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Economic Implications of Using SCMs

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ICR analyses how the integration of supplementary cementitious materials (SCM) and the strategies thereof has catalysed the cement industry’s economic landscape, fostering streamlined processes and enhanced resource utilisation, ultimately shaping a more resilient and profitable sector within India’s economy.

The way to look at any cementitious material in modern times would be to look at the carbon intensity inherent in it in terms of CO2 emissions, such as clinker, which forms the basis for making cement. After grinding the clinker (95 per cent) with gypsum and some correctives (together at 5 per cent), its emission intensity is 849-868 kg per tonne of output. Thus, when you produce ordinary Portland cement (OPC), which contains only clinker as the base cementitious material, the emission intensity is the highest at 750-860 kg of cement output. The lower end of the band is reserved for those who use the best technology that improves thermal efficiency and electrical efficiency.
Now, OPC could be the best suited for giving the early strength of cement measured by the compressive strength in MPa. Whether you take a 3-day or 7-day or 28-day strength, OPC would remain at the highest when you compare with any other form of cement that supplements clinker in the OPC with other cementitious materials like fly ash, slag, silica fume, natural pozzolans – such as calcined clays, shale and metakaolin, sugarcane bagass ash (SCBA) or rice husk ash (RHA).
The purpose of using supplementary cementitious material is two-fold:

  • Economic
  • Environmental
    The way to deal with this subject would be to look at the life cycle assessment of each of these and compute the impact. To make matters simple one may first look at the carbon intensity in each in terms of emissions and attach an appropriate environmental cost to it. Let us look at some of these numbers:
    Portland Pozzolana Cement (PPC) uses a mix of 60-65 per cent clinker, 5 per cent gypsum and 25-30 per cent fly ash thus taking the overall emission to an average 700 kg per tonne of cement. Efforts have been always to look at ways of maximising fly ash and PPC specifications allow for even 35 per cent fly ash to meet the compressive strength guidelines. However, we must note that compressive strength will be lower for 3 days, 7 days and 28 days for PPC when compared with OPC by at least 8-10 per cent. If one considers the cost of fly ash that is replacing clinker, the economic impact is huge as the cost of the former is a fraction of the latter.

Economic Implications
To compute the economic benefits of fly ash in PPC there are two important factors to be considered. The grinding units that are the final delivery points of cement units must be logistically located such that the cost of fly ash could be minimised. But this is a network optimisation question and the optimisation would entail outbound logistics cost of cement as well. Most advanced economies, India included, have looked at fly ash as an economic agent that not only turns waste into wealth but also reduces environmental impact of cement emissions (850 kg to 700 kg per tonne). The reduction in the landed cost of fly ash would further improve the economics through better logistics cost optimisation and mode-mix improvements. In recent times freight charges on rail in India for fly ash have been reduced to move fly ash over longer distances.
The environmental impact over long distance haulage of fly ash thus could be brought down
using rail as the mode, a crucial factor for the life cycle assessment.
The wider economic implication could be seen in the alternative deployment of a waste that was put to landfill is now an economic alternative to clinker. Some fly ash producers like NTPC or TATA Power or Adani Power, who together produce more than 100 million tonnes of fly ash per year, could be powerful actors to sway economic balance. Fly ash brick manufacturers who operate in the smaller concentrated networks, mostly SMEs, could be the next contenders in the value balance.
Slag based cement, uses 50 per cent clinker and 45 per cent slag and 5 per cent gypsum on an average. It is the next best example of SCM making a huge difference to the economic as well as environmental impact. By replacing a large amount of clinker, slag-based cement thus makes the emission intensity of cement come down to less than 500 kg per tonne of cement. This when looked at the back of the cost of slag vis-à-vis clinker, which it replaces in the cement, the economic implication is huge. The total production of blast furnace slag is growing, despite its environmental impact and it makes an economic case for GGBS.
However, blast furnace slag or the copper smelter slag, as inputs mixed together, is not free and must compete as commodities with clinker. But game theoretic approaches to price negotiations have fructified into either contracts that are short or medium term tenured (a sharp departure from the past) or pure spot contracts through auctions, that could be well mired in quasi-collusion dynamics of all kinds (in the past). Slag producers seeing an economic opportunity (as opposed to the environmental impact they face otherwise) have mostly experimented with a mix of spot and contracting strategy. The slag benefit in cement over clinker could be in the range of 30-40 per cent looking at the range of cost dynamics that would also include transportation cost by rail.
When one adds the CO2 emission impact benefit, fly ash and slag make a stunning case.

