Concrete steps towards a low carbon footprint

This is a high energy consumption industry that singularly accounts for 5 per cent of global carbon dioxide (CO2) emissions. During production of one tonne of material, it requires as much as 4. 7 million BTU of energy, equivalent to about 180 kg of coal — a key reason why it needs to remain ever vigilant of its role in environment degradation.

For the past two decades that is precisely what the cement industry has been busy with. Aware that it is indispensable to the global economy, needs to grow, and that concrete is the most important input for crucial infrastructure like buildings, bridges and roads, it has tried to reinvent its processes, reuse its resources and reduce its environmental abuse.

Luckily, this is one sector in which India has kept pace with global players. Egged on by emission regulations, a substantial number of its 139 large cement plants and 365 mini cement plants have been trying to match global best practices. Major players have consciously taken to the ‘India Low Carbon Technology Road Map’ developed in association with International Energy Agency, World Business Council for Sustainable Development and Cement Sustainability Initiative to be not only energy-efficient but also extremely competitive.

“Recent environment regulations have mandated industry to comply with new emission regulations, not only on particulate matter, but also on gaseous emissions, heavy metals and water. Regulators have adopted a system of online reporting of emissions from stacks and their remote calibration. All major plants are now converted to zero liquid discharge plants and many plants are becoming water positive,” says KN Rao, Director, Energy and Environment, ACC Limited.

He explains how the sector has embarked on an ambitious plan to bring down CO2 emissions by about 50 per cent by year 2050. The transformation has come about not only due to bringing about internal efficiencies to stay competitive, but also by ensuring that they constantly upgrade and improve these efficiencies. This spans the entire manufacturing chain — right from mines, where limestone is procured, to production processes, logistically efficient bulk transportation, energy efficiency and increasing use of renewable energy. This last would be a win-win for the sector as energy costs in the production of cement are estimated to be the highest, at 40-50 per cent of overall costs.

Systematic disruption

So, what are these measures that it has adopted? Purushothaman Ravichandran, President of Danfoss India, part of the Denmark-based Danfoss, says, “the Indian cement industry has continuously adopted clean technologies since the late Nineties and has systematically disrupted the use of energy in production. We can be proud that in the last two decades, despite challenging business cycles, we are globally best in energy usage and innovation.”

The measures adopted include improving thermal and electric efficiency, increasing the use of alternative fuels, seeking to substitute carbon-intensive clinker by use of low carbon materials, and developing carbon capture and storage mechanisms. According to data, the reduction in specific electric energy consumption was 32 per cent in 2015 from 1995 levels, while reduction in specific thermal energy consumption was 11 per cent during the same period.

The alternative fuels and raw material thermal substitution rate increased from 0.6 per cent in 2010 to 4 per cent in 2016.

A lot of this has been achieved by adopting best practices and experts vouch for that. “Having worked in several countries with the LafargeHolcim Group, one area I see Indian cement industry standing out is in continuous improvement and extensive sharing of best practices. This is an aspect other industrial sectors in India and the global cement industry can replicate and benefit from,” says Philip Mathew, Chairman, CII working group on World Class Cement Plants and Chief Manufacturing Officer, ACC.

According to industry estimates, the waste heat recovery potential in Indian cement plants is about 800 MW. Tapping this potential would result in monetary benefits of ₹1,400 crore and fuel saving of 2 million tonnes of coal and 12-15 per cent of power consumption of cement plants. The sector has widely adopted the use of variable frequency drives, best available manufacturing technology, latest automation and control systems in process and utilities. “Three of ACC plants are now in the top 10 list of global best cement plants across all 90 countries in LafargeHolcim group,” says Rao, with pride.

Water consumption

Another major thrust area in cement units has been water conservation. The reduction in process water consumption has been over 90 per cent by changing from wet technology to dry technology. This was brought about by reducing water consumption by 50 per cent in gas conditioning towers with installation of reverse air bag house and pulse jet bag filters and waste heat recovery.

The use of alternative fuels and raw materials by adopting co-processing approach, that is use of waste as raw material, has resulted in dual benefits of resource conservation and sustainable solution for waste management.

Kiran Ananth, Principal Counsellor, CII IGBC, says, “Cement industry has been a highly energy-intensive sector and most of the companies focused on its reduction and have managed to achieve significant progress. The first PAT (perform, achieve and trade) scheme of the Bureau of Energy Efficiency (BEE) also played a significant role. The PAT scheme II now under way during 2016-2019 is also expected to play an important role.”

Thermal substitution

Another factor is the overall thermal substitution rate in the industry that has increased from 0.6 per cent to 4 per cent. This is due to utilisation of more than 40 per cent of fly ash generated in power plants and 100 per cent of blast furnace slag for production of blended cement. There has also been increased use of pet coke, a refinery waste, as fuel in cement kilns.

In terms of heat recovery, more than 60 per cent of cement plants operate with 100 per cent captive power generation. Around 24 of them have waste heat recovery plants with 307 MW of installed capacity. There is an untapped potential of 500 MW.

What is significant is the cement sector’s resolve to further improve efficiencies. The consolidation in the sector through M&A activity and need to stay competitive is expected to sustain the momentum.

And as it strides towards its 2050 carbon footprint goals, it plans to continuously take stock of its progress. Veteran of the sector and whole-time director at JK Lakshmi Cement Ltd, S K Wali’s comment speaks volumes: “Over the last 40 years I have seen the industry growing economically as well as contributing to the cause of environment. Apart from being the most energy efficient, Indian cement plants are the largest consumers of fly ash. Also 70 per cent of them report their sustainability initiatives.”

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