In­dia's top three

Down to Earth - - COVER STORY -

The three high­est rated coal-based power plants in In­dia in the study by CSE are CESC, Budge Budge, in West Ben­gal; JSWEL, To­rana­gallu in Kar­nataka; and Tata, Trom­bay, in Ma­ha­rash­tra. While th­ese plants fol­low cer­tain best prac­tices, their over­all en­vi­ron­men­tal per­for­mance is av­er­age when com­pared to the global best. Since the plants are sub­crit­i­cal, their ef­fi­cien­cies were nowhere near those of the lat­est ul­tra­su­per­crit­i­cal plants. While their wa­ter use was rel­a­tively good, air pol­lu­tion con­trol and ash han­dling were a mixed bag with im­prove­ments needed.


It is a 750 MW ca­pac­ity (three 250 MW ca­pac­ity units) power plant lo­cated in densely pop­u­lated Pu­jali town of South 24 Para­ganas dis­trict in West Ben­gal and has an av­er­age age of 11 years.Although it uses sub­crit­i­cal tech­nol­ogy de­signed for 37 per cent ef­fi­ciency—far be­low that of the global best ul­tra­su­per­crit­i­cal (usc) tech­nol­ogy—its op­er­at­ing per­for­mance is com­mend­able. The plant avail­abil­ity av­er­aged 93 per cent dur­ing the last three years (2010-13), in­di­cat­ing very good main­te­nance. plf at 87 per cent was far bet­ter than the In­dian av­er­age. In fact, it used to be even higher but has dropped in re­cent years be­cause of low de­mand from the area.

Sec­ond, the plant has main­tained ef­fi­ciency of 35.7 per cent—although the ef­fi­ciency is just above the In­dian av­er­age, it is only 1.4 per­cent­age points be­low its de­sign,re­flect­ing good op­er­at­ing prac­tices. The plant has shown steady ef­fi­ciency im­prove­ment dur­ing the as­sess­ment pe­riod.

The most re­mark­able fea­ture of the plant is its ef­fi­cient wa­ter use de­spite abun­dant wa­ter sup­ply from the River Hooghly. The plant con­sumes only 2.2 cu­bic me­tres of wa­ter per MWh power gen­er­a­tion—seven cy­cles of con­cen­tra­tion (coc) in its cool­ing tow­ers means low wa­ter use; a zero liq­uid dis­charge sys­tem (zld) en­sures wa­ter dis­charged from var­i­ous uses is re­cy­cled back; fly ash is han­dled dry; boiler wa­ter is treated in an ad­vanced sys­tem to al­low re­use and re­duce losses.

Its 100 per cent fly ash utilisation record is also pos­i­tive,es­pe­cially since 76 per cent of to­tal ash is used for ce­ment and bricks.The plant sells its fly ash to ce­ment man­u­fac­tur­ers in Bangladesh. The plant has adopted many good prac­tices for han­dling ash, in­clud­ing pneu­matic stor­age in si­los,pneu­matic trans­port into barg- es and high con­cen­tra­tion slurry dis­posal. How­ever, its high con­cen­tra­tion ash dis­posal in an “emer­gency” pond was found prob­lem­atic with high fugi­tive emis­sion. It is the only plant in In­dia to have in­stalled a de-wa­ter­ing sys­tem for dis­posal of bot­tom ash,which is largely used for fill­ing of low-ly­ing ar­eas.

The com­pany was in com­pli­ance with wa­ter pol­lu­tion and waste man­age­ment. Un­like most of the plants in the sec­tor,the plant meets strict PM norms of 50-75mg/Nm3 ex­cept in some in­ci­dences where high stack PM emis­sions were recorded by the state pol­lu­tion con­trol board.

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