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Asok Kr. Dikshit, Richa Mazumder, Sanjeev Kr. Chaturvedi and Lok Pratap Singh, National Council for Cement and Building Materials (NCB), discuss the themes of sustainable development in India’s cement sector, in the concluding section of a three-part series.

Studies carried out in NCB in the area of raw material substitution are discussed below:

I. Investigation for Standardisation of High Magnesia (MgO) Clinker for the Manufacture of PPC and PSC Blended Cement
The objective of this study was to investigate the performance of PPC and PSC cements prepared from high magnesia clinker to utilise high MgO bearing low grade limestone for the manufacturing of Portland clinker resulting in preservation of natural resources and sustainable development. Four types of high MgO clinker samples containing MgO as high as upto 8.4 per cent from different cement plants were procured along with other cementitious and additive samples such as fly ash, GBF slag and gypsum for the manufacture of OPC, PPC and PSC. These cement samples were prepared by intergrinding the constituents in a laboratory ball mill keeping the fineness level 350±10 m2/kg. The results of investigation revealed that addition of fly ash and granulated blast furnace slag (GBFS) in the blended cements prepared from high MgO clinker samples were found to have potential effect on arresting the expansion caused by periclase (MgO). The minimum fly ash content was optimised to be 25 per cent by weight in case of PPC and the minimum slag content was optimised to be 35 per cent in case PSC while utilising high MgO clinker for the manufacture of blended cement. The performance results obtained so far are quite encouraging. Use of high magnesia (MgO) clinker for the manufacturing of the PPC and PSC will pave the way for utilisation of high MgO content low grade limestone containing high MgO resulting in increased mine life besides improved sustainability in cement manufacture.

II. Manufacture of Synthetic Gypsum from Marble Slurry for Subsequent use in
Cement Production

The generation of waste marble slurry in India is in the range of 5 to 6 million tonnes per annum. The heaps of this waste material occupy large land areas and remain scattered all around at the marble processing unit, affecting the environment, eco-system and health of the people in the area. The chemical composition of marble slurry indicates predominance of calcium carbonate which is a suitable raw material for various industrial applications. One of its possible areas of utilisation is its conversion into gypsum that can be used as set controller in cement industry. Marble slurry samples were collected from clusters at Kishangarh, Makrana, Rajsamand and Udaipur in Rajasthan and characterised for their physical and chemico-mineralogical properties. Samples of synthetic gypsum with well grown crystalline phases were prepared in the laboratory by inducing chemical reaction using sulphuric acid and marble slurry. The amount of sulphuric acid to be consumed in its complete reaction with marble slurry was found to be dependent on the composition of the marble slurry especially on CaO and MgO content. The physical characteristics like specific gravity and whiteness index of the laboratory prepared gypsum samples were found to be more or less comparable to mineral gypsum. The percentage purity of different synthetic gypsum samples prepared were 87.91, 89.55, 86.02 and 88.26 per cent.

III. Production of Synthetic Slag from Low Grade Limestone
For development of Synthetic Slag using low-grade limestone, a study was carried out at NCB laboratory. In this study laboratory slag samples prepared with low-grade limestones and other additive materials, which found to be conforming the IS: 12089-1987. These laboratories made synthetic slag samples as shown in Fig 9. were also investigated by optical microscopy as shown in Fig 10. They found to have maximum 92 per cent glass content, which is greater than 85 per cent as specified in IS-12089. PSC samples were prepared with 40 and 60 per cent synthetic slag replacing equal quantity of clinker. The performance of PSC blends prepared using synthetic slag sample equal quantity of clinker. The performance of PSC blends prepared using synthetic slag sample were found as per requirements of Indian Standard Specification, IS: 455-1989 for PSC. As the limestone, which is getting depleted and has reached to an alarming level where the availability of cement grade limestone in India has reduced to 8949 million tonnes only, Synthetic Slag may play a vital role to replace clinker or indirectly cement grade limestone. However, the main challenge would be to produce synthetic slag at industrial scale.

