Emissions from coal-based thermal power plants (TPPs) release sulfur dioxide (SO2), nitrogen oxides (NOx), carbon monoxide (CO), and particulate matter (PM), impacting the environment and human health. SO2 can oxidize in the atmosphere, forming sulfate (SO4) particulate matter. To address these concerns, the Ministry of Environment, Forest and Climate Change (MoEF&CC) revised air pollution norms on December 7, 2015. The new standards set limits for PM2.5, SOx, NOx, and mercury emissions, requiring many plants to install Flue Gas Desulfurization (FGD) units to reduce SO2 emissions and meet the new thresholds.
According to the Ministry of Power, in August 2024, FGD systems are being installed in 537 units across coal-based thermal power plants in India.
FGD Status Across the Country
The current status of FGD installation in coal-based thermal power plants is as follows:
- 39 units (19,430 MW) have completed FGD installation.
- 238 units (105,200 MW) have contracts awarded or are under implementation.
- 139 units (42,847 MW) are at various stages of the tendering process.
- 121 units (36,683 MW) are still in the pre-tendering process.
The details of completed FGD installations across different categories of thermal power plants are as follows:
- Category A: 11 units (4,390 MW)
- Category B: 2 units (1,160 MW)
- Category C: 26 units (13,880 MW)
Total: 39 units (19,430 MW)
Challenges in FGD Installation
Several challenges have been identified in the installation process of FGD systems:
Limited Vendor Capacity: FGD technology is new to India, and currently, there are only a few vendors with the capacity to supply and install FGD components. The vendor’s capacity is limited to about 16-20 GW (33 to 39 units) annually, and the installation time for each unit is approximately 44 to 48 months. This has created a gap between the demand for FGD systems and the supply of equipment.
Dependence on Imports: India has increased its manufacturing capability for FGD components from 70% to 80%. However, the country still depends on imports for certain critical components, leading to a drain of foreign exchange and delays in installation.
Design and Site-Specific Challenges: Each site for FGD installation comes with its unique set of challenges, including space constraints, layout differences, and varying requirements. This lack of standardization has made the installation process more complex.
Pandemic-Induced Disruptions: The COVID-19 pandemic disrupted supply chains, affecting the availability of materials and labour. Many subcontractors faced financial distress, which further delayed the installation process.
Procurement and Policy Changes: Changes in the procurement policy, in line with the “Aatma Nirbhar Bharat” initiative, have led to increased prices for materials and delays in procurement. Additionally, stringent pre-qualification criteria have limited the vendor base for FGD components.
Site Execution and Retrofitting Issues: Retrofitting FGD components in brownfield plants has posed challenges due to design issues, and standardization has not been possible. These retrofitting jobs often require re-engineering to address site-specific conditions.
Timelines and Compliance
The MoEF&CC has notified specific deadlines for the implementation of SO2 emission norms for thermal power plants. According to the MoEF&CC notification, the implementation timelines are:
- Category A (TPPs located within 10 km of NCR or million-plus cities): December 31, 2027
- Category B (TPPs in critical polluted areas): December 31, 2028
- Category C (TPPs in other areas): December 31, 2029
Thermal power plants that opt for retirement by December 31, 2030, will be exempt from compliance with these emission norms. Non-compliance will result in environmental compensation for the plants.
Recent Tender Updates
Below are some of the latest tenders and updates on ongoing projects:
Mauda Thermal Power Project (Maharashtra) – Balance Works for FGD System
On January 4, 2025, BHEL invited bids for the balance work of handling materials, erection, testing, commissioning assistance, and the application of final painting for the FGD system of Stage I of the 1,000 MW Mauda Thermal Power Project.
Ramagundam Super Thermal Power Project (Telangana) – Mechanical Works for FGD System
BHEL re-invited bids on December 31, 2024, for the erection and commissioning of mechanical works for the FGD systems in Units 4 of both Stage I and Stage II of the Ramagundam Super Thermal Power Project.
Bhilai Expansion Power Project (Chhattisgarh) – Civil and Structural Works for FGD System
BHEL invited bids for balance civil, structural, and architectural works for the FGD system in the 500 MW Bhilai Expansion Power Project on December 31, 2024.
Korba West Extension Power Project (Chhattisgarh) – Civil Works for FGD System
Bridge and Roof Company (India) Limited invited bids for general civil works for the implementation of the FGD system at the Korba West Extension Power Project on October 23, 2024.
North Chennai Thermal Power Station (Tamil Nadu) – Semi-Dry FGD System Installation
TANGEDCO re-invited bids on October 19, 2024, for the installation of a semi-dry FGD system at the North Chennai Thermal Power Station Stage I.
Barh Super Thermal Power Project (Bihar) – Mechanical Systems for FGD
BHEL invited bids on October 9, 2024, for the erection, testing, commissioning, and trial operation of mechanical systems for the FGD system at the Barh Super Thermal Power Project – Stage I.
Marwa Thermal Power Project (Chhattisgarh) – Civil Works for FGD System
Bridge and Roof Company (India) Limited invited bids for civil works related to the FGD system for the Marwa Thermal Power Project on October 4, 2024.
Lara Super Critical Thermal Power Project (Chhattisgarh) – ESP and FGD Mechanical Package
BHEL re-invited bids on September 27, 2024, for the erection and commissioning of electrostatic precipitators (ESP) and the FGD mechanical package at the Lara Super Critical Thermal Power Project Stage II.
Various other bids for the construction of chimneys, supply of electrical and C&I systems, and gypsum dewatering equipment for different thermal power projects have also been invited across the country.
The installation of FGD systems at coal-based thermal power plants in India is a critical step in addressing the country’s air pollution issues. However, challenges related to vendor capacity, design complexities, and policy changes continue to affect progress. Timely implementation of the MoEF&CC’s emission norms will be crucial for improving air quality and reducing health risks linked to SO2 emissions.
Photo credit: Adani Power