Low-carbon energy grids could help rock dust absorb more CO2

  • University of Sheffield researchers and colleagues have revealed how switching to a low-carbon supply chain lowers possible environmental impacts of using rock dust to absorb more carbon dioxide from the atmosphere
  • Applying rock dust to soils can be hugely effective at absorbing CO2, but the supply chain is extensive with major environmental challenges and impacts
  • New study shows how switching to greener electricity grids and using low-carbon transport systems to source and deploy rock dust can make it much more sustainable and a powerful tool to remove CO2 from the atmosphere
  • Results from the study could help assist policymakers who are considering using rock dust as part of their CO2 removal strategies to reach net zero emissions

Greener electricity grids could help us to use rock dust to remove more carbon dioxide from the atmosphere and reach net zero much quicker, according to a new study from researchers at the University of Sheffield.

The study, led by Dr Rafael Eufrasio from the University’s Advanced Resource Efficiency Centre, has found that using renewable energy and electric transport systems in the rock dust’s supply chains could provide a major boost to how much CO2 the technology can remove from the atmosphere when added to agricultural soils.

Adding rock dust to soils – known as enhanced rock weathering – could absorb up to 45 per cent of the atmospheric carbon dioxide needed for the UK to reach net zero, according to a recent study by scientists at the University. However, the technology has extensive supply chain that presents major environmental challenges with substantial environmental impacts.

But now, a new study published today (5 May 2022) in the journal Nature Communications Earth and Environment has found that using low carbon energy sources to help source the dust, as well as electric trains and vehicles to transport it, could make its supply chain much greener.

Twelve countries have previously been identified as having the highest potential for the large-scale implementation of the technology. As part of the study, the researchers from Sheffield used life cycle assessment modelling to assess the impact of each of the countries’ potential supply chains that would be used to deploy the rock dust on agricultural soils and what can be done to make them more sustainable.

Dr Rafael Eufrasio said: “As represented in the 2°C energy scenario, the benefits of shifting from fossil fuels to renewable energy sources improve the efficiency of enhanced rock weathering’s supply chain operations, such as rock grinding and the electrification of rail and road networks, particularly in countries with considerable transport distances.

“Our results indicate that the effects on the environment from using enhanced rock weathering will be consistently reduced in most of the nations we analysed. Thus, natural resources, ecosystems, and human health impacts from using enhanced rock weathering could also be significantly moderated.”

Professor Lenny Koh, co-head of the University of Sheffield Energy Institute and Director of Advanced Resource Efficiency Centre, said: “Our study provides the science base to assist policymakers who are considering using enhanced rock weathering as part of their mix of carbon dioxide removal solutions to achieve net-zero. Results from the study can help to inform decision making for investment and adoption of carbon dioxide removal strategies.

“Enhanced rock weathering can remove CO2 from the atmosphere, but it can also improve soil and crop health. These benefits, combined with a greener and more efficient supply chain, provide a strong rationale to support it as a competitive sustainable negative emissions technology.”

Professor David Beerling, Director of Leverhulme Centre for Climate Change Mitigation (LC3M) at the University of Sheffield, said: “Our study can help nations’ and their policymakers to prioritise the actions they need to take in order to meet net zero targets and mitigate climate change. The study represents an important step for understanding the sustainability of enhanced rock weathering as a carbon dioxide removal technology.”

The study, Environmental and health impacts of atmospheric CO2 removal by enhanced rock weathering depend on nations’ energy mix, is published in the journal Nature Communications Earth and Environment. Access the paper in full.

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