Clinker substitution
A very effective strategy towards resource management and reduce CO2 emissions is to substitute some of the Portland cement clinker with other materials. These are known variously as mineral additions or supplementary cementitious materials (SCMs), and also include almost inert materials, which may also be called fillers. Clinker can be blended with a range of alternative materials, including pozzolans, finely ground limestone and waste materials or industrial by-products. The most common clinker substitutes are reactive by-products from other industries: granulated blast furnace slag (GBFS),a by-product of pig-iron production in blast furnaces, and fly ash (FA), generated by burning coal to produce electricity.
The clinker-to-cement ratio (percentage of clinker compared to other non-clinker components) has an impact on the properties of cement so standards determine the type and proportion of alternative main constituents that can be used. To ensure the future use of other constituents, the cement industry is dependent on the local supply of these materials. The use of other constituents in cement and the reduction of the clinker-to-cement ratio means lower emissions and lower energy use. Other materials that can be used: Natural pozzolans, such as clays, shale and certain types of sedimentary rocks., Limestone (finely ground), which can be added to clinker (without being heated and transformed into lime), Silica fume, a pozzolanic material and a by-product in the production of silicon or ferrosilicon alloys, Granulated blast furnace slag (GBFS), Fly ash etc.
Apart from these NCB also worked on several projects like Portland Limestone Cement, Composite cement, Portland Dolomitic Cement etc. NCB in one of its projects has successfully utilised up to 15 per cent dolomite as an additive replacing equal quantity of clinker. The cement performance was found to be similar to that of control cement prepared without dolomite.
Similarly, NCB has carried out several studies on composite cement wherein combinations of fly ash and granulated blast furnace slag were used for preparing composite cement blends. BIS has brought out standard specification IS: 16415-2015 for composite cement on recommendations of NCB.
Development of Portland Composite Cement (Fly ash/Slag and Limestone based), Development of Portland Limestone Cement (PLC), utilisation of low grade limestone and mines rejects, Utilisation of Construction and demolished waste (C&D) waste based aggregates in concrete structures and pavements are some of the key areas, where Indian Cement Industry and NCB is working together towards natural resource management and promoting circular economy which are the key themes towards sustainable development in cement sector. Some of the work that has been carried out in NCB discussed below:

I. Investigations on Development of Portland Composite Cements based on Fly Ash and Limestone
Portland composite cement blends were prepared (80 nos.) with four types of clinker from different regions of India along with the regional available Fly ash and limestone. The materials were ground in a laboratory ball mill with a capacity of about 8 kg by inter-grinding method. The clinker inter-ground with 3.7 per cent of gypsum by mass is referred to as OPC. A series of tests was carried out on various mixes of limestone-fly ash cement mortars in order to investigate the effects of using different percentages of lime and fly ash as a replacement of cement on the compressive strength of such mortars at various ages. Different mix proportions were adopted for the experimental work. Clinker quality plays an important role on performance of limestone and fly ash based composite cements. PCC samples containing Fly ash and Limestone up to the level off 30 per cent and 7 per cent respectively comply with IS 16415-2015 at all ages. Lower levels of limestone additions show higher percentage of difference between IS requirements and obtained results. Whereas 10 per cent replacement shows marginal difference between IS requirements and obtained results. PCC samples of 5 per cent replacement of Flyash with Limestone comply performance with respective PPC samples at all ages.

II. Investigations on Portland Limestone Cement
European Standard EN-197-1 permits the use of maximum 35 per cent limestone in the manufacture of Portland Limestone Cement. Presently, in India, there is no standard on Portland Limestone Cement. The main objective of the study is to investigate the feasibility of using different grades of limestone in development of Portland Limestone Cement in order to formulate new Indian standard for its commercialisation along with lowering in clinker factor in cement for environmental sustainability. To carry out the study, different Portland Limestone Cement blends were prepared by inter-grinding of 10, 20 and 30 wt. per cent cement grade of limestone, dolomitic limestone and low grade limestone with OPC clinker and gypsum. The cement blends were designated as PLC-A, PLC-B and PLC-C corresponding to cement grade limestone, dolomitic limestone and low grade limestone. The trend of compressive strength development showed marginal reduction in strength development with increasing dosages of limestone in cement mix. However, increase in the early strength has observed with addition of low quality of limestone that may be attributed to the formation of monocarboaluminate phase.

Alternative Binders
The idea of alternative binders/novel cements is to introduce different raw materials in clinker and cement manufacturing processes without compromising the efficiency and quality of cement that will emit less CO2 and utilise less energy. Below is a detailed description of potential alternative binders/novel cements.
A. Alkali-Activated Cements: Alkali-activated cements belong to family of hydraulic cements that are characterised by a high content of aluminosilicates bonding phase. Aluminosilicates are not reactive with water, or their reaction is too slow. However, due to their high amorphous content, they hydrolyse and condense when placed in alkaline medium, forming 3-D polymeric structures that have load-bearing ability (Habert et al. 2014). In cements, the natural alkalinity of the system and portlandite fulfill these reactions, while in the absence of Portland cement, a strong base is needed to activate the amorphous aluminosilicates (Habert et al. 2014). Based upon the composition of cementitious components, alkali-activated cements are classified into five major categories (Shi et al. 2018)
I. Alkali-activated slag-based cements
II. Alkali-activated pozzolan cements
III. Alkali-activated lime-pozzolan/slag cements
IV. Alkali-activated calcium aluminate blended cements
V. Alkali-activated Portland blended cements
In NCB a study on Investigation on Development of Geopolymeric Cements has been carried out and discussed in detail below:

I. Development of Geopolymeric Cements
Investigation on formation and properties of geopolymeric cements based on alkali investigation of low lime coarser flyash have being taken up. The alkali treated flyash sample were subjected to initial thermal curing at two different temperatures upto 90° C for varying retention periods. SEM studies indicated the formation of geopolymers.


