Procyon Mukherjee discusses the importance of the thermal substitution rate in the use of alternative fuels in the first part of this two-part series.

It was 22nd October 2019, and we were in Wuhan, visiting the world’s largest kiln that was being installed with the design-TSR of 60 per cent, which meant from the inception the system would be ready to take in higher quantity of RDF, largely from the municipal wastes generated at Wuhan. The overall schema included several co-processing units near Wuhan and then the eventual logistics of moving them through barges on the Yangtse river and then through pipelines into the different sections of the kiln and the pre-heater. We were quite astonished to see that it was the municipality of Wuhan who came forward with the entire scheme including logistics that helped the setting up of the plant – essentially a means for incineration of the entire municipal waste of Wuhan.
The rest of the world may not have such a denouement, rather a step-by-step approach of increasing the TSR, with more and more usage of alternate fuels. Thus, in most cases it is an incremental approach, the investments included. It is worthwhile to look at the journey of alternate fuel usage in cement kilns across the world over the last three decades and what are some of the critical investment pathways for increasing TSR.
The first major use of alternative fuels in the cement manufacturing industry emerged during the mid-1980s. The primary goal in substituting fossil fuels was to enable the industry to remain economically competitive, as fuel consumption accounts for almost one-third of the cost of producing clinker. Any positive impact on the environment was considered an added benefit. Since then, there has been increasing sensitivity to the environmental impact of human and industrial activities. Beyond the cost-cutting benefits of alternative fuels, use of these fuels can contribute greatly to the environmentally sound disposal of waste and to the mitigation of greenhouse-gas emissions (GHG).
Therefore, key cement players started to consider alternative fuels as a lever to improve their contribution to sustainable development and as a key component of corporate social responsibility.
The data in the bracket is the current number for TSR. The obvious case in point is the stratospheric increase in TSR rates in Poland. This needs some discussion. The case study on Poland throws some pointers as to how the journey from zero to 88 per cent has been achieved. The notable steps have been:
1. The willingness of Polish cement companies to reduce their operating costs by quickly replicating the alternative fuel experience of international cement groups
2. The enforcement of Polish waste regulations in order to conform to relevant European

Union directives, namely the Waste Framework Directive, the Waste Incineration Directive and the Landfill Directive.
The second one is one of the fundamental reasons to drive the use of alternate fuel. The journey had its humble beginnings with a small state tax imposed on land fill waste (which was collected from the same people who produced the waste) and then the increase of this tax over time, with the transfer of responsibility of waste collection to the land fill operators. Parallelly the ‘extended producer responsibility’ sparked off the implementation of the first waste shredding line to produce refuse-derived fuel (RDF).
In 2005, Germany adopted a ban on the landfilling of recyclable and organic waste, leading to overproduction of RDF. Poland’s shift toward alternative fuel development based on RDF was thus supported by importation of the fuel from Germany for five years, before Germany increased its own waste burning capacity. At that point, the alternative fuel substitution rate in Poland reached 20 percent. In 2008, the state tax was increased sharply, climbing from €4 per tonne in 2007 to about €17 per tonne, with a further doubling announced within the next 10 years. The enforcement of this tax for municipal waste incited waste management companies to invest in alternative solutions.
At that point, shredding line operators were sourcing waste from the industrial sector (obtaining good-quality waste for a low gate fee) as well as from the municipal waste sector, with large cities being the main providers. The extension of sourcing to include municipal waste resulted in a degree of downgrading of RDF quality, but the cement sector continued the effort and pushed the substitution rate to 40 per cent in 2010.
Once the capacity of RDF production lines reached an equilibrium with the alternative fuel capacity of cement plants, the cement companies were able to pressure RDF producers to further improve the fuel quality. To face this new demand, RDF producers had to innovate, improving the quality of the RDF significantly through better sorting and drying sequences (thermal or biological). In parallel, the cement plants developed new tools to improve drying, such as by installing thermal dryers that used the waste heat from the kilns. A new increase to the state tax then put more waste on the market—and at a better price—confirming the trend toward alternative fuel use.
But the crucial area of investment remained how to arrest the pitfalls of high RDF usage in the kilns as there were issues around chlorine, kiln operational stability, enabling the efficient use of diverse and often challenging fuel types, integration of the system with usage of multiple fuels including diverse alternate fuels and monitoring and control. It is in this regard that several specific investments had to be targeted. The lead in this was taken by Germany and followed by all others to see how increase in thermal substitution rates did not come in the way of either impacting the efficiencies or the environment and efforts were directed to create not only a balance but a way to get to 100 per cent of alternate fuel usage, virtually paving the way for 100 per cent TSR.
Some of the most commonly used alternative fuels in the cement industry are biomass, industrial and domestic waste materials, scrap tires, and sewage sludge. The high temperatures, long residence times, and alkaline environment in the cement kiln can prevent the formation of hazardous volatile compounds, making it a suitable option for co-processing waste materials as alternative fuels during cement production. Although the substitution of fossil fuels such as coal and pet coke with alternative fuels can potentially reduce total CO2 emissions from the cement industry, the reduction potentials are often marginal (in the range of 1- 5 per cent for most cases and up to 18 per cent of current CO2 emissions in a few cases) and depend on the source of biogenic emissions. Moreover, due to higher concentrations of sulphur, nitrogen, chlorine, heavy metals, or other volatile matter in some alternative fuels, co-processing can increase emissions of non-CO2 air pollutants of concern in some cases. Thus, an eye on not increasing the emissions (not just CO2 but also SOX and NOX) became a priority. This required investments over time as the RDF usage increased.
Let us see some of these investments in details, like Chlorine By-Pass, Rotating Hot Disc, ID Fan Modification, ESP Fan Modification, etc would be needed the moment the TSR rates would be approaching plus 30 per cent:
1. Chlorine by-pass: This investment is directed at mitigating and protecting a number of
things like:

Managing chlorine build-up
– Alternative fuels like waste-derived fuels often contain high levels of chlorine. This can lead to an accumulation of alkali chlorides in the kiln system.
– Chlorine build-up can cause operational problems, such as the formation of buildups or rings in the kiln and preheater systems, disrupting the material flow and reducing efficiency.
Improving kiln operation stability: High chlorine content can lead to corrosion and fouling of equipment. By removing excess chlorine, the system operates more stably and with fewer maintenance interruptions.
Protecting product quality: Excess chlorine can impact the clinker quality, leading to undesirable properties in the cement. The bypass system helps maintain consistent and high-quality clinker production.
Facilitating use of diverse fuels: Many alternative fuels, such as municipal solid waste, industrial waste, or tires, are economical but contain high chlorine levels. The bypass system enables cement plants to use these fuels without compromising efficiency
or quality.
Reducing environmental impact: Chlorine in the kiln system can lead to the formation of dioxins and furans, which are harmful pollutants. By extracting chlorine from the system, the bypass reduces the risk of these emissions.
How the system works:
The chlorine bypass system extracts a portion of the kiln gas from a specific point (often the kiln inlet) where the alkali chlorides are in a gaseous form. These gases are cooled rapidly to condense and separate the chlorides, which are then collected and disposed of appropriately.

There are eight components of the system:

Gas extraction system

• Function: Extracts a portion of kiln gases from a strategic location, typically near the kiln inlet where volatile alkali chlorides are in gaseous form.

Key components:
– Gas ducts with high-temperature resistance.
– Dampers to control the volume of extracted gas.

Rapid cooling system

• Function: Quickly cools the extracted hot gases to condense alkali chlorides and other volatiles, preventing them from recirculating into the kiln system.
• Key components:
  – Water sprays or air quenching systems for
  rapid cooling.
  – Heat exchangers, if heat recovery is integrated.

Cyclones or bag filters

• Function: Separates condensed alkali chlorides and dust from the cooled gas stream.
• Key components:
  – High-efficiency cyclones for coarse particle separation.
  – Bag filters or electrostatic precipitators for fine particle removal.

Disposal system for collected byproducts

• Function: Safely manages and disposes of extracted chlorides and dust.
  Key components:

– Conveyors or pneumatic transport systems.
– Silos or containment units for storage before disposal.

