Jamshed N Cooper, Managing Director, HeidelbergCement India Ltd. and Zuari Cement, looks at energy consumption across various areas of cement production while emphasising the need to measure energy usage in terms of consumption vis-a-vis the cost per unit.
What kind of innovations in the area of energy consumption do you wish to see in the cement industry?
In cement manufacturing process, maximum energy is consumed at the clinkering stage. Electrical energy ranges from 50 to 80 units and thermal energy ranges from 2.9 to 3.25 GigaJoule per tonne. Therefore, clinkering stage is the one that becomes the focus of attention when it comes to adopting new technologies. Cement companies are always on a lookout for energy efficient kilns that are capable of operating with a combination of fuel mix and low on energy consumption. Resultant benefit also flows in by way of low CO2 generation.
To achieve economies of scale, mass continuous production needs to be achieved. For example, a million tonne kiln in today’s time is termed as an energy guzzler. As a thumb rule, a kiln of 5500 TPD is now the entry level. The general trend is to flog kilns of 5,000 TPD to deliver 6,000 TPD at the same time keeping MTBF (Mean Time Between Failure) at maximum, one would be able to optimise energy consumption.
Significant development has happened during the years and now we have fourth generation cross bar coolers which are energy efficient. Another potential area to reduce energy is by deploying VFDs in an optimal manner. Since VFDs are costly, payback analysis on case to case basis should be taken up and replacement of direct drives to be prioritised with a goal to do away with less efficient equipment.
Post clinkering, it’s the grinding stage that consumes a good amount of electrical energy. The industry has worked upon this area and have succeeded in implementing solutions to reduce energy consumption.
At one point of time, cement grinding used to take up to 50 to 60 units of power. The latest energy efficient mills we separator are able to grind clinker consuming as low as 20 to 25 units of energy.
Deployment of vertical roller mills (VRM) and prepress roller mills have led to productivity enhancement and reduced energy consumption on per ton output.
Use of AFR (Alternative Fuel Resource), is yet another avenue available to the cement industry to reduce its thermal energy cost and reduce CO2 footprint. Although, the heat requirement for the pyro-process remains the same, energy substituted from AFR has good potential in reducing costs. Power generation from waste heat recovery (WHR). has come a long way and the cement industry has wisely adopted this technology gainfully.
The drive to reduce energy consumption by the cement industry is now compelling us to embrace digital technology. Digitalisation is fast catching up in the cement industry and is becoming the harbinger in the area of energy optimisation and reduction of CO2 footprint.
How does automation and technology help in optimising the use of energy in cement plants?
Talking about automation, earlier we used to have a significant human interface for plant operations. For example, highly skilled workmen called “Burners” were required for operating kilns. These workmen used their experienced based judgement for controlling the kiln fuel to the kiln by watching the condition of the flame. Today, all of this is controlled from the Central Control Room (CCR) using state of the art digital technology making it possible to monitor plant operations with deft accuracy and speed At HeidelbergCement, we use Px Trends – a system that gathers system data and does trend analysis based on which it provides solutions to the operators for controlling various equipment. The big data gathered over the years offers immense potential to deploy Artificial Intelligence (AI) engines and optimise various operating parameters in real time automatically. Cement manufacturing deals with large volumes of raw materials and this compromises accuracy when it comes to measurement in real time. Given the volumes processed every minute, it’s humanly not possible to regulate their flows with accuracy nor easy to predict accurately the quality of raw materials being mined. By digitalising, we have created processes and methodologies custom built by HeidelbergCement that facilitate optimisation of fuel and energy.
HeidelbergCement Group has also invested in IT companies with a long term aim to digitalise its operations and become future ready. Our Group is relentlessly working to deploy digital technology as we believe that it holds the key to a better future. Remote management of our cement mills is one such example deployed in India to achieve improved productivity and control of the processes.
What is the energy consumption in one cycle of cement manufacturing process? Which process is the most energy intensive?
