Gas-based power generation utilizes gas turbines to convert natural gas into electricity, consisting of a compressor, combustion chamber, and turbine. In India, the focus is shifting from coal to gas due to environmental concerns and limited coal reserves, with substantial investments in gas power capacity expected. Although gas power plants have lower emissions and are more efficient, they face challenges such as lower output and starting issues compared to coal plants.

6. GAS-BASED POWER GENERATION

7. INTRODUCTION
• A GAS TURBINE IS A POWER PLANT ENGINE THAT CAN USE NATURAL GAS OR
OTHER LIQUIDS AS FUEL TO TURN MECHANICAL ENERGY INTO ELECTRICITY.
• THE GAS TURBINE POWER PLANT IS A THERMAL POWER STATION THAT CREATES
ELECTRICITY BY USING A TURBINE TO DRIVE AN ELECTRICAL GENERATOR OR MOTOR.
• IT CONSISTS OF A GAS-FIRED COMBUSTION TURBINE, HEAT RECOVERY STEAM
GENERATOR, AND ONE OR MORE ELECTRIC GENERATORS DRIVEN BY A GEARBOX
MOUNTED ON ITS SHAFT.
• GAS TURBINE POWER PLANTS USE GAS TURBINES AS THEIR PRIME MOVER TO
GENERATE ELECTRICITY. THESE UNITS COME IN VARIOUS SIZES RANGING UP TO 300
MW PLANTS.
• THE ENTIRE UNIT SITS IN ITS BUILDING OR ENCLOSURE CALLED A NACELLE, WHICH
CAN OPEN OR CLOSE DEPENDING ON ITS USE AND CONFIGURATION.

9. OPEN CYCLE GAS POWER PLANT LAYOUT

10. CLOSED CYCLE GAS POWER PLANT
LAYOUT

11. • AS WE KNOW GAS POWER PLANTS WORKS ON THERMODYNAMIC CYCLE, USING A
SERIES OR COMBINATION OF PROCESSES TO TRANSFORM ENERGY HENCE
EXTRACTING THE EXCESS ENERGY IN THE PROCESS WHICH IS CALLED THE NET WORK.
• A GAS POWER CYCLE CAN EITHER BE AN OPEN CYCLE OR A CLOSED CYCLE.
• IN A CLOSE CYCLE, THE WORKING FLUID IS RETURNED TO THE INITIAL STATE AT THE
END OF THE CYCLE AND IS RECIRCULATED WHILE IN THE OPEN CYCLE, THE WORKING
FLUID IS RENEWED AT THE END OF EACH CYCLES INSTEAD OF BEING RECIRCULATED.
• THE GAS POWER PLANT IS SIMPLY A MACHINE THAT CONSIST OF A COMPRESSOR
AND A TURBINE CONNECTED TOGETHER WITH A SINGLE SHAFT, HENCE AN
INTERMEDIATE COMBUSTION CHAMBER IN BETWEEN FLUID DUCTS CONNECTING THE
COMPRESSOR AND TURBINE.

12. MAIN COMPONENTS OF GAS POWER PLANT
• COMPRESSOR: THE COMPRESSOR USED IN THE PLANT IS GENERALLY OF ROTATORY TYPE. THE AIR AT
ATMOSPHERIC PRESSURE IS DRAWN BY THE COMPRESSOR VIA THE FILTER WHICH REMOVES THE DUST
FROM THE AIR. THE ROTATORY BLADES OF THE COMPRESSOR PUSH THE AIR BETWEEN STATIONARY BLADES
TO RAISE ITS PRESSURE. THUS AIR AT HIGH PRESSURE IS AVAILABLE AT THE OUTPUT OF THE COMPRESSOR.
• THE COMBUSTION CHAMBER: IT IS AN ENCLOSED SPACE OR REGION IN WHICH COMBUSTION
TAKES PLACE, ESPECIALLY IN AN ENGINE BUT IN THIS CASE IT IS LIKE A FURNACE. THE COMBUSTION
CHAMBER IS LOCATED IN BETWEEN THE COMPRESSOR AND THE TURBINE.
• THE TURBINE: THE PRODUCTS OF COMBUSTION CONSISTING OF A MIXTURE OF GASES AT
HIGH TEMPERATURE AND PRESSURE ARE PASSED TO THE GAS TURBINE.THESE GASES IN
PASSING OVER THE TURBINE BLADES EXPAND AND THUS DO THE MECHANICAL WORK. THE
TEMPERATURE OF THE EXHAUST GASES FROM THE TURBINE IS ABOUT 900F
• ALTERNATOR: THE GAS TURBINE IS COUPLED TO THE ALTERNATOR AS SEEN IN THE GAS
TURBINE PLANT LAYOUT. THE ALTERNATOR CONVERTS MECHANICAL ENERGY OF THE TURBINE
INTO ELECTRICAL ENERGY. THE OUTPUT FROM THE ALTERNATOR IS GIVEN TO THE BUS-BARS
THROUGH THE TRANSFORMER, CIRCUIT BREAKERS AND ISOLATORS.

