Three Areas of Innovation for Direct Air Capture Startups to Seize This Decade
Direct air capture, or DAC, is a fledgling technology that essentially reverses that process—capturing CO2 out of the air so it can be used or returned underground to be stored away safely in geologic formations.
By permanently removing large amounts of carbon from the atmosphere, DAC could provide an important “insurance policy” for the climate.
In addition to aggressive emissions reductions, the IPCC indicates that by 2050 the world may need to remove 2–20 gigatons of CO2 from the atmosphere annually. Such an undertaking will likely require a portfolio of carbon removal approaches—including both nature-based solutions such as tree planting and engineered solutions such as DAC or bioenergy with carbon capture and sequestration.
The problem: we’re nowhere near that scale today.
DAC in particular is in its infancy, with only 19 active plants capturing about 10,000 tons of CO2 annually (equivalent to the tailpipe emissions of about 2,000 cars). Current technologies for DAC are far too expensive to scale to billions of tons of removal per year. However, bipartisan support for DAC is growing, and a number of startups in the space are working to pioneer new approaches and drive down costs.
We see three main areas of innovation where current and future startups can focus to make DAC a robust and cost-effective part of the carbon removal portfolio.
1. Making Contact
To capture carbon from the air, a DAC system must first bring atmospheric CO2 into contact with a solid or liquid capture material, typically using giant fans. These “air contactor” systems can cost hundreds of millions of dollars at the high end. DAC systems that use solid filters instead of liquid solvents to chemically trap CO2 can take advantage of the much larger exposed surface area of the capture material to reduce the scale and cost of the air contactor.
But even these systems can still require tens of millions of dollars in air contactor equipment, not to mention substantial energy requirements that add to the total cost of carbon removal.
Several startups in the air contactor space are taking a novel approach to drive down the cost and energy requirements of DAC. Companies such as Heirloom, Carbon Collect, and Infinitree are developing passive air contacting approaches that rely on wind or natural airflow rather than large fans. Noya, a San Francisco–based startup, is taking a slightly different tack, piggybacking on the airflow of existing cooling towers to provide the air contactor mechanism for its carbon-removal process.
Even for startups that do not go fully passive, the high cost and energy demands of air contactors provide an area that is ripe for optimization to drive down both upfront and operating costs.
2. Better Capture through Chemistry
DAC systems capture CO2 via an acid-base reaction with a high-pH (basic) capture material—either a liquid or solid “sorbent.”
Advances in the chemistry of these capture materials show promise for increasing the CO2 capture rate and reducing the cost of the sorbents themselves. Solid sorbents in particular can require less energy when it’s time to release the captured CO2 for industrial use or for long-term sequestration underground. These solid filters can also be produced in more modular forms, potentially lowering the cost of manufacturing.
To quantify some of the innovation potential for solid sorbents, we looked at the impact of potential sorbent breakthroughs on the overall cost of CO2 capture.
Our analysis found that driving down the cost of the sorbents or making them more durable (with lifetimes of multiple years) can dramatically reduce the costs of carbon capture.
If such innovations were paired with low-cost renewable energy to further reduce operational expenses, the cost of removing one ton of carbon from the atmosphere with DAC would approach $60—about one-tenth of today’s costs.
3. Tailored Regeneration: Catch and Release
The final—and most energy-intensive—stage in an air capture system is the regeneration step, in which the CO2 is driven out of the capture material so it can be used or safely stored. Today’s leading approaches to DAC rely on large temperature or pressure swings to release the CO2 in a controlled fashion and prepare the sorbent material for reuse. Presently, this step takes approximately 7–13 gigajoules of energy for every ton of CO2 captured from the air. So removing the 4.6 tons of CO2 emitted by a single passenger vehicle annually would take about 30–60 GJ, which at the high end is nearly as much energy as the average US household consumes in a year.
The “tailored regeneration” of sorbents is an emerging alternative to subjecting the entire sorbent chamber to huge temperature swings. By designing special sorbents and tailoring the regeneration process to the unique properties of those materials, DAC innovators can reduce the energy required to release the CO2. For example, a tailored approach might use microwave energy to target the specific sites where CO2 binds to the sorbent material, or moisture swings to help release CO2 at lower temperatures.
At Third Derivative, we see a number of startups, including our portfolio company Mission Zero Technologies, leveraging electrochemistry in clever ways to lower the energy and cost required for CO2 capture and regeneration.
By harnessing clean electricity to drive chemical reactions, electrochemical approaches offer the potential to reduce the energy demands of DAC to approximately 2 GJ per ton of CO2, down from 7 GJ or more today.
Shaping the Future of DAC
Hard technologies like DAC take years to decades to develop. At Third Derivative, we see a need for investment in DAC technology development and de-risking now, so that DAC can mature fast enough to meaningfully contribute to a portfolio of carbon removal approaches in the coming decades.
Early investment can enable startups in this space to pursue innovations across air contactors, novel sorbents, and energy-efficient regeneration approaches. All of these innovations can drive down the cost of DAC technology and enable progressively larger-scale deployments, helping to ensure that this “insurance policy” for the climate is available if and when we need it.
This blog is a snapshot from the insight brief we're publishing next week on the future of direct air capture—so stay tuned.