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The atmosphere now contains roughly 3.2 trillion tons of CO₂—legacy emissions from decades of fossil fuel use that will continue warming the planet for centuries even if we stopped all emissions tomorrow. Reducing future emissions addresses only half the climate challenge; the other half requires actively removing CO₂ already in the air.
Direct air capture (DAC) carbon removal uses chemical processes to extract CO₂ directly from ambient air and store it permanently underground, offering one of the few scalable technologies capable of reversing past emissions. This guide covers how DAC works, current costs and deployment, quality considerations for DAC carbon credits, and how organizations can integrate this technology into credible climate strategies.
How Does Direct Air Capture Work
The DAC process follows three main stages that transform dilute atmospheric CO₂ into concentrated, pure gas ready for storage or use. While different companies use varying chemical approaches, the basic workflow remains consistent across technologies.
1. Capturing CO₂ From Air
Giant industrial fans—sometimes as tall as a four-story building—draw ambient air into collector structures that often look like cooling towers at power plants. As air flows through the system, it passes over or through the capture material, which might be a liquid solution or a solid filter. The capture material has been engineered to chemically bond with CO₂ molecules specifically, letting nitrogen, oxygen, and other atmospheric gases flow right past. Think of it like a highly selective sponge that only absorbs one thing.
2. Regenerating the Sorbent
Once the capture material fills up with CO₂, it needs to release that CO₂ and reset for another round. This regeneration step typically involves heating the material to temperatures between 80-900°C depending on the technology, or exposing it to steam. The heat breaks the chemical bonds holding the CO₂, releasing it as a concentrated gas stream—jumping from 0.042% concentration in air to 95-99% purity. After releasing its CO₂, the sorbent cycles back to start capturing again.
3. Compressing and Handling CO₂
The purified CO₂ gas gets compressed to reduce its volume for transport and storage. Compression typically brings CO₂ to what's called a supercritical state—above 31°C and 73 atmospheres of pressure—where it behaves partly like a liquid and partly like a gas. In this form, it can move through pipelines or trucks to permanent underground storage sites, or to facilities that use it to make products like sustainable jet fuel or concrete.
Key Direct Air Capture Technologies
DAC systems fall into several categories based on their chemistry and engineering approach. The two methods currently operating at commercial scale are liquid solvent systems and solid sorbent systems, though newer approaches continue to emerge from research labs.
Liquid Solvent Systems
Liquid solvent DAC uses alkaline solutions—typically hydroxide-based chemicals—that react with atmospheric CO₂ to form carbonate compounds. These systems capture CO₂ at relatively low temperatures but require heating to around 900°C to regenerate the solvent and release pure CO₂. Carbon Engineering pioneered this approach, drawing on decades of industrial chemistry knowledge. The main challenge is the high energy requirement for that regeneration step.
Solid Sorbent Systems
Solid sorbent technologies use porous materials with massive surface areas that CO₂ molecules stick to through physical or chemical bonding. These systems typically regenerate at lower temperatures—between 80-120°C—making them potentially compatible with waste heat or lower-grade renewable energy. Climeworks, which operates the world's largest DAC facilities in Iceland, uses proprietary filter materials that can be regenerated thousands of times before needing replacement.
Electrochemical and Emerging Approaches
Newer DAC methods explore using electrical currents to drive CO₂ capture and release, potentially cutting down on thermal energy needs. Other researchers are testing moisture-swing adsorption, which uses humidity changes instead of temperature to regenerate sorbents, and passive systems that rely on natural wind rather than energy-hungry fans. These technologies show promise for future cost reductions, but they're still mostly in laboratories or small pilot projects.
Global Project Pipeline and Leading DAC Plants
DAC deployment has accelerated dramatically since 2020, moving from small pilots to commercial operations across multiple continents. As of 2024, roughly 130 DAC plants operate worldwide, though most remain demonstration facilities capturing less than 1,000 tons of CO₂ annually.