Exploring Other Options
The next most talked about SCMs are silica fumes and natural pozzolans, but their use has been limited in most parts of the world due to economic evaluations, including logistics cost. However, this economics could be lopsided in Europe where fly ash is hardly available and slag could be following suit. Natural pozzolans like calcined clay and metakaolin are therefore in news today, especially in Europe. In India, for example, they could be traded at cement cost, whereas in Europe they could well be lower than the clinker cost.
Utilisation of fly ash in cement has been improving in India but it is still far from the developed world numbers. The old wet fly ash lying in ponds and the dry lying in ash mounds could together be in excess of 100 million tonnes. While the vertical roller mills (VRM) technologies offer great benefits overall ball mills in grinding for absorption of wet fly ash, some innovative methods to use wet fly ash without adding to cost have been developed by some. Similarly, those having a logistics advantage towards a mix of fly ash and slag have settled for composite cement that could use a blend of fly ash and slag in their grinding mix. These could offer negotiating leverage while settling contracts in fly ash and slag.
At the end, to weigh the environmental impact in concrete, which uses a mix of sand, gravel, cement and water, one must see the equation differently: in a one cubic metre of concrete, using 14 per cent cement in the mix, the CO2 emission would be of the order of 410 kg/cubic metre compared to 290 kg per cubic using 30 per cent fly ash in PPC.

  • Procyon Mukherjee

Concrete

The primary high-power applications are fans and mills

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Alex Nazareth, Whole-time Director and CEO, Innomotics India, explains how plants can achieve both cost competitiveness and sustainability by lowering emissions, reducing downtime and planning for significant power savings.

As one of the most energy-intensive industries, cement manufacturing faces growing pressure to optimise power consumption, reduce emissions and improve operational reliability. Technology providers like Innomotics India are enabling this transformation by combining advanced motors, AI-driven digital solutions and intelligent monitoring systems that enhance process stability and reduce energy costs. From severe duty motors built for extreme kiln environments to DigiMine AI solutions that optimise pyro and mill operations, Alex Nazareth, Whole-time Director and CEO, Innomotics India, explains how the company is helping cement plants achieve measurable energy savings while moving closer to their sustainability goals.

How does your Energy Performance Contracting model typically reduce power consumption in cement plants—e.g., MWh saved?
Our artificial intelligence-based DigiMine AI Pyro and Mill solutions developed specifically for the cement industry, supports our customers in improving their process stability, productivity and process efficiency. In Pyro, this is achieved by optimising fuel consumption (Coal / AFR), reducing Specific Heat Consumption and reduction in emissions (CO2, SOx and NOx) through continuous monitoring of thermodynamics in pyro and recommending set-points of crucial parameters in advance for maintaining stable operations.
Within the mill, this is achieved by improving throughput, reduce energy / power consumption and maintaining stable operations on a continuous basis. Our ROI-based value proposition captures the project KPIs like reduction of coal usage, increase of AFR, reduction of specific heat consumption (Kcal / Kg), reduction of specific power consumption (KWH / tonne), reduction of emissions, etc., by a specific percentage. This gives clarity to our customers to understand the investment vis-à-vis savings and estimate the recovery time of their investment, which typically is achieved within one year of DigiMine AI Pyro and Mill solutions implementation.

What role do digitalisation and motor monitoring play in overall plant energy optimisation?
Motors are being used extensively in cement production, and their monitoring play crucial role in ensuring continuous operation of applications. The monitoring system can automatically generate alerts for any anomaly / abnormalities in motor parameters, which allows plant team to take corrective actions and avoid any major equipment damage and breakdown. The alerts help maintenance team to plan maintenance schedule and related activity efficiently. Centralised and organised data gives overview to the engineers for day-to-day activities. Cement is amongst the top energy intensive industries in comparison to other industries. Hence, it becomes critically important to optimise efficiency, productivity and up-time of plant equipment. Motor monitoring and digitalisation plays a vital role in it. Monitoring and control of multiple applications and areas
within the plant or multiple plants becomes possible with digitalisation.
Digitalisation adds a layer on top of OT systems, bringing machine and process data onto a single interface. This solves the challenges such as system silo, different communications protocol, databases and most importantly, creates a common definition and measurement to plant KPIs. Relevant stakeholders, such as engineers, head of departments and plant heads, can see accurate information, analyse it and make better decisions with appropriate timing. In doing so, plant teams can take proactive actions before machine breakdown, enable better coordination during maintenance activities while improving operational efficiency and productivity.
Further using latest technologies like Artificial Intelligence can even assist operators in running their plant with minimal requirement of human intervention, which allows operators to utilise their time in focusing on more critical topics like analysing data to identify further improvements in operation.