On average, the electrical energy consumption for producing a tonne of cement ranges from 60 units to 90 units and is dependent on the type of cement produced and the technology deployed. In the same company, there could be multiple kilns and processes installed over different time horizons and the energy consumption for the same would not be similar. The latest technologies bank on large production lines that deliver optimal energy efficiency and would consume about 60 to 65 units.
What are the major challenges your organisation faces in managing the energy needs of the cement manufacturing process?
In today’s times and especially since the fuel prices have more than tripled, managing energy has become a fulltime job. Energy which used to constitute about 30 per cent of the manufacturing cost has now become close to 45 per cent. Therefore, managing our energy needs becomes one of the bigger challenges for us and the industry as well. HeidelbergCement has developed several ways to manage its energy needs and deploy customised systems that have been developed by the Group.
Energy consumed to manufacture a tonne of cement is measured in Kcal or Giga Joules but more relevant is how do we achieve the lowest cost per Kcal or Gj. It therefore becomes prudent to manage the fuel mix based on its landed cost at the plant. To be able to optimise the energy consumption and its cost, we constantly evaluate and keep altering our fuel recipes.
On one hand is the cost of various fuels and on the other is its consumption. In the cement manufacturing process, a lot of heat is lost if thermal radiation is not contained. “Heat Contained is Heat Saved”. Periodic and astute maintenance schedules not only hold the key to improve plant availability but go a long way in reducing energy consumption.
We constantly endeavor to replace fossil fuels with AFR and maximise power generation from WHR. Replacing high cost grid power with low cost renewable power such as solar and wind have remained in sharp focus for HeidelbergCement India. Over a period of the last few years, we have been able to reduce our energy consumption by upgrading the plant and machinery in our plants.
How does energy conservation impact the profitability of the organisation? What impact does it have on the productivity of the process?
As I mentioned, reduction in energy consumption results in reduction of manufacturing costs as well and adds to the bottom line. Replacing high cost conventional energy sources with WHR and low renewable energy sources helps us save enough to be able to invest and adapt to newer technologies. It’s a self-fulfilling cycle that improves the competitive advantage which in the Indian context is a necessity for survival and growth.
Productivity and Energy efficiency go hand in hand and every employee in our organisation understands this. Drop in productivity of any equipment gets reflected in terms of higher energy consumption per unit of cement produced. For example, a kiln of 5,000 TPD if operated to deliver an output of 5800 TPD clinker, the incremental energy requirement will be marginally higher in relation to the energy consumed when operated at 5000 TPD.
With oil prices shooting through the roof, what has been its impact on the cement industry?
Escalated fuel cost has dealt a severe blow to the cement industry. Fuel related costs have added the most to our woes. The costs have gone up by 20 per cent to 30 per cent during the last two years and continue to rise unabated. Due to overhang of capacity and intense competition, the cement industry has not been able to pass on the price increases to the consumers.
In December 2020, pet coke prices were about $50 per tonne. Today the same is close to US$ 220 which makes the increase 3x of what it was. Today imported coal is hovering in the range of US$195 to $200 per tonne. Looking at the geopolitical situation and the state of economies across the globe, it does not seem that fuel prices would relent much in the coming year or so.
While industry continues to strive and contain its costs by deploying efficient technologies, it has its limitations. The cost savings thus achieved fall significantly short when it comes to matching the pace at which raw material costs have been increasing.
The recent past declared quarterly financial results of cement companies, makes it obvious that if the industry fails to pass on the cost increases to the customers, it could have a debilitating effect on the foreseeable future of the industry.
What are the major compliances and standards for efficiently handling fuel and energy in the organisation?
The statutory compliances to be fulfilled by cement manufacturers are well defined by the respective Government agencies. When it comes to improving energy efficiencies, we have to achieve the targets under the PAT cycle. We have been witnessing over the years as to how the PAT cycle has shaped the industry’s approach to becoming energy efficient.
