Nearly all of the currently installed coal-fired capacity is based on sub-critical conventional steam cycle. Size distribution of the coal-fired installed capacity in 2005 indicates that 77% of the installed capacity is smaller than 250 MW in size. Only 23% capacity is equal to or larger than 500 MW units . Further, of the total 386 units, in 2005, about 10% (representing only 3% of the installed coal capacity) were more than 40 year old, and about 20% coal-fired capacity is 25 year or older. Average net efficiency of coal-fired power plants in India is reported to be 29%. Smaller, old units (less than 200 MW) have very low efficiency (<25%) and plant load factor (PLF) (<70%) . The best Indian power plants - 500 MW units -operate with a net efficiency of about 33%. In comparison, the average net efficiency for the 50 most efficient U.S. coal-based power plants is 36%, with the fleet average being 32% .
The current "standard" for coal-power technologies in India is the BHEL 500 MW sub-critical PC unit. These units are based on assisted circulation boilers with main steam pressure of 170 kg/cm2 . Currently, more than 25 of these units are in operation. Many power utilities are now entering the global markets for power plants through their tender process, which has the potential for bringing in new technologies to India. For example, the two NTPC super-critical power plants are based on Russian and Korean technologies - obtained through a global tendering process.
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