At a time when ‘carbon’ is a bad word and the world frowns upon greenhouse gas emissions, data from the Central Electricity Authority (CEA) shows what most observers have intuitively known—Indian coal-fired power plants devour a lot more coal than they should.
CEA studied the ‘heat rates’ – the amount of heat consumed to produce one kilowatt-hour of electricity – and found out that the country's power plants require 10 per cent more heat than they were designed for.
Back of the envelope calculations show that, even under liberal assumptions, coal-fired power plants consume 60 million tonnes of coal more than they ought to, which translates to avoidable emission of 42 billion tonnes of CO2 each year.
Even the 10 per cent deviation is believed to be conservative. CEA took a sample of 85 plants of various capacities from 100 MW to 500 MW and looked into their heat rates. The least was 13.8 per cent, for 500 MW plants. Most of the plants exceeded their design heat rates by 20 per cent.
It is a pity, because the problem can be fixed easily. Chandra Sekhar of CEA, who studied the heat rates, points to a “huge potential” for improvement.
One of the main reasons why our thermal power plants are coal guzzlers is due to their vintage status.
Of the 167,708 MW of coal-based plants, 36,000 MW are over 25 years old, which means some amount of fatigue is to be expected.
These plants are fit to be scrapped and replaced with more efficient, super-critical equipment wherever possible — and indeed, a programme for doing so is underway.
For the rest, the solution lies in common sense: maintain the plants properly, run them on sound technical principles and, when fatigue sets in, take them up in time for renovation and modernisation.
Evidently, in most cases it doesn’t cost much to fix these problems.Basic issues
As Chandra Sekhar notes, some of the maintenance issues are pretty basic — poor insulation here or a leaky sealant there. He points to “improper maintenance” of coal pulverisers due to “poor spare (parts) availability”.
“Planned maintenance can improve heat rates substantially without much effort,” notes M R Ganesan, a former Executive Director at BHEL and an expert on power plant equipment.
Ganesan reckons it is possible to get heat rate reductions equivalent of adding 10,000 MW by proper maintenance alone.
Like any equipment, power plants need an overhaul when they get old. Everybody knows that ‘Renovation and Modernisation’ is a low cost option to augment power supply, but CEA’s figures show that the progress here is shockingly tardy.
The target for the five-year period beginning 2012 was to take up 135 units of a capacity of 29,367 MW for life extension or renovation projects. As at end March 2015 the achievement was 24 units with capacity of 2,741 MW. More than half the plan period gone, but achievement is less than 10 per cent of the target.
Contrast this with the overall power capacity addition, where the record is shining: 80 per cent of the planned addition of thermal power capacity of 72,340 MW was completed by April. Clearly, the 12th Plan period target will be exceeded by a wide margin.
One issue with taking up R&M projects is that the plants will need to be shut for about a year — not many utilities can afford this. However, experts point out that this aspect would have been taken into account while the plans for R&M were formulated — hence the slippage is inexplicable.