MERITS OF COMBINED CYCLE GAS BASED POWER PLANTS

Why Combined Cycle Gas Based Power Plants in place of Coal Based Sub-critical Thermal Plant (500/600 MW)?

§ The coal stock is diminishing fast and it is becoming increasingly difficult to arrange adequate coal for steady operation of the existing Power Plants.

§ Most of the existing old Units are designed for operation with high GCV coal which is very scarce and costly now. As a result, due to non availability of sufficient quality coal, the existing old Units are suffering from huge generation loss as well as financial loss.

§ Inadequate supply of coal from open cast/underground mines. Dearth of adequate washed coal. Supply of bad quality coal with huge ash, stone and boulders.

§ Exorbitant price rise of Indian coal. Restriction for import of coal. Shortage in supply during monsoon.

§ Limitation of transportation of coal by Railways. Shortage of empty wagons.

§ Social threat in acquisition of agricultural land for green field project. It has become practically impossible to acquire land; may it be barren or single crop.

§ Scarcity of consumptive water availability from river/lake/barrage/dam.

§ Difficulty in Fly Ash Management; there is “No Taker” of such huge quantity of Fly Ash.

§ To combat increasingly stringent environmental norms of MOEF over the years during its life.

Advantages of Combined Cycle Gas Based Power Plants

§ Carbon emissions can be drastically reduced to combat ever increasing global warming threat

§ Guaranteed high cycle efficiency in the range of 59% (+) compared to 36% for coal based sub-critical 500/600 MW capacity thermal Units

§ Land requirement is significantly less; 80 acres for 1000 MW which is 1/10th of coal based sub-critical 500/600 MW capacity thermal Units

§ Total Manpower requirement is less; Man-MW ratio at least 50% less i.e. less job opportunity

§ PLF and Availability Factor is very high; 95% and above since forced outage is minimum

§ Consumptive water requirement is 60% less; a boost in favour of water conservation

§ Project cost is 3.5 Crore per MW compared to 5.5 Crore for 500/600 MW coal based Units

§ Carbon Credit Benefit will be available if the CCPP is installed by abandoning old coal based sub-critical Plants like Bandel TPS or installed as a brown field Project at Bakreswar TPP

§ Issuance of NOC by MOEF will be easy since there is no pollution threat from CCPP

§ Gestation period is 30 months for 1000 MW; this is 18 months less compared to coal based sub-critical 500/600 MW capacity thermal Units

§ In case of ICB, number of participating global Bidders will be high which is most unlikely for sub-critical 500/600 MW coal based thermal Units.

COMPARISON OF COMBINED CYCLE GAS BASED UNIT WITH COAL BASED THERMAL UNIT (500 MW CAPACITY - SUB-CRITICAL TECHNOLOGY)

Sl. No.	PARAMETER	Natural Gas Based Unit	Coal Based Thermal Unit
1	Efficiency (η %)	59.4 (Series701 F4)	36 (500 MW Unit)
2	Unit Heat Rate	1448 Kcal/KWh	2389 Kcal/KWh
3	Plant Load Factor	95%	80%
4	Availability	96%	85%
5	Reliability	99%	90%
6	Land Requirement for 1000 MW	80 Acres	800 Acres
7	Consumptive Water Requirement for 1000 MW	1400 M3/Hour	4000 M3/Hour
8	Environment Impact	Environment Friendly	High
9	Man-MW Ratio for 1000 MW	0.1	0.5
10	Gestation Period for 1000 MW	30 Months	48 Months
11	Installation Cost/MW	3.5 Cr. INR	5.5 Cr. INR
12	Fixed Cost per KWh (B)	X	Y (Y>X)
13	Variable Cost i.e. Cost of Fuel	A	B (A>B)
14	% Escalation on Cost of Fuel	30% higher	Base

FUTURE AHEAD (12^TH PLAN) WITH GAS BASED PROJECTS

• Gas-based combined cycle power plants have a substantial share of the overall installed capacity in India till 11^th Plan (2007-12).
• A good number of gas based combined cycle plants has been envisaged by Ministry of Power for implementation across the country during 12^th Plan (2012-17) to address environmental issues.
• Nearly 40 projects are awaiting clearance from Central Electricity Authority, Ministry of Power.
• Ministry of Power is now giving equal importance to set up more and more combined cycle and super/ultra-super critical plants during 12^th Plan Period (2012-17) to address adverse environmental effects.

PREPARED BY DEBABRATA DEY ON 25 MARCH, 2012