Our portfolio

Karbonetiq takes alkaline industrial residues that naturally absorb CO₂ from the air and cycles them through a low-cost, passive aeration system with sensors to measure how much carbon is captured. Their system could improve mineralization rates by increasing exposed surface area and minimizing deployment footprint, allowing projects to be co-located with existing industrial activities.

Limenet is developing a custom electric kiln to produce zero-carbon quicklime—a clean, fast-reacting feedstock. Limenet's carbon-free quicklime enables a range of promising approaches to scale, including surficial mineralization, ocean liming, and mineral looping DAC. It can also support broader decarbonization efforts by replacing industrial quicklime commonly used in applications like steel production and cement manufacturing.

pHathom captures CO₂ emissions from coastal bioenergy plants using a slurry of limestone, seawater, and biocatalysts inside a weathering reactor, forming a stable bicarbonate solution that can be safely discharged into the ocean. Their approach provides a critical storage solution for coastal projects across bioenergy with carbon capture and storage (BECCS), direct air capture (DAC), and industrial carbon capture and storage (CCS), enabling scalability where geologic injection is not feasible. Their biocatalyst could facilitate the wider use of limestone for other carbon removal approaches, including field weathering and inland water alkalinity enhancement.

Arbor uses waste biomass to create clean energy while capturing CO₂. This offtake will enable the launch of Arbor’s first commercial facility. It will also test the viability of a new BECCS approach that has a 99% CO₂ capture rate and can generate up to 1,000 kWh of clean energy per ton of CO₂ removed.

Hafslund Celsio is the largest supplier of district heating in Norway. They are proposing to retrofit the Klemetsrud waste-to-energy (WtE) facility with a CO₂ capture unit, followed by intermediate CO₂ storage at the Oslo harbor, ship transport to the North Sea, and geologic sequestration at Northern Lights.

Eion accelerates mineral weathering by mixing silicate rocks into soil. Their pelletized product is applied by farmers and ranchers to increase carbon in the soil, which over time makes its way into the ocean where it’s permanently stored as bicarbonate. Alongside their technology development, Eion is also conducting a novel soil study to improve the field's measurement of CO₂ uptake.

Phlair is developing an electrochemical approach to direct air capture that’s energy efficient and designed to work with intermittent renewable energy sources, like solar. This offtake will support Phlair’s first commercial-scale facility in Alberta, Canada.

CO280 is retrofitting a pulp and paper (P&P) mill to capture and store CO₂ that was absorbed from the atmosphere in biomass ("biogenic CO₂"). Black liquor, a byproduct of the P&P process, is combusted in a recovery boiler to recycle chemicals and provide heat for the process. The team will install a CO₂ capture unit to separate out the biogenic CO₂ from the recovery boiler flue gas. The CO₂ is then compressed and transported to a nearby geologic sequestration site.

CREW is building specialized reactors to enhance natural weathering. The container-based system creates optimized conditions to speed up the weathering of alkaline minerals, and the discharged water stores CO₂ from wastewater safely and permanently as bicarbonate ions in the ocean. CREW’s system makes measuring CO₂ removed easier and can react with CO₂ from a variety of sources, including direct air capture and biomass systems, to maximize scale.

Terradot spreads crushed basalt rock onto acidic and nutrient-depleted agricultural soils in Brazil. The rock material absorbs CO₂ from the air and soil, turning it into a form that enters runoff and permanent storage in the ocean.

CarbonRun adds crushed limestone to rivers to raise their pH, storing CO₂ as dissolved bicarbonate in the river and ultimately in the ocean. In addition to CO₂ removal, CarbonRun’s work also benefits river ecosystems locally by increasing the pH.

Alithic couples a solvent CO₂ capture process with a novel ion exchange method for efficient solvent regeneration. This process reacts CO₂ with industrial wastes and upgrades it into a material that can be resold for producing low-carbon concrete. Their approach has the potential for low-energy removal at scale and can be used flexibly across a wide range of alkaline feedstocks.

Alt Carbon spreads basalt on tea plantations in the Himalayan foothills, where the hot, humid environment helps speed up the natural reaction with water to remove CO₂ and store it as durable bicarbonate. This project uses a novel verification approach using metal tracers in the soil to reduce the cost of measurement and further understanding of weathering in new geographies. Alt Carbon’s project also improves soil health and provides additional revenue for farmers in an industry threatened by rising costs and climate change.

