Condenser: It is used to convert the steam exhausted from the turbine into the water so that it can be reused again in the boiler. There are two types of condensers are used and they are jet and surface condensers.5 (v) Feed Water Heaters: A feedwater heater is used in a conventional power plant to preheat boiler feedwater. The source of heat is steam bled from the turbines, and the objective is to improve the thermodynamic efficiency of the cycle.
6 (vi) Air Preheaters: After leaving the economizer, further heat from the flue gas is used to heat the incoming air using air preheater. Flue gas should not be cooled below the dew point to avoid corrosion of the air preheater.
7 (vii) Turbines: There are two types of turbines used:Impulse turbine: In this turbine, moving and fixed blades are used. The moving blades are mounted on the shaft and fixed blades are fixed to the casing of the turbine. Steam is passed through the fixed nozzles. The steam with high velocity comes out of the nozzle and impinges on the rotor blades.Reaction turbine: In this turbine, only fixed and moving blades are used. When high-pressure steam passes through fixed blades, then steam pressure drops down, and the velocity of steam increases.
8 (viii) Cooling towers: The cooling tower transfers the heat from the water’s heat to the air by directly or by evaporation of the water. So that water coming out of the condenser is reused.
Advantages of Thermal Power Plant
Fuel cost is comparatively low.
Installation requires less land compared to a hydropower plant.
The thermal energy production mechanism is simple and easy.
The initial cost is lesser compared to other power plants.
Easy maintenance.
Disadvantages
The huge production of CO2 which causes pollution.
Overall efficiency is less than 30%.
A huge amount of water is required.
Warm water comes out of the thermal power plant affects aquatic life.
Thermal engines require a huge amount of lubricating oil.
2.2.2 Major Thermal Power Plants in India
1 Sasan Ultra Mega Power Plant, Madhya Pradesh: It holds an installed capacity of 3,960 MW situated in Sasan Village of the Singrauli district. Reliance power owns this power plant integrated with a coal mine.
2 Tiroda Thermal Power Plant, Maharashtra: It holds an installed capacity of 3,300-MW plant which covers an area of 454.8 ha owned by Adani power. It uses water from the Wainganga River to go ahead with its operations.
3 Talcher Super Thermal Power Station, Odisha: It holds an installed capacity of 3,000 MW owned by NTPC situated in the Angul district of Odisha.
4 Vindhyachal Thermal Power Station, Madhya Pradesh: It holds an installed capacity of 4,760 MW owned by NTPC. Presently, this is the biggest thermal power plant in India.
5 Mundra Thermal Power Station, Gujarat: It holds an installed capacity of 4,620 MW owned by Adani power. Presently, this is the second biggest thermal power plant in India.
6 Mundra Ultra Mega Power Plant, Gujarat: This is another one situated in Kutch district holds an installed capacity of 4,000 MW owned by CGPL.
7 Rihand Thermal Power Station, Uttar Pradesh: It holds an installed capacity of 3,000 MW owned by NTPC. The plant generates and supplies electricity to different states in the northern part of India such as Uttarpradesh, Rajasthan, Delhi, Punjab, Haryana, and Himachal Pradesh.
8 Sipat Thermal Power Plant, Chhattisgarh: It holds an installed capacity of 2,980 MW owned by NTPC. This is the eighth largest thermal power plant in India.
9 Chandrapur Super Thermal Power Station, Maharashtra: It holds an installed capacity of 2,920 MW operated by Maharashtra state power generation company.
10 NTPC Dadri, Uttar Pradesh: It holds an installed capacity of 2,637 MW owned by NTPC. This is the sixth largest thermal power plant in India.
2.3 Gas-Based Power Generation
India’s power generation is contributed almost by all types of conventional and non-conventional power generating plants. But, it is always inclined toward the coal-based power generation. With the increasing new establishments and demands, it is stated that the natural availability of coal will be limited and the coal sector will face a shortfall in the upcoming future.
Due to the given limitations on coal, natural gas plays an important role in India’s power sector. As compared to coal, its environmental impacts are comparatively less, which makes gas-based power generation more attractive [5].
2.3.1 Basics of Gas-Based Power Generation
Gas-based power plant is similar to a steam turbine power plant, with the only difference that, here, we use compressed high-pressure air to rotate the turbine. The schematic diagram of a typical gas turbine power plant is shown in Figure 2.3. It has three major parts:
1 Compressor
2 Combustor
3 Turbine
The air or natural gas is compressed in the compressor. The compressed air then passes through the combustor where the air is combusted to high temperature and high pressure. This high-pressure air is used to run the turbine, which, in turn, rotates the alternator to produce electricity. This is a simple cycle gas plant. In a combined cycle gas plant, the heat produced from combustion is used for industrial purposes through a heat recovery steam generator [6, 7].
Figure 2.3 A typical gas turbine power plant.
2.3.2 Major Gas-Based Power Plants in India
Out of 65 gas-based power plants in India, 7 major power plants are owned by NTPC and they are given below:
| S. no. | Names | Commissioned capacity (in MW) |
|---|---|---|
| 1 | Anta | 419.33 |
| 2 | Auraiya | 663.36 |
| 3 | Kawas | 656.20 |
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