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Maximising AFR in Cement Manufacturing

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Shreesh A Khadilkar, Consultant and Advisor, and Former Director Quality and Product Development, ACC Ltd Thane, discusses the importance of optimising the use of alternative fuel and raw materials (TSR percentage) in cement production without affecting clinker quality.

We all know that in the calciner the CaCO3 undergoes calcination producing CaO, part of this CaO reacts with Al2O3, Fe2O3 SiO2 to form aluminates, ferrites, Belite and some CaO remain as uncombined CaO in the material that enters the kiln, this uncombined CaO further reacts, as the material passes through the kiln to form clinker of desired phase composition with at desired levels of free lime. If this uncombined CaO is less, the resultant clinker would have lower free CaO.
Due to fluctuations of moisture in the SAFR feed, the calciner outlet temperature tends to decrease/fluctuate although the calcination is complete, some of the above post calcination reactions of the CaO are decreased, as a result the uncombined CaO is higher, in the material entering the kiln. The reactions in the kiln are affected for the same throughput and either the clinker free lime is high or the clinker shows lesser C3S percentage (depending on the burnability of the kiln feed).
In plants equipped with XRD it would be possible to monitor the uncombined CaO in Hot meal and optimise the Calciner outlet temperatures so as to achieve the desired uncombined percentage of lime as explained above. If the value is much lower than the desired level it would indicate subsequent lower LSF in the clinker, so addition of lime sludge or limestone powder as explained above would maintain the desired clinker specs. These actions, if affected during the day, would help maintain the day’s average clinker quality.
Besides the variability of the moisture percentage, the ash percentage and its composition in SAFR could change the composition of calcining material and finally depending on these changes, the post calcination reactions would be affected, depending on the uncombined percentage of lime value (monitored by XRD of hot meal), the corrections as explained above would help correct the composition and maintain the burning zone performance and the resultant clinker quality. Thus, if the calciner outlet temperature / kiln inlet material / C6 material temp. (as the case may be) is maintained higher and necessary corrections are made through SAFR or through the kiln feed. We can maintain the uncombined CaO at desired level where we could get good kiln performance as well as a good/improved clinker quality even at a higher percentage of AFR/TSR.
In many plants there is a tendency to increase the clinker Fe2O3 as and when there is an excessive dust generation and dusty kiln performance, this attempt to increase Clinker Fe2O3 would not actually help in improving the kiln conditions and maintaining clinker quality. In another plant equipped with XRD, the limestone had higher Fe2O3 content and to compensate for the effect of the varying moisture of SAFR the Calciner outlet temperature was maintained at around 920oC so that the desired post calcination reactions could be achieved and the uncombined CaO (monitored by XRD of hot meal) was maintained at desired levels.
The clinker LSF also could be maintained but the Free CaO tended to be high. The hot meal XRD indicated that the belite formations were lower in hot meal as and when the clinker free lime was high. Although the Silica was contributed from the Solid AFR as this silica was sand/silt, which did not react, the clinker IR also was observed to increase by around 0.4 per cent use of pondash (having reactive silica) along with the solid AFR up to 1 per cent was observed to increase the Belite content of hot meal and the resultant clinker had desired phase formations with lower free lime. For calculation of PSF/Potential phase composition a correction was given to the clinker silica contents (by subtracting the change in IR of clinker).
Thus, it needs to be noted here that in RDF/MSW, SAFR the ash content may have coarse sand grains, which cannot at the calcination stage and it the burnability is sensitive to silica contents, such corrections of use of wet fly ash with the SAFR could be advantageous to maintain clinker quality. However, these corrections have to be affected during the day through XRD monitoring of Hot meal and subsequent Clinker (say after 40 minutes) so that at the end of the day the clinker is of desired quality specs.
Thus, in plants coprocessing higher levels of AFR it is recommended to have a ‘bi-hourly dashboard’ and the day average clinker consistency in Quality Monitored by ‘compliance percentage to clinker specs’ as shown in Tables 1 and 2.
Such a dashboard helps having the entire plant operations involved in taking bi hourly actions so as to maintain the quality and process targets with increase in SAFR/LQAFR thus, achieving a higher compliance percentage to clinker quality specs. This has enabled not only to maintain clinker quality but it also showed improvements in clinker quality.

