Mitigating climate threatsU.S. carbon-capture network could double global CO2 headed underground

With the right public infrastructure investment, the United States could as much as double the amount of carbon dioxide emissions currently captured and stored worldwide within the next six years, according to an analysis by Princeton University researchers.

The authors propose in the Proceedings of the National Academy of Sciences a pipeline network that would transfer carbon dioxide waste from ethanol refineries in the American Midwest — where grains are fermented to produce the alcohol-based fuel — to oil fields in West Texas. The captured carbon would then be pumped into near-depleted oil fields through a technique known as enhanced oil recovery, where the carbon dioxide helps recover residual oil while ultimately being trapped underground.

The researchers found that this capture-and-storage network could prevent up to 30 million metric tons of human-made carbon dioxide from entering the atmosphere each year — an amount equal to removing 6.5 million cars from the road. Currently, about 31 million metric tons of carbon dioxide annually are captured and stored worldwide.

Princeton says that the authors were motivated by a tax credit passed by Congress in the 2018 Bipartisan Budget Act to encourage investment in carbon capture and storage. Their analysis showed that this large-scale capture-and-storage network would only be possible — and profitable for the companies using it — if the tax credits are coupled with low-interest government loans to fund the necessary pipeline infrastructure. If governments provided low-cost loans for only half of the pipelines, the resulting smaller-scale network would still sequester 19 million metric tons of carbon dioxide per year.

“The new tax credits are the most significant policy incentivizing carbon capture, utilization and storage (CCUS) in the world today,” said first author Ryan Edwards, a AAAS Congressional Science and Engineering Fellow in Washington, D.C., who earned his Ph.D. in civil and environmental engineering from Princeton this year. Edwards worked on the analysis as a graduate student under co-author Michael Celia, director of the Princeton Environmental Institute (PEI) and the Theodora Shelton Pitney Professor of Environmental Studies and professor of civil and environmental engineering.