The Decarbonization Pathway for Japan’s Cement IndustryTake Urgent Actions to Align with the 1.5℃ Target

in Japanese

Renewable Energy Institute today released the report "The Decarbonization Pathway for Japan’s Cement Industry: Take Urgent Actions to Align with the 1.5℃ Target."

Cement has a history of more than 200 years and serves as a fundamental material for various types of social infrastructure, including buildings, tunnels, bridges, and dams. According to the International Energy Agency (IEA), the global cement industry accounts for about 6.2% of total global CO₂ emissions from direct sources. In Japan, the cement sector is the third-largest industrial emitter, following the steel and chemical industries. Against this backdrop, further decarbonization of the cement industry is urgently required.

In the manufacturing process, about 40% of CO₂ emissions come from energy-related sources—such as fuel combustion for high-temperature calcination of raw materials and the grinding of raw materials and products. The remaining 60% arises from process emissions, mainly from the thermal decomposition of limestone (CaCO₃ → CaO + CO₂), the primary raw material. Even if all the energy used were replaced with decarbonized fuels and renewable electricity, these process emissions would remain unavoidable—making cement production one of the so-called “hard-to-abate” industries. 

Nevertheless, scenario studies and technological developments aimed at decarbonizing the global cement industry are steadily progressing, and leading companies have begun to implement concrete actions. This report reviews the current status and challenges of the cement industry, introduces major decarbonization scenarios, and highlights priority actions that Japan’s cement sector should pursue in the years ahead. Through this publication, we hope to raise awareness of the importance of decarbonizing the cement industry and to accelerate its transition toward alignment with the 1.5℃ target.

 The English summary provides an overview of the cement industry, its manufacturing processes, challenges and measures for CO₂ reduction, global and Japanese decarbonization pathways, and a comparison with global best practices. It highlights the need for stronger measures to reduce process emissions and close the gap with global best practices.

View summary of the report in English 

 

Summary

Overview of the Cement Industry

CO₂ emissions from the global cement industry account for approximately 6.2% of total global emissions. In Japan, the cement industry is the third largest industrial emitter, following steel and chemicals, and thus faces strong decarbonization requirements. CO₂ emissions from cement production arise primarily during the manufacturing process. Approximately 40% of these emissions are energy-related, originating from the combustion of fossil fuels such as coal for clinker production, and electricity consumption for raw material and clinker grinding. The remaining 60%, which constitutes the majority, arises from the decomposition of limestone, the main raw material of cement. Accordingly, decarbonization in the cement industry requires not only the shift to non-fossil fuels and renewable electricity but also measures to reduce process emissions from raw materials.

The Japanese cement industry operates 28 cement plants, with a clinker production capacity of approximately 50 million tonnes per year. Cement types include Ordinary Portland Cement (OPC), produced by grinding clinker with gypsum, and Blast Furnace Slag Cement, produced by mixing OPC with additives such as ground granulated blast furnace slag (GGBS). In terms of domestic sales, OPC, widely used for building and civil engineering works, accounts for more than 70%. It is followed by Blast Furnace Slag Cement, which accounts for about 20% owing to its enhanced long-term strength, seawater resistance, and chemical durability, making it suitable for dams, ports, and other civil engineering applications.

Cement Manufacturing Process

Cement manufacturing consists of three main processes: raw material preparation, clinker burning, and finish grinding. In the raw material process, raw materials are proportioned to achieve the required chemical composition, then dried and ground. Recently, a wide range of alternative raw materials, including by-products and waste, have been utilized. In the burning process, the prepared raw meal is heated up to 1450 ℃ in a rotary kiln, producing clinker. During this stage, both fuel combustion and limestone calcination generate large amount of CO₂ emissions. Coal and petroleum coke are commonly used as kiln fuels, but to reduce emissions, alternative fuels such as waste plastics, waste oil, and wood chips are increasingly employed. In the finish grinding process, clinker is mixed with gypsum, ground, and made into OPC. Furthermore, blended cements are produced by adding GGBS or fly ash to OPC.

Challenges and Measures for CO₂ Reduction

Decarbonization of cement and concrete requires addressing both energy-related and process-related emissions, including electricity consumption. Based on cement production processes, applications, and the characteristics of cement and concrete, mitigation measures can be structured along short-term and medium-to-long-term timelines.

Global Pathways to Decarbonization in Cement

Even under unfavorable conditions, global studies on cement decarbonization have been advancing. The figure below illustrates the decarbonization transition plan for cement and concrete published by Mission Possible Partnership (MPP). Key features of the MPP roadmap include:

• • Clear emission reduction targets and measures for 2030 and 2035 aligned with the Paris Agreement 1.5 ℃ scenario.
• • Inclusion of concrete-related measures such as efficiency improvements in design and construction, in addition to cement-specific measures. 

 

Japan’s Cement Industry: Pathways and Challenges

In 2022, the Japan Cement Association (JCA) published its “Long-term Vision for Carbon Neutrality in the Cement Industry,” setting interim targets for 2030 and presenting an outlook for achieving carbon neutrality by 2050. However, compared with the Global Cement and Concrete Association (GCCA) targets, the following differences can be identified:

• • For the 2030 milestone toward 2050 decarbonization, the GCCA sets intensity-based emission reduction targets for cement and concrete, promoting maximum deployment of existing technologies such as the expansion of blended cements. In contrast, the JCA only specifies an aggregate CO₂ reduction target, with countermeasures limited to expanding waste-derived fuels and improving energy efficiency.
• • Regarding clinker factor assumptions, the GCCA projects values of 0.58 in 2030 and 0.52 in 2050, whereas the JCA assumes 0.825 and 0.80, indicating a conservative stance on expanding blended cement use.

Comparison with Global Best Practices

A comparison was conducted between Japanese cement producers and five leading companies—three multinational “cement majors” and two Asian firms particularly active in decarbonization. All five companies have obtained Science Based Targets (SBT) approval, claiming alignment with the 1.5 ℃ scenario.

Recent performance data show that these leading producers report Scope 1+2 emission intensities ranging from 486 to 592 kg-CO₂/t, largely driven by reduced clinker factors (0.6–0.7) achieved through widespread adoption of low-carbon blended cements. This is particularly notable in the case of India’s Dalmia Bharat. By contrast, the JCA reports emission intensity of 695 kg-CO₂/t and a clinker factor of 0.845, both approximately 30% higher.
 

Conclusion

A comparison of global cement decarbonization efforts with the current status of Japan’s cement industry highlights the following key challenges:

• 1. Delay in the adoption of blended cement.
• 2. Continued dependence on coal.
• 3. Slow uptake of renewable electricity.

To achieve the 1.5 ℃ target and avoid excessive reliance on CCUS, Japan’s cement industry must accelerate efforts toward 2030 and 2035. In particular, the strategic adoption and expansion of low-carbon blended cements is now imperative, and ensuring their business viability and long-term market penetration is of critical importance.