A few of the environmental compliances in India are more stringent than those applicable in developed economies. Nevertheless, the Indian Cement Manufacturers have time and again demonstrated their commitment to meet all the norms and standards laid down by the MoEF. As a good corporate citizen, we at HeidelbergCement take pride in ensuring total compliance with the laws of the land and the industry.
How often are audits done to ensure optimum use of energy and what is the suggested duration for the same?
We undertake all requisite audits periodically and file our reports as required under the law. As a responsible corporate, we do our own energy audits as well.
We believe in the philosophy of “Continuous Improvement”. Besides our internal standards, we benchmark our performance with our past best achievements and also that of our competitors and replicate the same. We strive to become better than the previous year.
At our India operations, we pursue a target to achieve a two-degree lower ambient temperature in our plants compared to than prevailing a Km away.
This journey we commenced in 2014 and now two of our cement plants have achieved the goal and the remaining ones are close to emerging winners. The average reduction for all our units operating in India now stands at 1.4 degree Celsius lower. This act of ours has led to creation of a cooler work environment and is resulting in higher productivity.
How have been the carbon emission norms for the cement industry in India vis-à-vis the World? What percentage of your carbon emission reduction target are you set to achieve by 2030?
The CO2 emission by the cement industry worldwide in 2018-19 reduced to 640 kg per tonne of cement from 760 kg per tonne in 1990 thereby recording a significant reduction of 16 per cent. At our India operations, we take pride in having achieved 585 kg CO2 per tonne of cement in 2018-19 from a level of 800 kg per tonne in 1990.
During FY 2021, CO2 emissions for our India operations stood at 570 kg per tonne of cement and now we strive to further reduce it to 550 kg by 2025. By 2030, we have the ambition to touch 534 kg CO2. In Central India, we manufacture 100 per cent blended cement with a CO2 footprint of 510 kg per tonne of cement pursuing a target to further reduce it to 495 kg by 2030. The group is pushing us to achieve this target and compete at Global levels.
CO2 emissions while manufacturing Cement is inevitable. When we say that we are going to achieve carbon neutrality, it implies that going forward deploying carbon capture or utilisation will come into play.
HeidelbergCement Group is poised to emerge as a pioneer in the cement industry as it continues to build the first of its king state of art carbon capture units in Norway. A delegation comprising members of DPIIT and NCCBM, visited the establishment to witness the same.
HeidelbergCement Group is working on close to eight carbon capture technologies which are at various Technological Readiness Levels (TRLs).
These include processes like post combustion, oxy fuel, lilac technology, direct separation, micro algae, hydrogen burning and kiln electrification. These pioneering efforts of our Group are poised to become a boon for the cement industry and the society as well.
Our slogan “Materials to Build Our Future” energises us day after day to renew our commitment to “making the world a wonderful place to live for our generations to come”.
Precast use of concrete promotes sustainability
Vijay Shah, Managing Partner, India Precast, advocates the use of precast concrete as he puts forth details about its manufacturing, uses and methods while emphasising the sustainability of the product.
Explain the process of casting concrete in shapes and what is the grade of concrete used for making these shapes?
Precast casting concrete elements are manufactured with the required steel reinforcement either in formwork, moulds or on steel plates with side shuttering etc. The concrete cast is made at a different location and is then transported to the site. Precast elements are made of minimum M20 to M50 grade of concrete.
What is the difference between precast and cast in-situ as uses of concrete?
- The use of concrete in the precast method and the cast in-situ method differs widely based on many factors.
- Precast concrete shapes are cast at a different location and are then transported to the site where construction work takes place while with the cast in-situ process, concrete is poured on-site.
- Curing of precast concrete is fast as it takes place under ideal and controlled conditions while the cast in-situ concrete takes relatively longer to get cured but can be easily used for two-way structural systems.
- For the precast concrete, the process is easy to do and is repeatable as the same moulds or framework can be used. This increases the value of construction and derives more value
- while cast in-situ adapts building shapes and post tensioning.
