power station

US-style power station; its cooling towers, or ‘smokestacks’, can clearly be seen.

Electricity supply from a power station to homes and workplaces. The electricity is transmitted along power cables at high voltage and low current. The voltage is reduced in stages by transformers, according to whether it is needed to power large factories or small houses.

A coal-fired power station (highly simplified). Coal enters the system through a hopper on the left and passes into the furnace after being pulverized. The coal burns inside the furnace, heating water in the boiler tube to steam. Hot gases are used to heat the steam further (superheat). The steam then passes to the turbines. There are usually three turbines – high, intermediate, and low pressure – which extract all the energy of the steam and turn the electricity generator.

Building where electrical energy is generated from a fuel or from another form of energy. Fuels used include fossil fuels such as coal, gas, and oil, and the nuclear fuel uranium. Renewable sources of energy include gravitational potential energy, used to produce hydroelectric power, and wind power.

The energy supply is used to turn turbines either directly by means of water or wind pressure, or indirectly by steam pressure, steam being generated by burning fossil fuels or from the heat released by the fission of uranium nuclei. The turbines in their turn spin alternators, which generate electricity at very high voltage.

The world's largest power station is Turukhansk, on the Lower Tunguska River, Russia, with a capacity of 20,000 megawatts.