Flue Gas Desulphurisation: In News
The Environment Ministry has exempted most coal-fired plants in India from installing Flue Gas Desulphurisation (FGD) systems aimed at reducing sulphur dioxide (SO2) emissions.
- Flue Gas Desulphurisation (FGD) is a pollution-control process that removes Sulphur Dioxide (SO₂) from the flue gases produced by the combustion of fossil fuels, especially coal.
- The key aim of FGD is to reduce SO₂ emissions, which are major contributors to acid rain and particulate matter pollution, harming crops, soil, water bodies, infrastructure, and human health.
- FGD systems typically use limestone (CaCO₃), lime (CaO), or ammonia (NH₃) to react with and neutralize SO₂ in flue gases.
- In 2015, India’s Environment Ministry mandated that all coal-fired thermal power plants must install FGD systems by 2017 to curb SO₂ pollution. There are about 180 such plants, comprising 600 individual units.
- This exemption decision was based on scientific studies suggesting:
- Indian coal has low sulphur content.
- SO₂ levels near plants with and without FGDs were similar.
- Sulphates may have a cooling effect, counteracting global warming.
- As of now, only ~8% of these units have installed FGDs, with most installations by NTPC (public sector). The rest failed due to vendor shortages, high costs, COVID-related delays, and an anticipated rise in power tariffs.
