Optimising direct air capture technologies for better environmental and social outcomes

Project duration: July 2023–June 2026

Project lead

Team

Ashok Luhar, Paul Feron and Aaron Thornton.

Opportunity

Direct air capture (DAC) technologies that remove carbon dioxide (CO₂) from the atmosphere are seen as an essential tool in the carbon dioxide removal portfolio if Australia is to meet its climate obligations under the Paris Agreement (2015).

Combined with permanent storage of CO₂, DAC technologies could make a profound contribution to reaching net-zero emissions. To realise this value, the technology must be deployed sustainably, and with full community consultation and acceptance.

Ideally, the design of DAC systems employs a multi-criteria approach, with a holistic balance between capture process performance, water and energy consumption, size and land area requirements, integration with renewable energy, and environmental considerations such atmospheric emissions and local footprint. This requires multi-disciplinary research that connects the individual DAC technology designs and their performance characteristics with the broader environmental impacts when deployed at scale. Currently, however, a methodology for environmental design optimisation of DAC systems is lacking. Closing this knowledge gap would provide science-based insights for design requirements to minimise potential environmental and social impacts, reduce capture costs, and inform standards for regulating DAC technology.

Goal

Our goal is to develop a novel, model-based, optimal design methodology for DAC that considers air quality and other environmental impacts, together with knowledge of local land-use settings and potential issues with large-scale deployment in rural and urban environments.

We’ll provide a range of conceptual DAC unit designs and their expected performance when assembled into an overall DAC system. We’ll also clarify the system-level environmental impacts and provide direction for optimised system performance based on the performance of individual units. This information can be used to inform the siting of DAC units, minimise potential environmental impacts, and pre-empt community questions and concerns with DAC technology.    

Barriers

Currently, DAC plants are small, prototype operations but, as they are scaled up for commercial deployment, it will be necessary to address a number of challenges including engineering problems, and environmental and social impacts.

How to integrate the interdependencies of the complex flow, dispersion and chemical processes that occur at a diverse range of spatial scales (i.e., from the DAC system scale to, say, urban scale) is a big challenge but one we’ll overcome using different modelling techniques to create an optimisation framework. DAC technologies also currently have no social licence to operate so addressing environmental and public concerns raised by stakeholders, regulators and the local community is essential in realising DAC as a valid, large-scale negative-emissions technology. Providing a research basis for design and deployment of DAC units will help to overcome concerns, and raise public awareness and confidence in the technology.

References

Climeworks (2022). https://climeworks.com

Carbon Engineering (2023). https://carbonengineering.com/our-technology/