13. WORKING PRINCIPLE OF GAS TURBINE
• A GAS TURBINE ENGINE DRAWS POWER BY BURNING FUEL IN A COMBUSTOR AND
DRIVING THE TURBINE WITH RAPIDLY FLOWING COMBUSTION GAS. IT IS MUCH LIKE HIGH-
PRESSURE STEAM DRIVES A STEAM TURBINE
• A SIMPLE GAS TURBINE CONSISTS OF THREE MAIN SECTIONS: COMPRESSOR, COMBUSTOR,
AND POWER TURBINE
• GAS TURBINES OPERATE ON THE PRINCIPLE OF THE BRAYTON CYCLE, WHICH MIXES
COMPRESSED AIR WITH FUEL AND BURNS IT UNDER CONSTANT PRESSURE CONDITIONS.THE
RESULTING HOT GAS EXPANDS THROUGH THE TURBINE TO DO ITS JOB.
• MAIN STEPS :
• AIR IS DRAWN INTO AN AIR INLET AND COMPRESSED BY A COMPRESSOR.
• FUEL IS THEN ADDED TO THE COMPRESSED AIR IN THE COMBUSTOR, MIXING WITH
FUEL AND IGNITING.
• THE BURNING GASES EXPAND THROUGH A POWER TURBINE WHICH DRIVES ONE OR
MORE GENERATORS TO PRODUCE ELECTRICITY.
• THE EXHAUST GASES EXIT THE TURBINE THROUGH AN EXHAUST SYSTEM.

14. • GAS TURBINES HEAT A MIXTURE OF FUEL AND AIR TO A VERY HIGH TEMPERATURE, ROTATING
TURBINE BLADES TO GENERATE ELECTRICITY. A ROTATING TURBINE DRIVES A GENERATOR
THAT CONVERTS ENERGY INTO ELECTRICITY. THE GAS TURBINE CAN EFFICIENTLY GENERATE
ELECTRICITY IN COMBINED CYCLE POWER PLANTS WITH STEAM TURBINES.
• THE AIR-FUEL MIXTURE IGNITES:
• HOT GAS SPINS TURBINE BLADES:
• ROTATING BLADES ROTATE THE DRIVE SHAFT
• THE ROTATION OF THE TURBINE DRIVES THE GENERATOR.
• GENERATOR MAGNETS MOVE ELECTRONS TO GENERATE ELECTRICITY.

15. ADVANTAGES AND DISADVANTAGES
ADVANTAGES :
• IT IS SIMPLE IN DESIGN AND SMALLER IN DESIGN AS COMPARED TO STEAM POWER STATION
• THE INITIAL AND OPERATING COSTS ARE MUCH LOWER
• IT REQUIRES COMPARATIVELY LESS WATER
• THE MAINTENANCE CHARGES ARE QUITE SMALL.
• THERE ARE NO STANDBY LOSSES
DISADVANTAGES
• THERE IS A PROBLEM WITH STARTING THE UNIT.
• THE NET OUTPUT IS LOW
• THE OVERALL EFFICIENCY OF SUCH PLANTS IS LOW
• LOW LIFE SPAN

