Why in News?

A high-powered committee led by Principal Scientific Advisor Ajay Sood has recommended scrapping the decade-old policy requiring Flue Gas Desulphurisation (FGD) units in all coal-fired thermal power plants.

The panel concluded that FGDs may no longer be necessary, marking a potential shift in India’s pollution control strategy.

The Environment Ministry is currently reviewing the committee’s recommendation. A final decision will be made by the Power and Environment Ministries.

What’s in Today’s Article?

• Flue Gas Desulphurisation (FGD)
• Current Compliance
• Committee Recommends Scrapping FGD Mandate
• Proposed Plant Classification and Compliance

Flue Gas Desulphurisation (FGD)

• FGD is a technology used to remove sulphur dioxide (SO₂) from the exhaust (flue) gases emitted by coal-fired power plants, industrial boilers, and other combustion sources.
• Working
  • When coal is burned, it releases sulphur dioxide (SO₂), which is harmful to human health and contributes to acid rain.
  • FGD systems scrub these gases, typically using a slurry of limestone (calcium carbonate) or lime (calcium oxide).
  • The SO₂ reacts with the slurry to form gypsum (calcium sulphate), a by-product that can be used in construction.

Current Compliance

• FGD units are required to be retro-fitted in TPPs to cut harmful sulphur dioxide (SO2) emissions. 
  • India has 180 coal-fired thermal power plants, each of them with multiple units.
  • The 600 TPPs, depending on their size, age, proximity to densely populous cities, and background pollution levels, were given different timelines by the Environment Ministry to comply with the FGD installation requirements.
  • Deadlines have been shifted three times, with the most recent extension coming on Dec 31, 2024.
• 92% of India's 600 thermal power plants (TPPs) units have not installed FGDs.
• In theory, the costs of non-compliance could run to crores of rupees in fines, though these have not materialised thanks to deadline extensions.
• Reasons for Historical Non-Compliance
  • High costs and limited vendor availability.
  • Potential rise in electricity tariffs.
  • COVID-19 delays.
  • Despite missing deadlines, penalties were avoided due to repeated deadline extensions.

Committee Recommends Scrapping FGD Mandate

• A high-powered expert committee led by Principal Scientific Advisor Ajay Sood has advised ending the mandatory installation of Flue Gas Desulphurisation (FGD) units in coal-fired thermal power plants (TPPs).
• Basis of Recommendation
  • SO₂ Levels Already Low
    • The committee cited findings from CSIR-NEERI, IIT Delhi, and NIAS, supported by:
      • Low ambient SO₂ levels (10–20 µg/m³ vs. the permissible 80 µg/m³).
      • Low sulphur content in Indian coal.
      • Negligible difference in SO₂ levels near TPPs with or without FGDs.
      • Low sulphur content in PM samples across India.
  • FGDs Could Increase CO₂ Emissions
    • Installing FGDs in all TPPs by 2030 could lead to:
      • An additional 69 million tonnes of CO₂ emissions, while only reducing SO₂ by 17 million tonnes.
      • The committee argued that removing short-lived SO₂ while adding long-lived CO₂ could worsen global warming.
  • Public Health Not at Risk
    • The committee concluded:
      • FGDs not essential for meeting National Ambient Air Quality (NAAQ) standards.
      • TPPs should still comply with 2015 norms on particulate matter and water use.
      • Relaxing SO₂ norms would not compromise public health if ambient standards are met.
  • Concerns
    • Experts pointed out that burning coal is India’s primary source of electricity.
    • As a result, India’s annual SO2 emissions has risen from 4,000 kilotonnes in 2010 to 6,000 kilotonnes in 2022.
      • In contrast, Indonesia averaged only 2,000 kt over the same period, even though India imports coal from there.
    • This is despite India’s strict SO₂ emission standard of 100 µg/m³ (compared to Indonesia’s 800 µg/m³).

Proposed Plant Classification and Compliance

• The committee recommends a tiered approach:
  • Category A: TPPs within 10 km of NCR or million-plus cities (66 plants) must install FGDs; only 14 have done so.
    • Currently, all these plants are required to comply by 2027.
  • Category B: Plants near critically polluted or non-attainment cities (72 plants) may get case-by-case exemptions.
    • These plants currently have a deadline of 2028.
  • Category C: The remaining 462 plants should be completely exempted.
    • These plants were given a 2029 deadline.
    • The committee has now recommended that Category C plants be exempted completely, along with some units in Categories A and B which were set up at least 20 years ago.