Vallur Conventional Thermal Power Plant, India

The Tamil Nadu Energy Company is building a 1,500MW thermal power plant at Vallur in Tiruvallur district, India. Tamil Nadu Energy Board (TNEB) has an equal stake in the project with NTPC (formerly known as the National Thermal Power Corporation). The total cost of the project is INR80bn (€100m).

The project's ground breaking ceremony took place in September 2007.

The project is being constructed in two phases. Phase I includes construction of two 500MW units. The 216t boiler drum of Unit 1 was erected in June 2010. Unit 1 is expected to come online by March 2011 after conducting necessary tests. Both units of phase I are expected to start production in 2011.

Phase II will consist of one unit of 500MW. Independent works on phase II had already begun in 2010 and is two to three months ahead of schedule. Production of phase II is expected to start from December 2012.

Vallur project finance

Phase I of the project costs about INR54bn ($1.15bn). The debt equity ratio of the project is 7:3. The Rural Electrification Corporation has sanctioned INR38bn ($809m) to meet the entire debt portion of the project.

The cost of phase II is estimated at INR30bn ($639m). REC advanced a loan of INR21bn ($447m) for the second phase in April 2010.

Plant details

Set up under the mega power project policy, the project will add nearly 24 million units a day to the grid. Of the 1,500MW generated, Tamil Nadu will take 750MW and the rest will go to Karnataka, Kerala and Puducherry.

The plant will consume 4.62mt of coal a year. Coal for the plant will be brought from Orissa through ship to Ennore port, from where it will be transported by road.

Development

India's Bharat Heavy Electricals won the INR130m contract in September 2009, to supply units for Vallur. The state-run power equipments maker is supplying and installing steam generator and steam turbine packages.

BHEL's work involves design, engineering manufacture, supply, erection and commissioning of the steam generators, turbine generators, electrostatic precipitators and associated auxiliaries, and controls and instrumentation systems.

The company produces boilers for power generation with ratings upwards of 30MW. For higher capacities, it offers the option of Once-Through type steam generators as well as conventional natural and controlled circulation types. BHEL steam generators feature tangential/wall and direct/indirect firing.

Technology

The boiler systems can be single- or two-pass type, with front/rear/side mill layout. They can have single/bi-drum arrangement with natural or controlled circulation. There is constant or sliding pressure operation, and hot or cold primary air systems.

Steam turbine speeds are 3,000rpm. The main steam is at 130–250bar at 500–540°C. Steam reheat is at 30–70 and 500–600°C. The back pressure is between 20 and 300mbar.

The plant will have six induced draft cooling towers (IDCT). The IDCTs have a capacity of 30,000m³/hr with nine cells of 21 x14m each. Sea water is used in the IDCTs. The sea water will be drawn from North Chennai Thermal Power Plant. Fresh waster will be produced from a desalination plant.

Power market

As one of the most industrialised of India's states, Tamil Nadu has many manufacturing companies in and around Chennai. It has a mix of nuclear, hydroelectric, wind power and thermal plants, and sells any surplus power to the neighbouring states of Andhra Pradesh and Karnataka.

BHEL outbid leading European equipment suppliers, Czech Republic-based Skoda and Italy-based Ansaldo, for the contract. BHEL recently also won three contracts for supplying and installing seven 500MW sets at Jhajjar sewerage treatment plants, Koderma thermal power station (TPS) and Durgapur Steel TPS.

BHEL is one of India's nine largest public sector undertakings (PSUs).

Another joint venture project, a 1,000MW plant at Tuticorin, recently received environmental clearance.

One 500MW additional unit each at the North Chennai thermal power station Ennore and the Mettur thermal power station have been proposed, along with a 500MW pumped storage hydro electric project at Kundah in the Nilgiris.

Bids have been floated for the North Chennai unit, and environmental and forest clearances are expected for the other two projects shortly.

The capacity of all the projects is 4,500MW. With an investment of INR600m per MW (including transmission and distribution costs), the total cost will be around INR260bn.

Tamil Nadu Energy Company is a joint venture company floated by the NTPC and Tamil Nadu Electricity Board. From an installed capacity of only 156MW with annual gross generation plus purchase of 630MU (million units) at independence, the TNEB has grown to producing over 10GW now. That includes 2,970MW from four thermal stations, 424MW from four gas turbine stations, 19MW from wind turbines, and 2,184MW from 37 hydro stations.

There is also 1,154MW coming from private sector projects, 2,859MW as Tamil Nadu's share from central generating stations, 335MW as external assistance and 175MW from captive power plants. The generating capacity from privately owned wind farms is 3.5GW.