16. CASE STUDY : “GAS BASED POWER GENERATION IN
INDIA”
• INDIA’S POWER GENERATION MIX IS CONSIDERABLY INCLINED TOWARDS COAL BASED
POWER GENERATION. CURRENT CAPACITY ADDITION AND NEW ESTABLISHMENTS SHOW
INCREASED SHARE OF COAL IN THE INDIAN ENERGY SECTOR.
• AS THE COAL RESERVES ARE LIMITED TO THEIR NATURAL AVAILABILITY AND ALSO DUE TO THE
STRINGENT ENVIRONMENTAL CLEARANCE, EXPANSION OF COAL MINING IS LIMITED IN
INDIA.
• IT IS PREDICTED THAT THE INDIAN COAL SECTOR WILL FACE SUBSTANTIAL SHORTFALL IN THE
QUANTUM OF COAL PRODUCTION THAT IS LIKELY TO CONTINUE IN FUTURE.
• NATURAL GAS IS A CLEAN FUEL AS COMPARED TO COAL AND CAN BE EFFICIENTLY USED IN
POWER GENERATION.
• AS THE DOMESTIC COAL SUPPLY IS GENERALLY OF LOW QUALITY WITH LOW CALORIFIC
VALUES, HIGH DEGREE OF ASH CONTENT AND ITS ADVERSE IMPACTS TO THE ENVIRONMENT,
GOVERNMENT OF INDIA ENCOURAGE GAS BASED POWER GENERATION IN INDIA.
• THE USE OF GAS IN POWER-GENERATION WAS INITIALLY PROMOTED BY THE GOVERNMENT
PRIMARILY WITH A VIEW TOWARDS ENVIRONMENTAL CONSIDERATIONS.

17. CURRENT SCENARIO IN INDIA :
• PETROLEUM AND GAS HAVE EMERGED AS THE MOST DYNAMIC ENERGY SECTORS IN INDIA.
THE WORLD ENERGY OUTLOOK (WEO) 2002 PROJECTS THE SHARE OF GAS IN INDIAN
TPES TO REACH 13% IN 2030, EQUIVALENT TO 97 BCM/Y (AS COMPARED TO 7 % OF
INDIA’S ENERGY MIX IN YEAR 2000, EQUIVALENT TO A CONSUMPTION OF 22 BCM/Y).
KNOW MORE ABOUT INDIAN ELECTRICITY SCENARIO
• PRODUCTION OF NATURAL GAS IS AT PRESENT AT THE LEVEL OF AROUND 132.83 MILLION
METRIC STANDARD CUBIC METERS PER DAY (MMSCMD).
• THE MAIN PRODUCERS OF NATURAL GAS ARE OIL & NATURAL GAS CORPORATION LTD.
(ONGC), OIL INDIA LIMITED (OIL), JVS OF TAPTI, PANNA-MUKTA AND RAVVA AND RELIANCE
INDUSTRIES LIMITED (RIL) WHICH HAS DISCOVERED GAS IN THE KRISHNA GODAVARI BASIN
AT ITS KG D6 BLOCK IN THE EAST COST OF ANDHRA PRADESH. OUT OF THE TOTAL
DOMESTIC PRODUCTION OF 132.83 MMSCMD OF GAS ABOUT 43% IS PRODUCED BY
RELIANCE INDUSTRIES LTD. (AS OF DECEMBER 2009) AND APPROXIMATELY 57% OF THE
GAS IS PRODUCED BY OTHERS.
• AS ON JUNE 30, 2011, AND AS PER THE CENTRAL ELECTRICITY AUTHORITY THE TOTAL
INSTALLED CAPACITY OF GAS BASED POWER PLANTS IN INDIA IS 17,706.35 MW. THIS
ACCOUNTS FOR 10% OF THE TOTAL INSTALLED CAPACITY. HERE IS A LIST OF SOME
PRESENT IN OPERATION PLANTS.

18. HOW GAS BASED POWER PLANTS
DIFFER FROM COAL BASED
PLANTS?
Gas-Based Plants Coal-Based Plants
Fuel Source Gas Coal
Fuel Supply Generally, more stable supply Susceptible to supply chain disruptions
Efficiency
Higher efficiency in converting fuel to
electricity
Lower efficiency compared to gas-based plants
Emissions Lower emissions (CO2, SOx, NOx) Higher emissions, especially CO2
Environmental Impact Generally considered cleaner
Higher environmental impact due to emissions
and mining
Flexibility
More flexible for rapid startup and
shutdown
Less flexible, longer startup and shutdown
times
Power Output
Typically, lower power output per unit
compared to coal
Higher power outp

