ACC strives to minimise its carbon footprint by turning all its operations green

ACC strives to minimise its carbon footprint by turning all its operations green

K N Rao, ACC, Director (Energy & Environment)

ACC perceives water conservation, water harvesting, energy efficiency, environment protection, CO2 reduction, optimisation of the use of natural resources and fossil fuels, preservation of biodiversity, safety as some of the most important pillars of operation, to be pursued very seriously for the survival of the business, says K N Rao ACC, Director (Energy & Environment). Excerpts from the interview.

How do you look at the sustainability issues in the cement industry?
Being one of India's oldest and most responsible cement manufacturers, sustainability has become an integral part of ACC's business model. The triple bottomline concept is embedded into our decision- making process to make the business more sustainable. ACC has witnessed 76 glorious years of the Indian cement industry's journey and withstood various challenges in that time. This is a clear indicator of ACC's sustainable business practices, which has helped it to withstand rough weather and grow strong, day by day.

Could you throw some light on the initiatives ACC has taken to reduceCO2?
Since 2006, ACC has been monitoring its CO2 emissions. Scope-I emissions from its cement manufacturing activities are monitored using the CSI-WBCSD protocol. Scope-II and III emissions are monitored using the GHG protocol.

Over and above, ACC has taken various steps for reduction of the levels of CO2emissions, such as:

  • Moving from wet / semi-wet process to dry process cement manufacturing.
  • Reduction of electrical and thermal energy by adopting energy-efficient technologies and products.
  • Enhanced use of alternative fuels.
  • Reduction of clinker factor and clinker usage in cement manufacturing.
  • Enhanced use of alternative raw materials.
  • Enhanced use of renewable energy.
  • Pursuing waste heat recovery systems.
  • Increasing renewable energy portfolio to reduce the use of fossil fuel- based electrical energy.
  • Increased usage of rail networks for bulk transport of cement.
  • Research on increased use of pozzolona during the manufacture of blended cements (PPC / PSC).
  • Green building design.

We have been authorised to use the CDP leadership logo in recognition of our continued leadership in CDP.

How do you assess the RPO regulations' impact?
The manufacturing process at ACC has been significantly impacted by RPO regulations. Most of the integrated plants are operating with a captive power plant to achieve energy security. In anticipation of the Renewable Purchase Obligations, ACC installed 19 MW of windmills in the states of Tamil Nadu, Rajasthan and Maharashtra to meet its RPO obligations; we have also earned renewable energy certificates in the process. While our long- term objective is to have sources of renewable energy for all plants, as a short-term measure, ACC has purchased Renewable Energy Certificates to meet RPO requirements.

What is ACC's goal on sustainability and what are the challenges it faces?
Our major objectives are to bring down CO2 intensity considerably, become water positive and biodiversity positive, reduce the use of natural raw materials and fossil fuels and ensure no harm is done to the environment. Many challenges lie ahead of us, especially when it comes to energy. With the currency depreciation, fuel costs are spiralling, thus raising the cost of thermal power generation. Quality coal and its availability, availability of quality raw materials like limestone, continues to be a concern. What's more, power shortages have compelled us to set up captive power plants (CPP) to fulfil our energy needs.

Then, there is the increased pressure of complying with mandatory energy regulations such as Perform, Achieve, Trade (PAT), where we must meet energy reduction targets as well as our renewable energy purchase (RPO) obligations. These provide both challenges and opportunities to make units green and self- sustainable in terms of power. Also, the continuous reduction in SEC, has, to some extent, helped mitigate the rising cost of electricity generation.

One of our units in Himachal Pradesh will be commissioning a waste heat recovery- based power generating unit of 7.5 MW capacity shortly. We are also planning similar units in other plants in a phased manner.

ACC is on track as per our stated goals. However, progress was not upto the mark in the renewable energy portfolio. This was due to recent changes in the government's fiscal policy with respect to wind energy, and the economic crisis. ACC is trying hard to increase the renewable energy portfolio in the coming days. A lot of investment has been made in improving energy efficiency by the installation of variable speed drives (VSDs). Capacity for water conservation and harvesting is increasing day by day across all ACC plants.

Could you brief us on the initiatives on the AFR front?
The main benefit of co-processing eventually reaches the people or society, as it is instrumental in solving local waste management problems. AFR utilisation helps in regional job creation, waste collection and in pre-treatment facilities, helps in saving public funds which otherwise would have been spent on building additional incinerators; here, the infrastructure (cement kilns) is already in place.

Additionally, through initiatives like HAAT (Heap, Acquire and Transport) and the sourcing of biomass from communities, ACC has ensured that biomass (used as an alternative fuel) procurement activities are designed around the agricultural practices of the local community. Only locally available biomass residues from traditional crops which are over and above the needs of the community are procured directly from the community. This initiative goes a long way towards supporting local priorities and making a positive social and economic difference to the local community.

Co-processing ranks higher on the waste disposal hierarchy and eliminates the need for landfills and incineration. ACC undertakes waste management only after the options to Reduce- Reuse- Recycle are exhausted and avoids the evils of resource destruction by way of incineration and containment by way of landfills.

AFR utilisation also helps in saving precious raw materials and fuels, thereby reducing the environmental impact of extraction (mining or quarrying), transporting and processing of raw materials. Disposal of waste through co-processing as AFR leaves no residue since the incombustible, inorganic content of the waste materials are incorporated into the clinker matrix. AFR utilisation reduces GHG emissions, which are expelled if waste is incinerated and traditional fuels are used in the cement production process.

Through these initiatives, ACC has tried to address and provide an environmentally and socially acceptable solution for industrial hazardous and non-hazardous waste, along with municipal sorted solid waste, thus ensuring a cleaner and greener tomorrow.

