Disclaimer: Copyright infringement not intended.

Context:

According to CSIR-NEERI’s draft report Analysis of Historical Ambient Air Quality Data Across India for Developing a Decision Support System, SO₂ emissions from India’s coal-based power plants are not significantly affecting ambient air quality, with standards mostly met. 

Key Details 

• The study aimed to assess the need for current flue gas desulfurization (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).
• 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, recommended phased FGD implementation in thermal power plants (TPPs) across India based on SO₂ concentration data from AURA (OMI) Satellite and MERRA2 reanalysis (2015-2019).

Should FGD be installed?

• 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.

Where is the SO₂?

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.

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.

Why is it important to control SO₂ emissions?

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.

According to the Ministry of Power, in 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).

Flue Gas Desulfurization (FGD)

Thermal Power Plants in India

READ ABOUT

flue gas de-sulphurisation

IMPORTANT COAL FIRED THERMAL POWER STATIONS 

Source:

DOWNTOEARTH