Report proposes zero carbon cement to cut global emissions by 8%

Climate solutions think tank, Beyond Zero Emissions has released a report detailing how Australia could develop the world’s first zero carbon cement industry, helping to wipe out 8% of all global emissions.

The report, Zero Carbon Industry Plan: Rethinking Cement, outlines five strategies to deliver a zero carbon Australian cement industry in 10 years and to turn the built environment into a carbon sink by changing the way we build.

These are:

  • Supplying 50% of cement demand with geopolymer cement. The reactions involved in making geopolymer cements do not generate greenhouse gases, and therefore zero emission geopolymer cements are possible.

  • Supplying 50% of cement demand with high-blend cements. Portland cement can be blended with other materials, reducing its carbon intensity. This strategy proposes increasing the proportion of replacement material to 70%, using fly ash, slag, clay and ground limestone .

  • Mineral carbonation. This strategy employs a new technology, mineral carbonation, to capture the emissions from the remaining production of Portland cement. With mineral carbonation, waste carbon dioxide is captured and chemically sealed within rock. Unlike conventional carbon capture and storage, there is no risk of leaking or need for monitoring post-storage. The process is applied in situ, and can produce substances with commercial value such as magnesium carbonate and silica.

  • Using less cement. By designing structures to use concrete more efficiently, utilising high strength cement, and replacing concrete with timber, overall cement consumption could be reduced by around 15% in 10 years.

  • Carbon negative cements. There is the long-term potential to develop magnesium-based cements which absorb carbon dioxide, and would therefore have a negative emissions profile.

The report suggested that the Australian Government set a national target to reduce the carbon intensity of cement, becoming progressively more stringent.

This target could be supported by public investment into research and deployment of low-carbon cements, similar to the support for renewable energy provided by the Clean Energy Finance Corporation and the Australian Renewable Energy Agency.

Further, Governments and the construction sector could prioritise the procurement of low carbon cement, and mandate their use for non-structural purposes.

The report is available here.

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