Direct air capture is often presented as a technological safety net for climate policy: giant machines pull carbon dioxide directly from the atmosphere, concentrate it, and then store it underground or put it to use.

The concept sounds simple. The physics and economics are not.

NCEA's brief, The Energy Impacts of Capturing CO₂ from the Air, examines whether direct air capture, commonly called DAC, can be deployed at a scale large enough to meaningfully affect the climate. Its conclusion is direct: DAC is extraordinarily energy-intensive, extremely expensive, and unlikely to produce a measurable climate benefit at the scale envisioned by its supporters.

Capturing CO₂ from the Air Is Fundamentally Difficult

Carbon dioxide makes up only about 0.042% of the atmosphere, or approximately 425 parts per million. That means DAC systems must process enormous volumes of air to capture relatively small amounts of CO₂.

To capture 1 billion tons of CO₂, even at a theoretical 100% capture efficiency, would require moving nearly 2.8 trillion tons of air. In practice, capture efficiencies are lower, which means even more air must be processed.

DAC systems use large fans to move air through chemical filters or sorbent materials. The captured CO₂ must then be separated from those materials, compressed, transported, and either stored underground or used in applications such as enhanced oil recovery.

Every step requires energy. NCEA estimates that real-world DAC systems could require roughly 1.8 to 3.6 megawatt-hours of electricity per ton of CO₂ removed when upstream and infrastructure requirements are included. By comparison, the average U.S. household uses about 850 kilowatt-hours of electricity per month—meaning removing one ton of CO₂ through DAC could require more electricity than an average American home uses in two months.

The Energy Requirements Quickly Become Enormous

The U.S. Department of Energy has cited potential DAC targets ranging from 100 million to 2 billion tons of CO₂ removal per year by 2050.

Even the lower target would require approximately 100 terawatt-hours of electricity using a relatively conservative assumption of 1 megawatt-hour per ton. Removing 2 billion tons would require more than 2,000 terawatt-hours: nearly half of total U.S. electricity consumption in 2025.

That electricity would need to be reliable and available around the clock. Using wind and solar power would require substantial overbuilding, along with batteries and other backup systems to keep DAC facilities operating when the wind is not blowing or the sun is not shining.

Using nuclear power would avoid the intermittency problem, but the scale would still be massive. Capturing 2 billion tons of CO₂ annually would require at least 260 gigawatts of new nuclear capacity—nearly three times the size of the existing U.S. nuclear fleet. NCEA estimates that building that capacity would cost more than $2 trillion before financing, transmission, and other infrastructure costs.

This illustrates a basic tradeoff: electricity used to capture carbon from the atmosphere cannot simultaneously be used by households, manufacturers, data centers, hospitals, or other businesses. DAC does not eliminate the need for energy. It adds another enormous demand to an already strained power system.

The Costs Are High—and the Climate Benefits Are Tiny

DAC's energy requirements are only part of the problem. The facilities themselves are expensive to build.

Occidental Petroleum's Stratos plant in the Permian Basin is designed to capture more than 500,000 tons of CO₂ annually. Its estimated capital cost is approximately $1.3 billion. Based on the plant's expected capacity, NCEA calculates an annualized capital cost of roughly $240 per ton of CO₂ captured, before accounting for energy, operations, and maintenance.

Other studies estimate total DAC costs ranging from approximately $330 to $630 per ton, depending on the technology and energy source.

Those costs would be difficult to justify even if DAC produced a substantial climate effect. But NCEA's analysis finds that the expected temperature impact is extremely small.

Removing 110 million tons of CO₂ in one year would lower average global temperatures by an estimated 0.0002 degrees Fahrenheit. Removing 2 billion tons would lower temperatures by approximately 0.004 degrees Fahrenheit: far smaller than the uncertainty in global temperature measurements.

Even under a scenario in which 2.2 billion tons of CO₂ were removed every year from 2030 through 2100, the estimated reduction in global temperature would be about 0.108 degrees Fahrenheit. NCEA notes that this effect would still be smaller than the typical uncertainty range in global temperature estimates.

In other words, DAC would consume vast amounts of energy and capital to produce a climate effect that would be difficult or impossible to measure.

Subsidies Do Not Change the Underlying Physics

The federal Section 45Q tax credit provides up to $162 per ton for CO₂ captured from the air and permanently stored underground, with lower credits for CO₂ used in enhanced oil recovery.

If DAC facilities capable of capturing 100 million tons annually were built by 2033, NCEA estimates that the tax credits could cost taxpayers approximately $18 billion per year—or $180 billion over the 10-year eligibility period.

Subsidies can encourage investment, but they cannot repeal the laws of thermodynamics or make an energy-intensive process inexpensive. They can also obscure the real cost of a technology by shifting expenses from project developers to taxpayers and consumers.

That does not mean every form of carbon capture should be treated identically. Capturing CO₂ from concentrated industrial emissions is a different technical challenge from removing CO₂ from ambient air. But policies should not assume that success in one application automatically translates to success in the other.

Why This Matters

The central issue is not whether DAC is innovative, but whether it is a practical use of scarce energy and public resources.

Every dollar and kilowatt-hour directed toward DAC has an opportunity cost. The same resources could support electricity generation, grid infrastructure, advanced nuclear research, industrial efficiency, or technologies that provide more immediate and measurable benefits.

Climate policies should be evaluated not only by their aspirations, but also by whether they produce meaningful benefits without undermining affordability, reliability, and economic growth.

Direct air capture may continue to have a role in research and small-scale experimentation. But treating it as a major solution to climate change would require extraordinary amounts of energy, materials, land, and taxpayer funding for minimal measurable results.

The better policy is realism: understand the physics, account for the full costs, and prioritize energy technologies capable of delivering reliable and meaningful benefits.