Cement is the most used industrial commodity required for development, but it is also responsible for high GHG emissions; so there is a need to create a balance between the nation’s growth and environment sustainability.
In 2018-2019, India had an annual cement consumption of 337 million tons, which is expected to increase up to 550 million tons by 2025. The major cement consuming sectors are housing and real estate (65%), infrastructure (25%), and commercial and industrial development (10%). This increase is attributed to various developmental schemes launched by the Government of India, including the Smart City Mission, Housing for All, Bharatmala Pariyojana, Pradhan Mantri Gram Sadak Yojana, Urban Transport Metro Rail Projects, etc.
Aided by suitable government foreign policies, several foreign players such as Lafarge-Holcim, Heidelberg Cement, and Vicat have invested in the country in the recent past. The per-capita consumption of cement in India is 240 kg, which is well below the global consumption of 530 kg (DIPP, 2020). This signifies that there is a huge economic opportunity to cater to the unmet demand in future.
Operational Parameters of Indian Plants
Average “specific heat consumption” and average “specific energy consumption” in the Indian cement industry is 3.1 GJ/tonne of clinker and 80 kWh/tonne of cement, respectively, which is lesser than the global average of 3.5 GJ/tonne of clinker and 91 kWh/tonne of cement, respectively. Despite this, a noteworthy progress by the Indian cement industry is in enhancing energy efficiency, though GHG emissions from the cement sector are still significantly high at 187 million tons of CO2e (in 2015-16).
Challenges and Avenues
This rising demand for cement also associates with it the environment damaging greenhouse gas (GHG) emissions. The cement industry alone is responsible for 8% of the total national emissions. These emissions are a product of electricity usage, combustion of fossil fuel and the calcination of limestone, which accounts for 13%, 31%, and 56%, respectively. The CO2 emission intensity of the Indian cement industry in 2018 was 576 kg CO2/ton of cement produced whereas the global average is 634 kgCO2/ton of cement produced.
As per the International Energy Agency (IEA) and WBCSD, emerging and innovative technologies, namely carbon capture and storage (CCS), renewable energy, have 48% emission reduction potential. Of late, renewable energy is gaining momentum.
Reduction in the clinker to cement ratio has the second-highest emission reduction potential (37%). This is being considered as a high priority now, as this not only reduces direct thermal emissions but also the process emissions, which contribute highly to the overall emissions from the cement industry and cannot be addressed through energy efficiency (EE) measures. There has been some progress in terms of identifying new alternate materials with lower clinker content and which, therefore, hold a bigger responsibility for India in the near future.
Circular Economy Concept - Usage of Alternate Fuels: Alternate fuels and EE have a CO2 reduction potential of 12% and 3%, respectively, which is very less as compared to the other two options. In recent years, the Indian cement industry has started using alternative fuels to further cut down emissions. The amount of alternative fuel used by the cement industry is defined by Thermal Substitution Rate (TSR), which refers to the percentage of alternative fuel used to replace fossil fuels. From the TSR level of 4% in 2016 (it was 0.6% in 2010), the Indian cement industry targets to achieve 25% TSR by 2025 and 30% by 2030.
With the use of circular economy principles (like use of SCMs, utilisation of construction and demolition waste through technologies like Smart Crusher) and design optimisation techniques (like bubble deck/voided concrete slab systems, confined masonry, and use of timber) the demand of cement can be optimised in the upcoming construction activities.
Renewable Energy: On the other hand, regarding the EE lever, most of the energy-efficient technologies are already implemented in the cement industry, leaving very little potential for decarbonisation. Additionally, to realise the leftover potential in EE, various interventions like waste heat recovery (WHR), installation of high energy efficient coolers, grinding systems, and the use of variable frequency drive (VFD) in process fans etc. are being implemented in indicant plants.
On one hand, cement is the most used industrial commodity required for development, but on the other hand it is also responsible for high GHG emissions. Therefore, there is a need to create a balance between the nation’s growth and environment sustainability. Moreover, to achieve climate change mitigation targets, in-line with the Paris Agreement, which attempts to limit the global temperature increase by 2°C at the end of this century, there is an urgent need to explore other opportunities (beyond energy efficiency) to limit GHG emissions from India’s cement industry.
Of late, a lot of research and development has taken place to develop low carbon cement alternatives like LC3, geopolymer binders, belite rich cements, and other novel cement formulations. Out of these options, LC3 and Geopolymer concrete have significant potential for emission reduction and are in the final stages of development in India.
To enable this transition there is a need for all stakeholders to come together and take up activities, including pilots, policy interventions as well as raising the awareness of these options to reduce emissions from the hard-pressed sector.
(The author is a Domain Expert in Cement in International Bodies, Mumbai).