From Buildings To Ocean Water, Startups Are Finding More Places To Stow Carbon

There is too much carbon in the atmosphere, and we have to find somewhere else to put it.

Preferably, somewhere stable and contained. Maybe deep underground. Potentially in some concrete. Or perhaps sucked into the vastness of the ocean.

Looking at funded startups in the carbon removal space, such ideas aren’t abstractions. Rather, they describe several business models around carbon removal that have collectively pulled in hundreds of millions of dollars from investors this year alone.

Funding records show that financings around carbon removal themes have accelerated in recent quarters, in tandem with climate data pointing to increasingly dire impacts should atmospheric carbon levels continue to rise. To some extent, it’s a recognition that, given the suboptimal adoption pace of clean energy sources, there’s an urgent need for other options.

“The thesis is we’re not going to transition fast enough,” said Peter Relan, a seed investor who recently launched a climate-tech incubator focused on carbon management. Its early investments include Equatic, a developer of technology that uses seawater to remove carbon dioxide from the atmosphere and produce green hydrogen.

Using Crunchbase data, we assembled a list of 13 companies touting intriguing carbon removal strategies:

Below, we look at some of the places where startups are planning to put all that carbon:

The ocean: Several startups are working on technologies and processes to store excess carbon in the ocean.

One of the more heavily funded is San Carlos, California-based Ebb Carbon, which proclaims that “the ocean is one of the largest carbon sinks on the planet.” The company landed a $20 million Series A in April around its stated mission to “remove gigatons of CO₂ from the air while reducing ocean acidification.”

Another, Pasadena, California-based Captura, has raised $12 million to use a process known as direct ocean capture to remove and capture oceanic CO₂. The process reportedly leaves a layer of decarbonized ocean water that will then react with the atmosphere to draw down an equivalent quantity of carbon dioxide.

The aforementioned Equatic, meanwhile, has secured seed funding for the rollout of its seawater electrolysis technology.

Soil: Another place to put carbon is in soil. This is the solution proposed by Loam Bio, an Australian startup that landed a $67 million Series B in February. The company says its technology “helps plants take CO₂ from the atmosphere and transform it into the most stable forms of soil carbon, turning the world’s croplands into giant carbon sinks.”

U.K.-based Undo also has its eyes on farmland, albeit with a rockier approach. The company uses a process called enhanced rock weathering to lock away carbon, producing a basalt rock it says can deliver nutrients to farm soil.

Deep underground: When it comes to storing carbon, perhaps deeper is better. To this end, San Francisco-based Charm Industrial picked up $100 million in Series B funding this summer for its plan to “put oil back underground.” The startup uses plants to capture carbon dioxide. It then converts biomass into a “stable, carbon-rich liquid” that it can then pump deep underground.

Burnaby, British Columbia-based Svante, the most heavily funded company on our list, is more broadly focused on making filters and machines that capture and remove CO₂ from industrial emissions and the air. However, it also has an underground storage angle, stating on its website that “the CO₂ we capture is concentrated to pipeline grade purity, which can be safely transported and stored underground or used to make other products.”

Carbfix, an Icelandic startup, has raised $117 million in grant-supported funding for what it describes as a permanent storage solution capable of “turning CO₂ into stone underground in less than two years.” Partners include Climeworks, a heavily funded Swiss direct air capture provider that works with Carbfix to store carbon.

Concrete and buildings: Our human-made environments of buildings and pavement are well-known for absorbing heat. But startups are betting that in the future we can do a better job producing materials and structures that actually help remove atmospheric carbon.

A couple months ago, we wrote about the robust funding environment for clean concrete. Among startups in the space, several are looking at ways to store carbon dioxide in concrete or remove atmospheric carbon in the production process.

The biggest round was a recent one: Dartmouth, Nova Scotia-based CarbonCure Technologies landed $80 million in July for carbon removal technologies that introduce recycled CO₂ into fresh concrete to reduce its carbon footprint.

Next is Brimstone Energy, a Berkeley, California-based company that raised $55 million last year to scale the making of “carbon-negative cement” through a process it says removes carbon dioxide from the air.

There’s also some dealmaking at the seed stage. Berlin-based EcoLocked secured initial funding last year to develop sustainable building materials by integrating biocarbon, with a stated goal to “turn buildings into carbon sinks.” Another seed startup, Finland-based Carbonaide, says it is working on ways to “turn concrete from a large emission source into a carbon sink.”

Will it work?

Of course, technology-driven approaches aren’t the only way to remove CO₂ from the atmosphere. Plants, for example, have been doing this for over 400 million years without any help from venture capitalists.

Today, however, analyses of pathways to limit global warming to 1.5°C generally incorporate human-led efforts at carbon dioxide removal, per an IPCC report. That said, authors also observed that “CDR deployed at scale is unproven, and reliance on such technology is a major risk.”

Still, the sums of money going into innovative approaches to stowing away carbon indicate investors believe these could turn into massively scalable businesses.

A couple big M&A deals in an adjacent space also show potential for returns.

In July, ExxonMobil announced plans to acquire Denbury Inc., a publicly traded developer of carbon capture, utilization and storage infrastructure, in a stock transaction valued then at a whopping $4.9 billion.

A month later, Occidental Petroleum agreed to pay $1.1 billion for Squamish, British Columbia-based Carbon Engineering, a developer of direct air capture technology that previously raised over $110 million in venture, strategic and grant funding.

Notably, these are acquirers better known for pulling fossil fuels out of the ground. But in an exceedingly slow M&A environment, it’s still significant that carbon capture and removal is one of a few areas where buyers are willing to spend big.