Around the world, many different energy sources are used to generate electricity at power plants. What they all have in common is the need to produce enough energy to drive the blades of gigantic turbines that will in turn generate electricity.
Traditionally, fossil fuels, oil, nuclear fission and gas are used to heat water in furnaces to produce steam vapour that will eventually move the blades of the turbines. In the case of gas, it can also be used to produce hot combustion gases that pass directly through and spin the blades of the turbines. So far as green technologies are concerned, hydro and wind power also use direct systems for converting energy into electricity; whereas geothermal, solar thermal and biomass methods (increasingly used in countries such as India) rely on producing enough heat to create steam as the first part of the process.
Inside the turbine, the heat energy is converted into mechanical energy with the spinning blades. These operate a generator, which converts the mechanical energy into electricity
The electricity produced by the generator travels from the power plant along cables to a ‘step-up’ transformer. This raises the pressure of the electricity from low voltage to high voltage. The reason for this is that, by increasing the voltage, electricity can be carried more efficiently across long distances – it can be raised as high as 756,000 volts. Then, power lines are used to carry the electric current to sub-station transformers, where the voltage is reduced to between 2,000 and 13,000 volts. From the sub-station, electricity is run through further power lines to another transformer (either on a pole or underground), where the pressure is lowered again to between 120-415 volts prior to being distributed directly into premises.