Renewable-powered carbon capture set to scale

Trees do it every day. They take carbon from the atmosphere and sequester it in their bodies.

But emulating this chemical process – engineering extraction of carbon dioxide from the air to then turn it into something else – is energy intensive and costly, posing barriers to commercialisation and uptake as a climate-solution.

Led by Professor Kathryn Mumford, researchers at the Melbourne Energy Institute have now engineered a novel approach for direct air capture (DAC) that addresses these challenges.

The process combines liquid-based carbon dioxide absorption with use of patented, engineered ‘nanocatalysts’ working at lower temperatures, using less energy, and enabling the process to run using renewables, such as solar.

“This technology puts direct air capture into a different perspective. Without radical changes, it simplifies the process and makes a huge difference by using renewables,” said Professor Mumford.

Typically, for solvent-based processes, after carbon dioxide is separated from the air, the liquid must be brought to a very high temperature to remove the captured carbon dioxide so that the solvent can be recycled and reused. This boiling step in the process requires high energy input, making it impractical in most cases to use renewable energy sources such as solar hot water.

Through the new approach, advanced “water-dispersible nanocatalysts” are added to the chemical solvent that can regenerate at a much lower temperature – at around 88 degrees Celsius compared to the usual 120-140 degrees. Additionally, only a small amount of the nanocatalyst is needed for the process to be effective – less catalyst, and less energy input means a huge reduction in cost.

This patented process for collecting carbon dioxide from the air is part of an integrated system for carbon capture, use and storage (CCUS) that will be put to the test in new pilot-scale facility at the University of Melbourne, working together with the university’s spin-off company, MK Collect and engineering firm, Innaco.

The goal? To deliver a scalable, commercial solution of carbon capture and use, ready for adoption by industry, over the next three years.

“This new technology developed at the University of Melbourne provides a valuable pathway for the accelerated commercialisation of a ground-breaking direct air capture,” said Innaco Director, Lars Herngren.

“The technology has significant potential to reduce the cost of capture by reducing the energy penalty associated with solvent regeneration, creating value through the production of high-value building material. Innaco strongly supports the commercialisation of this technology as it aligns well with our priorities and expertise in the development of advanced DAC systems in Australia,” he said.

Pending funding, the carbon capture process will be combined with a new mineralisation process that turns the CO₂ into valuable carbonate products, themselves saleable. The researchers are currently looking into opportunities to utilise the concentrated CO₂ for commercial products.

How it works: the combined process of carbon capture and mineralisation

At its conclusion, the technologies demonstrated through this project are expected to be fully prepared for commercial deployment. This means a bundle of both technical and commercial outputs, wrapped together, ready for market, including validated technical processes, detailed plant designs, and techno-economic analysis demonstrating feasibility at an industrial scale. Through its partnership with MK Collect, an established carbon capture company, the project also delivers workforce and market development.

Nationally, and globally, experts suggest capturing carbon already in the atmosphere will be a necessary contributor to our mix of climate change mitigation technologies, if we are to limit global warming to safe levels. This pilot program takes that potential a crucial step closer to reality.

For more information, please contact University of Melbourne’s Professor Kathryn Mumford.