Advantages and Disadvantages of Steam Turbines
- Since the steam turbine is a rotary heat engine, it is particularly suited to be used to drive an electrical generator.
- Thermal efficiency of a steam turbine is usually higher than that of a reciprocating engine.
- Very high power-to-weight ratio, compared to reciprocating engines.
- Fewer moving parts than reciprocating engines.
- Steam turbines are suitable for large thermal power plants. They are made in a variety of sizes up to 1.5 GW (2,000,000 hp) turbines used to generate electricity.
- In general, steam contains high amount of enthalpy (espacially in the form of heat of vaporization). This implies lower mass flow rates compared to gas turbines.
- In general, turbine moves in one direction only, with far less vibration than a reciprocating engine.
- Steam turbines have greater reliability, particularly in applications where sustained high power output is required.
Although approximately 90% of all electricity generation in the world is by use of steam turbines, they have also some disadvantages.
- Relatively high overnight cost.
- Steam turbines are less efficient than reciprocating engines at part load operation.
- They have longer startup than gas turbines and surely than reciprocating engines.
- Less responsive to changes in power demand compared with gas turbines and with reciprocating engines.