20 Teams Bring Cutting-Edge Solutions to XPRIZE Carbon Removal Final

May 08 2024

XPRIZE has announced the 20 finalist teams selected to compete in the last stage of XPRIZE Carbon Removal.

Removing carbon dioxide (CO2) from our planet’s atmosphere is one of the most crucial, yet difficult, challenges humanity has ever faced. These finalist teams are paving the way forward to achieve carbon dioxide removal (CDR) at a gigatonne scale by 2050. XPRIZE chose these finalists from over 1,300 teams from 88 countries for the transformative power of their solutions across the competition’s four tracks: air, ocean, land, and rocks.

Each finalist has demonstrated their potential to make contributions to a unique, novel CDR effort that rebalances Earth’s carbon cycle by removing CO2 directly from the atmosphere or the oceans and sequestering it durably and sustainably. Excess CO2 in the Earth’s atmosphere and oceans is the main driver of climate change, increasing risk of extreme heat, abnormal weather patterns, stresses on food production, and access to water as temperatures continue to rise. Significant climate interventions, involving both drastic emissions cuts alongside the rapid evolution of CDR technology, are needed to combat our climate crisis and mitigate global warming.

Now in the final stages of testing, XPRIZE Carbon Removal has challenged the final 20 teams to remove 1,000 net tonnes of CO2 during the final year of the competition. Teams will also be measured on the potential of their technology to scale towards removing carbon on a megatonne scale in the coming years, and at the gigatonne scale by 2050. 


A gigatonne is one billion metric tons, 2.2 trillion pounds, 10,000 fully-loaded U.S. aircraft carriers, 200 million elephants, or equal to the combined weight of all non-human land mammals in the world. 

Humans produced an estimated 36.8 gigatonnes of carbon emissions in 2023, contributing to the about 425ppm (parts per million) of CO2 in our atmosphere–a record high. This data comes from CO2 monitoring on Mauna Loa, Hawaii, and shows direct correlation to climate warming. The last time atmospheric CO2 amounts were at this level was in the Mid-Pliocene Warm Period, about 3 million years ago. Recent projections estimate that in order to successfully address the climate crisis, we will need to achieve gigatone scale carbon capture and storage by 2050. 

Learn more about the current state of the CDR industry and projections by downloading our new report Getting to Gigatonne: Scaling the Carbon Removal Industry that reports data from the Top 100 teams in the XPRIZE about their 2024 kilotonne demonstrations, projected removals from 2024-2030, megatonne scale projects, cost, emissions, and impact at gigatonne. 


XPRIZE Carbon Removal teams were evaluated over three years of the competition across three key areas: operations, sustainability, and cost. The 20 finalist teams displayed operational maturity towards removing 1,000 net tonnes of CO2 this year, a viable pathway to reaching megatonne scale in the coming years, and gigatonne scale in the years beyond. These teams also demonstrated an understanding of the environmental and social impacts of their work. 

XPRIZE Carbon Removal has four pathways towards which teams can pitch their solutions, each representing one area of the CDR industry:

  • Air
  • Rocks
  • Land
  • Oceans


Direct Air Capture (DAC) describes a class of climate tech technologies designed to remove CO2 from the ambient air. Unlike point-source CDR, where CO2 is captured directly at power plants and industrial facilities to reduce emissions emitted from those facilities, DAC removes already-emitted CO2 from the air and can be deployed anywhere, making it a versatile solution to combat global climate change. The process typically involves using chemical reactions or filters to capture CO2 from ambient, or outdoor, air. After the CO2 is trapped, it can be stored using various carbon storage techniques or used for other purposes such as synthetic fuel production, carbon-negative materials, or enhanced plant growth.

The following teams have presented solutions to the XPRIZE Carbon Removal “Air” track:

1. Airhive – HQ Location: UK, Demo Location: Canada
Airhive technology provides rapid CDR via a low-cost, non-toxic metal oxide-based sorbent. Airhive is partnering with CO2 storage provider Exterra, who will react Airhive’s air-captured CO2 with mine tailings through their proprietary process.

