Direct air capture
Direct air capture (DAC) is the process of pulling CO₂ out of ambient air. It is a cyclical process in which a sorbent or solvent undergoes repeated cycles of CO₂ capture and release. The stream of CO₂ can then be coupled with geologic sequestration or mineralization for permanent carbon removal.
- Tons contracted
- 187K
- Dollars contracted
- $121.6M
- Contracted companies
- 13
- Est. total capacity
- Functionally unlimited
- Average offtake price
- $646/ton
- Current price range
- $360–1,818/ton
The approach
There are a wide variety of DAC approaches being pursued to maximize performance, each with its own tradeoffs. While DAC is often portrayed as a choice between low-temperature and high-temperature approaches, the number of design considerations are much more varied, including passive vs active air contacting, the type of capture medium, the regeneration approach, and the source of regeneration energy. Any of these variables could be part of a successful, high-performing DAC project and need to be considered within a larger system to balance cost, energy, and tech risk.
| Pros | Cons | ||
|---|---|---|---|
| Type of air contacting | Active | Shorter cycle time: more CDR per air contactor surface area per unit time | More contacting energy required: requires up to 400 kWh/tCO₂ |
| Passive | Less contacting energy required | Longer cycle time: more contactor surface area needed | |
| Phase of capture medium | Liquid | Easy to operate as a continuous process | Aqueous solution, so potentially low amount of CO₂ per volume of liquid |
| Solid | Easy to operate at smaller scale/modularize | Lower throughput due to batch processing; solids handling can be tricky | |
| Type of capture medium | Commodity (e.g., KOH, CaCO₃) | Inexpensive, existing supply chains | Usually requires high-temp regeneration |
| Specialty chemicals | Allow for lower-temperature regeneration | Can be more expensive (e.g., amines on silica); harder to scale given immature supply chains | |
| Regeneration approach | Temperature swing absorption - low T (70-120°C) | Established process; can use a variety of heat sources with low energy prices (incl. thermal energy storage) | Lower thermodynamic efficiency because components like supports get heated that don't capture CO₂; sorbents typically have lower working capacity than lime |
| Temperature swing absorption - high T (~900°C) | Established process; leverages cheap sorbent with high working capacity (lime) | Lower thermodynamic efficiency because components like water and supports/packing get heated that don't capture CO₂; need either NG-CCS (fossil fuel concerns) or electrified kiln (higher energy prices) | |
| Electrochemical | Theoretically more efficient. Needs only electricity, so easier to integrate | Hard to have both high efficiency and current density (theoretical benefits haven't been realized yet) | |
| Moisture swing | Theoretically more efficient | Some approaches require a lot of water; less effective in humid regions; tends to produce low-purity CO₂ | |
| Source of regeneration energy | Mostly electricity | Could come from various sources: behind the meter or utility-scale solar and/or wind; less customization required so potentially higher learning rate | Much more expensive than heat on a $/MWh basis |
| Mostly heat | Much cheaper than electricity; could come from various sources like geothermal, nuclear, waste heat, solar thermal, etc. | Some configurations, like thermal integration with existing facilities, require customization which could mean lower learning rates |
DAC’s role in a CDR portfolio
DAC excels across many of Frontier’s purchase criteria. It is one of the easiest CDR pathways to verify (as there is a pure stream of CO₂ that can be directly measured), it has a very large potential CDR capacity compared to approaches that might be feedstock or site limited, and requires a relatively small physical footprint (most of the land needed is for energy for DAC, not the DAC facilities themselves).
DAC’s primary challenge is cost. The potential for DAC’s deployment is limited by (1) the total energy cost, (2) the total capex , and (3) the efficiency of the rest of the system, which is often influenced by the performance of the sorbent or solvent. DAC’s price today ranges from $500 to upwards of $1,800 per ton, reflecting high energy and capex needs. The feasible range for DAC costs at NOAK could be up to 2x higher than other pathways.
DAC’s role in the global CDR portfolio depends on (1) how quickly its cost comes down and (2) how successful other pathways are. If other CDR approaches scale effectively or if cheaper open systems pathways can reliably verify removals, DAC may play a more limited role in the long-term portfolio—unless it receives policy support.
DAC doesn’t share the capacity constraints of most other approaches. DAC will likely remain a more expensive approach with fewer co-benefits, but remains a valuable solution since its capacity is not constrained by feedstock or deployment sites like other pathways. In a future climate scenario where much more CDR is needed than currently expected (e.g., ~10 Gtpa), DAC can fill the gap when other approaches ‘cap out’ based on limitations like feedstock availability.
Investing in DAC today is critical to unlocking broader CDR policy. Regardless of DAC’s relative scale, investments today are necessary to ensure that it exists at any scale in the future. Because DAC is a focus of existing CDR-policy (e.g., DAC-specific 45Q tax credit) and some DAC technologies are further ahead in terms of scaling toward commercial operations, the success of early DAC facilities will be a critical driver of field-wide policy and market momentum.
