Established in 1985, state-owned power generation company West Bengal Power Development Corporation Limited (WBPDCL) has been supplying reliable power for over three and a half decades. Although its current installed capacity is predominantly coal based, the utility is taking small steps to embrace solar power through rooftop, ground-mounted as well as floating solar plants. It is also in the process of adopting emission control solutions for its fleet of coal-based plants in order to comply with the environmental regulations. Power Line takes a look at WBPDCL’s operations, achievements, challenges and future plans…
Installed capacity and operational performance
As of March 2021, WBPDCL’s coal-based installed capacity stood at 4,745 MW, comprising the 1,600 MW Sagardighi thermal power station (TPS), the 1,260 MW Kolaghat TPS, the 1,050 MW Bakreswar TPS, the 500 MW Santaldih TPS and the 335 MW Bandel TPS. In addition, Durgapur Projects Limited (DPL), a fully owned subsidiary of WBPDCL, has a 550 MW coal-based TPP.
WBPDCL achieved the highest ever yearly thermal power generation of 23,876 MUs during 2020-21, recording an increase of around 13 per cent from 21,124 MUs in 2019-20. Plant wise, the Sagardighi TPS, the Bandel TPS and the Bakreswar TPS recorded an increase in generation in 2020-21, as compared to that in the previous year, while the Kolaghat TPS and the Santaldih TPS registered a decline (see table).
Overall, WBPDCL’s plants recorded a plant load factor (PLF) of 57.5 per cent in 2020-21, compared to a PLF of 50.73 per cent in 2019-20. The highest PLF during 2020-21 was recorded by the Bakreswar TPS at 85.85 per cent and that of Santaldih stood at 78.61 per cent. These two plants ranked 9th and 22nd on the basis of PLF in the Central Electricity Authority’s merit order among the 25 best TPSs of India.
Also, WBPDCL achieved a plant availability factor of 78.43 per cent in 2020-21. Meanwhile, during the year, the utility attained the lowest yearly specific oil consumption of 0.45 ml per kWh, and the lowest yearly auxiliary power consumption of 8.5 per cent. Further, it achieved 70.95 per cent downtime reduction due to boiler tube leakage as compared to 2019-20. Meanwhile, generation from DPL’s TPS stood at 2,788 MUs in 2020-21, an increase of 24.8 per cent as compared to the 2,233 MUs recorded in 2019-20. The PLF of the plant increased from 39.6 per cent in 2019-20 to 57.87 per cent in 2020-21.
Besides thermal power, WBPDCL stepped into solar power generation with a 40 kW rooftop solar photovoltaic (PV) plant at Bidyut Unnayan Bhaban in 2014. Following the success of this project, WBPDCL has installed rooftop, ground-mounted as well as floating solar PV plants at many locations. Currently, the genco has an installed solar capacity of 25.58 MW, comprising 10.58 MW of rooftop solar, 10 MW of ground-mounted solar and 5 MW of floating solar. The 10 MW grid connected ground-mounted solar PV project and the 5 MW grid-connected floating solar PV project have been set up at the Sagardighi TPS. Meanwhile, rooftop solar PV plants have been installed on the roofs of 71 buildings of its power plants.
In order to secure fuel supply for its power plants, WBPDCL is also undertaking mining at several of its captive coal blocks allocated by the Ministry of Coal (MoC). These include Pachhwara (North), Barjore, Gangaramchak and Gangaramchak-Bhadulia, Barjora (North), Tara (East and West), and Kasta (East) and Deocha-Pachami and Dewanganj-Harinsingha. Of these, coal production has already started from the coal blocks of Pachhwara (North), Barjore, Gangaramchak and Gangaramchak-Bhadulia, and Barjora (North).
After obtaining all statutory permissions, coal production was started from the Barjore coal mine from April 2018 and from the Barjora (North) coal mine from May 2019. Meanwhile, coal production from Gangaramchak and Gangaramchak-Bhadulia, and Pachhwara (North) coal mines started from March 2019 and November 2019 respectively. The Tara (East and West) coal mine was reopened by WBPDCL in March 2020 and removal of overburden has started. Coal mining in Tara (East and West) was expected to commence from April 2021. Furthermore, the Kasta (East) coal mine is a Schedule III coal mine allocated to WBPDCL, with an abnormally high stripping ratio of 1:16 and further evaluation is under process for economic viability.