2. Heirloom – HQ Location: US, Demo Location: US
Heirloom pioneers a low-cost DAC technology capable of permanently removing CO2 at a billion-tonne scale by rapidly accelerating the natural process of capturing CO2 from the atmosphere to form limestone within days. Heirloom's carbon storage provider CarbonCure locks away this CO2 via mineralization in concrete materials, which are then used to build local infrastructure.

3. Octavia Carbon – HQ Location: Kenya, Demo Location: Kenya
Octavia Carbon is the Global South's first DAC company, leveraging renewable energy, geological advantages, and local talent to establish the first DAC+Storage plant in the Southern Hemisphere, Project Hummingbird, aiming to annually capture and permanently store 1000 metric tons of CO2 underground.

4. Project Hajar (44.01 & Air Capture) – HQ Locations: Oman and USA, Demo Location: Oman
Project Hajar, a collaboration between 44.01 and AirCapture, combines state-of-the-art DAC technology with pioneering CO2 mineralization technology, aiming to turn captured CO2 into rock.

5. Skyrenu – HQ Location: Canada, Demo Location: Canada
Skyrenu combines a DAC system with a rock carbonation process to treat asbestos mine tailings in order to lock away carbon forever.


The concept of using rocks to remove CO2 from the atmosphere is based on the fundamentals of mineral carbonation. This process occurs naturally over thousands of years as CO2 reacts with certain types of rocks to form stable minerals. By accelerating this process, we can harness the power of rocks to remove CO2 on a much faster timescale.

The following teams have presented solutions to the XPRIZE Carbon Removal “Rocks” track:

6. Arca – HQ Location: Canada, Demo Location: Australia 
Arca’s patented technology accelerates carbon mineralization in mine tailings and waste rock, creating an industrial-scale CDR solution by activating magnesium silicate minerals to transform ultramafic mine waste into a massive carbon sink.

7. Lithos –  HQ Location: US, Demo Location: US
Lithos Carbon accelerates the Earth's natural carbon cycle by deploying enhanced rock weathering (ERW) in agriculture to permanently remove CO2 from the air and improve crop yields and soil health for farmers. Lithos uses organic-grade volcanic basalt dust and state-of-the-art science to measure CDR, aiming to decarbonize the food system.

8. Mati – HQ Location: US, Demo Location: India 
Mati durably removes carbon from the atmosphere using basalt-based ERW in smallholder rice paddy farms. This process removes atmospheric CO2 while adding key nutrients to the soil, helping to restore degraded soils to the benefit of smallholder farmers.

9. Silicate – HQ: Ireland, Demo Location: Ireland 
Silicate Carbon uses surplus concrete from the building industry to amend agricultural land while harnessing natural geochemical processes to permanently remove CO2 from the atmosphere. By using accelerated mineral weathering, they are able to enhance soil pH, boost crop productivity, and reduce reliance on pesticides and fertilizers.

10. UNDO – HQ Location: UK, Demo Location: UK 
With nature-enabled ERW technology, UNDO generates permanent, high-quality CDR credits with added co-benefits to support businesses on their pathway to net zero.

11. Yuanchu – HQ Location: China, Demo Location: China 
Yuanchu is a pioneering startup focused on developing direct air mineralization (DAM) technology. With this technology, they hope to remove CO2 from the air and permanently sequester it in solid carbonated material on a gigatonne scale, with a cost of less than $200 per ton of CO2 in stable mineralization products that will last for 1000 years.


Plants are an effective way to efficiently capture CO2 from the atmosphere by leveraging photosynthesis and biomass can provide an effective vector for sequestering CO2 durably. Land-based CDR projects can also leverage the infrastructure and practices of existing industries (agriculture, energy, forestry, etc.) to boost their rate of deployment. 

The following teams have presented solutions to the XPRIZE Carbon Removal “Land” track:

12. Climate Robotics – HQ Location: US, Demo Location: US
Climate Robotics enables broad-scale agriculture adoption of biochar which builds soil health and removes excess carbon from the atmosphere. The company's mobile technology converts crop residues into durable biochar in the field, making the economics work for farmers and our ecosystems.  

