Australia’s Energy System

Australian Power Grids: The NEM, SWIS, NWIS & more

High voltage transmission lines connect Australia’s eastern states, South Australia and the Australian Capital Territory. This is referred to as the National Electricity Market (NEM). Some states, like Victoria (which connects to three other states), have higher levels of interconnection than others, like South Australia and Tasmania. 

There are two separate interconnected systems in Western Australia (the South West Interconnected System (SWIS) and the North West Interconnected System (NWIS)) and 35 other smaller grids. The Northern Territory has three smaller separate electricity systems.

Generation, Transmission, Distribution & Retail

  • Generators – power plants which produce electricity from an energy source, such as a coal, gas, hydro, wind, solar, or biomass. Larger power stations usually sell electricity to the wholesale electricity market.
  • Transmission network – transports electricity from large power plants, usually over long distances using high voltage power lines.
  • Distribution network – smaller, lower voltage power lines which distribute electricity to households and businesses.
  • Retailers – Purchase electricity at wholesale electricity prices and sell it to retail customers such as households and businesses.