All the large plants used to generate most of the large amount of electricity used throughout the world operate on the same basic principles. A working fluid is made to do work to drive a turbine. The turbine is coupled to a generator which generates electricity by the process of electromagnetic induction. In many cases theworking fluid is pressurized and at high temperature before it enters the turbine, as this greatly increases the efficiency

There are a number of working fluids currently in use, including water
(hydro and wave/tidal power), atmospheric air (wind farms) and
combusting gas or vapourized oil (gas-fired power stations. However,
the most common working fluid, used in coal-fired and oil-fired power
stations, and also nuclear plants, is steam. This article describes
both coal and oil fired plants as they are to all intents and purposes
identical but for the fuel used.

Power Plant in a Nutshell

At the simplest level, a power station is essentially a giant kettle
(the boiler) attached to a fancy windmill (the turbine) which drives
the generator. The back end of the turbine is attached to a condenser
which converts the steam back to water, which is then returned to the boiler to continue the cycle.

To increase efficiency, real power plants usually incorporate several
extra stages, described below:

• After the steam leaves the boiler it is fed back into the boier via
  the superheater, which heats the steam up to 565C before it enters
  the high-pressure turbine.
• After it leaves the turbine (having cooled to around 350C), the
  steam is agian fed back into the boiler, this time via the reheaters
  which heat the steam back up to 565C.
• The reheated steam is fed into the intermediate pressure turbines,
  and then into low pressure turbines (there may be an additional
  reheat stage between the intermediate and low pressure turbines)

The result of all these successive stages is to increase the
efficiency of the plant from around 20% for a simple boiler-turbine
setup, to around 35% for a multiple turbine configuration with
superheat and reheat stages.

Stages in Detail

The Boiler

The boiler is...