Actions: In plant with high TSR percentage without XRD
The hot meal samples at different kiln inlet material temperatures were collected at 870,900n and 930oC along with corresponding clinker samples (after say 40 minutes) and the XRD analysis was carried out at external labs. Through the bi-hourly dashboard actions the clinker compositions were maintained as per desired target. The XRD Mineralogy of Hot Meal and clinker XRD are tabulated in Table 3.
Although the plant maintains 95 per cent DOC, the XRD however indicates >99.5 per cent calcination. Thus, even in the absence of XRD using the bi-hourly dashboard optimisation of clinker quality can be made possible, however having an XRD (even a low watts XRD) would always be advantageous, especially if the kiln feed shows moderate burnability.

Other important considerations

  • As discussed above bi-hourly corrections made to clinker composition could be through the SAFR/RDF mix, in one plant it could be use of waste lime sludge/ in another plant use of wet pond ash/ in another use of limestone crusher dust/ high grade limestone powder depending on the corrections desired.
  • In case such materials are not available in the plant for corrections, the necessary actions bi-hourly, to adjust the clinker LSF, could be by changes in proportion of high ash coal + coal Petcoke mix in calciner or it could be even be targeting an appropriate kiln deed composition to accommodate the ash percentage of SAFR/RDF or bihourly changing the feed rate (TPH) of SAFR, as per the bi-hourly clinker composition requirements.
  • Reducing conditions can have substantial effects on clinker quality like problems with sulfur integration, Alite decomposition (strength reduction), conversion from C4AF to C3A (acceleration of setting), change in color of cement (from greenish grey to brownish), the detection of reducing conditions could be done using ‘Magotteaux Test’, it is important to assess the reducing conditions whether internal or peripheral, would indicate possible reasons.
  • Internal reducing conditions indicate that due to changes in liquid viscosity the larger clinker nodules are black from outside but yellow to brownish in the internal core. Such clinker nodules roll down from the transition zone with an unburnt core which disintegrates on cooling due to gamma C2S. Such nodules have high free lime, delocalised or peripheral reducing conditions due to larger size of solid AFR component (shredded size) showing CO peaks.
  • The Hot meal (2Cl+SO3) needs to be reliably monitored using XRF standards of Hot Meal. Every plant would have a threshold value of (2Cl+SO3), value >3.5 is reported to cause severe depositions at kiln inlet/riser duct/cyclones.
  • The kiln system should be able to handle the higher gas volumes (calciner , inlet and preheater).
    Increased percentage of AFR /TSR is associated with increase in limestone pile LSF which is linked to life of mines (Fig:2). This increase in limestone pile LSF would be more plant specific.
  • To lessen the impact on limestone Pile LSF/Mines life the plant would have to use, sweetener limestone (availability/cost), reduce the percentage use of high silica correctives with purer correctives, use petcoke or low ash coal (imported), use of waste lime sludges available from chemical industries.
  • As discussed earlier the plant could use a mix fuel (petcoke + high ash coal), or (mix of petcoke + high ash wastes like Dolochar/spent carbon etc.) in the calciner, the mix ratio could be changed so as to improve clinker LSF during the day (as a bi-hourly actions).
    High ash (high iron/high silica) wastes should not be fired through the kiln fuel; these wastes should be put through calciner fuel if feasible or along with solid wastes. It is always beneficial to have low ash coal (fuel) / petcoke in kilns.
  • It is recommended to use 4 per cent to 5 per cent high LSF Limestone in petcoke grinding (especially for kiln fuel). It improves the efficiency of petcoke grinding and would help to bind the sulphur during combustion in kiln, thus decreasing the SO3 of the hot meal. Using limestone decreases the SO3 fluctuations in the clinker and the excess of CaCO3 forms C3S clusters in the clinker, thus, improving clinker grindability.
  • Petcoke grinding is usually controlled at 1 per cent to 2 per cent on 90 microns. However in certain grinding systems, the 45 microns residue is observed to be as high as 26 per cent to 28 per cent which could create reducing conditions and initiate some coating formation in pre pre-transition zone in kilns.
  • Large storage yards to stock different types of solid AFR would help to mix the waste in certain proportions so as to achieve relative consistency in ash percentage or even chloride contents.
  • An auto-sampler with shredder on the solid AFR conveyor would be useful. However, the analysis time would be around 4 to 5 hours which is too high.
  • If the plant is reaching >25 per cent TSR, from a futuristics angle, having an online Cross Belt analyser like ‘Spectra Flow’ could help analyse moisture percentage, ash percentage and its constituents in real time, enabling rapid corrections to clinker compositions with necessary modifications to the kiln system even much higher TSR levels could be achievable.
  • Higher TSR levels invariably are associated with increase in Hot meal alkalis, chlorides and sulphates and would necessitate chloride bypass.
  • The procurement has a high responsibility of providing appropriate SAFR/RDF fuel of different ash percentage and of different chloride percentage (screened to remove sand/mud/stones).
  • Wastes having CaO rich ash would always be advantageous for the same TPH of solid AFR, the TSR percentage would be higher if the NCY of the sold AFR is higher.

