Carbon capture is often talked about as a climate solution, but a growing chorus of experts caution it may not be that effective, and in some cases could even add to greenhouse gas emissions.
"Direct air capture" promises to filter existing carbon dioxide out of the air, whereas "point-source capture" grabs carbon dioxide from smokestacks, ideally preventing emissions associated with things like steel, cement or power plants (like Saskatchewan’s coal-fired Boundary Dam project
) from even reaching the atmosphere.
But recent study of carbon capture processes casts doubt on their efficacy in reducing overall emissions.
In fact, a lot of captured carbon is being repurposed to extract more oil and gas.
“People have heard about carbon capture, they have this sort of warm and fuzzy idea that … this can be something good to save us. And that's because they have this impression that we can have carbon-neutral fossil fuels,” said June Sekera, a policy expert and visiting scholar at the New School in New York and senior research fellow at Boston University.
Sekera and a colleague reviewed 200 papers on the topic
, including direct air capture and point-source capture. While captured carbon can be stored in a number of ways (including underground and in concrete), it is estimated up to 81 per cent
is used in a process called enhanced oil recovery (EOR), a decades-old practice to extract remaining oil from an oil field.The oil industry has touted this process as win-win
— more efficient extraction and reduced emissions. Some research suggests that the EOR process could store about half of the carbon dioxide used to extract oil. But that means it still emits more CO2 than it captures.
“A carbon removal process can be labelled as 'net-negative' when it removes more carbon dioxide than the emissions required to achieve that removal. But in the case of enhanced oil recovery, the extraction of oil is not in service of carbon removal,” said Andrew Bergman, a PhD student in applied physics at Harvard University who contributed to a new book
on CO2 removal and is helping develop carbon removal technology.
“Talking about the 'carbon content' of oil extracted using enhanced oil recovery obscures the fact that [it’s] a process, very simply, for extracting oil," said Bergman via email. "Oil itself cannot be net-negative. Oil is oil.”
Rather than assume we can replace other oil extraction with this particular method, Sekera said we should push for public policy measures to reduce the demand for oil.
“We need energy,” she said. “We don't need fossil fuels to be that source of energy.”
By extending the life of fossil fuels, Sekera worries it will delay the switch to renewable energy. It’s a concern shared by Dale Marshall, national program manager with the organization Environmental Defence.
“Any time a government talks about fossil fuels being some kind of a bridge to a future sustainable world or a stepping stone to dealing with climate change, essentially what that means is we're going to delay the phasing out of fossil fuels,” said Marshall.
Direct air capture technologies that filter carbon dioxide from the atmosphere have been demonstrated at a small scale — including ClimeWorks
in Switzerland and Carbon Engineering in B.C. (see photo above). But they would require massive amounts of renewable energy in order to take more emissions out of the atmosphere than they emit.
Some suggest that while we need to quickly shift to renewable energy, we should also think about how carbon removal, like direct air capture, could fit into the larger emissions-reduction picture.
“Fossil fuel companies [being] involved in carbon removal is controversial,” said Shuchi Talati, a senior policy advisor with Carbon 180, a D.C.-based NGO. While she acknowledged that this sort of technology may be important in the interim, she said “the public should benefit from [carbon capture] technology.”
Talati said regulation and transparency of carbon capture would allow governments to procure carbon storage as a public service.
"In my ideal future, none of this carbon would be going towards enhancing the [oil] recovery,” she said. “It would be stored underground. And that's really how you benefit from that captured carbon — when you permanently lock it away, whether it's underground or in materials like concrete. I think using it for [oil] recovery is not a way that the public can profit from those actions."
— Molly Segal