Bypass gas cooling and conditioning system

• Function: Further conditions the bypass gas before reintegration into the system or venting.
• Key components:

– Cooling towers or gas conditioning towers.
– Water injection systems for temperature control.

Control and automation system

• Function: Monitors and optimises the bypass system to ensure it operates efficiently and safely.
• Key components:

– Sensors for temperature, pressure, and chlorine content.
– Programmable logic controllers (PLCs) for real-time adjustments.

Heat recovery system (optional)

• Function: Captures waste heat from the bypass gases for use in other processes, improving energy efficiency.
• Key components:

– Heat exchangers.
– Steam generators or preheaters.

Integration with main kiln system

• Function: Ensures that the bypass system operates in harmony with the kiln process without disrupting clinker production or fuel efficiency.
• Key components:

– Ducts and valves for gas reintegration or venting.
– Interfaces with kiln control systems.

2. Combustion chamber hot disc
The installation of a combustion chamber (hot disc) in cement kilns for alternate fuel installations serves several critical purposes, enabling the efficient use of diverse and often challenging fuel types. Here’s a breakdown of its key roles:

Efficient combustion of alternative fuels

• The hot disc provides a dedicated zone for the complete combustion of alternate fuels, including those with varying calorific values, moisture content, and particle sizes.
• This ensures that even low-grade or coarse fuels (e.g., tires, municipal solid waste, biomass, or industrial waste) can be burned effectively.

Improved heat transfer

• The combustion chamber is designed to optimise heat generation and transfer, supplying the kiln with the necessary thermal energy.
•  It reduces reliance on primary fossil fuels like coal or petcoke, lowering operating costs.

Reduced emissions

• Proper combustion in the hot disc minimises the release of harmful emissions, such as carbon monoxide (CO), volatile organic compounds (VOCs), and unburned hydrocarbons.
• This helps the cement plant meet environmental regulations and sustainability goal
• Enhanced kiln operation stability
• Burning alternative fuels in the combustion chamber isolates their impact from the main kiln, ensuring stable temperatures and operation within the kiln.
• It minimises disruptions caused by the inconsistent burning behaviour of alternative fuels.

Handling difficult fuels

• The hot disc is specifically designed to process fuels that are challenging to handle in the main kiln or calciner, such as large solid fuels (e.g., tires or large biomass pieces).
• The chamber’s design accommodates prolonged fuel residence time and high temperatures, ensuring complete combustion.

Optimised energy efficiency

• By burning alternate fuels close to the kiln inlet or calciner, the hot disc provides pre-heated gases to the kiln system, improving energy efficiency.
• It contributes to a more uniform temperature profile, enhancing clinker quality.

Increased use of waste-derived fuels

• Many cement plants aim to increase their Thermal Substitution Rate (TSR)—the percentage of energy derived from alternative fuels. The hot disc facilitates this transition by enabling higher volumes and more diverse types of alternate fuels to be used safely and efficiently.

Overall benefits
The hot disc system allows cement plants to:

• Reduce dependency on fossil fuels
• Lower operational costs
• Improve sustainability by using waste as a resource
• Comply with stricter environmental regulations.

Rotating hot disc

• Function: The central component where alternative fuels, such as coarse solids (e.g., tires, plastics, or biomass), are introduced and combusted.

Key features:

• Rotating design for even fuel distribution.

– High-temperature resistance to handle intense combustion conditions.
– Adjustable speed to optimise fuel combustion time and efficiency.

Fuel feed system

• Function: Delivers alternative fuels to the hot disc in a controlled manner.
• Key components:

– Conveyors, pneumatic systems, or screw feeders for fuel transport.
– Chutes or injection systems for precise fuel placement.
– Hoppers or silos for storage of alternate fuels before feeding.

Rajesh Kumar Nayma, Associate General Manager – Environment and Sustainability, Wonder Cement, in conversation with Kanika Mathur about CCUS technology.

Wonder Cement Limited (WCL), a leading player in the cement industry, is committed to sustainable practices and innovation in its operations. Rajesh Kumar Nayma, Associate General Manager – Environment and Sustainability at WCL, shares insights into the company’s efforts to integrate Carbon Capture, Utilisation, and Storage (CCUS) technology to combat climate change. Through advanced processes and renewable energy initiatives, WCL is paving the way for a greener cement industry.