Conclusion
The paper indicates and discusses in some details the avenues for increased TSR percentage without affecting clinker quality. However, depending on calciner retention time and air volume availability there would be a certain maximum TSR percentage that can be achieved. It may be noted here that the kiln system would necessitate suitable upgradation for achieving a much higher TSR percentage. It is needless to mention that XRF Models with standardless software for elemental analysis of solid/liquid AFR would be advantageous and as discussed having an XRD would be a necessity to maintain clinker quality at higher TSR percentage.
Clinkers with High MgO (>4.5 per cent) would be a challenge and optimising the CaO/SiO2 ratio would be a key to improve clinker quality use of XRD in such clinkers would be an asset.
Futuristically, ‘Torrefaction Process’ (the process of degrading organic materials in a nitrogen or inert environment within a temperature range of 200oC to 300oC) of bio wastes if extended suitably to MSW wastes and other solid AFR to produce a bio coal, could become an excellent opportunity for increased TSR for cement plants.
In this paper I have tried to share some observations in a generalised manner made at different plants with different AFR/TSR percentage which could be useful for other plants for their future road map on maximising TSR percentage.

About the author:
Shreesh Khadilkar, Consultant and Advisor brings over 37 years of experience in cement manufacturing, having held leadership roles in R&D and product development at ACC Ltd. With deep expertise in innovative cement concepts, he is dedicated to sharing his knowledge and improving the performance of cement plants globally.

Concrete

Cement Industry Backs Co-Processing to Tackle Global Waste

Industry bodies recently urged policy support for cement co-processing as waste solution

