Direct Air Capture – A lever for climate action, but cost-effective everywhere

Direct capture of CO2 from ambient air is considered an important future technology for climate protection. However, new research shows that weather conditions and location selection have a significant impact on efficiency and cost. For the first time, researchers at Julich calculated where such systems are feasible and not in Germany.

Currently, each German citizen is responsible for an average annual emissions of around 10 tons. This is roughly equivalent to the amount of emissions from four round-trip transatlantic flights between Frankfurt and New York, or the amount of CO2 absorbed by 500 trees over a year.

The focus is on new technologies that actively remove Co from the atmosphere, taking into account Germany’s ambitious climate targets aimed at achieving greenhouse gas neutrality by 2045. One of these technologies is direct air capture (DAC).

Forschungsentrum Jülich is currently investigating DACs, from materials and components to systems and integration into energy infrastructure and climate protection strategies. Scientists at Julich are currently conducting the first comprehensive study on how weather and location affect the economic viability and energy consumption of such DAC systems.

Results published in Advances in Applied Energy show that local conditions have a significant impact on efficiency and cost. This means that DAC blanket rollouts across the country are almost economically meaningless.

All methods are very energy intensive

The DAC system draws a large amount of air, extracts CO2, ensuring long-term storage, for example, at underground storage sites. “The two technologies are considered particularly promising,” explains Henrik Wenzel, lead author of Jülich Systems Analysis.

“One is a solid adsorbent-based adsorption process (LT-DAC), which requires a relatively low temperature of about 110°C to regenerate the filter material, and the other is a liquid solution-based adsorption process (HT-DAC).

In their study, the researchers calculated how temperature, humidity, and the possibilities of wind and solar energy affect the performance and cost of DAC systems in all 11,000 German municipalities. They used a high-resolution model that simulated hourly hourly interactions with weather, renewable energy supply, and DAC system operation. The focus was on standalone systems that operate completely independent of the power grid using locally generated wind or solar power.

200-1000 euros per ton

The results reveal significant differences. The energy demand of German DAC systems can fluctuate more than 100% per year, mainly due to temperature fluctuations and humidity levels. “Even within a day, the energy demand of a DAC system can change by up to 80%,” says Wenzel. “While LT-DAC systems’ energy consumption increases dramatically, especially at high humidity, the HT-DAC systems benefit from it.” The potential for wind and solar energy also plays a crucial role. This is because such energy can be used for a cost-effective supply to plants.

The most economically viable site is located in northern Germany, where wind energy is particularly abundant. “However, these energy source combinations can efficiently cover the fluctuating energy requirements of DAC systems, allowing low costs to be achieved in other parts of Germany with excellent solar and wind energy locations,” explains Wenzel.

Depending on the location and technology, CO₂ removal costs for 2045 could range from less than 200 euros per tonne to over 1,000 euros. “The more cost-effectiveness of which of the two DAC methods is, depends on the specific location of the region and weather conditions,” explains co-author Thomas Shev. “Therefore, both methods need to continue to be developed and sufficient capacity is available.”

It’s not a free pass to keep the core released

Researchers emphasize that DACs can be valuable levers for climate protection, but only if they are deployed in areas where weather and energy conditions optimally complement each other. “Our research shows that location is important when you want to efficiently remove it from the air,” explains Schöb. “It is essential to provide a detailed analysis of local weather conditions and energy possibilities to ensure cost-effective and wise use.”

Even if DAC alone technology is not sufficient to neutralize Germany’s current carbon footprint (approximately 10 t per person), strategic use can offset the inevitable residual emissions. However, this study also reveals that such solutions are not a free pass to continue to emit CO2. They require a lot of energy, are expensive and need to be carefully planned. Measures to avoid emissions remain the most important lever for effective climate protection.