Coal-based thermal power plant
The Nagai coal-based thermal power plant located in the Indian state of Tamil Nadu was commissioned in August 2019.
The 150MW power plant uses domestic coal blended with imported coal for generating power.
The project was jointly developed by Megha Engineering and Infrastructures (MEIL) and KVK Energy and Infrastructure with an estimated investment of Rs14.4bn ($229m). The plant construction commenced in 2005.
The power generated from the plant will be sold to six captive owners involved in cotton yarn manufacturing at a discounted tariff charged by the Tamilnadu Generation and Distribution Corporation (TANGEDCO) for a period of 15 years. The plant also has 130MW of power supply agreements with private agencies.
The Nagai coal-fired power plant is located on 93ha of land near Nannilam taluk village of Nagapattinam district.
The plant is in close proximity to the Tamil Nadu Electricity Board’s (TNEB) Thiruvarur substation, approximately 9km from the Karaikal port.
The thermal power plant features one 530t/h pulverised coal-fired natural circulation boiler and one 150MW condensing steam turbine. The boiler, supplied by Ansaldo, produces steam at 132kg/cm² pressure and 538°C temperature.
The steam turbines drive the turbo generator at a speed of 3,000 revolutions per minute (rpm). The steam generator at the plant comprises of a water-cooled condenser, a furnace and radiant convection superheaters.
The steam generator is designed as semi-outdoor equipment, while the turbine generator with all the auxiliary and feed cycle equipment is located indoors.
The plant is also equipped with a 125m-high chimney and an air-cooled condenser. Raw water required for the plant operations is supplied by the Tamil Nadu Water Supply and Drainage Board (TWAD).
Electrostatic precipitator with fly ash hoppers is used to capture the fly ash produced during the power generation.
The power generated at the plant is supplied to the 230kV substation in Thiruvarur via a 24.6km transmission line.
NPPL made a fuel supply agreement (FSA) with Mahanadi coal field (MCF) for the supply of coal.
The plant includes a coal storage facility with a capacity of 114t/h for coal storage.
The Nagai power project was financed through a combination of debt and equity. Equity financing was provided by KVK Group (74.01%), IFCI (24.4%) and captive owners (1.59%).
A consortium of Rural Electrification Corporation India Infrastructure Finance Company and SREI Infrastructure Finance provided term loan funding for the power plant. Khaitan Sud and Partners (KS partners) acted as the legal counsellor for the consortium, while NPPL was advised by its in-house team.
Nagarjuna Construction Company (NCCL) was appointed as the engineering, procurement and construction contractor (EPC) for the Nagai TPP. NCCL also delivered air-cooled vacuum steam condensers for the project, while the 150MW turbine generator was BHEL.
The civil, structural and architectural engineering works contract for the plant was awarded to Toshiba Plant Systems & Services Corporation (TPSC). The contract also included mechanical, electrical, control and instrumentation balance of plant (BOP) engineering work.
Ansaldo Caldaie Boiler India and Franco Tosi, subsidiaries of Gammon India, were awarded the contract to provide the boiler and turbine generator (BTG) units. The contract included the design, manufacture, erection and supervision of the BTG unit. The balance of works under the BTG package was undertaken by Gammon India’s EPC power division.
Edac Engineering was awarded the contract for erection, testing and commissioning of the plant’s boiler. Indomer Coastal Hydraulics conducted the modelling study for the plant.
Spark Power Engineering undertook optical ground wire installation and commissioning, while Voltech Manufacturing supplied boost charger and batteries for the plant.
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