Direct Air Capture: Scaling the Tech

Direct Air Capture (DAC) technology has moved beyond theoretical science and small-scale experiments. It is now entering a phase of rapid industrial deployment. With carbon dioxide levels in the atmosphere continuing to rise, companies and governments are investing billions to scale up facilities that act like giant vacuums for the sky. The goal is simple: remove CO2 directly from the air and store it underground permanently, all while driving down the price to make the process sustainable.

The Rise of "Mammoth" Facilities

For years, the conversation around DAC was dominated by small pilot programs. That changed dramatically in May 2024 when Climeworks switched on its “Mammoth” plant in Iceland. Located on a dormant volcano, this facility represents a significant leap in capacity.

While its predecessor, the “Orca” plant, captured about 4,000 tons of CO2 annually, Mammoth is designed to capture up to 36,000 tons per year once fully operational. That is roughly equivalent to taking 8,000 gas-powered cars off the road. Climeworks uses a solid sorbent filter system. Fans draw air into collector containers where highly selective filters trap the carbon dioxide. Once full, the collectors close, and the temperature rises to release the concentrated CO2 for storage.

The location in Iceland is strategic. The plant runs on renewable geothermal energy provided by ON Power. Partner company Carbfix then mixes the captured carbon with water and pumps it deep underground into basaltic rock formations. Through a natural chemical reaction, the carbon mineralizes and turns into stone in under two years.

The Texas Giant: Project Stratos

While Iceland hosts the largest currently operating plant, the United States is building something much bigger. 1PointFive, a subsidiary of Occidental Petroleum, is currently constructing the “Stratos” facility in the Permian Basin of Texas.

Stratos is aiming for a scale that dwarfs current operations. The facility is designed to capture 500,000 tonnes of CO2 per year. Unlike Climeworks’ solid filters, Stratos utilizes technology developed by Carbon Engineering which uses a liquid solvent to wash CO2 out of the air.

This project is a major test for the industry’s ability to scale. 1PointFive has already sold carbon removal credits to major buyers like Amazon, Airbus, and the Houston Astros to help finance operations. Construction is roughly 70% complete as of mid-2024, with the facility expected to come online in 2025.

The Economics: Chasing the $100 Goal

The biggest hurdle for DAC is not physics. It is finance. Currently, capturing a ton of carbon dioxide costs between $600 and $1,000. For the technology to be viable on a global scale, industry experts and the U.S. Department of Energy (DOE) agree that the cost must drop to roughly $100 per ton.

To bridge this gap, the U.S. government has intervened with massive funding. Under the Bipartisan Infrastructure Law, the DOE announced $3.5 billion in funding for regional Direct Air Capture Hubs. The first two major award recipients were Project Cypress in Louisiana (led by Battelle, Climeworks, and Heirloom) and the South Texas DAC Hub (led by 1PointFive).

Additionally, the Inflation Reduction Act significantly increased the 45Q tax credit. Companies can now receive up to $180 per ton for CO2 captured from the air and permanently stored. This subsidy is designed to keep companies afloat while they iterate on their technology to lower operational costs.

Innovations in Capture Technology

Reducing costs requires new methods. Heirloom Carbon, a partner in Project Cypress, uses a different approach involving limestone (calcium carbonate). Limestone naturally absorbs CO2. Heirloom heats limestone to release the gas for storage, then leaves the remaining calcium oxide out on trays to sponge up more CO2 from the air.

This process speeds up a natural geological cycle from years to just days. Because limestone is cheap and abundant, Heirloom believes this low-tech material approach could be the key to rapid cost reduction. They opened the first commercial DAC facility in the U.S. in Tracy, California, in 2023. While small (1,000 tons/year), it serves as the blueprint for their expansion into the Louisiana hub.

Key Players in the Market

Climeworks: Solid sorbent technology. Operator of Orca and Mammoth plants in Iceland.
Carbon Engineering (1PointFive): Liquid solvent technology. Developer of the Stratos plant in Texas.
Heirloom: Limestone looping technology. Based in California and expanding to Louisiana.
Global Thermostat: Solid sorbent technology. Focused on modular units for smaller-scale deployment.

Energy Consumption Challenges

Scaling this tech brings a new problem: energy usage. Separating CO2 from the air is energy-intensive. If a DAC plant runs on electricity generated by burning coal or gas, it defeats the purpose.

Facilities must be paired with renewable or low-carbon energy sources.

Geothermal: Used by Climeworks in Iceland. It provides constant, clean baseload power and heat.
Solar and Wind: Expected to power Project Stratos in Texas.
Nuclear: Several startups are exploring siting DAC modules near nuclear plants to utilize excess heat and electricity.

The industry must prove it can remove more carbon than it emits during the construction and operation of these massive plants. Life-cycle assessments are strictly monitored to ensure the “net removal” numbers are accurate.

Frequently Asked Questions

What is the difference between DAC and Carbon Capture and Storage (CCS)? CCS usually refers to capturing carbon at the source of emissions, such as a smokestack at a factory or power plant. DAC removes carbon specifically from the ambient air, meaning it can be located anywhere, not just near an industrial facility.

Is the stored carbon safe underground? Yes. When injected into the correct geological formations, such as deep saline aquifers or basalt rock, the carbon is trapped. In the case of mineralization (used in Iceland), the CO2 physically turns into rock, making leakage impossible.

How much land do these facilities require? DAC is relatively land-efficient compared to planting trees for carbon removal. A DAC facility requires significantly less surface area to capture the same amount of carbon as a forest, though it does require land for the renewable energy sources (solar panels or wind turbines) that power it.

Can the captured CO2 be used for anything else? Yes. While permanent storage is the goal for climate change, captured CO2 can be used to make synthetic aviation fuel, carbonated beverages, or plastics. This is often called Carbon Capture, Utilization, and Storage (CCUS). However, using the CO2 typically releases it back into the atmosphere eventually, whereas storage is permanent.