Vacuuming the Sky with Direct Air Capture

COP28 was not supposed to lead to a meaningful climate change pledge, not with a petrostate host country, the United Arab Emirates, that increased its greenhouse gas emissions by 7.5% in 2022 compared to a 1.5% worldwide average. That was the view of Al Gore at least, who came to that conclusion using satellite-derived emissions data from a coalition he co-founded called Climate TRACE. Nonetheless—or perhaps because only a petrostate could convince other petrostates to follow—the final statement from the United Nations Climate Change Conference held the signatories to “transitioning away from fossil fuels in the energy systems, in a just, orderly and equitable manner.”

Gore was nearly placated by the final statement, but he also didn’t want any caveats, like the reference further down in the text to a role for “abatement and removal technologies.” In particular, he was concerned about carbon capture and direct air capture, referring to them as research projects overhyped by fossil fuel companies, with “no cost reduction for 50 years.”

Gore’s disdain for carbon capture from smokestacks comes as no surprise given his concern that it will divert investment away from renewable energy. But direct air capture? The world’s first direct air capture plant, which uses filters to separate carbon dioxide from air, only began operating in 2021. Built by a company called Climeworks, it runs on renewable energy and has the capacity to remove up to 4,000 tons of carbon dioxide per year, which is about 1,000 times more efficient than trees from a land use perspective. It also stores the carbon dioxide permanently underground, as opposed to trees which release stored carbon dioxide when they decay, burn or are chopped down.

Gore prefers a different analogy for direct air capture: “These are giant vacuum cleaners that use an awful lot of energy,” he said in a TED Talk in 2023. “But it is tremendously useful. You know what it’s used for? The CEO of one of the world’s largest oil companies in the U.S. (Vicki Hollub of Occidental Petroleum) told us what’s it’s useful for: it’s useful for giving them an excuse for not ever stopping oil. A few months later, she said this gives us a new technology that gives us ‘the license to continue to operate.’ Some people call that a moral hazard. For them, the moral hazard is not a bug, it’s a feature as the old saying goes.”

He went on to show a picture of the Climeworks plant that showed air-conditioning-like units that suck air across filters to remove carbon dioxide.

“And so, let’s just look. This is state-of-the-art. It looks pretty impressive, doesn’t it?” Gore asked the audience, showing a photo of the backside of one of the units where white sacs resembling large condoms had been temporally installed for testing purposes. “I had the same thought,” he joked. “And the new model, seven years from now, each of these machines is going to be able to capture 27 seconds worth of annual emissions. Woo! That gives them a license to continue producing more and more oil and gas. Or so they claim.”

The new model he was referring to, a Climeworks project called Mammoth, is indeed expected to capture a modest 36,000 tons of CO2 per year. It’s a slow start for the company that was founded in 2009 by two friends who met on the first day of university in Switzerland and decided to start a company together that would do something positive for the planet. Their business model is premised on starting small with modular units that can be steadily added to and optimized along the way to capturing millions of tons per year in the 2030s and billions of tons per year by 2050.

A key driver for commercializing direct air capture will be driving down costs, including finding low-cost sources of clean energy. And costs should come down as the manufacturing of components ramps up and an increasing number of intelligent people devote themselves to finding cost efficiencies. That’s what led to stunning cost reductions in solar and wind electricity, battery storage and electric vehicles. “A decade ago they were visible on the horizon,” said Gore about those technologies in 2017, “but we had to rely on technology experts to reassure us they were coming.”

It was nearly impossible at the outset—and even more recently—to foresee just how significant the cost reductions would be. Solar, for example, has experienced a 10,000-fold reduction in cost since it was first used commercially in the 1950s. In contrast, Climeworks is aiming for a ten-fold reduction, from about US$1,000 per ton currently to US$100 per ton of CO2 captured by 2050.