- The work and rework in the usage of precast shapes is less, thus, reduces cost at the site
- while with the cast in-situ method there is a requirement of space allotment for concrete mix and necessary add-ins, that is added cost for the construction job.
Tell us about prestressed and reinforced concrete.
Prestressed concrete is a combination of high strength concrete and tensioned steel strands. This combination makes a strong structural unit that is useful in building roof slabs, bridge girders etc. Reinforced concrete is manufactured from a combination of high strength concrete and normal reinforcement bars.
Tell us more about the precast elements manufactured, their shapes and sizes.
Precast is one of the best ways to rapidly build industrial buildings, commercial buildings, affordable housing, mass, EWS, LIG housing, schools, hospitals, public buildings, agriculture railways, stadiums, sport centres, parking, bridges, airports etc. They have a higher productivity and quality set at industry level.
Various types of precast elements manufactures are:
- Solid load bearing floor slabs, load bearing walls, facades, sandwich wall panels and cladding panels
- Floor and roof slabs are made from prestressed load bearing hollow core concrete slab and ribbed slabs. They are also made from half floor slab or semi-finished floor slab with a lattice girder
- Precast stair cases, balcony, toilet pods, lift shafts, water tanks
- Prestressed lintel, frames, beams, columns and double-tee beams
- Internal partition walls are made with light-weight hollow core wall panels instead of AAC blocks or bricks
- Boundary walls, fencing poles, U-drainage or trenches, box culvert etc.
What is hollowcore concrete flooring and what is its lifespan?
Hollowcore slabs are precast, prestressed concrete elements that are generally used for flooring. Some of the advantages of using these flooring are longer lifespans and no propping, flexibility in designs, faster construction, lightweight structures, fire resistant structures, high load capacities and units manufactured specific to the project.
The maximum span of hollowcore floors will depend on the floor depth and the specific loadings imposed on the floor.
What are the quality standards followed while making precast shapes for any project?
Quality control is a very important aspect in the process of making precast concrete shapes. It is imperative to make precast shapes as per the exact requirement provided by the engineers and the construction party. To maintain the quality of product from our end,
- We ensure there are quality control systems and procedures in place along with a quality assurance plan. Our programme consists of tests, trials, and general procedures for acceptance.
- There is a laboratory and related facilities, which are required for the selection and control of the quality of materials and workmanship. The central quality laboratory is used for various quality control tests like cube test, workability test, slump test, sieve analysis etc. The materials used for making the final precast shapes also has to be shared for testing to various third-party laboratories with an advance intimation.
- All the necessary tests are carried out in respective batching plants or sites depending on the use of concrete at our facility.
- Documentation for all the tests conducted and their reports is maintained in records, for references and submission to the relevant authorities and the users of the same.
As precast use of concrete is conducted in a dedicated space and is in a monitored environment, it becomes easier to maintain high quality due to its repeatability factor. The necessary general precast machinery and moulds, steel tables, concrete batching and dispensing equipment, vibrating and finishing equipment and dedicated labour team help maintain the higher quality standards as compared to cast in-situ use of concrete.
How do you incorporate sustainability in the process of precasting?
Precast use of concrete promotes sustainability with its repeatability factor. There’s more planning involved in the process and equipment like the moulds, vibrating machine, finishing machine are all reusable elements of the process.
As mentioned, there is planning in precast use of concrete where only the required measure of concrete is mixed and poured into moulds that are made to precision as per the requirement of the project. The quantity is also previously defined, which means there is reduced to zero wastage of material.
This waste reduction leads to lesser needs of cleaning and clearing equipment, which may further be fueled by other energy sources. Thus, precast concrete, by large, is a sustainable means of building.
What are the advantages of using precast concrete?
There are multiple advantages of using a precast structure for any project like cost efficiency, speed, versatility, safety, sustainability and beauty.
