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Title: Unintended Consequences of the Global Reduction in Clinker-to-Cement Ratio

Author(s): Jean-Martin Lessard, Guillaume Habert, Arezki Tagnit-Hamou and Ben Amor

Publication: Symposium Paper

Volume: 349


Appears on pages(s): 394-407

Keywords: Economic optimization, Environmental impact, Material flow, Multiregional industrial symbiosis, Supplementary cementitious materials, Supply chains, Trade effects

DOI: 10.14359/51732760

Date: 4/22/2021

To decarbonize the portland cement sector worldwide, the Cement Sustainability Initiative recommends systematically reducing the clinker-to-cement ratio down to 60% by 2050. However, the sources of usable clinker substitutes - the supplementary cementitious materials (SCMs) - are unevenly distributed geographically and will become increasingly scarce in the future. Through a time-series material-product chain analysis, this paper investigates the multi-regional and multi-sectorial (cement, coal-fired electricity, and steel sectors) interactions that occur when increasing demand for SCMs in eastern Canada and Northeastern U.S., up to 2050. It tracks the trade effects and how it affects region-specific domestic flows of raw and secondary materials, end-product products, and greenhouse gas emissions. Although the lever is favorable overall, the results show unintended economic and environmental consequences across regions, with winners and losers. At the material level, benefits are influenced by the local availability of SCMs, which disadvantages Canadian regions due to the increasing remoteness of supply to meet demand. At the product level, decoupling blended cement production capacity from clinker production capacity allows the U.S. regions to reduce their dependence on Canadian cement imports. These new perspectives provide key geopolitical, environmental, and economic insights for better decision-making when developing sustainable initiatives.