Gore wasn’t always a direct air capture skeptic. His interest in large-scale carbon removal options emanated from a spontaneous 2006 visit to the home of Richard Branson, the billionaire founder of the Virgin group of companies, to promote his film, An Inconvenient Truth. The encounter inspired Branson to seek out climate solutions, which led to setting up a competition to devise a way to economically remove carbon from the atmosphere. It was called the Virgin Earth Challenge and a US$25 million prize would be awarded by a high-profile group of judges that included Gore.

A pool of thousands of applicants was eventually whittled down to 11 finalists, including five direct air capture proponents. For several years, they worked diligently on fulfilling the requirements set out by the Virgin Earth Challenge, which included demonstrating that the

proposed technology was viable based on future markets. Then, in 2019, a year after the IPCC published a report stating that carbon removal would need to be scaled up massively to limit the average temperature rise to 1.5 degrees Celsius, the Virgin Earth Challenge was terminated without awarding any prize money. Participants were informed that “the market conditions necessary to support commercial and sustainable investment in the relevant carbon removal techniques were not foreseeable.”

The $25 million in prize money is now significantly less meaningful to some of the participants. One of them, Climeworks, has raised over US$700 million in equity financing. Another, Carbon Engineering, which still hasn’t completed a commercial project, was acquired by Occidental Petroleum for US$1.1 billion in 2023.

The first project to use Carbon Engineering’s technology, referred to as Stratos, will initially capture a half million metric tons per year beginning in 2025. To help make the economics work, Occidental originally intended to use the captured carbon dioxide to displace other sources of carbon dioxide to inject into depleted reservoirs as part of the company’s enhanced oil recovery business. Now various customers, from the Houston Astros to All Nippon Airways, are lining up to purchase carbon removal credits from Stratos, so long as the carbon dioxide is permanently stored underground.

Occidental’s second project, the King Ranch Project in Texas, could store up to 30 million metric tons per year. The company is expecting to build another hundred or so megaton scale projects and may begin licensing them to build even more. “Then we can start to get into the hundreds of them and potentially the thousands that are going to need to be built,” said CEO Vicki Hollub.

Which leads to Gore’s proposal for dealing with the problematic amount of carbon dioxide piling up in the atmosphere. He ended his Ted Talk by suggesting that renewable energy will get us to net zero and then natural carbon cycles will take care of the rest by removing excess carbon dioxide: “If we stay at true net zero, in as little at 30 years, half of all the human-caused CO2 will come out of the atmosphere and into the upper ocean and the trees and the vegetation.”

That statement was based on a letter from a Duke professor named Drew Shindell. While Shindell does say that half of a given year’s anthropogenic carbon dioxide emissions will be naturally removed after about 30 years, he also says removal of the remaining emissions will take “much, much longer.” Shindell refers to a 2019 research paper that showed a couple of modeled scenarios. One of them suggests that after reaching net zero for atmospheric carbon dioxide (at a little over 500 parts per million), the planet could naturally return to its already dangerous current carbon dioxide concentration level in about 150 years. The other scenario extends beyond the graph; by extrapolation, it would be at least a few hundred years.

Gore has been a noble climate leader going all the way back to 1976, but his preference to rely solely on renewable energy to get to net zero, and not clean up what is already in the atmosphere, would be a disservice to future generations. As UN Secretary-General António Guterres said following the release of the Intergovernmental Panel on Climate Change’s 2023 report, “Our world needs climate action on all fronts—everything, everywhere, all at once.”

Direct air capture may prove to be stubbornly costly, but it’s more likely that costs will come down as they do for any technology that is mass produced. The biggest challenge for direct air capture, to be effective in mitigating climate change, will be everything else that comes with scaling up a massive new industry at an unprecedented rate.

At Modern West, we are optimistic that it’s a surmountable challenge, that we can successfully turn technology innovation into critical solutions. To that end, we are continuously looking at how we can influence the adoption of direct air capture and other climate mitigation technologies. Stay tuned for our next thought piece on climate finance…

Paul McKendrick, Senior Advisor, Carbon Removal at Modern West, is the author of Scrubbing the Sky: Inside the Race to Cool the Planet.