Green Tech

Carbon capture gains momentum as a climate fix, but the tech remains controversial

New startups are testing out methods for removing CO2, but they still have to prove it works.
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· 5 min read

Whether through rocks or wood or algae, sucking carbon from the atmosphere has been a dream of certain climate scientists for years. And while much of the technology remains unproven or too expensive to work at scale, some major climate projections bank on solutions like these eventually being part of an emission-reduction toolkit.

In recent weeks, there’s been momentum toward potentially realizing that dream. Graphyte, a buzzy startup backed by Bill Gates’s Breakthrough Energy Ventures, announced what it claims is a durable and less-expensive strategy to store carbon with the help of bricks of biomass. Heirloom Carbon, another much-hyped startup in the space, opened the country’s first commercial carbon-capture plant in California’s Central Valley.

Both companies claim to use inexpensive, easily obtained materials—Graphyte’s biomass can come from farming and timber operations, while Heirloom taps the natural properties of limestone—and the ability to scale in a way that the tech has historically struggled to do.

“It’s important to understand that carbon removal is not an excuse to keep emitting, or to slow down our transition to a clean energy economy—we need to keep innovating as fast as we can,” Bill Gates wrote in Breakthrough Energy’s inaugural annual report this week. “But it’s become clear that carbon removal will be a necessary tool to have in our toolkit.”

Rubber meets the road

Announcements like these mark a new phase for a technology that has become flush with government money through policies like the Inflation Reduction Act (IRA), according to PitchBook Data Senior Analyst John MacDonagh.

“We’re at the stage now where there’s obviously still a lot of development to do from a technological perspective. But we’re now starting to see, as we have this year, implementation and construction of mostly pilot plants,” MacDonagh told Tech Brew.

But the technology’s skeptics say all of this funding could be for naught if costs don’t come down and the efficiency necessary is never fully realized.

“Research is good, but [the government is] also spending a huge amount of money trying to foster the use of that technology—those technologies, actually—when it’s only been tested on a very small scale,” said David Schlissel, director of resource planning analysis at the Institute for Energy Economics and Financial Analysis. “[Companies] need to show that they can actually capture what they claim they can capture.”

A cash infusion

The UN’s Intergovernmental Panel on Climate Change said in its climate assessment this year that carbon dioxide removal “will be necessary to achieve net-negative carbon emissions,” though some reports have alleged that corporate interests helped shape the panel’s conclusions. In any case, a BloombergNEF report found that global investment in carbon capture and storage hit a high of $6.4 billion last year, thanks in part to favorable US policy.

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“Probably the main driving force behind carbon capture overall is just the regulatory and policy side,” MacDonagh said. “The reason we’ve seen so much growth for point-source and [direct air capture] is incentives from the IRA, which were expanded pretty substantially from what existed before, and also federal funding in the form of grants.”

Less expensive materials needed

Graphyte claims one of the biggest points in its favor is that it’s more affordable. The company condenses plant matter waste into dehydrated bricks, trapping carbon pulled from the air for long-term storage. The company claims its technology, called Carbon Casting, can reduce costs to $100 per ton of CO2 removed.

Heirloom doesn’t reveal how much its removal process costs, but experts estimate that direct air capture, the tech Heirloom utilizes, costs between $600 and $1,000 per ton, according to the New York Times. The company claims to use the natural properties of limestone to absorb carbon from the air and has inked carbon credit deals with the companies like Microsoft, Stripe, and Shopify as well as federal grants.

The $100-per-ton figure has long been a benchmark for carbon-removal efforts, which makes Graphyte’s claims seem encouraging if they can hold up at scale.

Schlissel said it’s still too early to tell whether these kinds of solutions can live up to the hype or how much of a role they will play in an overall climate solution.

“It’s hard to tell, given that the technology is so immature,” Schlissel said. “And the recent tests…are so small-scale that it’s impossible to know.”

But he emphasized that projections relying on this technology becoming viable in 2050 are not going to cut it in the race against the clock brought on by the climate crisis.

“We as a world are addicted to fossil fuels. Acknowledging you have a problem is one step toward recovery,” he said. “Direct air capture is absolutely the opposite of that. It’s saying, ‘Yeah, maybe we have a problem. But don’t worry about it for 30 years, because in 2050, we’ll be able to start plucking the CO2 out of the atmosphere.’”

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Tech Brew keeps business leaders up-to-date on the latest innovations, automation advances, policy shifts, and more, so they can make informed decisions about tech.