The performance of geopolymeric cement was found to be influenced by initial thermal curing conditions and therefore need optimisation. Investigations have also been carried out for preparation of cementitious binders at 27°C temperature using rationalised curing conditions by alkali activation of blends of fly ash with granulated blast furnace slag (GBFS) having 94 percent glass content. Studies indicated that ratio of fly ash and GGBFS in the blend affects the compressive strength property. The blend ratio as well as water content at fixed range of Na2O required to be optimised to obtain better compressive strength property. SEM image of alkali activated fly ash – GGBFS system cured for 28 days indicated formation of CSH gel along with NASH in this system resulting in development of compressive strength at 27°C
B. Belite-Rich Portland Cement: Belite-rich Portland clinkers are produced with the same process as ordinary Portland cement clinkers, but with less limestone in the clinker raw material mix, as well as lower clinkering temperatures so CO2 generation is reduced. The concept of belite-rich Portland cement is not new, but it takes advantage of the fact that modern OPCs have very high alite (C3S) contents. Market demand for rapid concrete hardening has driven cement manufacturers towards higher and higher alite contents, at the expense of higher
GHG emissions.
Belite-rich Portland cement belong to the same family as ordinary Portland cement in terms of clinker mineralogy, i.e., they are in the C2S-C3S-C3A-C4AF system. They are also commonly known as high belite cements (HBC). The difference in clinker composition lies mainly in the belite/alite ratio. For HBC the belite content is generally more than 40 per cent and alite normally less than 35 per cent, making belite the most abundant phase, as opposed to alite.
It has been established by various researches that belite-rich Portland cement typically exhibit similar setting times, lower water demands, lower heat evolution and early strength gain but
higher later age strength, and lower drying shrinkage compared with OPC. It has also shown better resistance to sulfates and chlorides, mainly due to the smaller proportion of portlandite in the hydration products.
It typically attains similar 28-day strengths to OPCs, and gain additional strength more rapidly than OPCs at later ages (Gartner et al. 2016).
A key reason they are not currently widely used is that they gain strength much more slowly than most OPCs. Such cements are well suited for niche markets where the strength gain after a few days is not critical. They are mainly employed for reasons of their low heat of hydration in the construction of massive concrete dams and foundations.
C. Calcium Sulfoaluminate (CSA) Cement: Calcium sulfoaluminate (CSA) cements are types of cements that contain high alumina content. To produce CSA clinker, bauxite, limestone, and gypsum are mixed together in a rotary kiln (Phair et al. 2006). By utilising CSA compositions, limestone quantity is reduced in the kiln that not only benefits in reduced thermal energy (up to 25 per cent) but also decreased CO2 emissions (up to 20 per cent) compared to the Portland cement. Industrial waste materials can also be used as raw materials for manufacturing CSA cements and thus calcium sulfoaluminate cements have significant environmental advantages.
It has the characteristics of early strength, high strength, high impermeability, high frost resistance, corrosion resistance, low alkali and low production energy consumption. They are widely used in rapid construction, rapid repair, winter construction, marine environments and underground engineering (Wang et al. 1999, Coppola et al. 2018). Its clinker is mainly composed of C4A3S (ye’elimite, 3CaO•3Al2O3•CaSO4) and ß-C2S (belite, 2CaO•SiO2). Among them, C4A3S is an early strength mineral that can quickly hydrate to AFt (ettringite, 3CaO•Al2O3•3CaSO4•32H2O) in the presence of gypsum to provide early strength (Hargis et al. 2013). Compared with C3S (alite, 3CaO•SiO2), the main mineral component of Portland cement, the formation temperature of C4A3S and the content of CaO are lower (Ali et al. 1994). Advantages of using CSA is that it not only saves a great deal of coal, power and limestone resources thus help in natural resource management but also reduces GHG emissions. However, it has many disadvantages also, such as the low percentage and slow hydration of C2S, resulting in no significant increase in the later strength of CSA and the formation of C4A3S, (ye’elimite) requires a large amount of natural gypsum and high-quality aluminium resources (Su et al. 2019).

