suggests that the next decade will determine whether CCUS scales from demonstration to a mainstream pathway for net-zero cement.

Cement forms the essential foundation of modern infrastructure—homes, roads, ports, hospitals, wind turbine bases, and transmission pylons. It is also one of the most challenging industrial products to decarbonise at scale. That’s why carbon capture, utilisation and storage (CCUS)—has shifted from a “nice to have” to a strategic necessity for many credible net-zero pathways.

Annual carbon dioxide (CO2) emissions from cement are around 1.6 Gt worldwide and could more than double by 2050. To many, decarbonisation involves replacing fuels, but cement differs: a significant portion of its emissions comes from chemical processes rather than fuel combustion.

Cement’s climate footprint is significant. Global cement production totals around 4 billion tonnes per year, produced across more than 3,100 plants worldwide. At this scale, even relatively modest emissions intensity results in substantial absolute emissions. As a result, cement production is widely estimated to account for around 7–8 per cent of global CO2 emissions.

A key step in cement production is the creation of clinker, an intermediate product that is ground into cement. Clinker forms by heating limestone (calcium carbonate), which breaks down into lime (calcium oxide) and releases CO2. Even with a kiln powered entirely by zero-carbon electricity, the calcination process will still emit CO2.

FutrureCoal’s Sustainable Coal Stewardship explores solutions for fossil fuel users. For example, clinker substitution using coal fly ash can significantly reduce emissions; however, it cannot eliminate the chemical release of CO2. CCUS is one of the few mature options capable of substantially removing the remaining CO2.

The IPCC considers cement a “hard-to-abate” sector. In its Sixth Assessment Report (AR6), it states that CCS is crucial to eliminate calcination emissions, which account for 60 per cent of GHG emissions in modern cement plants (IPCC). Worldwide, CCUS will deliver two-thirds of cement sector emissions reductions by mid-century (CemNet+1).

No single capture technology fits all plants, a variety is needed. These methods begin with proven post-combustion capture, then incorporate advanced, process-specific, and next-generation technologies as plants develop, energy systems decarbonise, and transport and storage infrastructure expand.

Global cement demand is strongly connected to urbanisation, infrastructure development, and housing. Mature markets may plateau, while emerging markets can experience rapid growth.

India is central to the global cement transition for three reasons: scale, growth trajectory, and the policy imperative to reconcile development with climate commitments.

The US Geological Survey (USGS) estimates India produced ~420 Mt in 2023 and ~450 Mt in 2024. That makes India one of the world’s largest producers, with continued capacity additions expected as infrastructure and housing demand grow.

Cement accounts for approximately 7–8 per cent of global CO2 emissions and around 5.8 per cent of India’s CO2 emissions in 2022, (GCCA). As India works toward its 2070 net-zero target, carbon capture, utilisation and storage (CCUS) will be an important component of its longer-term decarbonisation pathway.

India also highlights a broader reality: cement decarbonisation cannot rely on a single solution. Instead, it will require a combination of measures, likely including:

Carbon capture at cement plants is technically feasible, but still faces significant practical and economic challenges:

A challenging gas stream: Cement flue gas contains CO2 along with impurities and exhibits variable flow and temperature conditions. Capture units (amines, membranes, calcium looping, oxyfuel, etc.) need to be integrated carefully to avoid disrupting kiln operations.

Energy penalty and heat management: Many capture systems require significant energy, such as steam for solvent regeneration. Providing that energy without merely shifting emissions elsewhere is a design challenge; it encourages plants to research and develop low-energy solutions, waste heat recovery, blending low-carbon fuels, or all of the above.

Space constraints and retrofit limitations: Older plants may lack the physical footprint for large-scale capture equipment, compression, liquefaction, and CO2-handling infrastructure—especially in land-constrained industrial clusters.

Transport and storage are not “at the factory gate”: Even if capture is successful, you still need pipelines, shipping terminals, injection wells, permits, monitoring, and long-term liability frameworks. Cement CCS progresses most quickly where shared CO2 infrastructure is in place.

This is why projects increasingly cluster around hubs and why policy support and shared infrastructure are often the difference between pilot and commercial deployment.

A few projects demonstrate where the sector currently stands, progressing from pilots and studies into first-wave industrial deployment.

Brevik CCS (Norway): Heidelberg Materials inaugurated Brevik CCS in mid-2025, described as the world’s first industrial-scale CCS facility in the cement industry, designed to capture ~0.4 Mt CO2per year (Heidelberg Materials). CO2 will be shipped to Norway’s Northern Lights storage facility and the capture volume will equal half the plant’s total emissions at full capture (Reuters). Brevik is a blueprint to demonstrate end-to-end integration from capture to storage.