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Leading industry bodies, including the Global Cement and Concrete Association (GCCA), European Composites Industry Association, International Solid Waste Association – Africa, Mission Possible Partnership and the Global Waste-to-Energy Research and Technology Council, have issued a joint statement highlighting the cement industry’s potential role in addressing the growing global challenge of non-recyclable and non-reusable waste. The organisations have called for stronger policy support to unlock the full potential of cement industry co-processing as a safe, effective and sustainable waste management solution.
Co-processing enables both energy recovery and material recycling by using suitable waste to replace fossil fuels in cement kilns, while simultaneously recycling residual ash into the cement itself. This integrated approach delivers a zero-waste solution, reduces landfill dependence and complements conventional recycling by addressing waste streams that cannot be recycled or are contaminated.
Already recognised across regions including Europe, India, Latin America and North America, co-processing operates under strict regulatory and technical frameworks to ensure high standards of safety, emissions control and transparency.
Commenting on the initiative, Thomas Guillot, Chief Executive of the GCCA, said co-processing offers a circular, community-friendly waste solution but requires effective regulatory frameworks and supportive public policy to scale further. He noted that while some cement kilns already substitute over 90 per cent of their fuel with waste, many regions still lack established practices.
The joint statement urges governments and institutions to formally recognise co-processing within waste policy frameworks, support waste collection and pre-treatment, streamline permitting, count recycled material towards national recycling targets, and provide fiscal incentives that reflect environmental benefits. It also calls for stronger public–private partnerships and international knowledge sharing.
With global waste generation estimated at over 11 billion tonnes annually and uncontrolled municipal waste projected to rise sharply by 2050, the signatories believe co-processing represents a practical and scalable response. With appropriate policy backing, it can help divert waste from landfills, reduce fossil fuel use in cement manufacturing and transform waste into a valuable societal resource.    

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Industry Bodies Call for Wider Use of Cement Co-Processing

Joint statement seeks policy support for sustainable waste management

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Leading industry organisations have called for stronger policy support to accelerate the adoption of cement industry co-processing as a sustainable solution for managing non-recyclable and non-reusable waste. In a joint statement, bodies including the Global Cement and Concrete Association, European Composites Industry Association, International Solid Waste Association – Africa, Mission Possible Partnership and the Global Waste-to-Energy Research and Technology Council highlighted the role co-processing can play in addressing the growing global waste challenge.
Co-processing enables the use of waste as an alternative to fossil fuels in cement kilns, while residual ash is incorporated into cementitious materials, resulting in a zero-waste process. The approach supports both energy recovery and material recycling, complements conventional recycling systems and reduces reliance on landfill infrastructure. It is primarily applied to waste streams that are contaminated or unsuitable for recycling.
The organisations noted that co-processing is already recognised in regions such as Europe, India, Latin America and North America, operating under regulated frameworks to ensure safety, emissions control and transparency. However, adoption remains uneven globally, with some plants achieving over 90 per cent fuel substitution while others lack enabling policies.
The statement urged governments and institutions to formally recognise co-processing in waste management frameworks, streamline environmental permitting, incentivise waste collection and pre-treatment, account for recycled material content in national targets, and support public-private partnerships. The call comes amid rising global waste volumes, which are estimated at over 11 billion tonnes annually, with unmanaged waste contributing to greenhouse gas emissions, pollution and health risks.

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Why Cement Needs CCUS

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Cement’s deep decarbonisation cannot be achieved through efficiency and fuel switching alone, making CCUS essential to address unavoidable process emissions from calcination. ICR explores if with the right mix of policy support, shared infrastructure, and phased scale-up from pilots to clusters, CCUS can enable India’s cement industry to align growth with its net-zero ambitions.

Cement underpins modern development—from housing and transport to renewable energy infrastructure—but it is also one of the world’s most carbon-intensive materials, with global production of around 4 billion tonnes per year accounting for 7 to 8 per cent of global CO2 emissions, according to the GCCA. What makes cement uniquely hard to abate is that 60 to 65 per cent of its emissions arise from limestone calcination, a chemical process that releases CO2 irrespective of the energy source used; the IPCC Sixth Assessment Report (AR6) therefore classifies cement as a hard-to-abate sector, noting that even fully renewable-powered kilns would continue to emit significant process emissions. While the industry has achieved substantial reductions over the past two decades through energy efficiency, alternative fuels and clinker substitution using fly ash, slag, and calcined clays, studies including the IEA Net Zero Roadmap and GCCA decarbonisation pathways show these levers can deliver only 50 to 60 per cent emissions reduction before reaching technical and material limits, leaving Carbon Capture, Utilisation and Storage (CCUS) as the only scalable and durable option to address remaining calcination emissions—an intervention the IPCC estimates will deliver nearly two-thirds of cumulative cement-sector emission reductions globally by mid-century, making CCUS a central pillar of any credible net-zero cement pathway.

