How Gas Fired Power Plants Work
How gas power plants work
Today's world is still relying on hydrocarbon based fuels such as natural gas, oil and coal. The world's energy share of fossil fuel is approximately 84%. This is a clear indication that fossil fuels are still ruling the global energy share of electricity. Among various fossil fuels, natural gas is the cleanest and least polluting fuel of the world. It has also low emission of greenhouse gases which makes it environment friendly. These reasons make natural gas the number one choice for large power plants. Nature gas has also a lot of demand in the cooking sector and gas driven vehicles sector.
Generally gas fired power plants run by natural gas.
Basically a gas fired power plant consists of following components-
2. Combustion chamber
3. Gas turbine
4. Steam turbine
6. Step-up transformer
Compressor: Air is compressed before entering into the compressor chamber. In order to produce the maximum thermal efficiency, this hot air is then fed to the compressor chamber. After compressing it, this mixture is ready for combustion.
Combustion Chamber: Here the combustion process takes place. Hot air mixed with gas is fed to the combustion chamber before feeding it to the gas turbine.
Gas turbine: Natural gas is fed to the gas turbine in order to make it run. The purpose of a gas turbine is to produce rotation through a shaft connected with the generator. Actually the purpose of both turbine and generator is the same. But using those together in large power plants increases the working efficiency. The exhaust from the gas turbine is reused and returned to the compressor chamber in order to increase the efficiency of the power plant cycle.
Steam turbine: It is needed for a combined cycle power plant as a secondary unit to produce more steam. Therefore, the efficiency of the power plant is increased accordingly. Turbines are basically the largest part of the power plant consisting of a big rotor.
Generator: The basic principle of the generator is the same in all sectors. To produce electricity from the mechanical input. Which is then delivered to the step up transformer.
Step up transformer: Its function is to step up the voltage so as to deliver it to the long transmission line.
The working principle of gas power is quite easy to understand. First, let us discuss what a simple cycle gas plant is. High pressure gas is passed through the turbine which is connected to the generator by a connecting shaft. Turbine produces mechanical energy which is fed to the generator.
The generator then converts it to electrical energy in the form of electricity. Here, in this process, only one turbine and one generator is used. Therefore, it is called a simple cycle power plant. Another technology is called combined cycle power plant which is popularly used in large power plants. In this technology, a gas turbine is used with a steam turbine similar to use in coal power plants. But in spite of using coal to make steam, this type of power plant uses recycled gas to produce steam from water. The latter process is similar to a simple cycle power plant. Therefore, two turbines and two generators are used in this type of power plant. This two step process is highly efficient for producing electricity. Thus it is known as a combined cycle power plant.
Combined cycle power plants are very efficient. They can convert as much as 50% energy that is contained in natural gas. Compared to coal fired power plants, only 33% energy can be converted into electricity. Which makes gas fired power plants much superior than coal fired power plants. Government subsidies on natural gas making it more affordable to large commercial power plants. Natural gas is easy to transport. It is also less hazardous when carried by barrel or through pipeline.
Despite having many advantages, natural gas is still a source of fossil fuel. As a result, greenhouse gas emission happens. Natural gas should be transported with high care in order to avoid hazardous conditions. The reserve of natural gas in this world is approximately 80-100 years. So alternative sources of this fuel need to be researched.
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