More than 99 per cent of the greenhouse gases emitted from the manufacturing process is CO2
Global cement production has increased almost threefold from 1.4 billion tonnes in 1995 to 4.1 billion tonnes in 2014 and remained more or less stagnant since then.
With more than half of the world’s cement production, China is the largest cement producer. India is a distant second, with a share of 8 per cent as of 2020.
In 2019-20, India’s overall production stood at 334 million tonnes, with a capacity of 537 million tonnes. But cement, on which real estate and infrastructure are dependent, is a major contributor to greenhouse gas emissions.
As per the third biennial update report submitted to UNFCCC, in 2016, the cement sector of India contributed around 160 million tonnes or 5.63 per cent of the country’s total emissions.
In 2019-20, based on increase in production, CSE estimates it reached 213 million tonnes. CSE estimates showed that top 5 cement companies in terms of production – Ultratech Cement, ACC, Ambuja Cement, Shree Cement and Dalmia Cement – contributed almost 51 per cent of the CO2 emissions from the sector in India as of 2019-20.
These five companies also produce almost half of the cement in the country. CSE believes this is a huge opportunity for reducing emissions from the sector. Cement Manufacturing and GHG Emissions
More than 99 per cent of the greenhouse gases emitted from the manufacturing process is CO2. Limestone has been the main raw material for manufacturing cement and its conversion process is responsible for more than half the share of CO2 emissions during manufacturing.
The use of fossil fuels is the second biggest source of emissions during manufacturing cement- Around 40 per cent of the gases are emitted when fossil fuels such as coal and pet coke are combusted for converting limestone into lime.
The remaining 10 per cent of emissions is through electricity usage from the grid or captive power plant. Different types of cement are produced in India based on the amount and type of alternate raw materials replacing limestone during manufacturing.
Four prominent cement types in India are – Ordinary Portland Cement (OPC), Portland Pozzolana Cement (PPC), Portland Slag Cement (PSC) and Composite Cement (CC). Of these, 65 per cent is PPC.
Composite Cement is still less than 1 per cent. The BIS has made standards with respect to the composition and usage of these four types of cement. You can see the average CO2 emissions per tonne of cement from each of these four types of cement in the displayed figure as estimated by the Global Cement and Concrete Association.
Future Emission Scenarios for 2030 CSE has projected four CO2 emission scenarios for the year 2030:
Business-as-usual (BAU) scenario: This is based on emission factors of 2019-20 and estimated production of cement in 2030.
As per this scenario, CO2 emissions from the sector are projected to grow almost twice within this period.
Low-carbon-growth scenario: This is based on past emission reduction intensity achieved between 1996 and 2017 and estimated production of cement in 2030. As per this scenario, the CO2 emissions will increase 1.6 times and show a reduction of 18 per cent from the BAU scenario.
Improved low-carbon scenario: This is based on voluntary emission reduction targets set by large cement companies. As per this scenario, the CO2 emissions will increase 1.5 times and show a reduction of 23 per cent from the BAU scenario.
Accelerated low-carbon scenario: This has been proposed by CSE for 2030, but before we delve into this scenario, lets discuss the available pathways for the sector’s decarbonisation.
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