26 April 2022 |

Catching up on CDR


The past ~month has been a busy one for this climate tech vertical, including:

Enhanced visibility into billions of $s on the demand side

Significant movement on the venture capital + equity investment front

And on the supply side? The market remains highly supply-constrained. Hopefully, given all of the above, there should be no lack of incentives to ramp up carbon removal supply. That’s a key next step!  

Under the surface, there’s still lots more happening in carbon removal than meets the eye from the big headlines alone. A slightly less high-profile event that wrapped up last week is worth double-tapping on in this regard. I’m talking about the milestone award winners in the XPRIZE Carbon Removal competition.

XPRIZE is an overarching organization that frames itself as “the leader in prize competitions to accelerate breakthroughs that benefit humanity.”

Let’s explore what that’s all about 👇


 Luckily, before he set his sights on $40B+ for a Twitter takeover, Musk carved out $100M for carbon removal. The XPRIZE Carbon Removal competition is a 4-year, global competition for companies tackling the uniquely difficult challenge of removing CO2 from the atmosphere and sequestering it in a scalable, efficient manner. 15 ‘milestone award’ winning teams receive $1M in funding from the competition each year. This year, more than 1,100 teams applied.

What’s uniquely interesting and exciting about carbon removal is how different all the team’s approaches are. Carbon removal technologies span everything from attempts to accelerate natural processes like photosynthesis that evolution has refined for millions of years to entirely ‘engineered’ solutions. 

I figured it’d be worth exploring a few examples today.

💦 Planetary TechnologiesPlanetary Technologies removes CO2 from the atmosphere via electrochemical alkalinity enhancement. That’s a mouthful. Slightly more simply put, they iteratively rebalance the pH of the ocean. By eliciting a series of chemical reactions, the ocean absorbs more CO2 to re-achieve its desired state of equilibrium. Pretty neat! 

X-Factor: Planetary Technologies not only removes CO2 from the atmosphere. They also use that CO2 in hydrogen production. This multi-solve approach means removing and reducing emissions, as hydrogen production is often an emissions-intensive process. Even better yet? To alkalize the ocean, they use materials left behind by mining operations. Once used in the carbon removal process, the materials are less hazardous. 

A copper mine in Iran

🪨 Carbin Minerals: Wants to take mine tailings (i.e., leftover materials at mines after the primary extraction happens) and use them for carbon mineralization. Their tech focuses on optimizing and accelerating that process by which CO2 binds to specific materials, removes it from the atmosphere, and offers super long-term durability for how long the CO2 stays out of the atmosphere.

X-Factor: Shortages of rare earth metals for batteries and technologies like EVs aren’t years away. They’re here now. Global production of metals and minerals will accelerate in the coming decades, which means more mining, ecological harm, and lots of ‘spent’ mining sites and materials. If Carbin Minerals can repurpose those for carbon removal? That’s probably the next best thing to keeping the original ecosystem intact. 

🌬️ Sustaera: Sustaera’s is an engineered solution that uses abundant minerals as sorbents to capture CO2. They also focused on designing a system that is a) modular (i.e., easy to deploy and site) and b) optimized to work with renewable electricity, especially wind energy. 

X-Factor: Perhaps surprisingly, it isn’t a given that direct air capture companies use renewable energy to power their removal operations. It’s not a given that the grid will be 100% composed of renewables in 10-15 years. Best not to make that assumption! Plenty of carbon removal methodologies aren’t yet net-negative carbon (or as negative as they could be) because they don’t exclusively use renewables. 

Making a modular direct air capture system that runs on renewables could also help renewable developers maximize their energy generation capacity and reduce curtailment. In the same way that bitcoin mining is one way to valorize that stranded energy, carbon removal could be an even better option!

🪨 Heirloom: We’ve covered Heirloom recently after their Series A fundraise. Heirloom iteratively makes and then breaks down limestone to remove CO2 from the atmosphere. Here’s how we laid it out previously: 

  1. Heat limestone (calcium carbonate). 
  2. This process releases CO2 from the limestone (for capturing). 
  3. The remaining material is calcium oxide, which can then be exposed to air to trap more CO2, turning it back to limestone.
  4. Back to step #1. Heirloom cites the ability to repeat this process up to 15 times before the material can no longer capture more CO2.

X-Factor: One reason Heirloom (and other companies on this list) is exciting? Limestone is super cheap and abundant. Heirloom’s process is a good example (as is Planetary Technologies’) of solutions that aren’t exclusively ‘engineered’; they lean into natural processes and readily available materials (the ocean or limestone) to (ideally) lend more efficiency to their processes.


Regardless of where you net out on how much focus the world should pay to carbon removal relative to emissions reductions… the industry is blossoming. A vast portfolio of approaches to carbon removal is being developed, receiving funding, and will soon compete for increasingly robust market demand. This portfolio approach is perfect in my opinion – we may well find that 90% of the technologies don’t work or aren’t economically viable. Maybe that # will be 99%. 

Hopefully, the 1-5% will be so efficient and replicable that, given sufficient free-market demand + regulatory incentives, they can drive gigaton levels of carbon removal annually. 

Hopefully, they get there in the next decade or so 🤞.

Beyond the four examples above, there are many other remarkable examples across land, air, and sea. I’d love to dive deeper into a few more in the future, including the wonderfully named ‘Seaforestation’ from the Climate Foundation, which grows deepwater seawater regeneratively to make food and remove CO2 from the atmosphere. Global Algae also similarly scales algae production (on land) to soak up CO2 while growing proteins and biofuels. I’ve been chatting with several land-use and food production-focused climate techs, so maybe we can dive deep on a number of these collectively!