The largest operational facility is Climeworks' Mammoth plant in Iceland, which started up in 2024 with capacity to capture 36,000 tons of CO₂ per year. Iceland offers nearly ideal conditions: abundant geothermal energy provides both electricity and heat, while the island's basalt rock formations enable permanent storage through mineralization—the CO₂ reacts with rock to form solid carbonates within about two years.
In Texas, Occidental Petroleum's Stratos facility is under construction with planned capacity of 500,000 tons annually, which would make it the world's largest when it comes online. The project benefits from proximity to oil fields for CO₂ storage and access to Texas's growing renewable energy infrastructure. Other significant projects include facilities in Switzerland, Kenya, and the United Kingdom, with a global pipeline of over 130 projects in various development stages.
Direct Air Capture Cost and Market Outlook
The economics of DAC remain the technology's biggest barrier to widespread use. Current costs per ton of CO₂ removed vary widely based on facility size, energy sources, and how mature the technology is.
Current Cost Range Per Ton
Today's DAC facilities operate at costs between $600 and $1,000 per ton of CO₂ removed. Energy represents the largest expense, accounting for 40-60% of total costs depending on local energy prices and whether the facility uses renewable sources. For context, that's roughly 10-20 times more expensive than capturing CO₂ from a power plant smokestack.
Cost Reduction Levers
Several factors could drive costs down toward the $100-300 per ton range that analysts consider necessary for massive deployment:
- Economies of scale: Larger facilities spread fixed costs across more CO₂ captured, and manufacturing costs drop as production volumes increase
- Technology improvements: Better sorbent materials and process efficiency could cut energy consumption by 30-50%
- Cheap renewable energy: Access to low-cost wind, solar, or geothermal power dramatically reduces operating expenses
- Co-location benefits: Building next to CO₂ storage or utilization sites eliminates transport costs
Direct Air Capture Market Size Forecast
The DAC market is projected to grow from nearly nothing today to potentially $4-8 billion by 2030, driven by corporate net-zero commitments and government mandates for carbon removal. However, these projections depend heavily on continued policy support and technology breakthroughs actually materializing.
Technical, Energy, and Land-Use Challenges
Despite its promise, DAC faces real technical and resource constraints that affect how quickly it can scale up. Understanding these limitations helps set realistic expectations for what the technology can accomplish in the near term.
Heat and Electricity Demand
DAC systems are energy-intensive by nature because atmospheric CO₂ is so dilute. A facility capturing one million tons of CO₂ annually needs to process roughly 24 billion cubic meters of air. The fans alone consume substantial electricity, and the regeneration process adds major thermal energy requirements—total energy needs typically range from 1,500 to 2,500 kilowatt-hours per ton of CO₂ captured.
To put that in perspective, capturing one ton of CO₂ requires about as much electricity as an average US home uses in 2-3 months. Unless powered by renewable or low-carbon energy, DAC risks creating new emissions while removing old ones—potentially capturing only 0.5-0.7 tons of net CO₂ for every ton processed if using fossil fuel-based energy.
Water and Land Footprint
Water consumption varies by technology and climate, with some DAC systems requiring 1-5 tons of water per ton of CO₂ captured for cooling and humidity control. This creates potential conflicts in water-stressed regions, though closed-loop systems and air cooling can reduce consumption. Land requirements are relatively modest—a facility capturing one million tons annually might occupy 20-50 hectares—but siting requires access to energy infrastructure and CO₂ pipelines or storage.
Supply Chain and Materials
Scaling DAC to climate-relevant levels requires massive manufacturing capacity for specialized materials like sorbents, heat exchangers, and modular capture units. Current supply chains can't support this scale, and building them requires significant capital investment and time. Some sorbent materials also rely on specialty chemicals with limited production capacity, creating potential bottlenecks as the industry grows.
Environmental Impact and Carbon Sequestration Pathways
The climate benefit of DAC depends entirely on what happens to the captured CO₂. Different pathways offer varying levels of permanence, with major implications for how DAC credits get valued in carbon markets.