In September 2019, the MoC entered into an allotment agreement with WBPDCL for the Deocha-Pachami Dewanganj-Harinsingha coal block located in the Birbhum district of West Bengal. With estimated reserves of 2,102 million tonnes, the Deocha Pachami is the second largest coal mine in the world. Its social impact assessment study has been completed.
In respect of the Trans Damodar coal mine at Barjora, Bankura of DPL, the rehabilitation and resettlement package, along with the rate of land for purchase has been approved by the district purchase committee. The initial work of coal production from the mine has started with effect from November 2020.
In order to meet the environmental regulations stipulated by the Ministry of Environment, Forest and Climate Change, WBPDCL is in the process of retrofitting its existing projects with emission control equipment. The installation of flue gas desulphurisation (FGD) systems is at the tendering stage at the Bakreswar TPS, Sagardighi TPS and Santaldih TPS, while the dry solvent injection (DSI) system will be installed the Kolaghat TPS and Bandel TPS.
For the 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. Meanwhile, all plants are compliant with the specific water consumption norms. Opacity is under control in most of the plants, except at the Kolaghat TPS, for which action has already been initiated. For DPL’s TPS, the upgradation of electrostatic precipitators for unit 7 for suspended particulate matter control has been planned. Besides, FGD installation will be done based on suitability of technology, cost and space.
WBPDCL’s total revenue increased to Rs 101.07 billion in 2018-19 from Rs 92.78 billion in 2017-18. Its profit after tax, declined during this period to Rs 1 billion from Rs 1.03 billion. Meanwhile, its total expenditure increased to Rs 99.8 billion from Rs 91.45 billion.
One of the key projects being undertaken by WBPDCL is the installation of a supercritical unit at the Sagardighi TPS. WBPDCL has started preliminary works for setting up a 660 MW unit at the Sagardighi supercritical plant. It expects to complete the construction of the unit over the next three-and-a-half years. The financial closure of the Rs 44 billion project has been achieved, with debt from Power Finance Corporation. Bharat Heavy Electricals Limited has been awarded a Rs 35 billion order for supplying the boiler, turbine, generator for the unit. WBPDCL currently has four units totalling 1,600 MW in Sagardighi and the upcoming unit will increase the plant’s overall capacity to 2,260 MW. Apart from this, WBPDCL is expanding into the renewable energy space and plans to add 10 MW and 5 MW of floating solar plants at the Sagardighi TPS and Santaldih TPS respectively, and a 20 MW ground-mounted solar plant at the Santaldih TPS.
Challenges and the way forward
The genco is currently facing challenges due to low system demand and the associated backing down of plants. According to the company’s regulatory filings, during the past five years, there has been an abnormal forced backdown of units of WBPDCL, particularly at the Sagardighi TPS, Kolaghat TPS and Bandel TPS, resulting in a high rate of consumption of secondary fuel oil. Besides, the high cost of generation in old units such as the Kolaghat TPS and Bandel TPS also poses serious impediments. This is one of the reasons that the genco’s PLF is only 54.02 per cent. Further, despite all efforts, 100 per cent fly ash utilisation is still an issue with the genco. Other challenges with respect to emission control equipment, as assessed from the company’s regulatory filings, is a lack of response to bidding for all FGD packages, even after multiple extensions of time for bid submission. Further, the specific oil consumption has been higher for WBPDCL’s Sagardighi TPS, Kolaghat TPS and Bandel TPS due to poor quality of coal (low grade and high ash content) received at the feeding point, moisture content in coal, frequent start-ups and shutdowns, and ageing of units.
Notwithstanding these challenges, the company is optimistic about its future growth. It is investing in retrofitting its existing projects with emission control equipment to comply with environmental regulations. Going forward, its upcoming generation capacity in thermal and renewable energy is expected to ensure that it remains on a strong footing to cater to the state’s future power requirements.
(With inputs from a presentation by Subhasis Ghosh, Director, O&M, WBPDCL)