Air pollution in north India made headlines across the world when Air Quality Index (AQI) levels were recorded as over 1,500 a few weeks ago – unprecedented, experts said, even for a region that routinely ranks among the world’s most polluted.
Though crop residue burning contributes to such seasonal peaks, there’s a steady combustion source that is many times more polluting: thermal power plants.
Seasonal burning of the paddy crop residue coincides with lower temperatures and more stagnant winds, which causes a high level of pollutants to gather over the Indo Gangetic Plain over the winter.
This curtain of smog is mostly made up of PM2.5 particles – very fine, toxic pollutants that are released on the combustion of fuels or burning of biomass. But pollution from thermal power plants is continuous, and responsible for a sizable pollution load annually.
An analysis by the Centre for Research on Energy and Clean Air (CREA) found that thermal power plants emit 10 times more kilotonnes of PM2.5 compared to crop residue burning, and over 200 times more kilotonnes of sulfur dioxide, another harmful pollutant. In the National Capital Region alone, thermal power plants emit 16 times more sulphur dioxide compared to stubble burning.
“Despite the significant health and environmental impact of coal-fired power plant emissions, regulatory enforcement on these power plants remains far less stringent compared to the seasonal restrictions and penalties imposed on stubble burning,” the analysis says.
Curbing emissions from thermal power plants involves installing flue gas desulfurisation (FGD) systems, which filter sulphur dioxide – a precursor to PM2.5. Despite scientific consensus on the efficacy of FGD technologies, as well as existing mandates on their installation, the government has sent out mixed signals on the implementation of FGD.
On November 19, the Ministry of Power sought an extension on the installment of FGD in thermal power plants. Also in November, the NITI Aayog, the government’s foremost think tank, suggested thermal power plants could do away with FGD technologies altogether.
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Flue gas desulfurisation (FGD) is not a new technology. There’s a well-established global supply chain because installing it in the West and China is mandatory.
Ashwini Chitnis, energy specialist, Centre for Social and Economic Progress
“The biggest problem is that there’s a lack of understanding among stakeholders when it comes to the importance and enforcement of FGD,” said Shreya Verma, Programme Manager of industrial pollution at the Centre for Science and Environment. “Casting doubts over the need for FGD indicates to industry that they can continue to be lax with compliance.”
The first deadline for compliance with FGD is December 31, 2024, for power plants within a 10-kilometre radius of Delhi NCR. However, out of the four power plants that fall in this category, only one has fully complied, while another has partially complied, CREA’s analysis shows.
India’s sulphur dioxide emissions are rising
Coal fired power plants account for around 47 per cent of India’s total electricity generation capacity, but are the source for over 70 per cent of India’s power demand. Even though the government is making strides in establishing renewable energy capacity, coal continues to meet a bulk of the country’s electricity and power needs.
As the world’s third largest producer of coal, India is also among the top emitters of sulphur dioxide. In 2022, India emitted 16 per cent of the world’s sulphur dioxide, making it the world’s largest emitter of this gas.
Sulphur dioxide emissions from thermal power plants have grown since 2019, according to satellite images analysed by CREA. Between June 2022 and May 2023, thermal power plants released approximately 4,327 kilotonnes of sulphur dioxide. In Delhi-NCR alone, sulphur dioxide emissions from thermal power plants were found to be 281 kilotonnes.
Over the same period, burning 8.9 million tonnes of paddy straw in Punjab and Haryana resulted in 26.7 kilotonnes of particulate matter (PM2.5) and 17.8 kilotonnes of sulphur dioxide. Emissions from thermal power plants are “over 10 times and 240 times higher” than emissions from stubble burning, the analysis says.
“The challenge is not confined to centrally run power plants. FGD installation is lagging in private and state-operated power plants, and it’s these plants that have the maximum reduction potential,” said Manoj Kumar, an analyst at CREA and lead author of the paper.
The highest concentrations of sulphur dioxide were found in central and eastern states, which house a large number of thermal power plants – the Mahanadi basin (covering Chhattisgarh and Odisha), around Biswanathpur (Odisha), and Govind Ballabh Pant Sagar (Uttar Pradesh).
Installing FGD in thermal power plants can reduce emissions of sulphur dioxide from 4,327 kilotonnes to 1,547 kilotonnes, according to CREA. “This amounts to an overall reduction of approximately 64 per cent, highlighting the tremendous potential impact of FGD technology on reducing air pollution from coal-fired power plants,” says the analysis.
Compliance has been lax
The scientific evidence that FGD technologies reduce sulphur dioxide emissions is largely uncontested. Removing sulphur dioxide emissions can prevent the formation of secondary particles. Once sulphur dioxide is released, it can oxidise in the air to form sulphate aerosols, which form PM2.5.
In 2022, the Indian Institute of Technology, Delhi and the Central Electricity Authority found that FGD in 67 coal power plants could reduce surface sulphur dioxide concentrations by 55 per cent within a 60 to 80-kilometre radius, and reduce surface concentrations of sulfate aerosols by about 30 per cent, with reductions extending to 100 km from the emission source.
Globally, India has indicated its support for technologies like FGD when it agreed to phase down unabated coal power (“unabated” refers to emissions without any reductions). But domestically, the installation of FGD technologies has been marred by delays in compliance and laxity in enforcement. Less than 1 per cent of funds in India’s clean air programmes are directed towards controlling emissions from thermal power plants and other industrial sources, for example.
India introduced compliance norms for emissions from thermal power plants in 2015, first stipulating that all thermal power plants should install FGD and meet emission norms by December 2017. This deadline for FGD installation was then revised twice, on the instance of the Ministry of Power and Association of Power Producers, with staggered timelines introduced to facilitate installation.
According to the latest notification, issued by the Ministry of Environment in 2022, power plants within a 10-kilometre radius of Delhi NCR or cities having a population of more than a million people are required to meet compliance norms by December 31, 2024.
These are Category A plants. Category B plans, which are within a 10-kilometre radius of “critically polluted areas”, are required to comply by December 31, 2025, while the rest of the power plants in the country must comply by December 31, 2026. Missing these deadlines will make plants liable to pay Rs. 0.2 to Rs. 0.4 per unit of electricity generated, depending on the period of non-compliance.
Installing FGD can take up to three years. Out of 600 thermal power plants, only 44 have installed FGD systems, while bids for installation have been awarded for another 233 units.
In its letter on November 19, the Ministry of Power requested each category deadline be extended by 36 months, citing “major constraints” in timely compliance.
“These constraints are primarily limited to limited domestic manufacturing capacity due to limited vendor base, dependence on imports, and a sudden growth in demand to meet the stipulated timelines,” says the letter, which Mongabay India has seen.
Ashwini Chitnis, an energy specialist and Visiting Fellow at the Centre for Social and Economic Progress, says the reasons for seeking extensions have largely remained unchanged over the last ten years.
“FGD is not a new technology. There’s a well-established global supply chain because installing it in the West and China is mandatory. We routinely import equipment for other aspects of the energy sector, such as say, for solar panels. More importantly, it is not as though any efforts are being made to install FGDs, and they are being delayed due to such constraints. So, repeatedly citing such vague reasons for missing deadlines is unacceptable”, she said.
This story was published with permission from Mongabay.com.
