NTPC Ltd working on retrofitting its existing coal-fired thermal stations to enable imported coal blending of up to 30 per cent

NTPC Ltd is working on retrofitting its existing coal-fired thermal stations to enable imported coal blending of up to 30 per cent, as against the current boiler design limit of 10-15 per cent in most units.The move, which could boost overall operational efficiencies of generation units, has been necessitated on account of increasing shortages of domestic coal production.

In order to have long-term supply arrangement of imported coal, NTPC is scouting for both coal assets and fuel supply agreements in Indonesia, Australia, Mozambique and South Africa.

“We are working on retrofitting our units to enable blending of imported coal of up to 30 per cent,” the Chairman and Managing Director, Mr Arup Roy Choudhury, said. While for NTPC, the use of higher-calorific imported coal in its coal-fired stations could result in lower overall emissions, the move is likely to also translate into hikes in retail electricity tariffs due to higher costs of imported coal.Around 10 per cent imported coal blends is permissible due to boiler constraints at most existing thermal stations in the country. Higher blending of imported coal could cause boilers to burst due to the higher calorific value of imported coal.

Coal shortage

The Central Electricity Authority (CEA) — the Government's planning arm in the power sector — had earlier this year issued warnings about the possibility of plant shut-downs in the near future as domestic coal production has consistently failed to keep pace with the demand from the power sector.

As on November 15, of the 82 major thermal plants in the country, 29 had coal stock of less than 7 days, of which 16 were faced with fuel stocks of less than four days.Blending of low-ash, high-calorific imported coal is one of the options that have been under active consideration for some time now as a means of improving coal quality used in thermal power stations, instead of the practice of coal washing.As a step in the direction of increasing superior coal blends, the Centre has also asked state-owned equipment manufacturer Bharat Heavy Electricals Ltd to incorporate suitable modifications to its power plant designs to allow the greater use of imported coal.NTPC's total installed capacity is 32,694 MW, with 19 coal-fired and eight gas-based stations, located across the country. The company has tied-up with Coal India Ltd for about 130 million tonnes and it is importing another 13-14 million tonnes.