As demand for decarbonization grows, discussions surrounding carbon capture have gained momentum. However, the technology has also drawn mounting opposition. The fossil fuel industry’s involvement has raised the specter that it could be used to prolong oil and gas extraction. Costs, too, could limit its utility, and there are questions whether the technology can even be scaled up in the first place.
These concerns were a focal point of discussion during COP28 last year. In the coming years, the world will have to decide whether carbon capture can be deployed responsibly and how to handle carbon dioxide.
When should CCS be used?
There are two main ways machines are used to capture carbon. So-called point source carbon capture and storage (CCS) grabs CO2 at the smokestack of sites such as industrial plants. Other technologies pull already-emitted CO2 out of the air, a process called direct air capture (DAC).
Point source can be deployed at oil, gas, and heavy industry facilities. But research shows that the use cases where that would be beneficial to the climate are narrow.
Ben Grove, carbon storage manager at the Clean Air Task Force, said, "The real utility of carbon capture is addressing the hard-to-abate emissions that can’t be dealt with.”
One of those hard-to-abate is cement, which accounts for about 8% of global emissions. While parts of the cement-making process can be electrified, some of the emissions from production are "fundamental to the process,” said Emily Grubert, an associate professor of sustainable energy policy at the University of Notre Dame.
Startups like Brimstone are focused on cement decarbonization, but most of the techniques to clean up cement are far from ready for mass commercialization. "Unless you come up with a replacement or a vastly different formulation, there’s not a way around those emissions without using something like CCS,” said Grubert.
"Carbon capture will play a key part in helping all sectors of the global economy decarbonize, especially those hard-to-abate where there are no easy routes available through electrification,” said Michael Tholen, sustainability, and policy director at Offshore Energies U.K., which represents energy firms.
CCS used in fossil fuel plant
There are cases where CCS could be used on existing fossil fuel plants responsibly, according to Jennifer Wilcox, principal deputy assistant secretary in the U.S. Energy Department’s Office of Fossil Energy and Carbon Management. She gave the example of new natural gas-fired power plants, of which nearly 5.7 GW of new capacity were added in the U.S. in 2022, according to BloombergNEF.
But multiple lines of research suggest that may not be economically viable. A 2020 study by Grubert found three-quarters of U.S. power plants will be ready for retirement by 2035. A March report from the Institute for Energy Economics and Financial Analysis, a non-profit that advocates for a transition away from fossil fuels, found that power generation with CCS could make electricity more expensive compared to alternatives, including renewable energy plus storage. A 2019 study in Nature Energy shows renewables outcompete carbon capture on cost as well.
Scientists estimate that by mid-century, the world will need to remove billions of tons of CO2 from the atmosphere annually to limit warming to level of 1.5C. Current capacity globally is measured in thousands of tons per year, so there’s a large scale-up that needs to happen. But deploying the tech needs to be done in tandem with decarbonizing the economy.
How to handle captured CO2?
Research from BloombergNEF indicates that while the majority of announced direct air capture projects plan to store CO2 underground, 19% will be used as a feedstock for sustainable aviation fuel (SAF).
Aviation accounts for around 2% of global emissions, which is roughly on par with Japan or Germany. Decarbonization options are few and far between and using captured CO2 for fuel could make sense.
Turning CO2 into a feedstock for SAF could help achieve “a double dividend” compared to just storing underground, said Jonathan Foley, executive director of the nonprofit Project Drawdown. He emphasized that, even then, carbon capture should still only be applied at a small scale, rather than the billion-ton range that other research calls for, due to its high cost compared to renewables.
The fossil fuel industry has different designs for CO2. Rather than using it to create synthetic fuels, it wants to inject it into aging oil and gas fields to dislodge remaining oil, a process known as enhanced oil recovery (EOR).
The technique has been in use since the 1970s, but several oil firms want to scale it up. One of the biggest supporters of DAC, Occidental Petroleum, has made it clear that some of its projects will use CO2 to produce more oil. About 8% of CO2 captured will be used for EOR, according to BloombergNEF.
Only for carbon storage
Some DAC startups have drawn a line in the sand, refusing to allow the CO2 they capture to be used for procuring more fossil fuels. Climeworks’s CEO Christoph Gebald has said the company is only interested in "permanent underground storage, period,” and startup Heirloom has said that no CO2 removed by its technology will be used for EOR.
The oil and gas industry is among the biggest backers of carbon capture and storage. (Photo: Pixabay)
Heirloom’s head of climate policy and external affairs, Vikrum Aiyer, said, "I think that there should be guardrails for responsible carbon management for the broader industry as it develops.”
These guardrails are going to be necessary as the industry scales and more companies join the CO2 cleanup business, spurred on by tax incentives and growing government investment.