Cement production is a significant contributor to global environmental concerns, accounting for up to eight percent of worldwide CO2 emissions due to the intense heat required to process limestone. Researchers from ETH Zurich, in collaboration with Heirloom Carbon Technologies, have proposed a solution by integrating Direct Air Capture (DAC) technology into the manufacturing process. By utilizing electric kilns powered by renewable energy sources like wind or solar, the industry could potentially achieve a net-negative carbon footprint, significantly reducing the climate impact of cement production by 2050 while safely storing captured carbon underground.
The proposed method replaces traditional coal or gas-fired heating with electric kilns. During this process, the CO2 released from the limestone is captured immediately. The remaining material is then treated with water, creating a substance that actively absorbs additional CO2 from the atmosphere as it reverts to limestone. This captured gas is subsequently compressed and stored beneath the earth’s surface. According to lead author Vittoria Bolongaro, this calcium looping system is particularly promising because it can be integrated into existing industrial workflows, potentially cutting the climate impact of cement manufacturing by 78 percent.
While the technology demonstrates a clear path toward decarbonization, several hurdles remain before widespread adoption. The large-scale electric kilns required for this process are not yet in industrial use, and the economic feasibility of the transition has not been fully evaluated. Researchers emphasize that for the process to be truly effective, the energy powering the kilns must come from renewable sources. Future studies will need to determine whether the financial costs of implementing these systems align with the operational requirements of the global cement industry.