Alternative fuels
Alternative Fuel (AF) becomes more popular to the cement manufacturer due to increasing fossil fuel prices, limited fossil fuel resources and environmental concerns. Generally fossil fuels such as coal, petroleum coke (petcoke) and natural gas provide the thermal energy required for cement industry. Usage of AF cover all non-fossil fuels and waste from other industries including tire-derived fuels, biomass residues, sewage sludge and different commercial wastes (Nielsen et al. 2011). These alternative fuels not only reduce CO2 emissions but also contribute to waste management and promote circular economy principles. Additionally, advancements in technology and improved combustion processes have made the use of alternative fuels more efficient and cost-effective.
The use of alternative fuels in cement manufacturing not only promotes circular economy but also helps in natural resource management. It is also one of the effective methods of achieving lower production costs. The process of clinker production in kiln systems creates favourable conditions for use of alternative fuels which include: high temperatures, long residence times, an oxidising atmosphere, alkaline environment, ash retention in clinker, and high thermal inertia. These conditions make certain that the fuel’s organic part is destroyed and the inorganic part, including heavy metals is trapped and combined in the product.
The cement manufacturers are consuming all possible Alternative fuels like refuse-derived fuel (RDF), industrial plastic, biomass, tyre chips, waste generated by pharmaceutical industry, Paint industry, Agro industry, Paper industry, chemical industry etc. (Mohapatra et al. 2014; Shaw et al. 2017). It is proposed to use either solar energy or hydrogen gas to mitigate for future energy demand in cement plants. India also has plan to emerge as a global electrolysers manufacturing hub to meet domestic demand and to emerge as a leading electrolyser exporter in future.

Conclusion
NCB’s current Research areas are well aligned to national priorities and requirement of society at large and include research in the area of low carbon and multi component blended cements, alternative binders and cementitious materials, alternate fuels and raw materials, productivity and environment improvement in cement industry etc. The research outcomes from these projects will provide Indian cement, building materials and construction industry a technologically sound platform to further reduce CO2 emissions, energy consumption and resource and environment conservation, higher thermal substitution rates etc. to achieve sustainability and cost optimisation taking due care of national and international commitments. The Research and Innovation projects of NCB are well aligned with the vision and mission of Government of India like decarbonisation, implementation of circular economy, increased sustainability etc.

Acknowledgment
*The Authors wish to acknowledge the Director General of National Council for Cement and Building Materials (NCB) for giving permission for publication and DPIIT, Ministry of Commerce and Industry, GOI, through various R&D projects supporting financial support for sustainable development of cement Industry. The Authors also acknowledge all scientific and technical staff of NCB for cooperation through R&D work for sustainability of cement
industry related projects.
Conflict of interest: The authors have no conflicts of interest, financially and ethically, to publish in this review work.

For a full list of references, visit www.indiancementreview.com.

Concrete

Balancing Rapid Economic Growth and Climate Action

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Dr Yogendra Kanitkar, VP R&D, and Dr Shirish Kumar Sharma, Assistant Manager R&D, Pi Green Innovations, look at India’s cement industry as it stands at the crossroads of infrastructure expansion and urgent decarbonisation.