How is your company incorporating CCUS technology into its operations to promote sustainability?
To combat climate change and achieve Net Zero emissions by 2060, Carbon Capture, Utilisation, and Storage (CCUS) technology will play a pivotal role. Wonder Cement Limited (WCL) is actively collaborating with various technology providers to support this journey. Efforts include segregating greenhouse gas (GHG) emissions from stacks, implementing oxy-fuel technology, electrifying kilns, utilising 100 per cent solar energy within plants, and eliminating fossil fuel consumption.
WCL has conducted a comprehensive GHG inventory aligned with India’s COP26 commitments, aiming to achieve net-zero emissions. Technological innovations such as the installation of a 45 MW Waste Heat Recovery System (WHRS) and an additional 15 MW WHRB have been key milestones. These systems capture excess heat from production processes, converting it into energy and reducing carbon footprints. The company has also introduced advanced burner technology to lower NOx emissions and optimise energy consumption. Currently, WCL achieves less than 47 KWh/tonne of clinker and an SEC of less than 685 Kcal/kg of clinker—benchmarks among the best in the cement industry. These achievements reflect the company’s dedication to lowering environmental footprints through technological enhancements.

What challenges do you face in implementing CCUS in the cement manufacturing process, and how do you address them sustainably?
For India, CCUS is still an emerging concept. While some European companies have successfully implemented CCUS, the associated costs in the Indian context are currently prohibitive, approximately 2.5 to 3 times the cost of a cement plant. This makes large-scale implementation challenging. Some of the key challenges are:

• High project costs: The cost of implementing CCUS is 2-3 times higher than the cost of a cement plant.
• Energy-intensive operations: Operating CCUS facilities can double energy consumption, increasing operational expenses.
• Space requirements: CCUS infrastructure demands substantial space.
• Storage accessibility: Many Indian plants are located inland, far from oceans, complicating carbon storage options.

WCL is advocating for further research to optimise the utilisation of captured carbon, which could lower project and operational costs over time. The company is committed to exploring CCUS feasibility for its future projects and collaborating with technology providers to address these challenges sustainably.

How do you see CCUS contributing to achieving net-zero emissions?
CCUS is indispensable for achieving Net Zero emissions in the cement industry. Even with 100 per cent electrification of kilns and renewable energy utilisation, CO2 emissions from limestone calcination—a key raw material—remain unavoidable. The cement industry is a major contributor to GHG emissions, making CCUS critical for sustainability.
Integrating CCUS into plant operations ensures significant reductions in carbon emissions, supporting the industry’s Net Zero goals. This transformative technology will also play a vital role in combating climate change and aligning with global sustainability standards.

Any specific investments or partnerships made in CCUS research or deployment to support sustainable practices?
WCL has implemented several innovative technologies and process optimisations to minimise GHG emissions. Key initiatives include:

• Installation of WHRS and maximising renewable energy usage.
• Exploring the production of lower clinker cements such as LC3 and PLC, alongside increasing the share of blended cement like PPC.
• Engaging with consultants and technology providers to develop a comprehensive Net Zero and ESG roadmap.

Any success stories or pilot projects involving CCUS that have significantly impacted your sustainability goals?
We have invested in renewable energy projects to significantly reduce its carbon footprint. Key examples include:

• Solar power installations at Nimbahera Integrated Plant and Jhajjar Grinding Unit.
• 15 MW windmills at Pratapgarh.
• Renewable Power Purchase Agreements for grinding units in Aligarh, Uttar Pradesh, and Dhule, Maharashtra, replacing 50 to 60 per cent of energy demand from the grid and reducing GHG emissions.

The company is actively exploring CCUS installation for upcoming projects, assessing its viability in the Indian context.

Beyond CCUS, what other sustainable practices or innovations is your company implementing to reduce its environmental footprint?
WCL’s sustainability initiatives include:

Energy efficiency: Installing Variable Frequency Drives (VFDs), optimising differential pressures across bag filters, and enhancing kiln operations.

