How Many Thermal Power Plants are There in India

Introduction

A thermal power station is a specific type of power plant where heat energy is converted into electrical energy. Boiling water in a large pressure vessel using heat generates high-pressure steam that drives a steam turbine connected to an electrical generator. The low-pressure turbine exhaust is cooled in a steam condenser to create hot condensate, which is then added back to the heating process to create more high-pressure steam. This is an illustration of a Rankine cycle. Different energy sources, such as fossil fuels, geothermal, nuclear, solar, biofuels, and waste incineration, may be used to build thermal power plants. Some thermal power plants are constructed to produce heat for industrial uses, district heating, or water desalination in addition to electricity. Fuels like natural gas or oil can also be burnt directly in gas turbines (internal combustion). These facilities can be of the more productive combined-cycle or open-cycle varieties.

Examples of Thermal Power Plants

• Coal-Fired.

• Gas.

• Diesel or Liquid fuel.

• Geothermal.

• Biomass.

• Waste Material.

Types of Thermal Energy

Thermal power plants include the vast majority of coal-fired power plants, all-natural gas power plants, as well as nuclear, geothermal, solar thermal, and waste incineration facilities. Natural gas is mainly used in gas turbines and boilers. Waste heat from a gas turbine may be used to generate steam by passing hot exhaust gas through a heat recovery steam generator (HRSG).

The steam is then used in a combined cycle plant to run a steam turbine, enhancing overall efficiency. Power plants that produce electricity using coal, fuel oil, or natural gas are known as fossil fuel power plants.

Additionally, a number of biomass-powered thermal power plants have been developed. Sometimes, non-nuclear thermal power plants that don't use cogeneration, especially those that use fossil fuels, are referred to as conventional power stations.

They typically are built as large, constantly operating commercial electric utility power facilities. Almost all electric power plants use three-phase electrical generators to produce alternating current (AC) energy at frequencies of 50 Hz or 60 Hz. Large organisations may have their own power plants to provide heating or electricity to their buildings, especially those where steam is produced for other uses.

The majority of ships were propelled over the majority of the 20th century by steam-driven power systems. Typically, shipboard power plants use gearboxes to directly relate the turbine to the ship's propellers.

These ships' power plants also deliver steam to smaller turbines that turn electric generators to generate energy. Except for a few naval vessels, nuclear propulsion is only employed in marine applications.

A steam-driven turbine powers an electric generator, which in turn powers an electric motor for propulsion, in a number of turbo-electric ships. Cogeneration plants, also known as combined heat and power (CHP) facilities, generate both electric power and heat for space heating or for use in processes, such as the production of steam and hot water.

History of Thermal Power Plants

James Watt made substantial improvements to the reciprocating steam engine, which has been used to produce mechanical power since the 18th century. When the first central electrical power plants designed for commercial use opened in 1882 at Pearl Street Station in New York and Holborn Viaduct power station in London, reciprocal steam engines were used.

The development of larger and more efficient machine designs for central power plants followed the advent of the steam turbine in 1884. By 1892, turbines were seen to be superior to reciprocating engines because of their higher speeds, more compact equipment, and stable speed regulation that allowed for the parallel synchronous operation of generators on a common bus.

After 1905, reciprocating engines were totally supplanted by turbines in virtually all large central power facilities. The largest reciprocating engine-generator sets ever built for the Manhattan Elevated Railway were completed in 1901. Similar in rating, a contemporary turbine set would have weighed around 20% more. Each of the seventeen units had a 6000-kilowatt rating and weighed around 500 tonnes.

Thermal Power Generation Efficiency

The energy efficiency of a typical thermal power plant is defined as the amount of saleable energy produced in relation to the fuel's heating value. For a single-cycle gas turbine, the energy conversion efficiency ranges from 20 to 35%. At the pressure of 170 bar pressures and temperatures of 570 °C, modern fossil fuel plants function at 46% efficiency, compared to normal coal-based power plants that run at 35 to 38% efficiency.

Systems with coupled cycles are capable of producing higher values. Similar to other heat engines, their efficiency is limited and governed by the laws of thermodynamics. The Carnot efficiency states that increasing the temperature of the steam will result in higher efficiencies.

The operating efficiency of fossil fuel power plants with subcritical pressure ranges from 36% to 40%. Efficiency levels for supercritical systems are currently in the low to mid 40% range thanks to contemporary "ultra critical" designs that use pressures greater than 4400 psi (30.3 MPa) with multiple-stage reheat. At 705 °F (374 °C) and 3212 psi (22.06 MPa), there is not a phase transition from water to steam, but rather a constant decrease in density.

Most nuclear power plants currently operate at lower temperatures and pressures than coal-fired plants do in order to provide more conservative safety margins inside the systems that remove heat from the nuclear fuel. Their thermodynamic efficiency is therefore limited to 30–32%.

Some of the advanced reactor designs being thought about, like the very-high-temperature reactor, the Advanced Gas-cooled Reactor, and the supercritical water reactor, would operate at pressures and temperatures similar to those of existing coal plants, producing thermodynamic efficiency similar to that of those facilities.

Any energy that is not utilised to produce electricity must be released by thermal power plants as heat into the environment. Cooling towers or the use of cooling water can be used to condense and discard this surplus heat. The method of utilising waste heat for district heating is known as cogeneration.

Thermal power plants that produce both electricity and fresh water are known as desalination facilities. These plants are frequently found in dry areas with plentiful natural gas.

Other categories of power plants are subject to different efficiency limits. The bulk of hydropower facilities in the US(United States) has an efficiency of over 90%, whereas the efficiency of a wind turbine is limited by Betz's rule to about 59.3%, and actual wind turbines have a lower efficiency.

Electricity Cost

The direct cost of electricity generated by a thermal power plant is determined by the price of fuel, the facility's capital expenditures, operator labour, maintenance, and other elements like ash treatment and disposal. Indirect social or environmental costs, like the economic value of environmental impacts or the environmental and health effects of the full fuel cycle and plant decommissioning, are typically not assigned to generation costs for thermal stations in utility practice, but they may be included in an environmental impact assessment. These incidental expenses fall under the umbrella term of externalities.

Boiler and Steam Cycle

To thermally link the primary (reactor plant) and secondary (steam plant) systems, which both create steam, in a pressurised water reactor (PWR), a specific type of enormous heat exchanger is used. The nuclear energy sector refers to this machine as a "steam generator." Without the need for a separate steam generator, water boils inside the reactor core in a boiling water reactor (BWR).

In some industrial settings, steam may also be produced using heat recovery steam generators (HRSGs), which utilise heat from industrial operations, most typically hot exhaust from a gas turbine. The steam-producing boiler must provide steam at the required high purity, pressure, and temperature for the steam turbine that drives the electrical generator.

Boilers are not required in geothermal facilities since they employ sources of naturally produced steam. Where the geothermal steam is very corrosive or includes an excessive amount of suspended particulates, heat exchangers may be employed.

An economiser, a steam drum, and the furnace with its steam-producing tubes and superheater coils are all components of a fossil fuel steam generator. Safety valves are placed where they are needed to prevent too much boiler pressure. Forced draught (FD) fans, air preheaters, boiler furnaces, induced draught (ID) fans, fly ash collectors (electrostatic precipitator or baghouse), and the flue-gas stacks are all parts of the air and flue gas route equipment.

Conclusion

The creation of electrical energy, which can be considered one of the basic needs of life after water and food, is made possible by thermal power plants, one of the most significant components of the energy sector.