The cement industry plays an indispensable role in India’s infrastructure development and economic growth. As the world’s second-largest cement producer after China, India accounts for more than 8 per cent of global cement production, with an output of around 418 million tonnes in 2023–24. It contributes roughly 11 per cent to the input costs of the construction sector, sustains over one million direct jobs, and generates an estimated 20,000 additional downstream jobs for every million tonnes produced. This scale makes cement a critical backbone of the nation’s development. Yet, this vitality comes with a steep environmental price, as cement production contributes nearly 7 per cent of India’s total carbon dioxide (CO2) emissions.
On a global scale, the sector accounts for 8 per cent of anthropogenic CO2 emissions, a figure that underscores the urgency of balancing rapid growth with climate responsibility. A unique challenge lies in the dual nature of cement-related emissions: about 60 per cent stem from calcination of limestone in kilns, while the remaining 40 per cent arise from the combustion of fossil fuels to generate the extreme heat of 1,450°C required for clinker production (TERI 2023; GCCA).
This dilemma is compounded by India’s relatively low per capita consumption of cement at about 300kg per year, compared to the global average of 540kg. The data reveals substantial growth potential as India continues to urbanise and industrialise, yet this projected rise in consumption will inevitably add to greenhouse gas emissions unless urgent measures are taken. The sector is also uniquely constrained by being a high-volume, low-margin business with high capital intensity, leaving limited room to absorb additional costs for decarbonisation technologies.
India has nonetheless made notable progress in improving the carbon efficiency of its cement industry. Between 1996 and 2010, the sector reduced its emissions intensity from 1.12 tonnes of CO2 per ton of cement to 0.719 tonnes—making it one of the most energy-efficient globally. Today, Indian cement plants reach thermal efficiency levels of around 725 kcal/kg of clinker and electrical consumption near 75 kWh per tonne of cement, broadly in line with best global practice (World Cement 2025). However, absolute emissions continue to rise with increasing demand, with the sector emitting around 177 MtCO2 in 2023, about 6 per cent of India’s total fossil fuel and industrial emissions. Without decisive interventions, projections suggest that cement manufacturing emissions in India could rise by 250–500 per cent by mid-century, depending on demand growth (Statista; CEEW).
Recognising this threat, the Government of India has brought the sector under compliance obligations of the Carbon Credit Trading Scheme (CCTS). Cement is one of the designated obligated entities, tasked with meeting aggressive reduction targets over the next two financial years, effectively binding companies to measurable progress toward decarbonisation and creating compliance-driven demand for carbon reduction and trading credits (NITI 2025).
The industry has responded by deploying incremental decarbonisation measures focused on energy efficiency, alternative fuels, and material substitutions. Process optimisation using AI-driven controls and waste heat recovery systems has made many plants among the most efficient worldwide, typically reducing fuel use by 3–8 per cent and cutting emissions by up to 9 per cent. Trials are exploring kiln firing with greener fuels such as hydrogen and natural gas. Limited blends of hydrogen up to 20 per cent are technically feasible, though economics remain unfavourable at present.
Efforts to electrify kilns are gaining international attention. For instance, proprietary technologies have demonstrated the potential of electrified kilns that can reach 1,700°C using renewable electricity, a transformative technology still at the pilot stage. Meanwhile, given that cement manufacturing is also a highly power-intensive industry, several firms are shifting electric grinding operations to renewable energy.
Material substitution represents another key decarbonisation pathway. Blended cements using industrial by-products like fly ash and ground granulated blast furnace slag (GGBS) can significantly reduce the clinker factor, which currently constitutes about 65 per cent in India. GGBS can replace up to 85 per cent of clinker in specific cement grades, though its future availability may fall as steel plants decarbonise and reduce slag generation. Fly ash from coal-fired power stations remains widely used as a low-carbon substitute, but its supply too will shrink as India expands renewable power. Alternative fuels—ranging from biomass to solid waste—further allow reductions in fossil energy dependency, abating up to 24 per cent of emissions according to pilot projects (TERI; CEEW).
Beyond these, Carbon Capture, Utilisation, and Storage (CCUS) technologies are emerging as a critical lever for achieving deep emission cuts, particularly since process emissions are chemically unavoidable. Post-combustion amine scrubbing using solvents like monoethanolamine (MEA) remains the most mature option, with capture efficiencies between 90–99 per cent demonstrated at pilot scale. However, drawbacks include energy penalties that require 15–30 per cent of plant output for solvent regeneration, as well as costs for retrofitting and long-term corrosion management (Heidelberg Materials 2025). Oxyfuel combustion has been tested internationally, producing concentrated CO2-laden flue gas, though the high cost of pure oxygen production impedes deployment in India.
Calcium looping offers another promising pathway, where calcium oxide sorbents absorb CO2 and can be regenerated, but challenges of sorbent degradation and high calcination energy requirements remain barriers (DNV 2024). Experimental approaches like membrane separation and mineral carbonation are advancing in India, with startups piloting systems to mineralise flue gas streams at captive power plants. Besides point-source capture, innovations such as CO2 curing of concrete blocks already show promise, enhancing strength and reducing lifecycle emissions.
Despite progress, several systemic obstacles hinder the mass deployment of CCUS in India’s cement industry. Technology readiness remains a fundamental issue: apart from MEA-based capture, most technologies are not commercially mature in high-volume cement plants. Furthermore, CCUS is costly. Studies by CEEW estimate that achieving net-zero cement in India would require around US$ 334 billion in capital investments and US$ 3 billion annually in operating costs by 2050, potentially raising cement prices between 19–107 per cent. This is particularly problematic for an industry where companies frequently operate at capacity utilisations of only 65–70 per cent and remain locked in fierce price competition (SOIC; CEEW).
Building out transport and storage infrastructure compounds the difficulty, since many cement plants lie far from suitable geological CO2 storage sites. Moreover, retrofitting capture plants onto operational cement production lines adds technical integration struggles, as capture systems must function reliably under the high-particulate and high-temperature environment of cement kilns.
Overcoming these hurdles requires a multi-pronged approach rooted in policy, finance, and global cooperation. Policy support is vital to bridge the cost gap through instruments like production-linked incentives, preferential green cement procurement, tax credits, and carbon pricing mechanisms. Strategic planning to develop shared CO2 transport and storage infrastructure, ideally in industrial clusters, would significantly lower costs and risks. International coordination can also accelerate adoption.
The Global Cement and Concrete Association’s net-zero roadmap provides a collaborative template, while North–South technology transfer offers developing countries access to proven technologies. Financing mechanisms such as blended finance, green bonds tailored for cement decarbonisation and multilateral risk guarantees will reduce capital barriers.
An integrated value-chain approach will be critical. Coordinated development of industrial clusters allows multiple emitters—cement, steel, and chemicals—to share common CO2 infrastructure, enabling economies of scale and lowering unit capture costs. Public–private partnerships can further pool resources to build this ecosystem. Ultimately, decarbonisation is neither optional nor niche for Indian cement. It is an imperative driven by India’s growth trajectory, environmental sustainability commitments, and changing global markets where carbon intensity will define trade competitiveness.
With compliance obligations already mandated under CCTS, the cement industry must accelerate decarbonisation rapidly over the next two years to meet binding reduction targets. The challenge is to balance industrial development with ambitious climate goals, securing both economic resilience and ecological sustainability. The pathway forward depends on decisive governmental support, cross-sectoral innovation, global solidarity, and forward-looking corporate action. The industry’s future lies in reframing decarbonisation not as a burden but as an investment in competitiveness, climate alignment and social responsibility.