Anvil contacts highly reactive alkaline minerals with atmospheric CO₂ in a low-energy system that speeds up the mineralization process. The resulting solid carbonate minerals are then stored durably on-site and the removal can be easily measured. The team is targeting a promising feedstock and accelerating its broad use for removal at scale.

Capture6 uses electricity and saltwater in an electrochemical system to remove CO₂ while eliminating industrial waste streams. They use proven technologies and can flexibly integrate across a range of industrial processes to generate co-products like clean metals or freshwater, increasing the likelihood they can scale quickly and cheaply. This project also accelerates research around using low-carbon chemical byproducts productively.

Exterra Carbon Solutions uses a thermochemical process to transform mine waste into fast-dissolving alkaline minerals that can be used to remove carbon in a variety of ways. For their pilot, they are partnering with Planetary to mix their material into coastal outfalls where it draws down atmospheric CO₂ and is stored durably in the form of oceanic bicarbonate. Their process cleans up mine sites by eliminating asbestos residues and extracts valuable low carbon metals like nickel that can be sold to reduce the cost of removal.

Flux accelerates the natural ability of rocks to absorb CO₂ by spreading basalt on farms in Sub-Saharan Africa, a region with high weathering potential due to its humid, tropical climate. They are introducing field weathering to new regions and developing a tech platform to make robust, responsible measurement and future deployments easier. In addition to storing CO₂ as bicarbonate, the approach provides significant agronomic benefits to farmers who have historically had less access to soil amendments such as fertilizer or lime.

NULIFE uses a process called hydrothermal liquefaction to efficiently transform wet waste biomass into a bio-oil that is cheap to transport and is injected underground for permanent removal. Their process can destroy contaminants in waste biomass like PFAS and generates potential scalable co-products that lower the price of carbon removal.

Planeteers uses a novel pressure-swing process to convert limestone, a cheap and abundant feedstock, into hydrated carbonate minerals, a fast-dissolving material that can be a scalable feedstock for a range of carbon removal approaches. Their pilot project mixes this material into water treatment plant outflows where it reacts with CO₂ in the air to form durable bicarbonate. This approach is easy to measure and leverages existing infrastructure, reducing costs.

Silica applies basalt and other volcanic rocks across sugarcane farms in Mexico, where warm, wet conditions speed up the weathering of the materials and storage of CO₂ as bicarbonate. They are pioneering a novel approach that could make carbon removal measurement on small farms easier and cheaper and are working with consumer brands to demonstrate how carbon removal can be incorporated into agricultural supply chains.

280 Earth’s continuous direct air capture system is a flexible design built with commercially available components and can draw power from several sources, including electricity or industrial waste heat. The captured CO₂ stream is then stored permanently.

Exergi is retrofitting one of their biomass-based district heating facilities in Stockholm to capture CO₂ produced as a byproduct of the combustion process. The CO₂ is extracted from the flue gas by mixing it with a solution of potassium carbonate. The resulting potassium bicarbonate is heated, breaking it down into carbon dioxide and water. The extracted carbon dioxide is then transported away for permanent geologic storage.

Vaulted injects carbon-rich organic waste biomass deep underground for permanent storage. This disposal method also replaces harmful disposal practices like land application and incineration. As a spinoff from an established waste disposal company, Vaulted benefits from already-permitted well infrastructure, and a team with longstanding operational experience.

Lithos accelerates the natural ability of rocks to absorb CO₂ by spreading superfine crushed basalt on farmlands and measuring the removal empirically. They’re pioneering a novel measurement technique that more accurately quantifies the carbon permanently removed from enhanced weathering.

Over geologic timescales, CO₂ chemically binds to minerals and permanently turns to stone. Heirloom is building a direct air capture solution that accelerates this process to absorb CO₂ from the ambient air in days rather than years, and then extracts the CO₂ to be stored permanently underground.

CarbonCapture’s direct air capture machines use solid sorbents that soak up atmospheric CO₂ and release concentrated CO₂ when heated. CarbonCapture’s core innovation is making the capture system modular and upgradeable so that they can swap in best-in-class sorbents as they become available. The captured CO₂ stream is then stored permanently underground.

