Sign In or Create an Account.

By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy

Technology

Does Carbon Removal Need to Be Dumb To Work?

We may have been trying too hard.

Throwing carbon in the trash.
Heatmap Illustration/Getty Images

Most climate solutions are getting smarter. Solar panels can track the sun. Electric vehicles are equipped with the equivalent of an iPad and may soon be able to drive themselves (according to some people). Startups are inventing stoves with batteries that charge when energy is cheap and heat pumps that learn how you use your home and adjust accordingly.

But when it comes to permanently removing carbon dioxide from the atmosphere, the market is pushing in a different direction. There, it seems, there’s growing excitement for the dumbest, most primitive solutions companies can come up with.

The case in point this week is a $58 million agreement between Frontier, a fund started by tech companies to help grow the carbon removal market, and Vaulted Deep, a startup that collects food waste, poop, and other wet, sludgy, organic material and stashes it away underground. It’s the biggest deal Frontier has made to date, followed closely by a $57 million contract it signed in December with Lithos Carbon, which crushes up rocks and sprinkles the dust on agricultural fields. The rock naturally reacts with carbon dioxide in the air to form bicarbonate, which can essentially lock it away permanently.

There are at least 850 startups around the world trying to figure out the most effective, scalable, low-cost approach to cleaning up the legacy carbon pollution that’s warming the planet. Some of the most promising solutions have involved building big, energy-intensive systems that extract tiny amounts of carbon dioxide from the ambient air. One company I recently wrote about is manufacturing millions of tennis ball-sized sponges that will be stacked in trays, absorb carbon from the air, and then transferred into an oven to bake off the carbon.

Is it possible the answer could be as easy as pulverizing rocks and burying waste?

I ran my observation about the growing enthusiasm for dumb ideas past Hannah Bebbington, a strategy lead at Frontier, and she agreed — “totally,” she said, though she preferred the phrase “low-tech.” Compared to some of the earlier stars of carbon removal, Vaulted Deep and Lithos don’t require as much upfront capital investment or years and years of research and development. “At the end of the day, we are really excited about getting to gigaton scale carbon removal, and it doesn’t have to be the sexiest technology.”

So far, it seems, these lower-tech companies have been able to scale quickly. Vaulted Deep, for instance, launched at the end of August last year and has already delivered more than 2,400 tons of carbon removal. By comparison, the only operating direct air capture facility in the United States is capable of removing 1,000 tons of CO2 per year.

Vaulted Deep’s first project is in Kansas, where it is intercepting “woody waste” like grass clippings and tree trimmings that was destined to be incinerated. Once upon a time, when the plants were alive, they sucked up carbon from the atmosphere. If the clipping had been burned, the carbon would have been released back into the air. By slurrifying the waste and injecting it into a deep well, hundreds of feet underground, Vaulted Deep disrupts the cycle, potentially for millennia.

One advantage of this approach is that the carbon capture work is done for free, courtesy of photosynthesis. (Trees, of course, do this too, but not permanently.) Another is that Vaulted Deep uses mature technology to turn the waste into a slurry that can be injected underground. The company was spun out of Advantek, a waste management business that pioneered slurry injection in the 1980s. Most of the substances we inject into the layers of rock underneath our feet are pure liquid or gas, Julia Reichelstein, the CEO of Vaulted Deep told me. Advantek’s technology enables the company to take solid waste and, with minimal processing and energy, get it injection-ready.

The company’s third advantage is being able to pump its waste into “class five” wells, a designation made by the Environmental Protection Agency. Class five is sort of a catch-all category, encompassing shallow wells used for stormwater drainage and septic systems, to deep wells used for geothermal power. Regulations vary by type and by state, but in general, these are much more common and easier to permit than the “class six” wells used for carbon dioxide sequestration. “There’s, you know, 20, 30 years of permit history now on best practices on how you permit a slurry injection well,” Omar Abou-Sayed, the company’s co-founder, told me. “We comply with or exceed all those regulations. So this isn’t a case of, like, move fast and break things.”

All of this allows Vaulted Deep to charge less for carbon removal than many of its peers — closer to $400 per ton, as opposed to upwards of $600. Bebbington, of Frontier, thinks there’s a promising path to bring costs down a lot further if the company can achieve economies of scale by buying the sludgy organic waste in bulk, or move its injection wells closer to where the material originates.

But any climate solution involving biomass raises a host of questions about where the material came from, and what might have been done with it otherwise. Reichelstein said the company’s internal research found that there was almost a billion tons of bio-sludge produced in the U.S. annually. If it could capture all of it, the company estimated, it could sequester more than 300 million tons of carbon away from the atmosphere each year, after taking into account the emissions involved in collecting, processing, and injecting all that waste.