- The use of precast improves the quality and lifespan of any building
- It reduces the time of building, thus reducing the costs involved for all the other equipment and labour that goes in to the project, thus, proving to be cost effective
- The maintenance of a precast is lower due to its high quality and durability that is ensured while it is cast
- This method of using concrete is a sustainable option due to its repeatability
What are the major challenges you face in the process of making precast shapes and in their transportation?
The precast industry plays on volume and repetition. This is one of the major challenges as well.
The requirement of having to repeat the process
that contains a large volume of mixed concrete and getting the same perfection in the shapes is a cumbersome process.
The initial investment in setting up the precast plant and acquiring all equipment and moulds is high. With bulk shapes to be transported from one place to another and the requirement for site space and handling, this time of concrete use is more suitable for tier 2 and tier 3 cities.
How do precast elements or shapes help in the profitability of a construction activity?
As precast concrete is made at a different location than the construction site, the other jobs keep going on at the site and then the precast shapes are placed there. This reduces construction time to up to one-third to one-fifth as compared to cast in-situ concrete, thus, reducing cost of the construction.
Construction maintenance is reduced as the quality of their precast structures are monitored and carefully administered at the plant level. This means it adds to the reliability, durability, accuracy, and ability to produce architectural elements in any building adding to its quality and strength. Precast also provides insulation, thermal inertia and fire resistance and the possibility of integration with MEP (Mechanical, Electrical and Plumbing) from the start of the project.
How can precast concrete contribute towards affordable mass housing in India?
Defined shapes and technical requirements in precast concrete helps reduce the waste and increase the repeatability factor, thus, reduces the cost and time for any construction or building project. Higher control on quality, less time consumer leads to lesser need of labour and equipment on-site, which also adds to the profitability of the structure.
All factors combined bring down the overall cost of the project, leading to that benefit translating to the end consumer and bringing a surge of affordable mass housing in India.
Comparison Between Cast-in-situ (conventional method) versus Technology Drive Precast
Sr. No Criteria Conventional Construction Precast Construction 3D Modular/ Panel & Hollow Core Slab.
1 Natural resource consumption High 30 per cent saving
2 Labour Problem Heavy labour problem while work in progress Less labour required
3 Dependability on skilled labor 60 per cent Dependability
4 Time consuming Verv High Fast track
5 Initial investment Low High
6 Finishin Normal Excellent
7 Quality production Poor Excellent as factory based.
8 Material wastage High Least
9 Speed/ Productivity Low Excellent
10 Strength Good Excellent
11 Durability Low High
12 Structure weight/ Deed load Very heavy Reduced
13 Brick Block and Plastering Required No Need
14 Service like Electrical, plumbing & sanitary Break, Provide & Re-build Pre-embedded
The age of concrete blocks can be up to a 100 years
Nikita George, Director Operations, APCO Concrete Blocks and Allied Products, takes us through the manufacturing process of concrete blocks and its composition and also specifically discusses their patented product – cellular blocks.
Tell us about the type of concrete blocks that your organisation manufactures.
We manufacture mainly solid and cellular concrete blocks. The cellular block is our patented product, which has become increasingly popular due to its high utility value in the construction process. We are also gearing up to launch our new line of pavers and kerb stones by the end of August.
What is the composition of each type of block and what are their strengths?
Blocks constitute of mainly three items: Cement,
- Manufactured Sand and Stone Aggregates Our patented cellular blocks have a vast set of benefits:
- Lightweight: The cellular block is between 8 to 9 kg lighter than the solid block. This not only increases the productivity of the labour but also helps in reducing the overall steel requirement for the project.
- Thermal insulation properties: With the erratic weather conditions in India today, cellular blocks help in maintaining thermal insulation properties within the building. In a recent experiment conducted on a building, which used the cellular blocks, a marked reduction in temperature by three degrees was recorded.
- Sound insulation properties: Due to the hollow nature of these concrete blocks, the product is able to cut the decibel levels by 14 per cent.
- Compressive strength and water absorption properties: The cellular blocks exceed the ISO parameters for compressive strength and water absorption.
