Ensuring Environmental Safety

Progress in emission control by gencos

Since the Ministry of Environment, Forest and Climate Change (MoEFCC) notified new emission norms for thermal power plants (TPPs) in December 2015, gencos have been chalking out a number of strategies to ensure that their units comply with the new norms. They are actively working to deploy various emission control systems, including flue gas desulphurisation (FGD), selective catalytic reduction, selective non-catalytic reduction and electrostatic precipitators (ESPs) to ensure that their TPPs are able to meet the norms by the deadline.

According to the Central Electricity Authority’s data, as of February 2021, FGDs have been commissioned and are operational for 2,160 MW of capacity – four units of NTPC’s Dadri project (4×210 MW) and two units of CLP India’s Haryana project (2×660 MW). Meanwhile, bids have been awarded for 155 units aggregating 68,660 MW of capacity, which represents 40.5 per cent of the total planned capacity. Sector-wise, central gencos are taking the lead with 76.5 per cent of the planned capacity awarded, while private and state gencos have awarded 21.8 per cent and 7.2 per cent of the total planned capacity respectively.

Power Line takes a look at the progress on the installation of emission control systems made by public gencos and select state and private gencos, and their future plans…

Central gencos

NTPC Limited: NTPC has taken initiatives for FGD system installation for SOx emission control and optimisation, as well as the implementation of appropriate technologies for NOx  emission control. FGD systems are at various stages of implementation for 64.39 GW of its group capacity. FGD systems have already been commissioned for 1,340 MW of capacity. The first wet FGD has been commissioned and has become operational at NTPC’s 500 MW unit at the Vindhyachal Super Thermal Power Station (STPS), Madhya Pradesh. Besides this, NTPC has commissioned FGDs at four units of its Dadri project (4×210 MW), where it has opted for the dry sorbent injection technology. FGD system packages are under implementation for 58.94 GW of capacity and at various stages of tendering for 4.11 GW of capacity.

For NOx  control, combustion modification has already been implemented at 16 units aggregating 7.44 GW of thermal power capacity, while supply and installation of low NOx  combustion systems are under implementation for 14 GW of capacity. In November 2020, NTPC awarded an order to GE Power India Limited for setting up combustion modification technology at its 500 MW Barauni TPP Stage II (Units 8 and 9) in Bihar.

Damodar Valley Corporation (DVC): The genco has awarded FGD systems for its 500 MW and 600 MW units, and these are currently under implementation. These nine units, aggregating 4,700 MW, are the Bokaro A TPS (500 MW), Koderma TPS (2×500 MW), Durgapur Steel TPS (2×500 MW), Mejia TPS Units 7 and 8 (2×500 MW), and Raghunathpur TPS (2×600 MW). The total project cost is expected to be around Rs 28.43 billion, which will be funded in a debt-equity ratio of 7:3 with the debt portion already tied up. Also, for plants with capacity less than 500 MW, aggregating 1,840 MW, DVC will undertake a capital expenditure of Rs 11.06 billion in a debt-equity ratio of 7:3, wherein the debt is yet to be tied up.

State gencos

Gujarat State Electricity Corporation Limited (GSECL): Of GSECL’s 5,160 MW of coal- and lignite-based power plants, 3,140 MW is compliant with the particulate matter norms, while implementation of the norms is under way for the remaining 2,020 MW. All units of GSECL meet the NOx norms except the 800 MW Unit 8 of the Wanakbori TPP. In addition, GSECL has decided to address NOx issues after reviewing the results of NTPC’s pilot projects. Further, a detailed project report is under preparation for the installation of FGD systems at 14 old units aggregating 2,785 MW. Bids have been invited for another 1,000 MW and an order has been placed for the installation of the FGD at Unit 8 of the Wanakbori TPP.

Haryana Power Generation Corporation Limited (HPGCL): The utility is in discussions with equipment manufacturers regarding NOx control through modifications in the combustion chamber of the boiler. HPGCL had issued a notice inviting tenders during April-June 2019 for FGD installation at HPGCL’s power plant, wherein the company went for an international bidding process, in which all the participants were from China. However, to comply with the Government of India’s Atmanirbhar Bharat Abhiyan, the ongoing bidding process was scrapped and the process was reinitiated through domestic bidding, which has resulted in time delays.