Geological Storage
Permanent geological storage represents the most climate-beneficial pathway. Compressed CO₂ gets injected 1-3 kilometers underground into porous rock formations capped by impermeable layers that prevent escape. The CO₂ initially remains in gaseous or supercritical form but gradually mineralizes—reacting with surrounding rock to form solid carbonate minerals over years to centuries. This mineralization, particularly in basalt formations like those in Iceland, creates permanent storage with minimal reversal risk. Properly selected geological sites can sequester CO₂ for thousands to millions of years.
Carbon-Neutral Fuels
Captured CO₂ can be combined with hydrogen to synthesize liquid fuels like jet fuel or diesel. When these fuels burn, they release the same CO₂ that was originally captured, creating a closed carbon loop rather than permanent removal. This doesn't reduce atmospheric CO₂ concentrations, but it does enable hard-to-decarbonize sectors like aviation to use carbon-neutral energy. The climate benefit depends entirely on using renewable energy for both the DAC process and hydrogen production.
Building Materials and Products
CO₂ can be incorporated into concrete, plastics, and carbon fiber, storing it for decades to centuries depending on the product. Concrete carbonation permanently binds CO₂ into the material's chemical structure. The permanence varies widely: CO₂ used in beverages or chemicals that quickly decompose offers minimal climate benefit, while incorporation into long-lived building materials provides medium-term storage.
Policy Incentives and Regulatory Landscape
Government policy has emerged as the primary driver of DAC deployment, with financial incentives making projects economically viable despite high costs. The United States' 45Q tax credit offers $180 per ton of CO₂ captured via DAC and permanently stored, or $130 per ton for CO₂ used in qualifying products. This subsidy makes many DAC projects financially viable at current costs. The Bipartisan Infrastructure Law added $3.5 billion for four regional DAC hubs, each aiming to capture at least 1 million tons of CO₂ annually.
The European Union's Innovation Fund allocates billions of euros to support breakthrough clean technologies, including DAC, through grants covering up to 60% of capital costs. Several European countries are also exploring Carbon Contracts for Difference, which guarantee a minimum carbon price for removal projects. As DAC-generated carbon credits enter voluntary markets, standard-setting bodies like Verra and Puro.earth have developed protocols specifically for DAC projects, establishing requirements for measurement, verification, and permanence guarantees.
Evaluating DAC Carbon Credits for Quality and Integrity
DAC generates some of the highest-quality carbon removal credits available, but not all DAC credits are created equal. Rigorous evaluation across multiple dimensions helps buyers identify credits that deliver genuine climate impact.
Quality DimensionDAC CharacteristicsKey Evaluation QuestionsPermanence1,000-10,000+ years with geological storageIs storage geological or in products? What monitoring protocols exist?AdditionalityHigh (requires revenue to be viable)Would the project happen without credit sales? Is it policy-mandated?QuantificationVery high accuracy (±5%)How is CO₂ measured? Are lifecycle emissions deducted?
Permanence and Leakage Risk
DAC credits paired with geological storage offer near-permanent CO₂ removal, with properly selected sites showing leakage rates below 0.01% per century. However, buyers need to verify that storage sites have been geologically characterized and that long-term monitoring plans exist. Credits from DAC paired with CO₂ utilization in products offer lower permanence—potentially decades rather than millennia.
Additionality and Baseline Assessment
Additionality—whether the project would happen without carbon credit revenue—is generally strong for DAC projects because current costs far exceed any alternative revenue source. However, projects receiving substantial government subsidies raise questions about whether voluntary carbon credit sales represent additional climate benefit beyond what policy already incentivizes.