How green is ACC's operative processes?
ACC's product portfolio has approximately 90 per cent of blended cements which comprise both Pozzolona Portland Cement (PPC) and Pozzolona Slag Cement (PSC). PPC cement absorbs fly ash (waste from thermal base power plants) and PSC absorbs slag (waste from steel cement plants) in the cement manufacturing process. Some initiatives adopted by ACC to make its operations green are listed below:

  • Reduction of natural raw material used (limesstone). This leads to the reduction of CO2 emissions on account of calcinations.
  • Conservation of fossil fuels.
  • Absorption of industrial wastes, which otherwise pose a huge environmental problem.
  • Utilisation of alternative fuels and raw materials. This not only conserves fossil fuels and natural raw materials but also leads to the reduction of CO2 emissions.
  • Migrating to bulk transportation modes like using high capacity vehicles, use of railways lead to reduction in the Scope-III type of CO2emissions.
  • Enhancement of renewable portfolio to reduce Scope-II CO2 emissions.
  • Adoption of latest techniques during blasting process, like NONEL.
  • Transportation of limestone from mines to plant through closed conveyors.
  • Installation of state- of-the- art pollution control equipment to minimise emissions.
  • Utilisation of waste heat to reheat incoming material.
  • Closed water cooling circuit.

What do you think of the PAT scheme?
Ten plants of ACC (nine integrated plants and the Tikaria grinding unit) have been identified as DCs under PAT. Though PAT poses a significant challenge to capex investments, we see opportunities in long term growth. To make the most of it, our twin focus should be on improving efficiencies across the industry and reducing the use of thermal and electrical energy in the manufacturing process by generating and using renewable energy. Opportunities abound when it comes to energy efficiency. One can consider upgrading old plants, co-processing industrial and municipal waste in cement kilns, generating power from the waste heat in kilns, using waste from other industries like fly ash and slag in the manufacturing process. Besides this, improving the efficiency of CPP and making a paradigm shift to blended and composite cements to minimise CO2 emissions, are vital to the cement manufacturing process.

Brief us on the pollution control equipment in your plants.
ACC is continuously adopting the latest technologies in the area of air pollution control. For their cement kilns, ACC converted all the Electrostatic Precipitators (ESPs) into bag filters and consequently, reduced the usage of water for gas cooling while maintaining constant emissions irrespective of process changes. Similarly, regarding power plants, ESPs are being converted into hybrid filters. Bag filters have been installed in all the remaining areas. These initiatives have led to us achieving stack emissions of <30mg/Nm3 in most of the stacks, as against the statutory regulation of 50mg/Nm3.

In 2011, ACC set up a project at Gagal to generate power through waste heat recovery. Could you tell us something about it?
At Gagal, the WHR plant absorbs heat from its two kilns and two coolers. The expected energy generation potential from this initiative is approximately 7.5 MW.

One of ACC's plants was recently given a Greenco rating. Will ACC be replicating the move in other plants, too?
ACC's Thondebavi cement works is a grinding unit near Bangalore, and is the youngest family member of ACC. This plant has been awarded the Greenco Silver rating at the recently concluded Green Cementech-13th conference held at Hyderabad. The plant has made remarkable progress in the areas of energy and water conservation. Yes, ACC is aggressively pursuing the participation of other plants with this rating system.

What are the major challenges you face in making ACC completely green?
Considering the nature of the cement manufacturing process, the usage of limestone as raw material, the amount of the energy required, the amount of logistics involved, it is practically impossible to make cement manufacturing process totally green. However, ACC is trying its best to drive its operations towards a green manufacturing process by adopting various measures such as enhanced utilisation of alternative raw materials, enhanced utilisation of alternative fossil fuels, reduction of clinker factor, reduction of thermal energy both at kiln and CPP, migration towards bulk and rail transportation, enhancing the renewable energy portfolio, etc.

Where does the company see itself five years down the line?
ACC will continue to increase its efforts in the areas indicated above. This will, in turn, give benefits to the organisation such as reduction of carbon intensity, specific water consumption, specific thermal energy, specific electrical energy, improvement in environmental performance and conservation of raw materials, etc.

Energy Efficiency

Installation of variable frequency drives for both LV as well as HV drives.

Thermal imaging of kiln and pre- heaters to identify major thermal loss areas and subsequently their rectification.

Carrying out CFD studies on major process equipment.

Installation of a rota scale in the kiln coal dosing system. Creation of an energy conserving organisation .

Conducting regular energy audit for identification and implementation of energy saving opportunities.

Increasing the PRI (Production Rate Index), OEE and MTBF of all critical plant equipment.

Replacement of inefficient pumps, motors, fans and compressors with high efficiency equipment in some plants.

Replacement of pneumatic conveying with the energy- efficient mechanical conveying system.

Operational improvements like arresting of leakages, optimisation of mills, fans, compressors, interlocking of auxiliaries to avoid idle runs, improving the power factor, etc.

Green Challenges

Ever-increasing cost of fossil fuels. Unfavourable waste legislation.

Issues related to the availability of segregated waste.

Issues related to consistent quality and quantity AF availability. Trans- boundary movement of alternative fuels.

Pricing of alternative fuels. Increased demand for OPC.

Lack of standards for composite cements.

Lack of economically viable and proven technologies for utilising huge deposits of pond /dump ash.

Inadequate infrastructure to granulate all blast furnace slag generated.

Long distance between sourcing of Pozzolonic materials (for manufacturing blended cements) and cement plants and issues related to logistics. Exorbitant pricing of blending material.

Long payback and lack of financial incentives, making it difficult for aggressive exploration of the WHRS option.

Lack of robust new technologies.

Huge requirement of financial resources.

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