And yet, “The definition of a ‘waste’ is highly contested,” Freya Chay, program lead at the nonprofit CarbonPlan, which analyzes the integrity of different carbon removal approaches, told me.

For example, some companies are eyeing the use of agricultural waste like corn stalks, which are often left to decompose in fields, but also add nutrients to the soil. If the corn waste is removed and processed and buried underground, will that increase the use of carbon-intensive fertilizer? What if the waste was going into a landfill? There, it would have broken down eventually, but much more slowly than if it had been burned.

These questions get more complicated as projects that utilize waste biomass scale up. Once there’s more of a market for the material, will those counterfactuals that support what Vaulted Deep is doing — like that the waste would have been incinerated — still hold? “It's really hard to govern system-level risks with project-level rules, but that is the situation we are in,” said Chay.

At a second project location, in Los Angeles, Vaulted Deep is collecting sewage from the city’s wastewater treatment facilities that otherwise would have been trucked hundreds of miles out of the city and spread on farmland to decompose, releasing CO2 both during the transport and as it decays. The city has actually been paying Advantek to dispose of some of its sewage since 2008. But now, because of the Frontier deal, the company will drop its fee, allowing the city to divert even more of the waste for slurry injection.

Chay didn’t have any immediate concerns about Vaulted Deep’s biomass sourcing. In fact, she highlighted the co-benefits the company would provide. Oftentimes biomass waste is contaminated with toxic chemicals, and Vaulted Deep is preventing it from getting dumped in communities. “We should celebrate that,” she said.

Editor’s note: This story has been updated to correct the type of waste diverted for the Kansas project.

Green

You’re out of free articles.

Subscribe today to experience Heatmap’s expert analysis 
of climate change, clean energy, and sustainability.
To continue reading
Create a free account or sign in to unlock more free articles.
or
Please enter an email address
By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy
Climate

Does Microsoft’s Clean Energy Pullback Actually Matter?

Giving up on hourly matching by 2030 doesn’t mean giving up on climate ambition — necessarily.

Clean energy and the Microsoft logo.
Heatmap Illustration/Getty Images

Microsoft celebrated a “milestone achievement” earlier this year, when it announced that it had successfully matched 100% of its 2025 electricity usage with renewable energy. This past week, however, Bloomberg reported that the company was considering delaying or abandoning its next clean energy target set for 2030.

What comes after achieving 100% renewable energy, you might ask? What Microsoft did in 2025 was tally its annual energy consumption and purchase an equal amount of solar and wind power. By 2030, the company aspired to match every kilowatt it consumes with carbon-free electricity hour by hour. That means finding clean power for all the hours when the sun isn’t shining and the wind isn’t blowing.

Keep reading...Show less
Blue
Energy

Regulatory Reform Is Headed for the Nation’s Largest Grid

PJM Interconnection has some ideas, as does the state of New Jersey.

Josh Shapiro and Mikie Sherrill.
Heatmap Illustration/Getty Images

We’ve already talked this week about Pennsylvania asking whether the modern “regulatory compact,” which grants utilities monopoly geographical franchises and regulated returns from their capital investments, is still suitable in this era of rising prices and data-center-driven load growth.

Now America’s biggest electricity market and another one of that market’s biggest states are considering far-reaching, fundamental reforms that could alter how electricity infrastructure is planned and paid for over 65 million Americans.

Keep reading...Show less
Green
Climate Tech

Funding Friday: Robots Want Fast-Charging Batteries

Big fundraises for Nyobolt and Skeleton Technologies, plus more of the week’s biggest money moves.

A Skeleton factory.
Heatmap Illustration/Getty Images, Skeleton

Following a quiet week for new deals, the industry is back at it with a bunch of capital flowing into some of the industry’s most active areas. My colleague Alexander C. Kaufman already told you about one of the more buzzworthy announcements from data center-land in Wednesday’s AM newsletter: Wave energy startup Panthalassa raised $140 million in a round led by Peter Thiel to “perform AI inference computing at sea” using nodes powered by the ocean’s waves.

This week also saw fresh funding for more conventional data center infrastructure, as Nyobolt and Skeleton Technologies both announced later-stage rounds for data center backup power solutions. Meanwhile, it turns out Redwood Materials is not the only company bringing in significant capital for second-life EV battery systems — Moment Energy just raised $40 million to pursue a similar approach. Elsewhere, investors backed an effort to rebuild domestic magnesium production, and, in a glimmer of hope for a sector on the outs, gave a boost to green cement startup Terra CO2.

Keep reading...Show less
Green