Airhive is building a geochemical direct air capture system using an ultra porous sorbent structure that can be made out of cheap and abundant minerals. This sorbent reacts rapidly with atmospheric CO₂ when mixed with air in Airhive’s fluidized bed reactor. Coupled with a regeneration process that’s powered by electricity to release the CO₂ for geologic storage, this provides a promising approach to low-cost DAC.

Alkali Earth uses alkaline byproducts, like steel slag, as gravel aggregates for building road surfaces. The calcium- and magnesium-rich minerals in the gravel react with atmospheric CO₂ to form stable carbonates, storing it permanently while cementing the road surfaces. Spreading the gravel across roads increases the surface area exposed to CO₂ and leverages road traffic to agitate the gravel further, accelerating CO₂ uptake.

Banyu uses sunlight to capture CO₂ from seawater and store it permanently. A reusable, light-activated molecule that becomes acidic when exposed to light causes carbon dissolved in seawater to degas as CO₂, which is then compressed for storage. Because only a small portion of the visible light spectrum is needed to trigger the reaction and the light-activated molecule can be reused thousands of times, this is a highly energy-efficient approach to direct ocean removal.

CarbonBlue has developed a calcium looping process to remove CO₂ from seawater or freshwater. Their novel mineralization, dissolution and brine hydrolysis regeneration releases CO₂ captured from water without needing any external feedstock of minerals or chemicals. The reactors are highly energy efficient and require a low enough regeneration temperature to enable utilization of waste heat.

EDAC Labs uses an electrochemical process to produce acid and base. The acid is used to start the recovery of valuable metals from mining waste, and the base is used to capture CO₂ from air. The acid and base streams are then combined to produce metals that can be sold for applications such as batteries, and solid carbonates which permanently store CO₂. The EDAC Labs process is energy efficient, uses abundant mine wastes, and produces valuable revenue-generating co-products.

Holocene captures CO₂ from air using organic molecules that can be produced at low cost. In the first step of their process, CO₂ is captured from air when it comes into contact with a liquid solution. In the second step, a chemical reaction crystallizes the material as a solid. That solid is heated up to release the CO₂, minimizing energy wasted in heating water. Their process runs at lower temperatures, further reducing the energy required and increasing energy flexibility.

Mati applies silicate rock powders to agricultural fields, starting with rice paddy farms in India. These rocks react with water and CO₂ to produce dissolved inorganic carbon that is subsequently stored in the local watershed and eventually in the ocean. Mati relies on rice field flooding and higher subtropical temperatures to accelerate weathering, and extensive sampling and soil and river modeling to measure removal and deliver co-benefits to smallholder farmers.

Planetary harnesses the ocean for scalable removal. They introduce alkaline materials to existing ocean outfalls like wastewater plants and power station cooling loops. This speeds up the sequestration of CO₂ safely and permanently as bicarbonate ions in the ocean. Planetary then verifies the removal through advanced measurement and modeling techniques.

Spiritus uses a sorbent made from a readily available polymer with a high capacity for CO₂. The CO₂-saturated sorbent is regenerated using a novel desorption process, capturing the CO₂ and allowing the sorbent to be reused with less energy than a higher-heat vacuum chamber typically used in direct air capture approaches. The high-performance, inexpensive sorbent and lower regeneration energy provide a path to low cost.

Carboniferous sinks bundles of leftover sugarcane fiber and corn stover into deep, salty, oxygenless basins in the Gulf of Mexico. The lack of oxygen in these environments–and therefore absence of animals and most microbes–slows the breakdown of biomass so it is preserved and stored durably in ocean sediments. The team will experiment to determine the stability of sunken biomass as well as the interaction with ocean biogeochemistry.

Rewind sinks agricultural and forest residues to the oxygenless bottom of the Black Sea, the largest anoxic body of water on Earth. Oxygenless water dramatically slows biomass decomposition. The lack of living organisms in the Black Sea limits any potential ecosystem risks. Through pilot deployments, the team will examine the durability of sunken biomass and better ways to measure and model the carbon removed.

Charm Industrial has created a novel process for preparing and injecting bio-oil into geologic storage. Bio-oil is produced from biomass and maintains much of the carbon that was captured naturally by the plants. By injecting it into secure geologic storage, they’re making the carbon storage permanent.