MRV and Third-Party Verification
Measurement, reporting, and verification for DAC is relatively straightforward compared to nature-based solutions because CO₂ flows through engineered systems with multiple measurement points. Reputable projects use continuous monitoring of CO₂ concentrations, flow rates, and purity at capture and injection points. Third-party verification by accredited auditors confirms that measurement systems are calibrated and that lifecycle emissions from energy use, materials, and transport are properly deducted.
Integrating DAC Credits Into Corporate Climate Strategies
For companies building net-zero strategies, DAC credits serve a specific role distinct from emissions reductions and other carbon removal approaches. Leading climate frameworks emphasize that emissions reductions come first, with carbon removal addressing only residual emissions that cannot be eliminated. Within a carbon removal portfolio, DAC credits offer the highest permanence and lowest reversal risk, making them particularly suitable for neutralizing long-lived or hard-to-abate emissions like aviation or certain industrial processes.
The EU's Corporate Sustainability Reporting Directive and CDP reporting frameworks increasingly require detailed disclosure of carbon credit use, including credit type, vintage, and permanence. DAC credits clearly fall into the removal category and, when paired with geological storage, can be reported with high permanence ratings. The Science Based Targets initiative distinguishes between "neutralization"—permanent carbon removal that counterbalances residual emissions—and "compensation"—funding emissions reductions elsewhere. DAC with geological storage qualifies as neutralization, but companies need to demonstrate they've exhausted reduction opportunities before relying on it.
For organizations evaluating DAC credits as part of their climate strategy, Senken's AI-powered Quality Framework assesses credits against over 600 quality metrics, helping identify top-tier projects that meet rigorous standards for permanence, additionality, and verification.
Common Misconceptions and Realities About DAC
DAC generates significant debate, with both excessive optimism and unwarranted skepticism clouding understanding. Here are the realities behind common misconceptions:
- Misconception: DAC can replace emissions reductions. Reality: DAC is far too expensive and energy-intensive to substitute for reducing emissions at their source. It complements aggressive decarbonization, not replaces it.
- Misconception: DAC is fully mature and ready to scale. Reality: While technically proven at pilot scale, DAC faces significant cost, energy, and supply chain barriers before it can deploy at climate-relevant scales.
- Misconception: DAC has no environmental downsides. Reality: DAC facilities consume significant energy and water, and if powered by fossil fuels, may create more emissions than they remove.
- Misconception: All DAC credits equal permanent removal. Reality: DAC credits vary significantly in permanence depending on whether CO₂ is permanently stored geologically or used in products with shorter lifespans.
Moving Forward With High-Quality DAC Credits
Direct air capture represents one of humanity's few options for addressing the CO₂ already warming our planet, offering measurable, verifiable, and potentially permanent carbon removal. Yet the technology's promise depends entirely on rigorous implementation—proper energy sourcing, permanent storage, accurate accounting, and transparent verification.
For organizations incorporating DAC into their climate strategies, quality assessment is paramount. The difference between high-integrity DAC credits and lower-quality alternatives can mean the difference between genuine climate impact and greenwashing risk. Companies serious about climate leadership recognize that carbon credit quality directly affects both environmental outcomes and reputational risk.
FAQs About Direct Air Capture Carbon Removal
Is direct air capture the same as point-source carbon capture?
No, direct air capture removes CO₂ directly from ambient air while point-source capture targets concentrated emissions from industrial facilities before they reach the atmosphere. DAC works with CO₂ concentrations around 420 parts per million, while point-source capture handles concentrations 10-100 times higher.
How much energy does direct air capture require per ton of CO₂?
DAC systems typically require 1,500-2,500 kilowatt-hours of energy per ton of CO₂ captured, split between electricity for fans and heat for regenerating the capture material. This energy intensity means DAC needs renewable or low-carbon energy sources to deliver net climate benefits.
Can small companies purchase direct air capture carbon credits?
Yes, DAC carbon credits are available through specialized platforms and carbon credit marketplaces, with some providers offering credits in quantities as small as one ton. However, prices typically range from $600-1,000 per ton currently, making DAC credits significantly more expensive than most alternatives.