested into carbon capture and storage (CCS) globally. A total of 41 commercial projects are now running worldwide; almost all are operated by large fossil fuel companies.
An estimated 83% of the world’s current CCS capacity features compressed CO2 injected into the ground via pipelines to extract oil, a process called enhanced oil recovery. Roughly 40% of that carbon leaks back into the atmosphere in the process, Mark Jacobson, a civil and environmental engineering professor at Stanford University, who was not involved in the study, told Mongabay by phone.
Zhang’s study found that most future projects plan to keep carbon underground rather than using it to assist in oil production. But this approach would require heavy public funding as there’s currently little incentive to do so, especially for the fossil fuel companies that receive the bulk of the current and planned government subsidies for CCS.
So far, the projects overpromise and underperform, an energy economics report concluded. Operational projects have the capacity to capture up to 65 million tons of carbon globally. But a report found that a sample of facilities are only capturing between 33% and 90% of their maximum capacity.
According to Jacobson, the carbon emissions math also doesn’t add up when you look at the bigger picture: CCS facilities require huge amounts of energy and infrastructure to operate and are largely used to extract more oil, which will eventually lead to more emissions.
After factoring in all the associated emissions from a CCS facility, they may even end up emitting more than they capture, he added.
Banner image: Shell’s carbon capture infrastructure at the Scotford Complex in Alberta, Canada. Image by Alberta Newsroom via Flickr (CC BY-NC-ND 2.0).
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