Kiln electrification key to decarbonisation of manufacturing in cement industry
The cement industry is one of the largest contributors to global greenhouse gas (GHG) emissions, primarily due to the energy-intensive nature of cement production processes. Concrete, made from cement, is the second most consumed material in the world, after water.
Cement production heavily relies on fossil fuels like coal and natural gas. Globally, the cement industry contributes about 8 per cent of global carbon dioxide (CO2) emissions. This dependence on fossil fuels is a significant source of GHG emissions.
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Electrification of kilns in the cement industry is one of the main pathways to reduce CO2 emissions by moving away from fossil fuel-based energy sources to cleaner electricity.
Decarbonising through kiln electrification
Clinker is the primary raw material in cement. Nearly 90 per cent of the total CO2 emissions (scope 1 and 2) come from clinker production. Around 40 per cent of these emissions are thermal emissions from burning fossil fuels, 50 per cent are process-related emissions and the remaining 10 per cent mostly come from electricity consumption.
The process of making clinker from limestone, known as calcination, takes place in the pre-calciner and kiln. The manufacturing process in the pre-calciner and kiln requires high temperatures, up to 900 degrees Celsius and 1,450 degrees Celsius, respectively.
At present, these processes are entirely dependent on burning fossil fuels. Electrifying the kiln could reduce the 40 per cent of thermal emissions resulting from fossil fuel combustion."
Kiln electrification is the process of replacing fossil fuel-based energy sources with electricity generated by renewable or low-carbon sources such as wind, solar, hydroelectric, or nuclear power.
An electrified kiln powered by renewable energy could significantly reduce emissions from cement production. Furthermore, using carbon capture, utilisation and storage with kiln electrification from renewable sources can reduce net manufacturing emissions to zero.
However, this promising technology also presents its own set of challenges.
Coolbrook, a Finnish electrification and technology company, has made significant progress in the field of kiln electrification. The company has committed to beginning the commercial-scale deployment of its innovative rotodynamic heater (RDH) technology by 2025.
The RDH, Coolbrook’s flagship product, can reach extremely high temperatures — up to 1,700 degrees Celsius — that are required in manufacturing processes in hard-to-abate sectors like cement, iron and steel, and petrochemicals.
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The technology company has partnered with ABB Ltd, a multinational automation company, to develop these RDHs. The RDH works by heating air, nitrogen, and process gases to high temperatures. The heated gas is then used outside the heater to replace the burning of fossil fuels in process heating.
According to Coolbrook, the RDH can be retrofitted in existing kilns to reduce costs. However, the company has yet to achieve the temperatures required in a cement kiln, which are over 1,400°C. In 2023, the technology demonstrated that it could reach a temperature of 1,000°C at their pilot plant in Brightlands, Netherlands.
Coolbrook has established multiple partnerships with Indian companies. In 2022, Ultratech and Coolbrook signed a Memorandum of Understanding (MoU) to jointly explore the use of RDH technology to electrify the cement manufacturing process.
A similar deal was made more recently in 2024 between the Finnish company and JSW Group to decarbonise their steel and cement manufacturing.
Apart from the official press releases about these partnerships, the companies have not revealed details about the commencement of any pilot projects.
Swedish firm SaltX also signed an MoU with Dalmia Cements in June 2023 to work on electrification. SaltX is striving to produce low-carbon cement with its electric arc calciner. Globally, Swedish energy firm Vattenfall and cement manufacturer Cementa are experimenting with plasma generators at their Gotland cement plant in Slite, Sweden.
It should be noted that all of these projects are in their early stages.
Lauri Peltola, chief commercial officer, Coolbrook said:
By harnessing the power of electrification alongside Coolbrook’s RDH, the Indian cement industry can lead the way in adopting environmentally friendly practices while maintaining competitiveness in the global market. As the demand for cement continues to rise with urbanisation and infrastructure development, electrification presents a viable solution to meet the associated energy demand sustainably. By leveraging renewable energy sources, the industry can contribute to a more resilient and sustainable energy ecosystem.
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“Overall, the pathway to full electrification of the cement industry in the next five to ten years looks very promising, as RDH has the potential to eliminate the need for burning fuels in cement manufacturing, revolutionising the way we think about cement production and offering a pathway towards a more sustainable and efficient cement industry in India,” he added.
Renewable energy challenge
To effectively reduce emissions through kiln electrification, the electricity used must come from renewable sources. However, industrial deployment of renewable energy presents significant challenges for various industries.
Firstly, electricity generated from renewable sources such as wind or solar is not continuously available. Energy storage solutions are required to ensure an uninterrupted supply.
India is currently grappling with several issues related to battery storage solutions. The raw materials required for these batteries are rare and not readily available in the country. Furthermore, the cost of renewable energy combined with storage is higher than that of conventional thermal power from the grid.
Pilots need to roll-out soon
Kiln electrification offers a promising pathway for reducing GHG emissions in the global cement industry, presenting opportunities for innovation, sustainability, and climate action. However, the cement industry may face a number of challenges along the way.
Therefore, pilot projects need to roll out soon to realise the full potential of this decarbonisation pathway. Continued research, innovation, and collaboration among industry stakeholders will be crucial to accelerate the adoption of electrification technologies.
According to Coolbrook, their RDH technology could potentially reduce global CO2 emissions from the cement industry by 1,000 million tonnes per year.
Some potential barriers to implementing electrification in the cement industry are:
Cost: The initial investment required for electrification infrastructure can be substantial, although long-term operational savings and potential carbon pricing mechanisms could offset these costs.
Reliability: Ensuring a reliable electricity supply, especially in regions with intermittent renewable energy sources, poses a significant challenge. Electrifying kilns will dramatically increase the electricity demand of cement plants. A transition period, during which a mix of thermal and renewable energy is used, may be necessary to ensure cost-effectiveness and an uninterrupted electricity supply.
Scalability: India is the world’s second-largest cement producer. Scaling up electrification technologies to meet the demands of large-scale cement production is essential for achieving meaningful reductions in CO2 emissions.
The Indian cement industry is among the most efficient globally regarding energy efficiency and CO2 emission intensity. The industry is also pursuing several major strategies, such as increasing the proportion of blended cement production, which has a lower limestone content, and standardising calcined clay cement.
To reduce thermal energy, companies are increasingly co-firing alternative fuels or refuse-derived fuels. Additionally, companies should start considering kiln electrification, which has substantial potential.
Low-carbon investments could be supported by the forthcoming compliance-based Indian Carbon Market. Given the growing demand, rapid urbanisation, and expanding health and economic infrastructure, the cement industry must continue to drive decarbonisation efforts.
Kiln electrification holds considerable promise and could become a crucial aspect of low-carbon growth for the industry.