How A Thermal Power Station Works
A thermal power station is a power station that uses heat to generate electricity.
In a thermal power station, water is boiled in large pressure vessels to produce high-pressure steam. The steam then drives a turbine connected to an electrical generator. The electrical generator then converts the kinetic energy of the rotating turbines into electricity by a process called electromagnetic induction.
The low-pressure exhaust steam from the turbine passes through a steam condenser where it is condensed to water and recycled back to the boilers.
How heat is generated in a thermal power station
There are various ways in which the water is heated in a thermal power station, such as using:
- fossil fuels, e.g the Hwange power station in Zimbabwe which uses coal as a source of heat
- nuclear power, e.g the Grafenrheinfeld nuclear power plant in Bavaria
- solar energy
- waste incineration.
Advantages of thermal power
- It requires less space as compared to the hydro-electric power station.
- Can provide a continuous supply of energy as compared hydroelectric power which relies on the amount of water in the dam and solar power stations which rely on the availability of sun.
Disadvantages of thermal power
- The running and maintenance costs of a thermal power station are more than those of a hydroelectric power station.
- It produces a lot of smoke and fumes which pollutes the atmosphere.
- Requires skilled personnel to erect and maintain the power station.
- The overall efficiency of the thermal power stations is low.
Examples of Thermal Power Stations
Hwange Thermal Power Station in Zimbabwe
Hwange Thermal Power Station is located in the North Western part of Zimbabwe near Hwange Colliery Open Cast Mine. It is the largest coal-fired power station in Zimbabwe with a maximum generating capacity of 920MW from four 120MW and two 220 MW power generation units supplying about 40% percent of Zimbabwe’s electricity needs.
Coal is supplied to the power station by an overland conveyor belt which is 6 km long from Hwange Colliery Company Limited as well as by trucks. Water is piped 44 kilometers from the Zambezi River into two 150,000 m3 reservoirs next to the power station.