Which of your high-efficiency IEC low-voltage motors deliver the best energy savings for cement mills or fans?
Innomotics India offers a range of IEC-compliant low-voltage motors engineered to deliver superior performance and energy savings, particularly for applications such as cement mills, large fans, and blowers. Innomotics has the complete range of IE4 motors from 0.37kW to 1000kW to meet the demands of cement industry. The IE5 range is also available for specific requirements.

Can safe area motors operate safely and efficiently in cement kiln environments?
Yes, safe area motors are designed to operate reliably in these environments without the risk of overheating. These motors have ingress protection that prevents dust, moisture ingress and can withstand mechanical stress. These motors are available in IE3 / IE4 efficiency classes thereby ensuring lower energy consumption during continuous operation. These motors comply with relevant Indian as well as international standards.

How do your SD Severe Duty motors contribute to lower emissions and lower cost in heavy duty cement applications?
Severe duty motors enhances energy efficiency and durability in demanding cement applications, directly contributing to lower emissions and operational costs. With high-efficiency ratings (such as IE3 or better), they reduce power consumption, minimising CO2 output from energy use. Their robust design handles extreme heat, dust and vibration—common in cement environments—ensuring reliable performance and fewer energy losses.
These motors also lower the total cost of ownership by reducing downtime, maintenance and replacement frequency. Their extended service life and minimal performance degradation help cement plants meet sustainability targets, comply with emissions regulations and improve overall energy management—all while keeping production consistent and cost-effective.

What pump, fan or compressor drive upgrades have shown approximately 60 per cent energy savings in industrial settings and can be replicated in cement plants?
In the cement industry, the primary high-power applications are fans and mills. Among these, fans have the greatest potential for energy savings. Examples, the pre-heater fan, bag house fan, and cooler fans. When there are variations in airflow or the need to maintain a constant pressure in a process, using a variable speed drive (VSD) system is a more effective option for starting and controlling these fans. This adaptive approach can lead to significant energy savings. For instance, vanes and dampers can remain open while the variable frequency drive and motor system manage airflow regulation efficiently.

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Concrete

We conduct regular internal energy audits

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Shaping the future of low-carbon cement production involves integrating renewables, digitalisation and innovative technologies. Uma Suryam, SVP and Head Manufacturing – Northern Region, Nuvoco Vistas, gives us a detailed account of how.

In an industry where energy consumption can account for a significant portion of operating costs, cement manufacturers are under increasing pressure to adopt sustainable practices without compromising efficiency. Nuvoco Vistas has taken a decisive step in this direction, leveraging digitalisation, renewable energy and innovative technologies to drive energy efficiency across its operations. In this exclusive conversation, Uma Suryam, SVP and Head Manufacturing – Northern Region, Nuvoco Vistas, shares its approach to energy management, challenges of modernising brownfield plants and its long-term roadmap to align efficiency with India’s net-zero vision.

How has your company improved energy efficiency over the past five years?
Over the past five years, we have prioritised energy conservation by enhancing operational efficiency and scaling up renewable energy adoption. Through strategic fuel mix optimisation, deployment of cleaner technologies, and greater integration of renewables, we have steadily reduced our environmental footprint while meeting energy needs sustainably.
Technological upgrades across our plants have further strengthened efficiency. These include advanced process control systems, enhanced trend analysis, grinding media optimisation and the integration of solar-powered utilities. Importantly, grid integration at our key plants has delivered significant cost savings and streamlined energy management.
A notable milestone has been the expansion of our solar power capacity and Waste Heat Recovery Systems (WHRS). Our solar power capacity has grown from 1.5 MW in FY 2021–22 to 5.5 MW, while our WHRS capacity has increased from 44.7 MW to 49 MW, underscoring our commitment to sustainable energy solutions.

What technologies or practices have shown the highest energy-saving potential in cement production?
One of our most significant achievements in advancing energy efficiency has been the successful commissioning of a 132 KV Grid Integration Project, which unified three of our major manufacturing units under a single power network. This milestone, enabled by a dedicated transmission line and a state-of-the-art Line-In Line-Out (LILO) substation, has transformed our energy management and operational capabilities.
With this integration, we have substantially reduced our contract demand, eliminated power disruptions, and enhanced operational continuity. Supported by an optical fibre network for real-time communication and automation, this project stands as a testament to our innovation-led manufacturing excellence and underscores Nuvoco’s vision of building a safer, smarter, and sustainable world.

