Difference Between Gas Turbine and Steam Turbines

What is a Gas Turbine?

A gas turbine generates rotational motion from a heat differential, which in this case is caused by combustion. 

What is a Steam Turbine?

Steam turbines use a steam mixture to turn a shaft to produce the desired rotary motion.

The primary similarity between the two is that they both convert kinetic energy from pressurized gas or steam into energy for generating electricity.

The major difference between  Gas turbines and Steam Turbines:

Steam turbines utilize only steam, while Gas turbines utilize an external source of fuel such as natural gas or petroleum gases. 

A gas turbine engine uses the hot expanding gases from burning fuel to turn a shaft, which then powers an electric generator. A steam turbine engine uses the high-pressure steam from boiling water to turn a shaft, which also then powers an electric generator.

Steam turbines are typically more efficient than gas turbines and are therefore more commonly used in larger power plants.

Gas turbines are faster to get up to speed than steam turbines, making them better for smaller or more intermittent loads.

Steam turbines are better for larger or more constant loads as they can run at slower speeds.

Gas turbines are also smaller and more efficient than steam turbines, making them better suited for smaller applications such as home generators.

A gas turbine, as the name suggests, uses gas as the main working fluid. The gas is compressed and then mixed with air in a combustion chamber. The mixture is then ignited and the heat from the burning gases is used to expand the gasses and turn the turbine blades.

A steam turbine uses water as its working fluid. The water is boiled into steam in a boiler, which is then passed into the turbine where it expands and turns the blades.

Conclusion:

Gas turbines use natural gas, while steam turbines use water heated to create steam. 

In a gas turbine, this conversion takes place through a series of rotating blades, which direct high-pressure gases from combustion cylinders through a set of turbines to produce power at extremely high temperatures and pressures. A steam turbine operates on the same principle but uses pure water vapor as its working fluid instead of hot compressed air because it needs to operate under vastly lower atmospheric pressure than most other types of turbine systems.