Innovating direct air capture for carbon dioxide removal

The challenge

Improved efficiency and lower overall costs for DACS

Along with deep and urgent emissions reductions, carbon dioxide removal (CDR) is an essential part of climate mitigation efforts. CDR technologies actively remove carbon dioxide (CO₂) from the atmosphere, sometimes referred to as 'ambient air'.

Direct air capture (DAC) is one of these CDR technologies and offers significant potential for large-scale, permanent novel carbon dioxide removal when paired with resilient storage solutions (DACS).

DACS is currently responsible for removing about 0.01 megatonnes (Mt) CO₂ from ambient air per year. Current estimates by the International Energy Agency suggest this needs to grow to 980 Mt CO₂ by 2050.

Currently, key challenges are holding us back from large-scale deployment of DACS. The main barrier is the current cost of DAC, driven in large part by its significant energy consumption.

What is DACS?

DACS describes a range of technologies that use chemical or physical processes to separate and remove CO₂ from the atmosphere.

DACS often uses a two-step process: first capturing and filtering CO₂ from ambient air using a selective liquid or solid material, then processing the CO₂ -laden material.

Once the CO₂ is processed to the level of purity required, it is transported for either:

• Storage in deep geological or ocean reservoirs, or
• Conversion to make long-lived products such as building materials.

Our response

Tackling the scientific challenges of DACS

There is a wide range of DACS technologies in development at CSIRO. A number of different solid and liquid adsorbent materials are being researched (e.g. amine-based materials, metal-organic frameworks and zeolites) as well as mineral-based materials.

Our research is tackling key scientific challenges associated with DACS. Our focus is on managing resource consumption and operating cost, market readiness and design optimisation.

High resource consumption and cost

When DAC units intake air, they must filter CO₂ from competing molecules like water, oxygen and nitrogen. Current technology is inefficient at capturing CO₂ molecules due to the large volumes of air required for processing. The low concentration of CO₂ molecules in air (roughly 1 in 2,500 molecules) results in high water and energy requirements to move it through DAC machines, leading to increased costs. For DAC to be deployed at scale, it needs to achieve cost parity with other carbon dioxide removal approaches at $100/tonne CO₂. Another challenge is excessive consumption of natural resources (e.g. water, land) and the potential impact on other vital sectors (e.g. renewable energy).

Our research includes:

• Developing novel air-liquid contacting concepts that may result in lower energy requirements for moving liquid and air and potentially lower equipment costs.
• Investigating game-changing absorbents that potentially offer higher solubility, CO₂ reactivity, and stability that will help reduce the overall cost of DAC.
• Conducting socioeconomic analysis on DAC to understand how large-scale deployment may impact society given its energy and resource-intensive requirements.

Readiness to market

Improved DAC efficiency requires new, porous materials to capture CO₂  from the air. However, the discovery of new materials can be long, expensive and risky given the number of novel materials available (roughly 45,000 as of 2025). Reduced time in materials discovery could reduce overall delays in the deployment of DAC technologies. Given the urgency and likely need for scaled DAC deployment by 2030, we need to accelerate progress in this area.

Our research includes:

• Reducing the time that's required to discover new materials by training machine learning models to identify the most suitable capture materials for DAC.

Optimal design and deployment

Currently, DAC plants are small, prototype operations. As they are scaled up for commercial deployment, it will be necessary to address several challenges including engineering problems, and environmental and social impacts. Large-scale DAC could potentially impact communities and the environment if design principles are not embedded in their early development. Left unmitigated, this could create barriers around social acceptance and low awareness of their co-benefits.

Our research includes:

• Considering the impacts of the environment on DAC across a range of weather conditions and locations.