• 3R principles: Emphasising reduce, reuse and recycle to optimise resource utilisation and waste management.
  Waste co-processing: Utilising over 50,000 tonnes of RDF/plastic waste and ensuring proper disposal of hazardous waste like used oil and lead-acid batteries.
• Alternative raw materials: Substituting natural resources with industrial by-products like red mud, chemical gypsum and ETP sludge.
• Plastic waste management: Increasing recycled content in PP bags and achieving Extended Producer Responsibility (EPR) targets.
• Carbon sequestration: Planting over 250,000 trees, sequestering 5,000-10,000 tonnes of CO2 annually.
• Water conservation: Operating as a water-positive organisation, with a focus on rainwater harvesting and groundwater recharge.

How do you balance the cost challenges of CCUS with your commitment to sustainable development?
WCL prioritises environmental stewardship alongside financial sustainability. While CCUS implementation involves high costs, WCL sees opportunities in mechanisms such as Carbon Border Adjustment Mechanism (CBAM), carbon trading, and Renewable Energy Certificate (REC) trading. These avenues provide financial incentives to offset the initial investment in green technologies.

ICR discusses India’s rapid advances in renewable energy, on track to exceed its 2030 targets, even as the rising energy demands challenge complete reliance on sustainable sources.

The cement industry, a cornerstone of infrastructure development, has long been associated with high emissions, particularly of CO2. This sector alone is responsible for approximately 8 per cent of global carbon dioxide emissions, primarily due to the energy-intensive processes of clinker production and calcination. Beyond carbon emissions, cement production also generates particulates, nitrogen oxides (NOx), sulphur oxides (SOx), and other pollutants, contributing to environmental degradation and health risks. With the global push towards sustainable practices and carbon neutrality, addressing emissions in the cement industry has become imperative.
According to Climate Change Performance Index, India ranks 7 in 2024. India receives a high ranking in the GHG Emissions and Energy Use categories, but a medium in Climate Policy and Renewable Energy, as in the previous year. While India is the world’s most populous country, it has relatively low per capita emissions. Data shows that in the per capita GHG category, the country is on track to meet a benchmark of well below 2°C.
India’s situation underscores the complexity of transitioning to sustainable energy systems in the face of rising and fluctuating energy needs. International support is crucial for India to access advanced technologies, financial resources, and best practices that can accelerate its transition to a sustainable energy future. Our analysis shows that with current policies, India will overachieve its conditional NDC targets of achieving 50 per cent non-fossil capacity by 2030, so it could set stronger targets. India has ambitious renewable energy plans as outlined in the National Electricity Plan 2023 (NEP2023) aiming for a share of installed capacity of 57 per cent and 66 per cent in 2026-27 and 2031-32, respectively. Share of renewable energy capacity in India reached 44 per cent, ranked fourth in the world in renewable energy capacity installations in 2023, after China, the US and Germany. The NEP2023 is reflected in the lower bound of our current policy and action pathway.
India has seen a steady increase in renewable energy deployment, including both utility-scale and rooftop solar, leading to the share of coal capacity dropping below 50 per cent for the first time. However, this increase in renewable energy capacity is barely able to keep up with the surging demand. As a result, the electricity generation share of renewable energy, including large hydro, remains at around 18 per cent, showing no improvement since last year. Investment in renewable energy projects in India are projected to increase by over 83 per cent to around USD 16.5 bn in 2024, with fossil fuel companies also diversifying their investments into the renewable sector. Despite this, India has not committed to phasing out coal power or fossil gas.
The National Electricity Plan indicated a temporary halt in coal capacity addition, but current under-construction capacity exceeds the threshold stated in these plans. While new gas power projects have been abandoned, the utilisation of existing gas power plants has increased to meet energy demand driven by severe heat stress.