Arca is capturing CO₂ from the atmosphere and mineralizing it into rock. They work with producers of critical metals, transforming mine waste into a massive carbon sink. With autonomous rovers, their approach accelerates carbon mineralization, a natural process storing CO₂ permanently as new carbonate minerals. By creating a system that works directly at the mine site, Arca avoids the cost and emissions of moving material to processing facilities.

Captura is harnessing the ocean for scalable removal by designing an electrochemical process to separate acid and base from seawater. The acid is used to remove CO₂ that’s present in seawater, which is injected for permanent geologic storage. The base is used to treat and return the remaining water safely to the ocean, and the ocean then draws down further CO₂ from the atmosphere. Captura is developing optimized membranes to increase electrical efficiency and reduce removal costs.

Carbon To Stone is developing a new form of direct air capture, in which a solvent that binds CO₂ is regenerated by reacting with alkaline waste materials. By replacing conventional solvent regeneration using heat or pressure changes with direct mineralization of low-cost alkaline wastes such as steel slag, the team can significantly reduce the energy, and thus the cost, required. The CO₂ is durably stored as solid carbonate materials that can be used for alternative cements.

Cella increases the options for safe and secure carbon storage via mineralization. They accelerate the natural process that converts CO₂ into solid mineral form by injecting it into volcanic rock formations together with saline water and geothermal brine waste, with an approach that lowers cost and minimizes environmental impacts. Cella’s technology integrates low-carbon geothermal heat and can be paired with a variety of capture methods.

Inplanet accelerates natural mineral weathering to permanently sequester CO₂ and regenerate tropical soils. They partner with farmers to apply safe silicate rock powders under warmer and wetter conditions that can result in faster weathering rates and thus faster CO₂ drawdown. The team is developing monitoring stations to generate public field trial data to improve the field’s understanding of how weathering rates vary under tropical soil and weather conditions across Brazil.

Kodama Systems and the Yale Carbon Containment Lab are deploying a proof-of-concept method of storing waste woody biomass by burying it in anoxic chambers underground, preventing decomposition. The team will experiment with how chamber conditions and above-ground disturbances impact durability and reversal risk.

Nitricity is exploring the potential of integrating carbon removal into a novel process for the electrified production of clean fertilizer. This process combines carbon-neutral nitrogen compounds, phosphate rock and CO₂, producing nitrophosphates for the fertilizer industry and storing CO₂ durably as limestone. This new pathway could present a low-cost storage solution for dilute CO₂ streams with co-benefits of decarbonizing the fertilizer industry.

AspiraDAC is building a modular, solar-powered direct air capture system with the energy supply integrated into the modules. Their metal-organic framework sorbent has low temperature heat requirements and a path to cheap material costs, and their modular approach allows them to experiment with a more distributed scale-up.

This project, a collaboration between 8 Rivers and Origen, accelerates the natural process of carbon mineralization by contacting highly reactive slaked lime with ambient air to capture CO₂. The resulting carbonate minerals are calcined to create a concentrated CO₂ stream for geologic storage, and then looped continuously. The inexpensive materials and fast cycle time make this a promising approach to affordable capture at scale.

RepAir uses clean electricity to capture CO₂ from the air using a novel electrochemical cell and partners with Carbfix to inject and mineralize the CO₂ underground. The demonstrated energy efficiency of RepAir’s capture step is already notable and continues to advance. This approach has the potential to deliver low-cost carbon removal that minimizes added strain to the electric grid.

Travertine is re-engineering chemical production for carbon removal. Using electrochemistry, Travertine produces sulfuric acid to accelerate the weathering of ultramafic mine tailings, releasing reactive elements that convert carbon dioxide from the air into carbonate minerals that are stable on geologic timescales. Their process turns mining waste into a source of carbon removal as well as raw materials for other clean transition technologies such as batteries.

Living Carbon wants to engineer algae to rapidly produce sporopollenin, a highly durable biopolymer which can then be dried, harvested and stored. Initial research aims to better understand the field’s thinking on the durability of sporopollenin as well as the optimal algae strain to quickly produce it. Applying synthetic biology tools to engineer natural systems for improved and durable carbon capture has the potential to be a low-cost and scalable removal pathway.