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Power station, facts about power stations

Electricity is our most important source of power, but we cannot yet produce it directly from a natural source of energy, such as coal or water. First we must convert this energy into mechanical power to spin an electrical generator. This is what happens in a power station.

The two most important kinds of stations are those which burn fuel to produce steam and those which harness the energy of falling water. (See Famous dams). In these stations, the steam or the rushing water spins turbines which are connected to the generator.

Power station, facts about power stations - heat may be derived from nuclear fuel

Power station, facts about power stations

In a power station, heat energy is converted into electrical energy. The heat may be derived from burning coal or from nuclear fuel. But whatever the source of heat, hot gases turn water in the boiler tubes into steam which passes into the turbine. The revolving shaft of the turbine drives the generator. The steam condenses and is returned to start the cycle again

Two-thirds of the world's power stations are steam-operated. The most common fuels are coal and oil. They are burned to heat water in boilers to produce steam at a high temperature and pressure.

Several countries have nuclear power stations which use uranium as nuclear fuel. Heat is produced when the uranium atoms split. (See Facts about nuclear energy). Thereafter, it is used to produce steam and spin turbines as in conventional stations.

Once the electricity has been produced, it must be distributed to consumers many miles away. This is done through cables, or transmission lines, usually carried above ground on pylons. The voltage, or 'pressure', of the electricity produced by the generator is not high enough for transmission over long distances. Therefore, it is 'stepped up' by a device called a transformer. It is transmitted in this form to local sub-stations which step it down low enough to be used by the consumer.

Turbine - facts about power stations and nuclear fuel

Power station, facts about power stations

Giant turbines are used to drive generators in power stations, producing enormous quantities of electricity.

The various power stations in a region, or even a country, are connected with one another by what is called a grid system of power lines. This means that electricity from one station can be sent to another when the other is overloaded.

Included in the grid are small, standby stations that are used only at times of peak demand, when the system is overloaded. Many have generators powered by diesel engines or gas turbines, which can be started up at short notice.

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