Process emissions vs energy emissions
Cement’s carbon footprint is distinct from many other industries because it stems from two sources: energy emissions and process emissions. Energy emissions arise from burning fuels to heat kilns to around 1,450°C and account for roughly 35 to 40 per cent of total cement CO2 emissions, according to the International Energy Agency (IEA). These can be progressively reduced through efficiency improvements, alternative fuels such as biomass and RDF, and electrification supported by renewable power. Over the past two decades, such measures have delivered measurable gains, with global average thermal energy intensity in cement production falling by nearly 20 per cent since 2000, as reported by the IEA and GCCA.
The larger and more intractable challenge lies in process emissions, which make up approximately 60 per cent to 65 per cent of cement’s total CO2 output. These emissions are released during calcination, when limestone (CaCO3) is converted into lime (CaO), inherently emitting CO2 regardless of fuel choice or energy efficiency—a reality underscored by the IPCC Sixth Assessment Report (AR6). Even aggressive clinker substitution using fly ash, slag, or calcined clays is constrained by material availability and performance requirements, typically delivering 20 to 40 per cent emissions reduction at best, as outlined in the GCCA–TERI India Cement Roadmap and IEA Net Zero Scenario. This structural split explains why cement is classified as a hard-to-abate sector and why incremental improvements alone are insufficient; as energy emissions decline, process emissions will dominate, making Carbon Capture, Utilisation and Storage (CCUS) a critical intervention to intercept residual CO2 and keep the sector’s net-zero ambitions within reach.

Where CCUS stands today
Globally, CCUS in cement is moving from concept to early industrial reality, led by Europe and North America, with the IEA noting that cement accounts for nearly 40 per cent of planned CCUS projects in heavy industry, reflecting limited alternatives for deep decarbonisation; a flagship example is Heidelberg Materials’ Brevik CCS project in Norway, commissioned in 2025, designed to capture about 400,000 tonnes of CO2 annually—nearly half the plant’s emissions—with permanent offshore storage via the Northern Lights infrastructure (Reuters, Heidelberg Materials), alongside progress at projects in the UK, Belgium, and the US such as Padeswood, Lixhe (LEILAC), and Ste. Genevieve, all enabled by strong policy support, public funding, and shared transport-and-storage infrastructure.
These experiences show that CCUS scales fastest when policy support, infrastructure availability, and risk-sharing mechanisms align, with Europe bridging the viability gap through EU ETS allowances, Innovation Fund grants, and CO2 hubs despite capture costs remaining high at US$ 80-150 per tonne of CO2 (IEA, GCCA); India, by contrast, is at an early readiness stage but gaining momentum through five cement-sector CCU testbeds launched by the Department of Science and Technology (DST) under academia–industry public–private partnerships involving IITs and producers such as JSW Cement, Dalmia Cement, and JK Cement, targeting 1-2 tonnes of CO2 per day to validate performance under Indian conditions (ETInfra, DST), with the GCCA–TERI India Roadmap identifying the current phase as a foundation-building decade essential for achieving net-zero by 2070.
Amit Banka, Founder and CEO, WeNaturalists, says “Carbon literacy means more than understanding that CO2 harms the climate. It means cement professionals grasping why their specific plant’s emissions profile matters, how different CCUS technologies trade off between energy consumption and capture rates, where utilisation opportunities align with their operational reality, and what governance frameworks ensure verified, permanent carbon sequestration. Cement manufacturing contributes approximately 8 per cent of global carbon emissions. Addressing this requires professionals who understand CCUS deeply enough to make capital decisions, troubleshoot implementation challenges, and convince boards to invest substantial capital.”