Padeswood (UK): Heidelberg’s cement plant at Padeswood has its CCS project construction slated to start in 2025 and net-zero cement production targeted for 2029 (Reuters). This underscores how public funding and CO2 infrastructure (Liverpool Bay storage) can unlock investment timelines.

LEILAC (Belgium): The EU-supported LEILAC project at Heidelberg Materials’ Lixhe cement plant in Belgium is testing a novel approach that targets process emissions rather than combustion emissions. The pilot facility is designed to capture approximately 18,000 tonnes of CO2 per year, with the follow-on LEILAC-2 phase exploring pathways to scale the technology toward commercial deployment (CINEA).

North America: In the United States, Holcim’s Ste. Genevieve cement plant has completed a front-end engineering and design (FEED) study assessing commercial-scale carbon capture, targeting up to 95 per cent of total CO2 emissions using an Air Liquide capture technology (OSTI). While not every FEED study progresses to a final investment decision, these projects provide important insight into where cement-sector carbon capture could realistically be heading.

India is exploring multiple technical approaches instead of a single solution. The country’s strategy involves government-backed testbeds to reduce risks in real-world plant conditions and industry roadmaps that show CCS/CCUS is essential for deep emission cuts. The Indian government is establishing five CCU testbeds in the cement industry through a public–private partnership (ETInfra.com+1). It focuses on hubs and storage options as enabling infrastructure to develop at scale (GCCA). India has launched a first-of-its-kind cluster of five CCU testbeds for the cement sector, organised as academia–industry pilots under a PPP model (ETInfra.com+1) including:

Why the “hubs + storage” framing matters for India? Capture at plant level is only part of the solution: meaningful scale also relies on gas transport, permanent storage, and the development of CO2 hubs (Clean Energy Ministerial+1). This hub approach is particularly relevant because it can:

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, absent 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.

The emergence of operational projects such as Brevik, the expansion of hub-linked initiatives across Europe, and a growing pipeline of pilots and front-end engineering studies indicate that the sector is beginning to move from ambition to execution. The coming decade will be decisive in determining whether CCS remains a premium, limited pathway, or becomes a mainstream industrial standard for delivering net-zero cement.

Paul Baruya, Director of Strategy and Sustainability, FutureCoal, is a strategy and sustainability leader shaping FutureCoal’s vision for the role of coal in a net-zero future, bringing deep expertise in energy markets, emissions modelling, and transition pathways.

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.

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.

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.”

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.”

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.

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.

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.”

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.

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

suggests CCUS is the indispensable final lever for cement decarbonisation in India, moving from pilot-stage today to a policy-driven necessity.

In this interview, MM Rathi, Joint President – Power Plants, Shree Cement, offers a candid view on India’s CCUS readiness, the economic and technical challenges of integration, and why policy support and cluster-based infrastructure will be decisive in taking CCUS from pilot stage to commercial reality.

CCUS is critical and ultimately indispensable for deep decarbonisation in cement. Around 60 per cent to 65 per cent of cement emissions arise from limestone calcination, an inherent chemical process that cannot be addressed through energy efficiency, renewables, or alternative fuels. Clinker substitution using fly ash, slag, and calcined clay can reduce emissions by 20 per cent to 40 per cent, while energy transition measures can abate 30 per cent to 40 per cent of fuel-related emissions. These are cost-effective, scalable, and form the foundation of decarbonisation efforts.

However, these levers alone cannot deliver reductions beyond 60 per cent. Once they reach technical and regional limits, CCUS becomes the only viable pathway to address residual

process emissions. In that sense, CCUS is not an alternative but the final, non-negotiable step toward net-zero cement.

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.

Retrofitting CCUS into existing Indian cement plants presents multiple challenges. Many plants have compact layouts with limited space for capture units, compressors, and CO2 handling systems, requiring modular and carefully phased integration.

Kiln flue gases contain high CO2 concentrations along with dust and impurities, increasing risks of fouling and corrosion and necessitating robust gas pre-treatment. Amine-based capture systems also require significant thermal energy, and improper heat integration can affect clinker output, making waste heat recovery critical.

Additional challenges include higher power and water demand, pressure drops in the gas path, and maintaining kiln stability and product quality. Without careful design, CCUS can impact productivity and reliability.

