From generator to home

Most large power stations are built in a location close to the source of energy that drives the turbine which then operates a generator. The principles of how a generator works can be explored using the interactive Java ap The generator on the interactive learning guide.

The energy mix of electricity generating plants in NSW is changing. Electricity infrastructure planning is important.  The NSW electrical energy generation mix and location of where the power plants exist now and in the immediate future can be found here.

A review of this report will demonstrate the extensive range of companies and government agencies that are involved in building power generation stations and researching technologies to enable efficient and profitable generation of electricity to power homes, industry and public amenities such as street lighting.

Sources of electricity

Around 90% of NSW's electrical energy comes from burning coal. The other 10% comes from other sources such as gas, hydroelectric, wind turbines and biomass. Currently Australia has a renewable energy use target of 20% renewable energy sources to be used to generate electricity by the year 2030.

This website discusses some issues around the greater reliance on renewable energy going forward. 


A generator uses electromagnetic induction to produce electricity. This process involves spinning the metallic conductors (wires) in the coil of the generator through a region of magnetic field.

For example, in a coal-fired power station, the coal is burnt and the energy from the burning coal is used to create steam. This steam is then forced through pipes to drive a turbine which provides the energy to rotate the conducting coils of the generator.

View an animated virtual tour of a coal fired power plant. 

Nearly all generators operate on a very similar basis except for solar cells where the energy in the sunlight is converted directly into electrical energy.

Read a report from the NSW Business Chamber that highlights the characteristics of energy sources used for generating electricity including disadvantages and advantages.  

Distributing power

Once the generator has produced electrical energy, transformers are used to step-up the voltage to distribute the power through transmission wires.

By transporting the power at very high voltage the currents required are much smaller and this allows the energy transfer to be far more efficient. Remember: Power = voltage x current.

After travelling through the transmission lines at very high voltage of 330 to 500 kV [1 kV = 1000V], transformers are then used to step-down the voltage, first in a large transmission substation to 33kV or 11kV, and then again closer to users in a zone or distribution substations. Another transformer on a power pole or in a big green box on the street, lowers the voltage to a much safer value to create the domestic supply voltage of 240V.


Electrical cord