Technology pathways for cement
Cement CCUS encompasses a range of technologies, from conventional post-combustion solvent-based systems to process-integrated solutions that directly target calcination, each with different energy requirements, retrofit complexity, and cost profiles. The most mature option remains amine-based post-combustion capture, already deployed at industrial scale and favoured for early cement projects because it can be retrofitted to existing flue-gas streams; however, capture costs typically range from US$ 60-120 per tonne of CO2, depending on CO2 concentration, plant layout, and energy integration.
Lovish Ahuja, Chief Sustainability Officer, Dalmia Cement (Bharat), says, “CCUS in Indian cement can be viewed through two complementary lenses. If technological innovation, enabling policies, and societal acceptance fail to translate ambition into action, CCUS risks becoming a significant and unavoidable compliance cost for hard-to-abate sectors such as cement, steel, and aluminium. However, if global commitments under the Paris Agreement and national targets—most notably India’s Net Zero 2070 pledge—are implemented at scale through sustained policy and industry action, CCUS shifts from a future liability to a strategic opportunity. In that scenario, it becomes a platform for technological leadership, long-term competitiveness, and systemic decarbonisation rather than merely a regulatory burden.”
“Accelerating CCUS adoption cannot hinge on a single policy lever; it demands a coordinated ecosystem approach. This includes mission-mode governance, alignment across ministries, and a mix of enabling instruments such as viability gap funding, concessional and ESG-linked finance, tax incentives, and support for R&D, infrastructure, and access to geological storage. Importantly, while cement is largely a regional commodity with limited exportability due to its low value-to-weight ratio, CCUS innovation itself can become a globally competitive export. By developing, piloting, and scaling cost-effective CCUS solutions domestically, India can not only decarbonise its own cement industry but also position itself as a supplier of affordable CCUS technologies and services to cement markets worldwide,” he adds.
Process-centric approaches seek to reduce the energy penalty associated with solvent regeneration by altering where and how CO2 is separated. Technologies such as LEILAC/Calix, which uses indirect calcination to produce a high-purity CO2 stream, are scaling toward a ~100,000 tCO2 per year demonstrator (LEILAC-2) following successful pilots, while calcium looping leverages limestone chemistry to achieve theoretical capture efficiencies above 90 per cent, albeit still at pilot and demonstration stages requiring careful integration. Other emerging routes—including oxy-fuel combustion, membrane separation, solid sorbents, and cryogenic or hybrid systems—offer varying trade-offs between purity, energy use, and retrofit complexity; taken together, recent studies suggest that no single technology fits all plants, making a multi-technology, site-specific approach the most realistic pathway for scaling CCUS across the cement sector.
Yash Agarwal, Co-Founder, Carbonetics Carbon Capture, says, “We are fully focused on CCUS, and for us, a running plant is a profitable plant. What we have done is created digital twins that allow operators to simulate and resolve specific problems in record time. In a conventional setup, when an issue arises, plants often have to shut down operations and bring in expert consultants. What we offer instead is on-the-fly consulting. As soon as a problem is detected, the system automatically provides a set of potential solutions that can be tested on a running plant. This approach ensures that plant shutdowns are avoided and production is not impacted.”

The economics of CCUS
Carbon Capture, Utilisation and Storage (CCUS) remains one of the toughest economic hurdles in cement decarbonisation, with the IEA estimating capture costs of US$ 80-150 per tonne of CO2, and full-system costs raising cement production by US$ 30-60 per tonne, potentially increasing prices by 20 to 40 per cent without policy support—an untenable burden for a low-margin, price-sensitive industry like India’s.
Global experience shows CCUS advances beyond pilots only when the viability gap is bridged through strong policy mechanisms such as EU ETS allowances, Innovation Fund grants, and carbon Contracts for Difference (CfDs), yet even in Europe few projects have reached final investment decision (GCCA); India’s lack of a dedicated CCUS financing framework leaves projects reliant on R&D grants and balance sheets, reinforcing the IEA Net Zero Roadmap conclusion that carbon markets, green public procurement, and viability gap funding are essential to spread costs across producers, policymakers, and end users and prevent CCUS from remaining confined to demonstrations well into the 2030s.