Understanding Emissions in Cement Production
Primary Sources of Emissions: Cement production emissions stem mainly from three sources: calcination, fuel combustion, and electricity use. During calcination, limestone is heated to produce clinker, releasing CO2 as a by-product. This process alone accounts for roughly 60 per cent of emissions in cement manufacturing. The remaining emissions result from burning fossil fuels in kilns to achieve the high temperatures needed for calcination and from electricity consumption across production stages.
Raju Ramchandran, SVP Manufacturing (Cluster Head – Central), Nuvoco Vistas, says, “We consistently track air emissions from fuel combustion in our cement manufacturing and power generation operations. The burning of fossil fuels releases pollutants such as Oxides of Sulphur (SOx), Oxides of Nitrogen (NOx), and Particulate Matter (PM), which require stringent monitoring.”
“We ensure compliance with regulatory standards by using the Continuous Emission Monitoring System (CEMS) to monitor these emissions. For the FY 23-24, both our stack and fugitive emissions have stayed within the permissible limits set by Pollution Control Boards. Moreover, our ongoing monitoring of fugitive emissions ensures that we meet the prerequisite air quality standards,” he adds.
In addition to CO2, the cement industry releases various pollutants that pose risks to air quality and public health. These include particulate matter, NOx, and SOx, which can lead to respiratory and cardiovascular issues, acid rain, and ecosystem imbalances.
Governments worldwide are setting increasingly stringent regulations to curb industrial emissions. Standards such as the EU Emissions Trading System and India’s National Action Plan on Climate Change encourage cement manufacturers to adopt cleaner technologies. Many countries now impose limits on NOx, SOx and particulate emissions, with the aim of minimising the industry’s environmental impact.

Challenges in Reducing Emissions
High carbon intensity of cement production: Cement’s high carbon intensity largely stems from the chemical reactions involved in transforming limestone into clinker, making emissions difficult to reduce without altering core processes. Additionally, achieving the necessary kiln temperatures requires significant energy, often derived from coal or natural gas.
Operational limitations: Altering the traditional cement production process can compromise the quality and durability of the end product. Adapting existing production lines for lower emissions involves extensive R&D and technical trials to ensure the finished cement meets industry standards.
Financial constraints: The cost of implementing green technology is high, creating economic challenges, particularly for smaller cement manufacturers. Equipment upgrades, energy-efficient kilns, and carbon capture facilities require considerable investment, which many companies find difficult to justify without strong financial incentives.
Balancing market demands and environmental goals: With global infrastructure demands rising, the cement industry faces pressure to meet growing production needs while simultaneously working to reduce emissions. Balancing these competing demands requires innovation, efficient resource management, and support from stakeholders.

Technological Innovations for Emission Reduction
Alternative fuels and energy sources: One of the most effective ways to reduce emissions is by replacing fossil fuels with alternatives like waste-derived fuels, biomass, or biofuels. Some manufacturers are incorporating solar and wind energy to power auxiliary processes, further reducing reliance on traditional energy sources.
Sudhir Pathak, Head- Central Design & Engg (CDE), QA, Green Hydrogen, Hero Future Energies, says, “The cement industry is one of the largest consumers of grid power (Scope 2) and also a guzzler of in-process fossil CO2 (Scopem1) including process-based CO2 through limekilns. Decarbonisation can be achieved only up to 50 per cent to 60 per cent through plain hybrid solar and wind. However, for achieving balance 40 per cent, storage is essential, be it chemical or mechanical. Today, HFE is ready to provide such bespoke storage solutions as is evident through several complex RTC tenders that we have won in the last 6-8 months floated by agencies like SECI, NTPC and SJVN. These include tenders for FDRE projects, peak power, load following, etc. Further, regarding green hydrogen and its derivatives, we are ready to apply these for decarbonising industrial heating and mobility.”
Carbon Capture and Storage (CCS): CCS technology captures emissions at the source, storing CO2 to prevent it from entering the atmosphere. Recent advancements in CCS technology make it a viable option for large-scale cement plants, although high costs and infrastructure requirements remain obstacles to widespread adoption.
Clinker Substitution: Reducing clinker content is a promising method for emission reduction, achieved by using supplementary cementitious materials (SCMs) such as fly ash, slag, and calcined clay. These materials not only reduce CO2 emissions but also enhance the durability and performance of cement. SCMs are gradually becoming industry-standard components, especially in eco-friendly and green cement products.
Rajesh Kumar Nayma, Assistant General Manager – Environment, Wonder Cement, says, “The use of AFR plays a critical role in our strategy to reduce the environmental footprint of cement production. By substituting traditional fossil fuels with waste-derived alternatives like biomass, refuse-derived fuel (RDF) and industrial by-products, we significantly lower CO2 emissions and reduce the demand for natural resources. The utilisation of supplementary cementitious materials (SCMs), such as fly ash, helps in reducing clinker consumption, which is a major source of carbon emissions in cement production. This not only decreases our reliance on energy-intensive processes but also promotes waste recycling and resource efficiency. AFR adoption is an integral part of our commitment to the circular economy, ensuring that we minimise waste and optimise the use of materials throughout the production cycle, ultimately contributing to a more sustainable and eco-friendly cement industry.”
“WCL is exploring transitioning from fossil fuels to cleaner alternatives like biofuels or hydrogen or RDF/plastic waste/other hazardous waste. Till date, 5 per cent TSR has been achieved, while the intent is to achieve more than 20 per cent TSR. WCL is utilising the hazardous and other waste as an alternative fuel or raw material. We have used more than 3 lakh metric tonne of hydrogen waste and other waste in FY-2023-24,” he adds.
Improving energy efficiency is critical for emissions reduction. Technologies like high-efficiency kilns, heat recovery systems, and process optimisation techniques are helping manufacturers achieve more output with less energy. These measures reduce the carbon footprint while lowering operational costs.

