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Apex public policy think tank NITI Aayog’s recent office memorandum has raised questions about the necessity of flue gas desulfurisation (FGD) installations in India’s thermal power plants (TPP). At a meeting on August 21, 2024, Council of Scientific & Industrial Research-National Environmental Engineering Research Institute (CSIR-NEERI) recommended that no additional equipment, such as FGD, is required for sulphur dioxide (SO₂) emission control.
CSIR-NEERI’s draft report, titled Analysis of Historical Ambient Air Quality Data Across India for Developing a Decision Support System, looked at data from TPPs, coal mining areas and Central Pollution Control Board’s (CPCB) online and offline monitoring data.
The study aimed to assess the need for current FGD regulations in Indian TPPs. It concluded that SO₂ levels from 467 Central Control Room for Air Quality Management stations operated by CPCB and 486 sites managed by TPPs across India showed only 13 sites exceeded the prescribed limit of 80 micrograms per cubic metre and only in the fourth quartile (less than 25 per cent of data).
Surprisingly, the NEERI draft report — underpinning the recommendation that FGDs are unnecessary in TPPs — has not been made public and even regulatory agencies lack access to it.
According to CSIR-NEERI, SO₂ emissions from India’s coal-based power plants are not significantly affecting ambient air quality, with standards mostly met. Instead, the report suggested that regulatory attention should shift to controlling particulate matter (PM), which has exceeded limits based on Online Continuous Emission Monitoring System or OCEMS data.
CSIR-NEERI recommended that new FGD installation orders be paused and TPPs with installed FGD be treated as experimental sites for data collection to assess cost-effectiveness and the impact on power tariffs.
The office memorandum claims that the chairperson of Central Electricity Authority (CEA) noted a similar study by Indian Institutes of Technology-Delhi, which purportedly arrived at the same conclusion as CSIR-NEERI. However, this appears to be inaccurate.
IIT Delhi’s report, Study to Assess the Compliance of Thermal Power Plants in India to New SO₂ Emission Norms (2015) and Lay Out Phased Plan for FGD Implementation, actually recommended phased FGD implementation in TPPs across India based on SO₂ concentration data from AURA (OMI) Satellite and MERRA2 reanalysis (2015-2019).
“A systematic setup is being created to undermine the push for a SO₂ control mechanism,” said Nivit Kumar Yadav, programme director for sustainable industrialisation and renewable energy at think tank Centre for Science and Environment.
He further highlighted that provisions for FGD systems, such as allocating installation space, were under pressure to be included in the early 2000s environmental impact assessments of TPPs, which finally became mandatory in 2015.
A timeline of events show extension of compliance deadlines.
2015: The Union Ministry of Environment, Forest and climate change (MOEF&CC) introduced strict emission norms for coal-fired TPPs, with a compliance deadline of 2017.
2017: The Union Ministry of Power requested an extension of seven years and the Supreme Court eventually granted five more years, till 2022, with Delhi-National Capital Region (NCR) plants to comply by 2019.
2020: In February, CEA recommended installing FGD only where ambient SO₂ exceeded 40 microgrammes per normal cubic metre.
2021: A notification from MoEF&CC on April 1 directed constitution of a task force with representatives from the environment and power ministries, CEA and CPCB. The task force was constituted April 16, 2021 to disaggregate 596 coal TPPs based on location, creating categories A, B, and C with different compliance deadlines.
The compliance deadlines for parameters other than SO₂ norms varied by category. Category A covered plants located within a 10-kilometre radius of NCR or cities with populations exceeding one million. These plants must meet compliance requirements by December 31, 2022.
Category B included plants within a 10-km radius of critically polluted areas or non-attainment cities, with a deadline of December 31, 2023. Lastly, Category C encompasses all remaining plants, which were expected to comply by December 31, 2024.
The categorisation by the task force puts approximately 22 per cent of the capacity in Category A and Category B. Nearly 78 per cent of the coal power capacity is placed under Category C.
2022: Deadlines were revised, with the latest notification in September specifying new timelines for SO₂ compliance for non-retiring TPPs.
Coal-based TPPs again had different deadlines for meeting emission norms, depending on their category and proximity to specific areas.
For Category A, which includes plants located within a 10-km radius of NCR or cities with populations exceeding one million, the deadline to comply with parameters other than SO₂ norms is December 31, 2022, while for SO₂ norms, it is December 31, 2024.
Category B comprises plants within a 10-kilometre radius of critically polluted areas or non-attainment cities, with compliance deadlines of December 31, 2023, for parameters other than SO₂ and December 31, 2025, for SO₂ norms.
Finally, Category C includes all remaining plants, which must meet compliance by December 31, 2024, for parameters other than SO₂, and by December 31, 2026, for SO₂ norms.
On one hand, NITI Aayog argued against the necessity of FGDs in TPPs. Yet, the Prime Minister recently inaugurated an FGD installation in Bokaro, Jharkhand, creating confusion around FGD installations in TPPs.
Installing FGD systems is costly, at Rs 1-2 crore per megawatts, leading to an added charge of 0.50-0.55 paise per unit, which increases electricity generation costs. If FGD implementation continues, consumers may face additional costs, while coal power plants and regulators avoid accountability for market-driven technology prices.
In 2023, India consumed approximately 1,155.3 million tonnes of coal, with the coal-based thermal power sector accounting for 826.64 million tonnes. Indian coal has a sulphur content ranging from 0.35 to 0.4 percent, which is relatively low compared to Chinese or Indonesian coal.
However, the calorific value (CV) of Indian coal is about half that of imported coal, leading to double the consumption for each MWe generated. During combustion, the sulphur in coal combines with oxygen, forming SO₂, which is released into the environment unless effective capture mechanisms are in place. This raises the question: where is all the SO₂ generated from coal combustion going?
The SO₂ emitted from coal combustion in India is transformed into sulphates in the atmosphere, which contributes to an increase in particulate matter (PM2.5). India is the world’s largest emitter of sulfur oxides, emitting nearly two to three times as much as China, which has already implemented abatement measures in its power plants.
In 2019, India surpassed China to become the largest SO₂ emitter globally, emitting nearly twice the amount of Russia, the second-largest emitter. SO₂, along with PM2.5 and PM10, poses severe health risks, increasing the likelihood of stroke, heart disease, lung cancer, and premature death.
Given the harmful effects of SO₂ on human health, controlling its emissions is crucial. SO₂ also reacts with nitrogen oxides (NOx) to form PM2.5 and PM1, both of which have serious health implications and contribute to haze. High NOx levels in Indian coal-fired power plants enhance the conversion of SO₂ into fine PM.
“How come the policymakers of the country suddenly realised that FGD is not required to control SO₂ emissions? Till August 2024 about 60 percent of country's coal capacity has either installed FGD or under implementation phase. Whereas 40 per cent are at various stages of tendering or pre-tendering process. Such decisions will pose significant health risks to the population,” said Shobhit Srivastava, programme manager at CSE.
According to the Ministry of Power, in August 2024, FGDs were being installed in 537 units across the country’s coal-based TPPs. The current status of FGD installation as per the ministry is as follows:
FGD installed in 39 units (19,430 MW).
Contracts awarded or installations underway in 238 units (105,200 MW).
Units in various stages of tendering process: 139 units (42,847 MW).
Units in the pre-tendering process: 121 units (36,683 MW).