13. Mash Makes – HQ Location: Denmark, Demo Location: India
MASH Makes pioneers pyrolysis and gasification technology, which converts agricultural waste into carbon-negative energy and biochar for soil amendment, actively combating carbon emissions

14. NetZero – HQ Location: France, Demo Location: Brazil
NetZero's mission is to scale biochar as a climate and agricultural solution by focusing on the abundant unused crop residues in the tropics. They proprietary technology of mid-size, automated, highly optimized, and easily replicable pyrolysis plants, and operate an end-to-end model that fosters local farmer involvement as both suppliers of biomass and clients of biochar. This streamlines logistics, enhances traceability, and promotes local buy-in. 

15. Takachar – HQ Location: India, Demo Location: Kenya
Takachar uses MIT technology to construct a decentralized internet-of-things-enabled reactor network, facilitating rapid and profitable scaling of biochar deployment, independent of carbon offset credits. They use patent-pending, low-cost, and portable hardware. This enables village-based production of customizable biochar-based fertilizers from locally available crop residues, ultimately improving farmers' crop yields by up to 30% and net income by 50%, thereby advancing climate justice.

16. Vaulted Deep – HQ Location: US, Demo Location: US
Vaulted Deep delivers scalable, permanent, carbon removal by geologically sequestering carbon-filled organic wastes. They use a patented slurry sequestration, which involves geological injection of minimally processed wastes for permanent (10,000+ year) carbon removal.


Earth’s oceans are powerful forces of nature that already hold more carbon than any other part of our planet’s biosphere, but they have the potential to contribute more. The variability of the ocean allows many different types of CDR to be used, such as microalgae cultivation or deep sea storage. Oceans’ sheer scale means that successful ocean-based CDR solutions have the opportunity to scale massively. 

The following teams have presented solutions to the XPRIZE Carbon Removal “Oceans” track:

17. Captura – HQ Location: US, Demo Location: US 
Captura provides a scalable, low-cost direct ocean capture (DOC) carbon removal solution. They produce a measurable stream of CO2 for sequestration with only seawater and renewable energy. This process requires no external additives and produces no byproducts. DOC requires no freshwater, has a minimal land footprint and can operate with intermittent power.

18. Ebb – HQ Location: US, Demo Location: US
Ebb Carbon is pioneering a new carbon removal solution by enhancing the ocean's natural ability to safely store CO2. Their electrochemical ocean alkalinity enhancement method has the potential to remove excess CO2, while reducing ocean acidity, at low-cost and large-scale. 

19. Kelp Blue – HQ Location: Netherlands, Demo Location: Namibia
Kelp Blue cultivates giant kelp (macrocystis pyrifera) in farms off the coasts of Namibia, New Zealand, and soon Alaska, utilizing innovative submerged structures to overcome scaling limits of sheltered water benefitting from local nutrient upwelling systems. The harvested canopy biomass is processed into sustainable agricultural and packaging products while the remaining biomass naturally sequesters carbon, supports biodiversity, and provides ecological benefits.

20. Planetary –  HQ Location: Canada, Demo Location: Canada 
Planetary leverages ocean alkalinity enhancement (OAE) to enhance the ocean's natural carbon removal capabilities. They use the ocean carbon platform (OCP), a product that facilitates CO2 “weathering” through the safe addition of antacid to seawater, to qualify alkalinity sources, automate operations, ensure ocean safety, and measure and monetize carbon removal.

In addition to these 20 finalist teams, the judges selected three “XFactor Teams” – Metalplant, Gigablue, and Alaska Future – who, while not advancing to the Finals, deserved special recognition for their exciting and novel carbon capture technology concepts with significant potential impact. 


XPRIZE is also pleased to announce the release of the Top 100 teams who represent a new generation of CDR innovators. The teams represent 25 countries and a great many CDR pathways. These teams are all currently removing CO2 or working to do so for the first time this year, a significant milestone for the industry and a step towards becoming carbon neutral. 


The final stage of the competition will take place over the next year as finalist teams are challenged to demonstrate 1,000 net tonnes of CDR. These demonstrations will be judged on their fully considered cost, operational performance, and ability to meet sustainable scalability requirements. The grand prize winner will take home $50M in April 2025, while $30M will be distributed amongst the runners up.

XPRIZE would like to thank all individuals, teams, and entities involved with finding a solution to this grand challenge. 

Learn more and get involved at xprize.org/carbonremoval.