The Role of SCMs
SCMs serve as partial replacements for clinker, providing a dual benefit of reduced carbon emissions and improved product resilience. The use of materials like fly ash and slag also helps mitigate industrial waste, contributing to a circular economy. Fly ash, slag, and silica fume are among the most widely used SCMs. Each has unique properties that contribute to cement’s strength, workability, and durability. By incorporating SCMs, manufacturers can produce cement with a lower environmental footprint without compromising quality.
While SCMs are effective, several obstacles hinder their widespread adoption. Supply chain constraints, material variability, and lack of technical standards are challenges that manufacturers face. Additionally, geographic limitations impact access to certain SCMs, creating disparities in their usage across regions.

Policy and Industry Collaboration
Policies play a critical role in driving green transitions within the cement industry. Carbon credits, tax incentives, and funding for R&D are some measures governments have introduced to support emission reduction. India’s Perform, Achieve, and Trade (PAT) scheme is an example of a policy incentivising industrial energy efficiency.
Collaborations between government entities, private corporations, and research institutions foster innovation and accelerate the adoption of sustainable practices. Partnerships can also help address funding gaps, allowing companies to explore new technologies without bearing the full financial burden.
International frameworks such as the Paris Agreement and industry-led efforts like the Global Cement and Concrete Association (GCCA) are setting targets for sustainable cement production. These initiatives encourage the sector to adopt environmentally friendly practices and set a roadmap toward achieving net-zero emissions.

Towards a Net-Zero Future
Reaching net-zero emissions is an ambitious but necessary goal for the cement industry. Realistic targets, set with interim milestones, allow companies to gradually transition to greener processes while maintaining production efficiency. Continued investment in R&D is crucial for discovering new methods of emission reduction. Emerging technologies such as carbon-negative materials, alternative binders, and low-carbon clinkers hold promise for the future, potentially transforming cement production into a more sustainable process.
Increasingly, consumers and investors are prioritising sustainability, placing pressure on companies to reduce their environmental impact. This shift in consumer sentiment is driving the cement industry to adopt green practices and focus on transparency in emissions reporting.

Conclusion
The journey toward reducing environmental impact in the cement industry is complex and multifaceted, requiring a combination of innovation, policy support, and industry collaboration. By adopting alternative fuels, implementing carbon capture technology, integrating SCMs, and improving energy efficiency, the industry can take significant strides in minimising its carbon footprint. Achieving sustainability in cement production is essential not only for the industry’s future but also for the planet’s well-being. Together, industry players, policymakers, and consumers can support the transition to a net-zero future, ensuring that cement remains a vital yet sustainable component of global infrastructure.

– Kanika Mathur