Daimler Trucks, eBay and a US energy company were among the recent buyers of carbon offsets created by projects that involved injecting carbon dioxide underground in order to extract more oil.
Three US-based extraction projects were eligible to generate credits because their processes involved the capture of CO2. But this was used as a way to extract fresh oil that would otherwise have been inaccessible, a procedure known as “enhanced oil recovery” (EOR).
The offsetting rules that the credits were created under ignored the emissions associated with the extracted oil.
Nearly 3mn credits from the three projects, which cannot generate new offsets following a rule change, have been used by buyers to compensate for carbon emissions. Each offset is supposed to represent a tonne of carbon that has been permanently avoided or removed from the atmosphere.
“Offsetting emissions with these credits is complete nonsense,” said Gilles Dufrasne, policy officer at Carbon Market Watch. “If the captured carbon enables an increase in oil extraction, then obviously this must be part of the calculation, and would likely negate any supposed climate benefits.”
Stuart Haszeldine, professor of carbon capture and storage (CCS) at Edinburgh university, said that in the US it had “never been accepted that the extra oil produced [by the EOR process] has a carbon footprint”.
Offsets are very widely used by companies to mitigate their carbon emissions. They are generated by environmental projects such as tree-planting, with money from the sale of the credits used for funding.
Between 2000 and 2008, under now-defunct offsetting rules, the three US EOR projects generated a combined 12.4mn offsets. Although the schemes can no longer generate new credits, companies can still buy those created before the change.
One of the three schemes was developed by US oil and gas company Merit Energy and the offsets seller Blue Source. The project used carbon that had been captured from an ExxonMobil facility for oil extraction.
In March, DJR Operating, another US oil and gas group, used 150,000 offsets from the Merit project. Canadian power generator TransAlta also used 376,000 of these credits in 2015, while eBay bought 1,700 between 2020 and 2021, according to data from the American Carbon Registry.
Ebay said it “did not include [the offsets] in our carbon neutrality achievement for 2021”. TransAlta declined to comment, and DJR did not respond.
Customers of third-party offsets seller Terrapass, including Daimler Trucks, have used 73,000 credits from the three legacy schemes since 2020.
Terrapass said its customers had “supported dozens of renewable energy and greenhouse gas destruction projects”. Daimler Trucks said the credits had conformed to the “strict protocols” governing offsets when generated.
In April, a landmark UN report on climate change said it would be essential to remove carbon from the atmosphere to limit warming to 1.5C above pre-industrial levels. Experts stressed that CCS should be used by sectors such as cement and steelmaking, where absolute emissions are unlikely ever to reach zero.
Proponents of EOR say the process provides a market for captured carbon emissions and will help accelerate the development of carbon capture technology.
Merit Energy and Blue Source did not respond to requests for comment.