Complying with the revised emission norms is one of the key priorities of Indian thermal-based power generation companies. Developers are opting for flue gas desulphurisation (FGD) systems to meet sulphur oxide (SOx) norms, and are using combustion modification as the preferred solution for meeting nitrogen oxide (NOx) norms. The Central Electricity Authority (CEA) has prepared a detailed phasing plan for FGD upgrades across 440 units, aggregating 166 GW of capacity by 2022. However, the progress of FGD installations has been sluggish so far.
As per the initial notification issued by the Ministry of Environment, Forest and Climate Change in 2015, thermal projects were required to comply with emission standards by December 2017. Given the various challenges faced by power generators, the timeline was subsequently extended to December 2022. Despite extension, the progress has remained slow, with bids awarded for only 40 per cent of the identified capacity (as of February 28, 2021) for the supply and installation of FGD systems.
Moreover, during the same period, only 1 per cent of coal and lignite-based projects had commissioned FGD system. As per the timelines issued by the CEA, 18 per cent of the identified capacity, that is, 31 GW, was supposed to complete FGD installation by December 2020. Performance varies depending on the ownership. FGD implementation by the centrally-owned power units has been progressing at a much faster pace as compared to the private and state-owned units. As of February 28, 2021, bids were awarded for 86 per cent of the planned FGD capacity, at centrally-owned units as compared to only 8 per cent for private and 27 per cent for state-owned capacities.
Despite the progress made in awarding bids by public gencos (state and central sectors), as of February 2021, FGD systems had been commissioned only at four 210 MW units of NTPC Limited’s Dadri thermal power plant (TPP). However, as per the CEA, bids have been awarded for 52.06 GW by public gencos, representing around 48 per cent of the planned capacity. Notices inviting tenders (NITs) have been issued for 86.63 GW (80 per cent of the planned capacity). Overall, public gencos have made better progress in the issuing of tenders and awarding of bids than private gencos, which have issued tenders for around 73 per cent (44.69 MW) of the planned capacity and awarded bids for 27 per cent (16.6 MW).
To control SOx emission, NTPC has installed an FGD system in stage-V of Vindhyachal super TPP (STPP). The same is under commissioning at Bongaigaon, Dadri and Jhajjar plants. Further, orders for over 56 GW of capacity have been placed and replication is being explored at the remaining stations.
Power Line takes a look at the progress in the installation of FGD systems by gencos and their future plans…
NTPC
NTPC has taken the initiative for FGD system installation for SOx emission control and optimisation as well as implementation of appropriate technologies for NOx emission control, to comply with the revised emission norms as per the stipulated timeline, at its power plants. In all upcoming greenfield projects, NTPC will adopt advanced and high efficiency technologies such as super critical boilers at new stations, DeNOx and FGD.
For SOx control, the first wet FGD has been commissioned and has become operational at NTPC’s 500 MW unit at Vindhya-chal STPP, Madhya Pradesh. Besides this, NTPC has commissioned FGDs at four units of its Dadri project. It has opted for the dry sorbent injection (technology for these units. Further, FGD system is at an advanced stage of implementation at the 490 MW units of the Dadri project by Bharat Heavy Electricals Limited, with technology from Mitsubishi Power Works, Japan. NTPC has awarded various packages for the execution of FGD. The total thermal capacity picked for FGD implementation by NTPC exceeds 62 GW. Of this, FGD tenders for more than 59 GW worth Rs 290 billion have already been awarded, while FGD systems for around 2 GW of capacity are under implementation. During 2019-20, NTPC awarded contracts for wet limestone-based FGD systems for a capacity aggregating 25,810 MW.
In order to comply with the applicable environmental norms notified by MOEF&CC vide gazette notification dated December 7, 2015 pertaining to sulphur dioxide, FGD systems will be required to be installed in existing as well as under-construction coal-fired power plants. NTPC, along with its joint venture companies, has around 155 units aggregating 65 GW capacity, including all operating as well as under-construction units. The company is taking a lead role in FGD implementation. Till date, NTPC has issued tenders for 139 units of around 63 GW capacity, covering both operating as well as under-construction units, except some smaller units. Further, FGD installation work in 57,260 MW of capacity is under way. This showcases NTPC’s commitment towards a greener environment. The SO2 and NOx emission levels in the country will plummet to 30 per cent of what they are at present after installing FGD technology, even if another 70 GW of capacity is added from the current year.
