Oil field
​The extraction, transport and refining of crude oil account for between 15 and 40 percent of total greenhouse gas emissions from transport fuels such as gasoline and diesel.
Photo: Haizhen Du/Shutterstock

New study reveals real size of crude oil’s carbon footprint

Emissions from crude oil extraction are a significant part of the total emissions of fossil fuels. A new comprehensive study recently published in Science also shows that emissions are far higher than the industry's own estimates.
"Knowledge of greenhouse gases emissions associated with the extraction of crude oil makes us more aware of the full lifecycle climate impacts of using oil and it will also be helpful when it comes to evaluating which measures would be most cost effective to reduce emissions," says Sonia Yeh, Professor of energy and transport systems at Chalmers.
The extraction, transport and refining of crude oil account for between 15 and 40 percent of total greenhouse gas emissions from transport fuels such as gasoline and diesel. Different crude oils can have very different physical properties that require more energy to extract and refine than others. But the major difference in the climate impacts of different oil extract is actually how much methane, a powerful greenhouse gas, being released or burned in large quantities at extraction, activities known as flaring, venting, and fugitive emissions. 

– Although fossil free sources for energy are on the rise for the electricity sector, our demands for crude oil still continue to rise and it is unlikely to peak anytime soon. So reducing transport emissions or at least preventing oil extraction to become more and more carbon intensive is crucial, says Sonia Yeh, at the Department of Space, Earth and Environment at Chalmers.

In the recently published study “Global carbon intensity of crude oil production" (Masnadi et al, Science) the total petroleum well-to-refinery emissions is estimated to be 1,7 Gt CO2 eq, which is 42 per cent higher than the estimations made by the industry and constitute 5 percent of global total emissions. In comparison, total global emissions from aviation is roughly 2.7 percent.  

The study, which sums up 10 years of research from a global research network, also highlights several ways to reduce these emissions. On the one hand, it suggests leaving the densest and most energy-consuming oil in the ground and focusing on other less carbon intensive sources. On the other hand, it is about reducing the flaring, venting and fugitive emissions of methane.  

The study shows that if the amount of methane released into the atmosphere is reduced to the same levels that have been achieved in Norway, there is a potential to reduce 40% of total emissions from oil production. But both changes require political leadership and economic and policy instruments, according to Sonia.

– Don’t forget that methane is a product that can be captured and used, but in many countries it is considered not worthwhile or uneconomical to capture and put methane into pipelines. But if it would cost significantly more to let it out in the atmosphere the industry might reconsider. Unfortunately, the Trump administration is instead considering making it even easier to release methane into the air, which would be a step in the wrong direction”. (Read more in the New York Times article: Trump Administration Wants to Make It Easier to Release Methane Into Air​​). 

Sonia thinks that research can be even better at measuring and characterizing sources of emissions, and if society want to address these emissions, then politicians must create new rules and guidelines, and monitor how they are managed. Oil companies can also be much better at following up on these things themselves to show their environmental commitments and leaderships.

– This important analysis gives both our politicians and the oil companies greater access to information to fully measure and compare the effects of oil emissions. if you don’t measure it you can’t control it.

Text: Christian Löwhagen. 
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Published: Wed 26 Sep 2018. Modified: Fri 28 Sep 2018