The XPRIZE Carbon Removal is a $100 million global competition aimed at tackling climate change and rebalancing Earth’s carbon cycle. Funded by Elon Musk and the Musk Foundation, this competition is the largest incentive prize in history. The competition seeks to incentivize the development of carbon removal solutions that can achieve net negative emissions, including nature-based, direct air capture, ocean-based, mineralization, and other approaches. The goal is to develop efficient solutions that can collectively achieve the 10-gigaton-per-year carbon removal target by 2050.
The XPRIZE Carbon Removal competition will run for four years, from April 22, 2021 (Earth Day) to Earth Day 2025. The grand prize winner must demonstrate that their innovation is capable of removing 1,000 metric tons of carbon dioxide (CO₂) from the atmosphere or oceans and storing it in a safe, cost-effective way.
Direct air capture (DAC) is one of the methods being explored by various teams participating in the XPRIZE Carbon Removal competition. DAC involves extracting CO₂ directly from the atmosphere and storing it permanently in an environmentally benign way. In this article, we introduce some XPRIZE Carbon Removal companies who specialize in DAC technology.
Carbyon, a Netherlands-based company founded in 2019, develops DAC technology that uses a fast swing process by means of a continuously rotating drum. The rotating drum comprises activated carbon fiber membranes. The surface of fibers are functionalized with a monolayer of amines that are used as CO₂ adsorbents. Such a thin surface sorbent allows a rapid CO₂ absorption at ambient temperature and fast regeneration below 100 ºC. Thereby, one cycle of absorption and regeneration occurs in less than 5 seconds. The fast swing CO₂ capture process is the key to lower the energy consumption as well as the cost of the machine.
Carbofex, a Finnish company founded in 2016, has developed a simple and efficient thermal pyrolysis system that continuously converts biomass into non-energent biochar in the absence of oxygen. The biochar contains very few polycyclic aromatic hydrocarbon (PAH) compounds. This is accomplished by thermally treating the biomass inside a conveyor reactor system through the use of water vapor. Syngas produced in the conveyor reactor flows in the opposite direction of the traveling to-be-processed biomass. Syngas transfers heat to biomass. The cooled syngas is combusted by a gas burner to directly heat the conveyor reactor system. The entire process is self-sustaining. Since 2019, Carbofex’s solution has captured over 3,000 tons of CO₂.
Heirloom Carbon (Heirloom), an American company founded in 2020, uses limestone (CaCO₃) to capture CO₂ from the air and store it safely and permanently. Limestone is heated in renewable-energy powered calciners to remove CO₂ and produce Ca(OH)₂ sorbents from the hydration of CaO powders. Ca(OH)₂ sorbents are placed on vertically stacked trays, and algorithms are used to optimize their capacity to absorb CO₂ in different environmental conditions. Heirloom’s DAC technology accelerates the natural property of limestone, reducing the time it takes to absorb CO₂ from years to just three days. The company claims that its technology has the lowest peer-reviewed, at-scale cost of any direct air capture technology on the market.
Sustaera, an American company founded in 2021, uses renewable electricity and monolithic structured material assemblies to capture CO₂ directly from the air. In a monolithic structured material assembly, a monolithic substrate with a honeycomb-like structure is positioned between two mesh electrodes. The monolithic substrate’s channel walls are coated with layers of conductive desorption and sodium carbonate (Na₂CO₃) sorbent. The Na₂CO₃ sorbent absorbs CO₂ from the airflow within the channels. To regenerate sorbent, the conductive desorption layer receives renewable electricity input via the mesh electrodes and in-situ heats the sorbent layer to quickly liberate CO₂ at a low temperature, thus minimizing energy input and reducing costs significantly.
TerraFixing, a Canadian company founded in 2020, develops Direct Air Capture technology based on temperature vacuum swing adsorption (TVSA) cycle to capture and yield high purity CO₂ from cold, dry air by using low-cost Li-X or Na-X zeolite adsorbents. This unique TVSA process allows TerraFixing’s DAC technology to have low operating energies, as low as 1 MWh per metric ton of CO₂, making it a cost-effective solution for CO₂ capture. The vision of TerraFixing is to achieve the gigaton capture scale by 2050 by developing the technologies, partnerships, and business opportunities.
Verdox, an American company founded in 2019, has developed electroswing adsorption cells with patterned electrodes that contain quinone materials to capture CO₂ from the air and emission sources like aluminum production. The patterned electrode comprises conductive carbon scaffold which is coated with electroactive quinone materials and extends into a polymer gel electrolyte to capture and liberate CO₂ by applying a current at select voltages in ambient temperature. The patterned electrode has multiple gas regions that facilitate the diffusion of CO₂ to quinones. Verdox’s electrochemical carbon removal technology offers a more energy-efficient approach to capturing CO₂ compared to traditional carbon capture technologies. The latter often require large amounts of heat and have inherent inefficiencies.
What do you think about the technologies of the above companies for carbon removal? Do you know any other promising carbon removal tech startups?