Maharashtra State Power Generation Company Limited (Mahagenco): The utility has initiated the e-tendering process for installing FGD systems at its major units at Koradi (3×660 MW), Bhusawal (2×500 MW), Chandrapur (5×500 MW), Khaperkheda (1×500 MW), Parli (3×250 MW) and Paras (2×250 MW). It has also initiated the e-tendering process for its six older 210 MW units at Koradi and Khaperkheda. All this installation work is expected to be completed within the next two to three years. It has installed high performance ESPs with 99.9 per cent efficiency, low NOx burners and ambient air quality monitoring equipment, and is planning to upgrade the ESPs and pollution control equipment in its old units.

Telangana State Power Generation Corporation Limited (TSGENCO): TSGENCO has completed the feasibility study for the installation of FGD systems at the 1,100 MW Kakatiya TPP (both the 500 MW Stage I and 600 MW Stage II) and the 500 MW Kothagudem TPP Unit 2. In 2018, the utility awarded an order worth Rs 10 billion to BHEL for supply of FGD systems for the 800 MW Kothagudem TPP Stage VII and the 4×270 MW Bhadradri TPP. The order for the Bhadradri TPP also covers modifications in the boiler and ESPs to meet the revised emission norms. BHEL is currently executing these projects on an EPC basis.

West Bengal Power Development Corporation Limited (WBPDCL): WBPDCL is in the process of retrofitting its existing projects with emission control equipment. The installation of FGD systems is at the tendering stage at the Bakreswar TPS, Sagardighi TPS and Santaldih TPS, while the dry solvent injection system will be installed at the Kolaghat TPS and the Bandel TPS. For NOx reduction, offers have been made by original equipment manufacturers for the Bakreswar TPS, Sagardighi TPS and Santaldih TPS, while the remaining plants are NOx compliant. In addition, for Durgapur Projects Limited’s (a fully owned subsidiary of WBPDCL) TPS, FGD installation will be done based on suitability of technology, cost and space.

Private gencos

CLP India: CLP India’s 2×660 MW Jhajjar power plant was built in 2012-13. At that time, the new environmental norms were not in place, though the company had already installed an emission control system. The FGD system at the Jhajjar plant has been fully operational since February 2019. In fact, in Delhi-NCR, it is the only plant that is SOx compliant. The company is expecting a revision in NOx emission norms, which will make them NOx compliant as well.

Tata Power: To meet the SOx emission norms, bids have been awarded for the installation of FGD systems at the 4,000 MW Mundra power plant of Coastal Gujarat Power Limited, the 2×525 MW Maithon power plant and the 2×210 MW Jojobera plant. Further, FGDs have been planned for the 3×660 MW Prayagraj power project of Renascent Power, which is a Tata Power group company. Since Mundra is a coastal plant, the company is considering using a seawater-based FGD system. In the case of Maithon, wet limestone-based FGD is being considered on the basis of life cycle cost analysis. In the case of Jojobera Unit 1, which has a useful life of around 10 years, the company is exploring semi-dry-type or wet FGD technology. For the Prayagraj plant, it plans to install wet limestone-based FGD. Tata Power curtailed SOx emissions at both units of the Trombay TPS by installing seawater-based FGD, long before the regulatory notification on controlling SOx emissions was released. To address the issue of NOx emissions, low burners and over-fire air dampers have been made an integral part of the installed boilers.

Challenges and the way forward

The market for emission control equipment, especially FGD systems, is evolving in India. TPPs have made slow progress in complying with the revised emission norms, with only 1 per cent of the identified capacity having commissioned FGD systems so far. The key challenges hampering the market is the limited availability of vendors, dependence on imports, financial constraints on developers, uncertainty regarding cost recovery, and supply chain issues due to the Covid-19 pandemic. Taking cognisance of developers’ concerns, the MoEFCC, in April 2021, extended the timelines for TPPs to comply with the emission norms by one to two years, depending on the location of the plant. The new rules have also introduced a penalty mechanism for non-compliant operation by power plants beyond the specified timeline. To conclude, the extension in timeline will provide a relief to TPPs, especially in the private sector, given the challenges faced by these plants in securing funding and equipment to comply with the emission norms. However, going forward, strict adherence to the implementation timeline is desirable. n

Nikita Gupta



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