Northwestern University researchers, in partnership with ClimateWorks Foundation, have developed a new blueprint for reducing carbon emissions in concrete, the world’s most-used building material.
The report, “Decarbonizing Concrete: Deep decarbonization pathways for the cement and concrete cycle in the United States, India and China,” was published today (March 16) on ClimateWorks’ website. It highlights multiple ways — including production-size mitigation measures and demand reduction by use of lean construction and sustainable building materials — to drive the cement industry toward net-zero emissions by 2050.
“One clear conclusion we arrived at in the course of our research is that there is no single solution, but rather a range of small and large changes that will be necessary to achieve net-zero emission targets,” said Eric Masanet, the project’s principal investigator.
At the time of the research, Masanet was an associate professor of mechanical, chemical and biological engineering at Northwestern’s McCormick School of Engineering. He now is the Duncan and Suzanne Mellichamp Chair in Sustainable Science for Emerging Technologies at the University of California, Santa Barbara.
The second most-used substance in the world after water, concrete is responsible for almost 10% of energy-related carbon dioxide emissions. The demand for it also continues to rise globally, especially in China, India and the United States.
“As the world rapidly approaches 1.5 degrees Celsius of warming, we need to be more ambitious in our efforts to reduce greenhouse gas emissions from cement and concrete,” said Surabi Menon, vice president of global intelligence at ClimateWorks Foundation. “The need is becoming even more acute as governments — the U.S. included — increasingly turn to investments in infrastructure as a way to help economies recover from the COVID-19 pandemic.”
The new report presents a life-cycle analysis of the entire cement and concrete cycle, identifying key decarbonization levers and opportunities, and modeling the combined contribution of these approaches. Using real-world data to generate illustrative pathways for mid-century decarbonization, the report specifies 30 levers for lowering emissions, including more efficient kilns and greater use of bioderived fuels, and emerging technologies such as greener cement chemistries, materials efficiency, and carbon capture and utilization.
The research examines two scenarios — production-centric and whole-systems approaches — for how cement and concrete can be decarbonized across the life cycle.
The production-centric approach explores ways to reach net-zero emissions solely through measures that reduce the carbon intensity of cement and concrete production. In line with existing business models, this scenario leverages technological improvements to the cement and concrete manufacturing processes and primarily relies on the cement and concrete industries to take action.
In contrast, the whole-systems scenario considers a wider portfolio of levers, with an emphasis on reducing demand for cement and concrete. Success with this approach will require industry to embrace new business models, technological advancement and the need for rapid development of enabling policy regimes, including the mobilization of support from a larger group of stakeholders, ranging from architects to the general public.