Climate Tech

A primer on carbon capture tech, which is netting billions in investment

Breaking down two key types of carbon capture tech, which could be crucial to climate goals.
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Halldor Kolbeins/Getty Images

· 6 min read

There are many potential ways to keep carbon dioxide out of the air. Establishing new forests can increase the amount of CO2 absorbed by trees. Planting certain crops on farmland can boost the amount of carbon stored in the soil. Artificially accelerating carbon mineralization can turn more CO2 into rock.

With the help of the volunteer-led OpenAir network, you could even make your own device to pull a few grams of CO2 from the air in your house each day.

While there are numerous ways to capture or remove carbon, one big question is which methods will be able to scale rapidly this decade. Since, as the IPCC report released last week reminds us, we need to not only eliminate new emissions, but also remove billions of metric tons of CO2 per year in order to meet climate goals.

The bipartisan infrastructure law provides more than $11 billion to support the growth of carbon capture, utilization, and storage (CCUS) technology as well as carbon removal tech. Most of that funding will be invested in two specific methods: One aimed at mitigating emissions from heavy industry, and another that can pull CO2 out of the air. Let’s break down the difference between these two types of carbon-capture tech.

Decarbonization definitions

Point-source carbon capture aims to stop the carbon-dioxide emissions produced by power plants or industrial operations from entering the atmosphere. The infrastructure law passed last year includes $3.5 billion for carbon-capture demonstration projects at power plants and industrial facilities over the next five years.

Point-source capture is a way to keep industrial processes from adding new carbon emissions, but it doesn’t remove the CO2 that’s already in the atmosphere.

“That is basically emissions avoidance rather than carbon removal,” Peter Minor, director of science and innovation at climate-focused nonprofit Carbon180, told Emerging Tech Brew. “That prevents more emissions from going into the atmosphere, but doesn’t actually solve this problem of, ‘how do we stop the climate change that’s already built in?’”

Carbon removal is the goal of direct air capture (DAC). This technology pulls CO2 already present in the atmosphere out of the air, and the infrastructure law includes $3.5 billion to build four DAC hubs in the US.

While reducing emissions as much as possible is essential, experts say DAC will also play an important role in meeting climate goals and keeping warming to a minimum. By 2030, the global CCUS capacity needs to be able to remove 1.6 billion tonnes of CO2 annually in order to reach net zero by 2050, according to the International Energy Agency. Today, the industry removes about 40 million tonnes per year.

Carbon180

Drawbacks and differences

Some climate experts and environmental groups are skeptical about the promise of carbon-capture tech, arguing that the priority should be transitioning to cleaner energy. Pulling carbon from the air is extremely energy-intensive and critics say fossil-fuel companies are pushing point-source capture as part of the industry’s greenwashing efforts.

On top of those issues, both point-source capture and DAC are very expensive today. Companies have spent hundreds of millions of dollars on point-source capture capabilities only to shut them down because of the high cost of operations.

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One problem is that every point-source capture project has to be customized to the industrial process it aims to clean up, Minor says.

“A gas power plant to a steel plant to a chemicals manufacturing facility—they’re all pretty different, and the requirements are different,” he said. “Today, every instantiation of point-source capture is kind of a one-off thing, and that is a challenge from a manufacturing and a cost-reduction perspective.”

From a physics perspective, it’s actually easier to pull carbon out of the air or liquid byproduct from industrial processes because the CO2 is much more concentrated than in the air we breathe, he added.

Still, a 2020 study found that more than 80% of proposed commercial carbon-capture efforts globally have failed, either because the projects were too costly or the technology didn’t work as expected. And growth of CCUS capacity over the last decade has fallen short of expectations for the tech when it received $3.4 billion of federal funding from the American Recovery and Reinvestment Act of 2009 following the financial crisis.

Meanwhile, DAC is still an early technology that hasn’t reached a scale that makes it affordable.

Companies like Microsoft and Stripe that are buying captured CO2 from the DAC company Climeworks, for example, are spending upwards of $500 per metric ton. The industry is aiming for an economically viable $100 per metric ton and in the meantime, at least one startup, Supercritical, is working to aggregate demand for carbon removal in order to make it more accessible to smaller customers. So far, though, DAC has been a solution available mostly to companies with the will and the resources to devote millions of dollars to their climate commitments.

But Minor says this doesn’t mean DAC is a less effective option in the long term.

“What’s interesting about direct air capture is, even though it’s trying to pull CO2 out of the air, which is much more diffuse—350 to 400 parts per million versus maybe thousands, or even tens of thousands, of parts per million—is that we can build these and deploy them effectively anywhere,” he said. “So you can really drive down cost through economies of scale, and building many of these over the course of several decades.”

Research indicates the industry will need more than 300 times the current DAC capacity to reach the goal of $100 per metric ton.

Another advantage of DAC is the ability for carbon-removal companies to choose strategic locations for facilities.

Point-source carbon capture has to happen at the site of the power plant or industrial operation, meaning that the captured CO2 then has to be transported to wherever it will be stored.

“How do you get it from point A to point B? You could try trucking it. You could put it on trains maybe—that’s tough. That’s why a lot of people talk about pipelines. But there’s also a lot of issues with pipelines,” Minor said. “What’s nice about direct air capture is since you can deploy it anywhere, put it where the storage is. Simplify that issue and create less challenges around how we actually create the infrastructure for doing all of this.”





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