How do you ensure quality standards for the concrete blocks manufactured?
With our 50 years of experience in the concrete blocks manufacturing industry, we have continually evolved and tried our best to stay relevant with the international quality standards. Quality control begins with procurement of good quality raw material. Fortunately, we have our own crushers to cater to our production units. This helps us negate undesirable raw materials. State of the art machinery and a strong base of SOP help mitigate errors. Above all, of these we have a skilled set of managers who have over 25 years of experience in the concrete blocks field.
Tell us about the sustainability and environmental benefit while manufacturing and while using these blocks in construction?
The blocks that we manufacture follow the highest quality parameters that give a very long life span. When used in building, the age of concrete blocks can be up to 100 years. The blocks used in these buildings at the time of demolition can be re-crushed and used to manufacture the same product again. And since concrete blocks are one of the strongest products available in the market, the on site damages are virtually zero. Unlike native methods of concrete production, we use only M-sand. There is no usage of river sand hence, safeguarding our environment. Also, as mentioned before, concrete blocks can be reused even after the lifespan of a building. This cuts down on further usage of raw materials.
What are the key benefits that any builder can get from using your concrete blocks?
The concrete blocks industry to a large extent can still be categorised in the unorganised sector. Due to this, there is a lot of disparity in pricing and quality in the market. At APCO, with our 50 years of experience, we have won the trust of our customers by consistently proving the highest quality of our products and on-time delivery.
With our 5 production units strategically located around Bangalore city, we have the capability of producing up to one lakh blocks per day. This allows us to consistently supply large quantities to our customers. Our customers can also be assured that the quantity of blocks that leave our plants is the same quantity that will be unloaded at the site.
Apart from this as mentioned in the earlier answers, our cellular blocks host a wide range of benefits during and even after the construction of a building.
How do these concrete blocks contribute to the profitability of construction?
When APCO came into the market in the early ’70s, the construction industry was heavily reliant on the traditional clay bricks. It took us about 10 years before we got our first big break. And since then, the construction market has not looked back. There have been multiple competitors in the walling solutions market but in terms of pricing and quality no other product comes close. Most people build a house once. At APCO, we believe in making that house a home. We provide unrivalled quality and a fair price to all our customers!
What does the near future hold for APCO Concrete Blocks and allied products?
We will be launching our new product line of pavers and kerb stones by August and we are working towards APCO being present in a few more states around India.
Effects of Macronomics
In any industry, it always helps to take into account the macro perspective as it aids one in navigating the broader economic trends. As per the assessments of the April-June quarter (Q1), India’s gross domestic product (GDP) increased 13.5 per cent, which was lower than RBI’s estimated 16.2 per cent. A fiscal deficit of Rs 3.41 trillion was noted during the April-July period this financial year.
Moody’s Investors Service has revised India’s economic growth projection for 2022 to a reduced 7.7 per cent. The downward revision is due to rising interest rates, an uneven monsoon and global demand slowdown, which is not surprising as the Russia-Ukraine war continues to cast its shadow. The eight core infrastructure sectors, including cement, slowed down to 4.5 per cent in July, which afforded the service sector to shine in the first quarter.
Taking a bird’s eye view of the cement sector, the upward moving trends are looking promising and that has kept optimism buoyed amongst the players. Monsoon is a tricky time for the cement industry as construction takes a backseat and price fluctuations in cement are rife.
As per Kotak Institutional Equities report, cement prices have declined about a percent sequentially in the second quarter. Cement price was recorded at Rs 384 per 50 kg bag in August pan-India. In spite of a sluggish season, the demand is likely to soar in the coming months, and the key players in the industry are anticipating robust growth.
There is a lot that’s underway for cement manufacturers in terms of alternative raw materials, energy efficiency and eco-friendly processes. Given the infrastructure and construction boom that India is witnessing today, the cement segment is likely to perform well. However, the challenges that the sector faces are unique to it, and it remains to be seen how cement brands will innovate to overcome them.