At capture costs of US$ 80-150 per tonne of CO2, CCUS can increase cement production costs by US$ 30-60 per tonne, potentially raising cement prices by 20 to 40 per cent. Initially, producers absorb the capital and operating costs, which can compress margins. Over time, without policy support, these costs are likely to be passed on to consumers, affecting affordability in a highly price-sensitive market like India. Policy mechanisms such as subsidies, tax credits, carbon markets, and green finance can significantly reduce this burden and enable cost-sharing across producers, policymakers, and end users.

Carbon utilisation can play a supportive and transitional role, particularly in early CCUS deployment. Applications such as concrete curing and mineralisation can reuse 5 to 10 per cent of captured CO2 while improving material performance. Fuels and chemicals offer niche opportunities but depend on access to low-cost renewable energy. However, utilisation pathways are limited in scale and often involve temporary carbon storage. With India’s cement sector emitting over 200 million tonnes of CO2 annually, utilisation alone cannot deliver deep decarbonisation.

Long-term geological storage offers permanent sequestration at scale. India has significant potential in deep saline aquifers and depleted oil and gas fields, which will be essential for achieving net-zero cement production.

Government policy support is central to making CCUS commercially viable in India. Without intervention, CCUS costs remain prohibitive and adoption will remain limited to pilots.

Carbon markets can provide recurring revenue streams, while capital subsidies, tax incentives, and concessional financing can reduce upfront risk. Regulatory mandates and green public procurement can further accelerate adoption by creating predictable demand for low-carbon cement. CCUS will not scale through market forces alone; policy design will determine its pace and extent of deployment.

In the near term, CCUS is most viable for large, modern integrated plants due to economies of scale, better layout flexibility, and access to waste heat recovery. Mid-sized plants may adopt CCUS selectively over time through modular systems and shared CO2 infrastructure, though retrofit costs can be 30 to 50 per cent higher. For older plants nearing the end of their operational life, CCUS retrofitting is generally not economical, and decarbonisation efforts are better focused on efficiency, fuels, and clinker substitution.

Over the next decade, CCUS is expected to shift from a competitive advantage to a regulatory necessity. In the short term, early adopters can access green finance, premium procurement opportunities, and sustainability leadership positioning. Beyond 2035, as emissions regulations tighten, CCUS will become essential for addressing process emissions. By 2050, it is likely to be a mandatory component of the cement sector’s net-zero pathway rather than a strategic choice.

In a two-part series, Consultant and Advisor Shreesh A Khadilkar, discusses how advanced additive formulations allow for customised, high-performance and niche cements.

Cement additives are chemicals (inorganic and organic) added in small amounts (0.01 per cent to 0.2 per cent by weight) during cement grinding. Their main job? Reduce agglomeration, prevent pack-set, and keep the mill running smoother. Thus, these additions primarily improve, mill thru-puts, achieve lower clinker factor in blended cements PPC/PSC/PCC. Additionally, these additives improve concrete performance of cements or even for specific special premium cements with special USPs like lower setting times or for reduced water permeability in the resultant cement mortars and concrete (water repellent /permeation resistant cements), corrosion resistance etc

The Cement additives are materials which could be further differentiated as:

When cement additives are used as grinding aids or quality improvers, in general the additives reduce the inter-particle forces; reduce coating over grinding media and mill internals. Due to creation of like charges on cement particles, there is decreased agglomeration, much improved flowability, higher generation of fines better dispersion of particles in separator feed and reduction of mill filling level (decrease of residence time). However, in VRM grinding; actions need to be taken to have stable bed formation on the table.

It has been reported in literature and also substantiated by a number of detailed evaluations of different cement additive formulations in market, that the cement additive formulations are a combination of different chemical compounds, composed of:

1. Accelerator/s for the hydration reaction of cements which are dependent on the acceleration effect desired in mortar compressive strengths at early or later ages, the choice of the materials is also dependent on clinker quality and blending components (flyash / slag) or a mix of both.

2. Water reducer / workability / wet-ability enhancer, which would show impact on the resultant cement mortars and concrete. Some of the compounds (retarders) like polysaccharide derivatives, gluconates etc., show an initial retarding action towards hydration which result in reducing the water requirements for the cements thus act as water reducers, or it could be some appropriate polymeric molecules which show improved wet-ability and reduce water demand. These are selected based on the mineral component and type of Cements (PPC/PSC /PCC).

3. Grinding aids: Compounds that work as Grinding Aid i.e. which would enhance Mill thru-put on one hand as well as would increase the early strengths due to the higher fines generation/ or activation of cement components. These compounds could be like alkanol-amines such as TIPA, DEIPA, TEA etc. or could be compounds like glycols and other poly-ols, depending on whether it is OPC or PPC or PSC or PCC manufacture.

