On Friday, the US Department of Energy announced that it chose the first two sites to host facilities that will pull carbon dioxide out of the atmosphere and permanently store it underground. The sites in Louisiana and Texas will be funded by money set aside in the bipartisan infrastructure bill that was passed early in President Biden's term in office. They represent a major step for the US, as they're not linked to a specific source of carbon emissions, and the CO2 they capture won't be used for extracting fossil fuels.

They also represent a major step globally, as each facility is expected to have 250 times the capacity of the largest currently in operation.

In the long-term, it's hoped that these facilities will operate as a service to reverse a century of unchecked carbon emissions. The danger, however, is that they'll eventually be used to offset ongoing emissions and provide a rationale for the continued use of fossil fuels.

Out of thin air

There are two approaches to capturing carbon. One is to pull it out of the exhaust of fossil-fuel-burning equipment, such power plants or the furnaces of large buildings. This is more efficient since the CO2 starts at a high concentration. But it directly ties the carbon capture to the continued burning of fossil fuels—it helps limit emissions but doesn't do anything to help with all the carbon we've already placed in the atmosphere. While this form of carbon capture has been used tactically to try to forestall the regulation of coal plants, it's likely to play a significant role under the Environmental Protection Agency's planned limits on greenhouse gas emissions.

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The new facilities, in contrast, will pull their CO2 directly from the atmosphere. This can also be used to offset emissions from current sources, such as aircraft and automobiles, that are difficult to control otherwise. But they can also be used to handle what have been termed "legacy" emissions—the carbon placed into the atmosphere over the past century, which is already causing problematic warming.

The head of the DOE, Secretary of Energy Jennifer Granholm, emphasized this, saying, "Cutting back on our carbon emissions alone won’t reverse the growing impacts of climate change; we also need to remove the CO2 that we’ve already put in the atmosphere."

To that end, the infrastructure bill included money to fund the development of direct air capture (DAC) facilities. Today's funding will go to a partnership led by a subsidiary of Occidental, a company with a long history in the petroleum industry. It will be located in Texas, south of Corpus Christi. The second project being funded will be located near Lake Charles, Louisiana. It's also a partnership and led by Batelle, a non-profit company with a long history of managing national lab facilities for the DOE.

Combined, the two projects are expected to be able to sequester 2 million tonnes of carbon dioxide each year—about 500 times the capacity of any existing DAC facilities. The DOE estimates that will be the equivalent of taking roughly half a million cars off the road.

That's a lot, but the DOE estimates that reaching the Biden administration's goal of a net-zero US by 2050 will require at least 400 million tonnes to be sequestered annually, and perhaps as many as 1.8 billion. So, while this is a key step, reaching our climate goals will require vast capacity expansion.