The Emissions Come from Clinker
Concrete is composed of aggregate and binder. Portland cement, the binder that is used the vast majority of the time, is responsible for over 90% of concrete’s emissions1. Nearly 95% of cement’s emissions come from clinker1, which accounts for 91.4% of the material substance of cement3.
Clinker is produced by heating limestone and clay to 1,450°C, which precipitates a chemical reaction called calcination. Energy emissions from heating the kilns accounts for 35% of concrete’s emissions. The calcination process releases CO2 in great amounts, resulting in 53% of concrete’s emissions1.
Reducing the impact of clinker is key to decarbonizing the sector. This can be done by reducing and replacing the amount of clinker used in cement and concrete. These solutions are ready today and reduce both the costs of production and environmental impact of concrete1.
Concrete in Context
Globally, the cement and concrete industry is highly localized1. The average travel distance for in-situ concrete is 16km/10miles2. The average distance for concrete’s raw materials is 48km/30miles2. On one hand, that makes it difficult to make widespread change across the global system. On the other hand, it makes it easier for individual stakeholders to make change within their local context.
Collaboration is the Cure
The most important key to success is collaboration. This globally localized industry can only cure the emissions problem with a mix of supply-side and demand-side solutions that are explored collaboratively among all stakeholders to develop compliant and appropriate low-carbon solutions. Decisions made at every level affect all other stakeholders.