Utilisation or storage
Carbon utilisation pathways are often the first entry point for CCUS in cement because they offer near-term revenue potential and lower infrastructure complexity. The International Energy Agency (IEA) estimates that current utilisation routes—such as concrete curing, mineralisation into aggregates, precipitated calcium carbonate (PCC), and limited chemical conversion—can realistically absorb only 5 per cent to 10 per cent of captured CO2 at a typical cement plant. In India, utilisation is particularly attractive for early pilots as it avoids the immediate need for pipelines, injection wells, and long-term liability frameworks. Accordingly, Department of Science and Technology (DST)–supported cement CCU testbeds are already demonstrating mineralisation and CO2-cured concrete applications at 1–2 tonnes of CO2 per day, validating performance, durability, and operability under Indian conditions.
However, utilisation faces hard limits of scale and permanence. India’s cement sector emits over 200 million tonnes of CO2 annually (GCCA), far exceeding the absorptive capacity of domestic utilisation markets, while many pathways—especially fuels and chemicals—are energy-intensive and dependent on costly renewable power and green hydrogen. The IPCC Sixth Assessment Report (AR6) cautions that most CCU routes do not guarantee permanent storage unless CO2 is mineralised or locked into long-lived materials, making geological storage indispensable for deep decarbonisation. India has credible storage potential in deep saline aquifers, depleted oil and gas fields, and basalt formations such as the Deccan Traps (NITI Aayog, IEA), and hub-based models—where multiple plants share transport and storage infrastructure—can reduce costs and improve bankability, as seen in Norway’s Northern Lights project. The pragmatic pathway for India is therefore a dual-track approach: utilise CO2 where it is economical and store it where permanence and scale are unavoidable, enabling early learning while building the backbone for net-zero cement.

Policy, infrastructure and clusters
Scaling CCUS in the cement sector hinges on policy certainty, shared infrastructure, and coordinated cluster development, rather than isolated plant-level action. The IEA notes that over 70 per cent of advanced industrial CCUS projects globally rely on strong government intervention—through carbon pricing, capital grants, tax credits, and long-term offtake guarantees—with Europe’s EU ETS, Innovation Fund, and carbon Contracts for Difference (CfDs) proving decisive in advancing projects like Brevik CCS. In contrast, India lacks a dedicated CCUS policy framework, rendering capture costs of USD 80–150 per tonne of CO2 economically prohibitive without state support (IEA, GCCA), a gap the GCCA–TERI India Cement Roadmap highlights can be bridged through carbon markets, viability gap funding, and green public procurement.
Milan R Trivedi, Vice President, Shree Digvijay Cement, says, “CCUS represents both an unavoidable near-term compliance cost and a long-term strategic opportunity for Indian cement producers. While current capture costs of US$ 100-150 per tonne of CO2 strain margins and necessitate upfront retrofit investments driven by emerging mandates and NDCs, effective policy support—particularly a robust, long-term carbon pricing mechanism with tradable credits under frameworks like India’s Carbon Credit Trading Scheme (CCTS)—can de-risk capital deployment and convert CCUS into a competitive advantage. With such enablers in place, CCUS can unlock 10 per cent to 20 per cent green price premiums, strengthen ESG positioning, and allow Indian cement to compete in global low-carbon markets under regimes such as the EU CBAM, North America’s buy-clean policies, and Middle Eastern green procurement, transforming compliance into export-led leadership.”
Equally critical is cluster-based CO2 transport and storage infrastructure, which can reduce unit costs by 30 to 50 per cent compared to standalone projects (IEA, Clean Energy Ministerial); recognising this, the DST has launched five CCU testbeds under academia–industry public–private partnerships, while NITI Aayog works toward a national CCUS mission focused on hubs and regional planning. Global precedents—from Norway’s Northern Lights to the UK’s HyNet and East Coast clusters—demonstrate that CCUS scales fastest when governments plan infrastructure at a regional level, making cluster-led development, backed by early public investment, the decisive enabler for India to move CCUS from isolated pilots to a scalable industrial solution.
Paul Baruya, Director of Strategy and Sustainability, FutureCoal, says, “Cement is a foundational material with a fundamental climate challenge: process emissions that cannot be eliminated through clean energy alone. The IPCC is clear that in the absence of a near-term replacement of Portland cement chemistry, CCS is essential to address the majority of clinker-related emissions. With global cement production at around 4 gigatonnes (Gt) and still growing, cement decarbonisation is not a niche undertaking, it is a large-scale industrial transition.”

