Bodil Recke, ABB Process Industries, discusses the strategies driving the cement industry's transition to sustainability.
Cement is integral to economic growth, and demand is on the rise as urbanisation increases and infrastructure projects escalate worldwide. However, with cement production responsible for around 7% of global CO2 emissions, the industry must reconcile its necessity with its environmental impact. Addressing this challenge means rethinking the fundamentals of cement production, from energy sources to material composition. Emerging strategies, including electrification, carbon capture, alternative materials, and digitalisation are shaping the path toward sustainability.
Decarbonisation demands an integrated approach that considers the entire value chain, from raw material extraction to final application. It goes beyond the implementation of isolated technological solutions, instead requiring a comprehensive shift in process efficiency, material usage, and policy alignment.
Reducing emissions through electrification
For decades, cement production has depended on fossil fuels to power the high temperatures required for clinker formation. The initial step to move away from this has been to replace fossil fuels with various waste materials, like plastics or agricultural waste. Electrification is one of the most discussed strategies for decarbonising cement production as it involves shifting energy inputs from fossil fuels to electricity, ideally from renewable sources. However, the transition to electrification is complex and presents various operational challenges. At the heart of cement production, cement kilns require continuous high temperatures, which grid-based electricity alone cannot reliably supply in many parts of the world. The volatility of electricity supply, particularly in regions where the grid remains heavily reliant on coal, creates significant risk. Electrification could help reduce direct emissions by switching to cleaner electricity, but there are still complexities related to energy reliability, cost, and scalability that remain.
While renewable energy sources are central to this transition, direct partnerships are becoming critical. By securing dedicated renewable energy supplies as partners, cement plants can reduce their exposure to fluctuating energy costs and instabilities in the grid. This could stabilise the energy input costs in cement production while reducing emissions from energy consumption. Coupled with robust energy storage systems for continuity and reliability, electrification can significantly reduce emissions. From electric plasma-based calcination and rotary kiln electrification to electric arc calciners capable of reaching the necessary high temperatures, electrification also offers a cleaner means of processing raw materials.
Electrification has emerged as a strategy for decarbonising cement production as it offers an opportunity to shift away from fossil fuels. Ongoing developments in technologies such as electric plasma-based calcination and rotary kiln electrification provide alternatives to the traditionally fuelled kilns. Alternatively, electric arc calciners, capable of reaching the high temperatures needed for cement production, offer a cleaner means of processing raw materials.
Decarbonisation through electrification is one strand of the solution which must be considered alongside its operational and infrastructural challenges. Replacing fossil-fuel-fired kilns with electric alternatives can generate the necessary heat cement manufacturers need while significantly cutting back on emissions. However, a shift in energy policy and infrastructure development is required to overcome energy supply volatility and cost considerations.
Beyond fuel substitution
Transitioning from traditional fossil fuels to alternative energy sources, such as biomass or municipal waste, is a viable avenue for reducing emissions in cement production. However, these alternative fuels (AFs) have distinct combustion characteristics that can affect process stability. Biomass and waste-based fuels typically have lower energy content compared to coal, and their combustion can result in inconsistent temperatures and potentially affect the chemistry or increase emissions of certain pollutants.
To mitigate these issues, cement producers must invest in modifying kiln technologies and optimising their combustion processes to ensure that AFs can be used effectively without compromising the quality of the final product. Furthermore, this fuel substitution must be accompanied by broader energy efficiency improvements across cement production.
Rather than implementing isolated upgrades, cement producers should consider the adoption of a plant-wide strategy for optimising energy use. This could include integrating renewable energy sources, improving energy storage, and ensuring that heat recovery systems are used to their full potential.
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