References

  • Infomerics, “Indian Cement Industry Outlook 2024,” Nov 2024.
  • TERI & GCCA India, “Decarbonisation Roadmap for the Indian Cement Industry,” 2023.
  • UN Press Release, GA/EF/3516, “Global Resource Efficiency and Cement.”
  • World Cement, “India in Focus: Energy Efficiency Gains,” 2025.
  • Statista, “CO2 Emissions from Cement Manufacturing 2023.”
  • Heidelberg Materials, Press Release, June 18, 2025.
  • CaptureMap, “Cement Carbon Capture Technologies,” 2024.
  • DNV, “Emerging Carbon Capture Techniques in Cement Plants,” 2024.
  • LEILAC Project, News Releases, 2024–25.
  • PMC (NCBI), “Membrane-Based CO2 Capture in Cement Plants,” 2024.
  • Nature, “Carbon Capture Utilization in Cement and Concrete,” 2024.
  • ACS Industrial Engineering & Chemistry Research, “CCUS Integration in Cement Plants,” 2024.
  • CEEW, “How Can India Decarbonise for a Net-Zero Cement Industry?” (2025).
  • SOIC, “India’s Cement Industry Growth Story,” 2025.
  • MDPI, “Processes: Challenges for CCUS Deployment in Cement,” 2024.
  • NITI Aayog, “CCUS in Indian Cement Sector: Policy Gaps & Way Forward,” 2025.

ABOUT THE AUTHOR:
Dr Yogendra Kanitkar, Vice President R&D, Pi Green Innovations, drives sustainable change through advanced CCUS technologies and its pioneering NetZero Machine, delivering real decarbonisation solutions for hard-to-abate sectors.

Dr Shirish Kumar Sharma, Assitant Manager R&D, Pi Green Innovations, specialises in carbon capture, clean energy, and sustainable technologies to advance impactful CO2 reduction solutions.

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Carbon Capture Systems

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Nathan Ashcroft, Director, Strategic Growth, Business Development, and Low Carbon Solutions – Stantec, explores the challenges and strategic considerations for cement industry as it strides towards Net Zero goals.

The cement industry does not need a reminder that it is among the most carbon-intensive sectors in the world. Roughly 7–8 per cent of global carbon dioxide (CO2) emissions are tied to cement production. And unlike many other heavy industries, a large share of these emissions come not from fuel but from the process itself: the calcination of limestone. Efficiency gains, fuel switching, and renewable energy integration can reduce part of the footprint. But they cannot eliminate process emissions.
This is why carbon capture and storage (CCS) has become central to every serious discussion
about cement’s pathway to Net Zero. The industry already understands and accepts this challenge.
The debate is no longer whether CCS will be required—it is about how fast, affordable, and seamlessly it can be integrated into facilities that were never designed for it.

In many ways, CCS represents the ‘last mile’of cement decarbonisation. Once the sector achieves effective capture at scale, the most difficult part of its emissions profile will have been addressed. But getting there requires navigating a complex mix of technical, operational, financial and regulatory considerations.

A unique challenge for cement
Cement plants are built for durability and efficiency, not for future retrofits. Most were not designed with spare land for absorbers, ducting or compression units. Nor with the energy integration needs of capture systems in mind. Retrofitting CCS into these existing layouts presents a series of non-trivial challenges.
Reliability also weighs heavily in the discussion. Cement production runs continuously, and any disruption has significant economic consequences. A CCS retrofit typically requires tie-ins to stacks and gas flows that can only be completed during planned shutdowns. Even once operational, the capture system must demonstrate high availability. Otherwise, producers may face the dual cost of capture downtime and exposure to carbon taxes or penalties, depending on jurisdiction.
Despite these hurdles, cement may actually be better positioned than some other sectors. Flue gas from cement kilns typically has higher CO2 concentrations than gas-fired power plants, which improves capture efficiency. Plants also generate significant waste heat, which can be harnessed to offset the energy requirements of capture units. These advantages give the industry reason to be optimistic, provided integration strategies are carefully planned.

From acceptance to implementation
The cement sector has already acknowledged the inevitability of CCS. The next step is to turn acceptance into a roadmap for action. This involves a shift from general alignment around ‘the need’ toward project-level decisions about technology, layout, partnerships and financing.
The critical questions are no longer about chemistry or capture efficiency. They are about the following:

  • Space and footprint: Where can capture units be located? And how can ducting be routed in crowded plants?
  • Energy balance: How can capture loads be integrated without eroding plant efficiency?
  • Downtime and risk: How will retrofits be staged to avoid prolonged shutdowns?
  • Financing and incentives: How will capital-intensive projects be funded in a sector with
    tight margins?
  • Policy certainty: Will governments provide the clarity and support needed for long-term investment
  • Technology advancement: What are the latest developments?
  • All of these considerations are now shaping the global CCS conversation in cement.