What role does digitalisation play in achieving energy efficiency in your operations?
Digitalisation plays a transformative role in driving energy efficiency across our operations. At Nuvoco, we are leveraging cutting-edge technologies and advanced digital tools to enhance productivity, optimise energy consumption and strengthen our commitment to sustainability and employee safety.
We are developing AI-enabled dashboards to optimise WHRS and kiln operations, ensuring maximum efficiency. Additionally, our advanced AI models evaluate multiple operational parameters — including fuel pricing, moisture content and energy output — to identify the most cost-effective fuel combinations in real time. These initiatives are enabling data-driven decision-making, improving operational excellence and reducing our environmental footprint.

What is your long-term strategy for aligning energy efficiency with decarbonisation goals?
As part of India’s climate action agenda, the cement sector has laid out a clear decarbonisation roadmap to achieve net-zero CO2 emissions by 2070. At Nuvoco, we view this as both a responsibility and an opportunity to redefine the future of sustainable construction. Our long-term strategy focuses on aligning energy efficiency with decarbonisation goals by embracing innovative technologies, alternative raw materials and renewable energy solutions.
We are making strategic investments to scale up solar power installations and enhance our renewable energy mix significantly by 2028. These initiatives are a key part of our broader vision to reduce Scope 2 emissions and strengthen our contribution to India’s net-zero journey, while continuing to deliver innovative and sustainable solutions to our customers.

How do you measure and benchmark energy performance across different plants?
We adopt a comprehensive approach to measure and benchmark energy performance across our plants. Key metrics include Specific Heat Consumption (kCal/kg of clinker) and Specific Power Consumption (kWh/tonne of cement), which are continuously tracked against Best Available Technology (BAT) benchmarks, industry peers and global standards such as the WBCSD-CSI and CII benchmarks.
To ensure consistency and drive improvements, we conduct regular internal energy audits, leverage real-time dashboards and implement robust KPI tracking systems. These tools enable us to compare performance across plants effectively, identify optimisation opportunities and set actionable targets for energy efficiency and sustainability.

What are the key challenges in adopting energy-efficient equipment in brownfield cement plants?
Adopting energy-efficient technologies in brownfield cement plants presents a unique set of challenges due to the constraints of working within existing infrastructure. Firstly, the high capital expenditure and relatively long payback periods often require careful evaluation before investments are made. Additionally, integrating new technologies with legacy equipment can be complex, requiring significant customisation to ensure seamless compatibility and performance.
Another major challenge is minimising production disruptions during installation. Since brownfield plants are already operational, upgrades must be planned meticulously to avoid affecting output. In many cases, space constraints in older facilities add to the difficulty of accommodating advanced equipment without compromising existing layouts.
At Nuvoco, we address these challenges through a phased implementation approach, detailed project planning and by fostering a culture of innovation and collaboration across our plants. This helps us balance operational continuity with our commitment to driving energy efficiency and sustainability.

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Concrete

Enlight Metals Supplies 3,200 Tonne of Steel for Navi Mumbai Airport

The airport is set to become Asia’s largest air connectivity hub.

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Enlight Metals has supplied 3,200 metric tonne of steel for the newly inaugurated Navi Mumbai International Airport, marking a major contribution to one of India’s largest infrastructure projects and reinforcing the company’s commitment to supporting national development.

The Navi Mumbai International Airport, developed under a Public-Private Partnership led by the Adani Group, was inaugurated today by Prime Minister Narendra Modi. The airport is set to become Asia’s largest air connectivity hub, enhancing regional connectivity, boosting economic growth, and expanding trade opportunities. Prime Minister Modi described the project as a “glimpse of Viksit Bharat,” highlighting its transformative impact on infrastructure and development in the region.

“The supply of 3,200 metric tonne of steel for this key project aligns with our focus on supporting critical infrastructure development through reliable and timely metal sourcing. Enlight Metals is committed to enhancing transparency and efficiency in the steel supply chain, contributing to projects integral to India’s growth objectives,” said Vedant Goel, Director, Enlight Metals.

Enlight Metals has implemented technology-driven solutions to strengthen supply chain efficiency, ensuring consistent availability of construction materials for large-scale projects nationwide. Its contribution to the Navi Mumbai International Airport underscores the company’s growing role in supporting India’s infrastructure development initiatives.

This milestone reflects Enlight Metals’ ongoing engagement in delivering quality materials and timely services for major national projects, further cementing its position as a reliable partner in India’s infrastructure sector

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