Characteristics of great projects
Currently, there is no clear leader in DAC technology. The cost estimates for different DAC approaches vary widely. This will likely change as the pathway matures, but today, Frontier is pursuing multiple DAC approaches, seeking projects that have:
Systems with differentiated, steep cost curves. We prioritize projects that minimize the total cost per ton by optimizing across cost, efficiency and capacity. While it’s not yet known which process configuration is best, it’s likely that this optimal system excels across multiple attributes: maximizes learning rate through deployment strategy, minimizes energy for CO₂ separation, has an outperforming capture material, is flexible and modular in its deployment, etc. These companies are set up for fast, ‘cheap’ iteration cycles and have a more compelling path to $150/tCO₂. Given DAC’s higher starting cost, this particularly steep cost curve is important, since it makes it more plausible that a team can secure enough demand to scale and become competitive with companies who may be further along today.
Real-world ability to execute and scale. To execute at speed this decade, companies must have the right political support, stakeholder engagement strategy, energy strategy, financing plan, and partner network.
A compelling path to compete with leading DAC companies. Given the maturity of this pathway relative to others, any emerging, novel DAC project must demonstrate a way to catch up and surpass existing suppliers. This could include strategies to scale and reduce costs quickly or plans to partner with or license technology to larger companies.
A clean energy strategy that meets our Procurement Principles. It is essential that near-term scaling of DAC sources energy responsibly so it does not compete with other grid decarbonization priorities. To that end, we want to ensure that projects either build behind-the-meter energy sources or procure new additional clean energy in a way that fully counterbalances emissions associated with grid electricity use.
Frontier’s DAC portfolio
Frontier has purchased from a number of exciting DAC projects that match these characteristics. Below are examples from our portfolio.
280 Earth
- Track
- Offtake - 2024
280 Earth uses a continuous process design, ultra-low grade waste heat, and off-the-shelf components to achieve a steep cost-down curve. Their flexible system design allows them to use electricity or integrate with facilities like data centers to use waste heat and provide cooling services as a co-benefit.
Heirloom
- Track
- Offtake - 2023
Heirloom uses limestone, a cheap, technically proven sorbent, combined with passive air contacting to drive down energy and engineering costs. Their path to scale and low costs relies largely on capex declines, economies of scale, and operational excellence, rather than breakthroughs in sorbent or regeneration technologies.
Phlair
- Track
- Offtake - 2024
- Prepurchase - 2023
Phlair has developed a highly efficient electrochemical process to regenerate a capture solvent and release CO₂. Their system’s flexibility allows it to be run at maximum capacity when solar electricity is abundant and cheap, or ramp down capacity when electricity cost is high. Additionally, their technology is built upon existing and growing supply chains which reduces their capex and will allow them to scale up more quickly.
Holocene
- Track
- Prepurchase - 2023
Holocene captures CO₂ from air using organic molecules that can be produced at low cost. CO₂ is captured from air when it comes into contact with a liquid solution. Then, 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.
Spiritus
- Track
- Prepurchase - 2023
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.
Purchase targets
Frontier continues to look for new purchases from DAC companies that complement our existing portfolio and address gaps that accelerate the field more broadly.
Offtake priorities
We are looking for novel projects that meet our criteria for great DAC projects, meaningfully beat the key performance metrics in our current portfolio, meet the eligibility criteria listed in the Offtake RFP, and have:
- Differentiated steep cost curves with high learning rate potential
- Strong execution likelihood given high capex investments
- The ability to integrate with novel mineralization storage approaches to hedge permitting timelines for geologic storage
- The ability to flexibly ramp capacity to respond to the availability of excess low-cost clean energy resources
If you are a carbon removal company that meets Frontier’s offtake eligibility criteria and is addressing at least one of our purchase targets, please take the next step to apply.
Apply for offtake
Prepurchase priorities
We are also looking for earlier-stage companies with novel, potentially breakthrough approaches that are addressing the following innovation areas:
Efficient and flexible energy use
DAC continues to be one of the highest-cost approaches given its energy requirements. We’re particularly interested in approaches that can flexibly ramp capacity to respond to the availability of excess low-cost clean energy resources. We are also looking for approaches with ultra-low energy requirements or that can procure energy efficiently, such as through the use of waste heat or heat pump technology; integration with clean, firm power or heat generators like geothermal and nuclear; or integration with behind-the-meter renewables and energy storage.
Accelerating in-situ and ex-situ mineralization for CO₂ storage
The near-term capacity of geologic CO₂ storage has been a challenge for many CDR approaches given ongoing Class VI well permitting delays. We’re looking for novel in-situ and ex-situ mineralization approaches paired with carbon capture (e.g., DAC and BECCS) to diversify storage options and offer a hedge against near-term capacity constraints.
Apply for prepurchase