From pilots to practice
Moving CCUS in cement from pilots to practice requires a sequenced roadmap aligning technology maturity, infrastructure development, and policy support: the IEA estimates that achieving net zero will require CCUS to scale from less than 1 Mt of CO2 captured today to over 1.2 Gt annually by 2050, while the GCCA Net Zero Roadmap projects CCUS contributing 30 per cent to 40 per cent of total cement-sector emissions reductions by mid-century, alongside efficiency, alternative fuels, and clinker substitution.
MM Rathi, Joint President – Power Plants, Shree Cement, says, “The Indian cement sector is currently at a pilot to early demonstration stage of CCUS readiness. A few companies have initiated small-scale pilots focused on capturing CO2 from kiln flue gases and exploring utilisation routes such as mineralisation and concrete curing. CCUS has not yet reached commercial integration due to high capture costs (US$ 80-150 per tonne of CO2), lack of transport and storage infrastructure, limited access to storage sites, and absence of long-term policy incentives. While Europe and North America have begun early commercial deployment, large-scale CCUS adoption in India is more realistically expected post-2035, subject to enabling infrastructure and policy frameworks.”
Early pilots—such as India’s DST-backed CCU testbeds and Europe’s first commercial-scale plants—serve as learning platforms to validate integration, costs, and operational reliability, but large-scale deployment will depend on cluster-based scale-up, as emphasised by the IPCC AR6, which highlights the need for early CO2 transport and storage planning to avoid long-term emissions lock-in. For India, the GCCA–TERI India Roadmap identifies CCUS as indispensable for achieving net-zero by 2070, following a pragmatic pathway: pilot today to build confidence, cluster in the 2030s to reduce costs, and institutionalise CCUS by mid-century so that low-carbon cement becomes the default, not a niche, in the country’s infrastructure growth.

Conclusion
Cement will remain indispensable to India’s development, but its long-term viability hinges on addressing its hardest emissions challenge—process CO2 from calcination—which efficiency gains, alternative fuels, and clinker substitution alone cannot eliminate; global evidence from the IPCC, IEA, and GCCA confirms that Carbon Capture, Utilisation and Storage (CCUS) is the only scalable pathway capable of delivering the depth of reduction required for net zero. With early commercial projects emerging in Europe and structured pilots underway in India, CCUS has moved beyond theory into a decisive decade where learning, localisation, and integration will shape outcomes; however, success will depend less on technology availability and more on collective execution, including coordinated policy frameworks, shared transport and storage infrastructure, robust carbon markets, and carbon-literate capabilities.
For India, a deliberate transition from pilots to practice—anchored in cluster-based deployment, supported by public–private partnerships, and aligned with national development and climate goals—can transform CCUS from a high-cost intervention into a mainstream industrial solution, enabling the cement sector to keep building the nation while sharply reducing its climate footprint.

– Kanika Mathur

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