19. GAS POWER PLANTS IN INDIA :
Power station Operator State (location) Installed Capacity
IPGCL Gas Turbine Power Station
IPGCL
IPGCL NCT Delhi 270.00
Pragati Gas Power Station PPCL NCT Delhi 330.40
Pampore Gas Turbine Station I J&K Govt Jammu & Kashmir 75.00
Pampore Gas Turbine Station II J&K Govt Jammu & Kashmir 100.00
Ramgarh Gas Thermal
Power Station
RVUNL
Rajasthan
413.00
Dhuvaran Gas Based CCPP-I GSECL Gujarat 106.62
Utran Gas Turbine Power
Station
Mahagenco Maharashtra 672.00
Goa Gas Power Station RSPCL GOA 480.00
Basin Bridge Gas Turbine Power
Station
TNEB Tamil Nadu 120.00
Thirumakottai Gas Turbine Power
Station
TNEB Tamil Nadu 108.88
Kuttalam Gas Turbine Power Station TNEB Tamil Nadu 101.00
Karaikal Gas Turbine Power Station TNEB Tamil Nadu 95.10
Dholpur Combined Cycle
Power Station
RVUNL Rajasthan 330.00
National Capital TPP NTPC Uttar Pradesh
Essar Combined Cycle Power Plant ESSAR Gujarat 515.00
Lanco Kondapalli Power Plant- I
Lanco
Lanco Andhra Pradesh 368.13
Samarlakota Combined Cycle Power
Plant
Reliance Andhra Pradesh 220.00

20. THE CENTRAL ELECTRICITY AUTHORITY UNDER MINISTRY OF POWER. IT
MONITORS 62 GAS BASED POWER STATIONS, WITH A TOTAL CAPACITY OF 23,845 MW
USING GAS AS PRIMARY FUEL
• TOP GAS-BASED POWER PLANTS IN INDIA INCLUDE: NTPC ANTA CCPP
(RAJASTHAN), NTPC AURAIYA CCPP (UTTAR PRADESH), NTPC DADRI CCPP
(UTTAR PRADESH), NTPC FARIDABAD CCPP, KAWAS GAS CCGT (GUJARAT),
ESSAR HAZIRA GAS CPP (GUJARAT), PRAGATI GAS CCGT (DELHI), GVK
JEGURUPADU GAS CCGT (ANDHRA PRADESH), LANCO KONDAPALLI GAS
CCGT (ANDHRA PRADESH), AND SAMALKOT/PEDDAPURAM GAS CCGT
(ANDHRA PRADESH).
• KEY POINTS ABOUT THESE PLANTS:
• MAJOR OPERATOR: NTPC (NATIONAL THERMAL POWER CORPORATION)
OPERATES A LARGE NUMBER OF GAS-BASED POWER PLANTS ACROSS INDIA.
• LOCATIONS: MAJOR GAS POWER PLANTS ARE SITUATED IN STATES LIKE
RAJASTHAN, UTTAR PRADESH, GUJARAT, DELHI, AND ANDHRA PRADESH.
• PLANT NAMES TO NOTE: ANTA, AURAIYA, DADRI, FARIDABAD, KAWAS,
ESSAR HAZIRA, PRAGATI.

21. • TOTAL POWER GENERATION : COUNTING NUMEROUS OTHER SMALL GAS POWER PLANTS
AND OTHER GAS FIRED COMBINED CYCLE POWER PLANTS PRODUCES TOTAL ENERGY OF
13711.27 MW.
• INDIA’S RISING DEPENDENCE ON NATURAL GAS CAN BE SEEN IN FIGURE BELOW
CONCLUSION :
• GIVEN LIMITATIONS ON THE USE OF COAL FOR POWER GENERATION DUE TO ITS
ENVIRONMENTAL CONSEQUENCES, QUALITY AND SUPPLY CONSTRAINTS, GAS WILL PLAY AN
INCREASINGLY IMPORTANT ROLE IN INDIA’S POWER SECTOR. WHILE IT IS TRUE THAT INDIA IS
NOT A BIG PRODUCER OF NATURAL GAS BUT NEW INTERNATIONAL IMPORT POLICIES/TREATIES
WITH SOME GULF COUNTRIES AND DOMESTIC EXPLORATIONS CAN BRING SOME HOPE FOR
THE INDIAN ENERGY SECTOR.

22. THANK
YOU