1. Reduce Agglomeration ; Cement particles get electrostatically charged during grinding; stick together ; form “flocs” ; block mill efficiency ; waste energy. Grinding aid molecules adsorb onto particle surfaces ; neutralise charge ; prevent re-agglomeration.

2. Improve Powder Flowability; Adsorbed molecules create a lubricating layer; particles slide past each other easier ; better mill throughput ; less “dead zone” buildup.

;Also reduces caking on mill liners, diaphragms, and separator screens ; less downtime for cleaning.

3. Enhance Grinding Efficiency (Finer Product Faster) ; By preventing agglomeration, particles stay dispersed ; more surface area exposed to grinding media ? finer grind achieved with same energy input ; Or: same fineness achieved with less energy ; huge savings.

:

4. Reduce Pack Set and Silo Caking, Grinding aids (GA) inhibit hydration of free lime (CaO) during storage ,  prevents premature hardening or “pack set” in silos. , especially critical in humid climates or with high free lime clinker.

It may be stated here that overdosing of GA , can cause: – Foaming in mill (especially with glycols) ? reduces grinding efficiency, retardation of cement setting (especially with amines/acids), odor issues (in indoor mills) – Corrosion of mill components (if acidic aids used improperly)

The best practice to optimise use of GA is , Start with 0.02 per cent to 0.05 per cent dosage , test fineness, flow, and set time , adjust up/down. Due to static charge of particles, the sample may stick to the sides of sampler pipe and so sampling need to be properly done.

Depending on type of Cements i.e. OPC, PPC, PSC, PCC, the grinding aids combinations need to be optimised, a typical Poly carboxylate ether also could be a part of the combo grinding aids

The cement additives can also be tailor made to create specific niche properties in Cements, OPC, PPC, PSC and PCC to create premium or special brands. The special niche properties of the cement being its additional USP of such cement products, and are useful for customers to build a durable concrete structure with increased service life.

Such properties could be:

High early strengths: Use of Accelerators. These are chemical compounds which enhance the degree of hydration of cement. These can include setting or hardening accelerators depending on whether their action occurs in the plastic or hardened state respectively. Thus, the setting accelerators reduce the setting time, whereas the hardening accelerators increase the early age strengths. The setting accelerators act during the initial minutes of the cement hydration, whereas the hardening accelerators act mainly during the initial days of hydration.

Chloride salts are the best in class. However, use of chloride salts as hardening accelerators are strongly discouraged for their action in promoting the corrosion of rebar, thus, chloride-free accelerators are preferred. The hardening accelerators could be combinations of compounds like nitrate, nitrite and thiocyanate salts of alkali or alkaline earth metals or thiosulphate, formate, and alkanol amines depending on the cement types.

However, especially in blended Cements (PPC/PSC/PCC the increased early strengths invariably decrease the 28 Day Strengths. These aspects lead to creating combo additives along with organic polymers to achieve improved early strengths as well as either same or marginally improved 28 Days strengths with reduced clinker factor in the blended cement, special OPC with reduced admixture requirements. With use of appropriate combination of inorganic and organic additives we could create an OPC with substantially reduced water demand or improved slump retentivity. Use of such an OPC would show exceptional concrete performance in high grade concretes as it would exhibit lower admixture requirements in High Grade Concretes.

PPC with OPC like Properties: With the above concept we could have a PPC, having higher percentage flyash, with a combo cement additive which would have with concrete performance similar to OPC in say M40/M50 concrete. Such a PPC would produce a high-strength PPC concrete (= 60 MPa @ 28d) + Improved Workability, Durability and Sustainability.

Another interesting aspect could also be of using Ultrafine fine flyash /ultrafine slags as additions in OPC/PPC/PSC for achieving lower clinker factor as well as to achieve improved later age strengths with or without a combo cement additive.

The initial adhesion property at sites of especially PPC/PSC/PCC based mortars can be improved through use of appropriate organic polymers addition during the manufacture of these cements. Such Cements would have a better adhesion property for plastering/brick bonding etc., as it has much lower rebound loss of their Mortars in such applications.

It is needless to mention here that with use of additives, we could also have cement with viscosity modifying cement additives, for self-compaction and self-leveling concrete performance.

Use of Phosphogypsum retards the setting time of cements, we can use additive different additive combos to overcome retardation and improve the 1 day strengths of the cements and concretes.

The concluding part of this article will appear in the next issue of ICR.

Shreesh Khadilkar, Consultant & Advisor, Former Director Quality & Product Development, ACC, a seasoned 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.