Economics: The central barrier
No discussion of CCS in the cement industry is complete without addressing cost. Capture systems are capital-intensive, with absorbers, regenerators, compressors, and associated balance-of-plant representing a significant investment. Operational costs are dominated by energy consumption, which adds further pressure in competitive markets.
For many producers, the economics may seem prohibitive. But the financial landscape is changing rapidly. Carbon pricing is becoming more widespread and will surely only increase in the future. This makes ‘doing nothing’ an increasingly expensive option. Government incentives—ranging from investment tax credits in North America to direct funding in Europe—are accelerating project viability. Some producers are exploring CO2 utilisation, whether in building materials, synthetic fuels, or industrial applications, as a way to offset costs. This is an area we will see significantly more work in the future.
Perhaps most importantly, the cost of CCS itself is coming down. Advances in novel technologies, solvents, modular system design, and integration strategies are reducing both capital requirements
and operating expenditures. What was once prohibitively expensive is now moving into the range of strategic possibility.
The regulatory and social dimension
CCS is not just a technical or financial challenge. It is also a regulatory and social one. Permitting requirements for capture units, pipelines, and storage sites are complex and vary by jurisdiction. Long-term monitoring obligations also add additional layers of responsibility.
Public trust also matters. Communities near storage sites or pipelines must be confident in the safety and environmental integrity of the system. The cement industry has the advantage of being widely recognised as a provider of essential infrastructure. If producers take a proactive role in transparent engagement and communication, they can help build public acceptance for CCS
more broadly.

Why now is different
The cement industry has seen waves of technology enthusiasm before. Some have matured, while others have faded. What makes CCS different today? The convergence of three forces:
1. Policy pressure: Net Zero commitments and tightening regulations are making CCS less of an option and more of an imperative.
2. Technology maturity: First-generation projects in power and chemicals have provided valuable lessons, reducing risks for new entrants.
3. Cost trajectory: Capture units are becoming smaller, smarter, and more affordable, while infrastructure investment is beginning to scale.
This convergence means CCS is shifting from concept to execution. Globally, projects are moving from pilot to commercial scale, and cement is poised to be among the beneficiaries of this momentum.

A global perspective
Our teams at Stantec recently completed a global scan of CCS technologies, and the findings are encouraging. Across solvents, membranes, and
hybrid systems, innovation pipelines are robust. Modular systems with reduced footprints are
emerging, specifically designed to make retrofits more practical.
Equally important, CCS hubs—where multiple emitters can share transport and storage infrastructure—are beginning to take shape in key regions. These hubs reduce costs, de-risk storage, and provide cement producers with practical pathways to integration.

The path forward
The cement industry has already accepted the challenge of carbon capture. What remains is charting a clear path to implementation. The barriers—space, cost, downtime, policy—are real. But they are not insurmountable. With costs trending downward, technology footprints shrinking, and policy support expanding, CCS is no longer a distant aspiration.
For cement producers, the decision is increasingly about timing and positioning. Those who move early can potentially secure advantages in incentives, stakeholder confidence, and long-term competitiveness. Those who delay may face higher costs and tighter compliance pressures.
Ultimately, the message is clear: CCS is coming to cement. The question is not if but how soon. And once it is integrated, the industry’s biggest challenge—process emissions—will finally have a solution.

ABOUT THE AUTHOR:
Nathan Ashcroft, Director, Strategic Growth, Business Development, and Low Carbon Solutions – Stantec, holds expertise in project management, strategy, energy transition, and extensive international leadership experience.

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Concrete

The Green Revolution

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MM Rathi, Joint President – Power Management, Shree Cement, discusses the 3Cs – cut emissions, capture carbon and cement innovation – that are currently crucial for India’s cement sector to achieve Net Zero goals.

India’s cement industry is a backbone of growth which stand strong to lead the way towards net zero. From highways and housing to metros and mega cities, cement has powered India’s rise as the world’s second-largest producer with nearly 600 million tonnes annual capacity. Yet this progress comes with challenges: the sector contributes around 5 per cent of national greenhouse gas emissions, while also facing volatile fuel prices, raw material constraints, and rising demand from rapid urbanisation.
This dual role—driving development while battling emissions—makes cement central to India’s Net Zero journey. The industry cannot pause growth, nor can it ignore climate imperatives. As India pursues its net-zero 2070 pledge, cement must lead the way. The answer lies in the 3Cs Revolution—Cut Emissions, Cement Innovation, Capture Carbon. This framework turns challenges into opportunities, ensuring cement continues to build India’s future while aligning with global sustainability goals.