State gencos
GSECL – Of the 5,160 MW of coal- and lignite-based power plants of Gujarat State Electricity Corporation Limited (GSECL), 3,140 MW is compliant with the particulate matter norms and implementation is underway for the remaining 2,020 MW. All units of GSECL meet the NOx norms except the 800 MW unit-8 of 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 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 FGD at unit-8 of Wanakbori TPP. The cost of FGD without operations and maintenance for all these capacities is estimated at Rs 22.24 billion.
HPGCL – Haryana Power Generation Corporation Limited (HPGCL) is in discussion with equipment manufacturers for NOx control through modification in the combustion chamber of the boiler. HPGCL has already completed the work of rectifying the electrostatic precipitator in almost all its thermal units. In addition, the utility is meeting the norms of specific water consumption and mercury. The company issued NITs during April-June 2019 for the installation of FGD at HPGCL’s power plant, where the company went for an international bidding process, in which all participants were from China. However, to comply with the Atmanibhar Bharat Abhiyan initiative of the Government of India, the ongoing bidding process was scrapped and the process has been reinitiated through domestic bidding, which has resulted in time delays.
WBSEDCL – West Bengal State Electricity Distribution Company Limited is also deploying FGD systems at its power plants. The installation of FGD at its Bakreswer TPP, Santaldih TPP and Sagardighi TPP is in the tendering stage, while the utility has installed dry solvent injection systems at Kolaghat TPP and Bandel TPP.
Issues and concerns
Despite continued efforts, there are numerous reasons for delays in the installation of FGD systems such as limited global vendor and sub-vendor capability to supply FGDs and delay in the award of tenders due to a lack of technical and operational expertise regarding FGD technology in the market and among power utilities. Environmental concerns, particularly relating to coal-based thermal stations, have emerged as a major challenge to the sector. In December 2015, MOEF&CC notified the new standards for water consumption, particulate matter, SOX, NOX and mercury for thermal power stations. To comply with these norms, TPPs need to implement emission control equipment such as FGDs, selective catalytic reduction, and selective non-catalytic reduction, along with necessary combustion modifications and retrofits. Despite many challenges such as unavailability of space and lack of proven technology for high ash domestic coal, these power plants have to undergo necessary retrofits to comply with the norms progressively by 2022. The cost of retrofitting appropriate systems to meet these norms will have an adverse impact on tariffs. Logistics and supply chain management for sourcing consumables and disposing of the waste generated impose additional challenges. With the changing environmental norms and land acquisition issues, ash disposal is a serious challenge. Further, as per new environment norms, all plants have to achieve 100 per cent ash utilisation from 2020-21. NTPC, in its endeavour to promote ash utilisation, is considering implementation of a fly ash classification system and bagging plant for its upcoming coal-based thermal power projects.
Outlook
NTPC has been conventionally producing electricity through coal and gas. Many design upgradations such as new supercritical and ultra-supercritical based capacity additions and process innovations such as high concentration slurry disposal, real-time monitoring of pollutants and zero liquid discharge have been implemented to reduce the carbon footprint. With a focus on curbing the release of SOx and other undesirable emissions into the environment, NTPC is commissioning FGD systems at various stations. NTPC has also increased its solar-, wind- and hydro-based capacities, with negligible emissions.
The MoP, in consultation with the CEA, is recommending a reasonable extension of timeline because of the Covid-19 pandemic and the import ban. It has proposed an extension of six months to two years on a case-to-case basis. The CEA and MoP are also holding regular meetings with bankers so that issues related to loans for independent power producers can be resolved. Since provisional tariff has not been granted, the Forum of Regulators has agreed to issue investment approval on a case-to-case basis. The Central Electricity Regulatory Commission (CERC) has already recognised revised environmental norms as a “change in law” event, and is also planning to amend its tariff regulations for 2019-24 in order to incorporate the cost of FGD systems in tariff calculations. In September 2020, CERC also floated a staff paper on the mechanism for compensation for competitively bid thermal generating stations for change in law on account of compliance with the revised emission standards of the MoEF&CC, in cases where power purchase agreements do not have explicit provisions for such compensation. Going forward, the industry is likely to see an uptake in FGD system installation, as the issues are being resolved through regulatory reforms and FGD orders have been placed for a substantial thermal capacity.