Cut: Reducing emissions, furnace by furnace
Cement production is both energy- and carbon-intensive, but India has steadily emerged as one of the most efficient producers worldwide. A big part of this progress comes from the widespread use of blended cements, which now account for more than 73 per cent of production. By lowering the clinker factor to around 0.65, the industry is able to avoid nearly seven million tonnes of CO2 emissions every year. Alongside this, producers are turning to alternative fuels and raw materials—ranging from biomass and municipal waste to refuse-derived fuels—to replace conventional fossil fuels in kilns.
Efficiency gains also extend to heat and power. With over 500 MW of waste heat recovery systems already installed, individual plants are now able to generate 15–18 MW of electricity directly from hot exhaust gases that would otherwise go to waste. On the renewable front, the sector is targeting about 10 per cent of its power needs from solar and wind by FY26, with a further 4–5 GW of capacity expected by 2030. To ensure that this renewable power is reliable, companies are signing round-the-clock supply contracts that integrate solar and wind with battery energy storage systems (BESS). Grid-scale batteries are also being explored to balance the variability of renewables and keep kiln operations running without interruption.
Even logistics is being reimagined, with a gradual shift away from diesel trucks toward railways, waterways, and CNG-powered fleets, reducing both emissions and supply chain congestion. Taken together, these measures are not only cutting emissions today but also laying the foundation for future breakthroughs such as green hydrogen-fueled kiln operations.

Cement: Innovations that bind
Innovation is transforming the way cement is produced and used, bringing efficiency, strength, and sustainability together. Modern high-efficiency plants now run kilns capable of producing up to 13,500 tonnes of clinker per day. With advanced coolers and pyro systems, they achieve energy use as low as 680 kilocalories per kilogram of heat and just 42 kilowatt-hours of power per tonne of clinker. By capturing waste heat, these plants are also able to generate 30–35 kilowatt-hours of electricity per tonne, bringing the net power requirement down to only 7–12 kilowatt-hours—a major step forward in energy efficiency.
Grinding technology has also taken a leap. Next-generation mills consume about 20 per cent less power while offering more flexible operations, allowing producers to fine-tune processes quickly and reduce energy costs. At the same time, the use of supplementary cementitious materials (SCMs) such as fly ash, slag and calcined clays is cutting clinker demand without compromising strength. New formulations like Limestone Calcined Clay Cement (LC3) go even further, reducing emissions by nearly 30 per cent while delivering stronger, more durable concrete.
Digitalisation is playing its part as well. Smart instrumentation, predictive maintenance, and automated monitoring systems are helping plants operate more smoothly, avoid costly breakdowns, and maintain consistent quality while saving energy. Together, these innovations not only reduce emissions but also enhance durability, efficiency, and cost-effectiveness, proving that sustainability and performance can go hand in hand.

Carbon: Building a better tomorrow
Even with major efficiency gains, most emissions from cement come from the chemical process of turning limestone into clinker—emissions that cannot be avoided without carbon capture. To address this, the industry is moving forward on several fronts. Carbon Capture, Utilisation and Storage (CCUS) pilots are underway, aiming to trap CO2 at the source and convert it into useful products such as construction materials and industrial chemicals.
At the same time, companies are embracing circular practices. Rainwater harvesting, wastewater recycling, and the use of alternative raw materials are becoming more common, especially as traditional sources like fly ash become scarcer. Policy and market signals are reinforcing this transition: efficiency mandates, green product labels and emerging carbon markets are pushing producers to accelerate the shift toward low-carbon cements.
Ultimately, large-scale carbon capture will be essential if the sector is to reach true net-zero
cement, turning today’s unavoidable emissions into tomorrow’s opportunities.

The Horizon: What’s next
By 2045, India’s cities are expected to welcome another 250 million residents, a wave of urbanisation that will push cement demand nearly 420 million tonnes by FY27 and keep rising in the decades ahead. The industry is already preparing for this future with a host of forward-looking measures. Trials of electrified kilns are underway to replace fossil fuel-based heating, while electric trucks are being deployed both in mining operations and logistics to reduce transport emissions. Inside the plants, AI-driven systems are optimising energy use and operations, and circular economy models are turning industrial by-products from other sectors into valuable raw materials for cement production. On the energy front, companies are moving toward 100 per cent renewable power, supported by advanced battery storage to ensure reliability around the clock.
This vision goes beyond incremental improvements. The 3Cs Revolution—Cut, Cement, Carbon is about building stronger, smarter, and more sustainable foundations for India’s growth. Once seen as a hard-to-abate emitter, the cement sector is now positioning itself as a cornerstone of India’s climate strategy. By cutting emissions, driving innovations and capturing carbon, it is laying the groundwork for a net-zero future.
India’s cement sector is already among the most energy-efficient in the world, proving that growth and responsibility can go hand in hand. By cutting emissions, embracing innovation, and advancing carbon capture, we are not just securing our net-zero future—we are positioning India as a global leader in sustainable cement.

ABOUT THE AUTHOR:
MM Rathi, Joint President – Power Management, Shree Cement, comes with extensive expertise in commissioning and managing over 1000 MW of thermal, solar, wind, and waste heat power plants.

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