The restructuring of Australia’s power system is accelerating, as coal-fired generators exit and new wind and solar generators connect throughout the grid. The AEMC today published detailed maps which track this changing generation mix over the past 50 years. 

View national map showing generators in 2002 and 2019.

The change in location and type of generation has implications for two new rule change requests initiating today on marginal loss factors. When you transport electricity across a network of poles and wires, some of it is lost as heat. Marginal loss factors are calculated so customers don’t pay for power they don’t get. 

The amount of power lost depends on:

  • the distance of the generator from customers - more power is lost the further it has to travel
  • the voltage and resistance of the transmission lines - the “quality” of the line
  • how much power is flowing through the line - a more heavily loaded line means more heat and more losses.

As the type and location of generators changes, they are getting different signals about how much of their power will be lost in transportation.

Loss factors have always changed year by year – depending on where new generators are being built and where other generators are closing. What’s changing is the predictability of these loss factors, due to the rapid pace of new generators joining the system and the location of these generators.

The maps show that many new generators are connecting:

  • at the remote edges of the national grid, often a significant distance away from electricity consumers, so electricity has further to travel
  • in places where lots of other generators are already connected, so some lines are becoming heavily loaded – making them hotter and power losses worse.

As the generation mix changes, and power lines in some areas become more congested, it is essential that new investment in generation and transmission is coordinated. This is the focus of the AEMC’s proposed reforms to the way generators access and use the network to enable the right investment, in the right place at the right time so electricity can be delivered to consumers at the lowest possible cost.  

New South Wales

View NSW map

In 2002 New South Wales featured a few large coal fired power stations concentrated to the north and west of Sydney, plus the Snowy hydro scheme and a few gas fired power stations providing the bulk of generation. There was no large-scale wind or solar power.

By 2019 more than 30 wind and solar farms had joined the grid, spread throughout the state, particularly in south west New South Wales.


View Victoria map

In 2002 electricity generation in Victoria was concentrated in the LaTrobe Valley, with large coal-fired power stations and some gas plants supplying the main load centre of Melbourne. Power also came from Snowy hydro scheme in the north east, plus two wind farms on the southern coast.

Over the next 15 years, the amount of wind generation rose significantly, and by 2019 more than twenty wind farms had connected to the grid, mostly dispersed throughout north west Victoria. Also, six new solar farms joined the network along the border with New South Wales. Two utility-scale storage batteries were also added to firm a solar farm and a wind farm. 

Meanwhile, the amount of coal-fired power decreased significantly with the 2017 exit of Hazelwood station which supplied around 20 per cent of Victoria’s electricity consumption, and to a lesser extent with the exit of Anglesea coal power station in 2015.


View Queensland map

In 2002 the main generation sources in Queensland were coal plants near the load centres of Brisbane and Rockhampton/Gladstone, gas plants in more remote locations, biomass plants along the coast and three mini-hydro power stations. By 2019 more than 15 solar farms had joined the system, along with a number of new gas plants.

South Australia

View South Australia map

Large-scale electricity generation in South Australia in 2002 was all coal, diesel and gas. By 2019, coal-fired power had completely exited the state, and 19 new wind farms and three new solar farms had entered, as well as two utility-scale batteries and two grid-connected emergency back up diesel generators.


View Tasmania map

Electricity generation in Tasmania is dominated by hydro power, which has supplied around 80 per cent of the state’s power since 2002. The generation mix in Tasmania has been relatively stable, although in recent years the Tamar Valley oil-fired power station was converted to a gas-fired power station, and two wind farms joined the mix in the north east and south east corner of the state.

Read more about marginal loss factors

Media: Bronwyn Rosser, Communication Specialist, 02 8296 7847; 0423 280 341

The information contained in the maps, including the location and generation type, has been prepared by the AEMC as general guidance and for information purposes only. The information is based on publicly available sources, and has not been independently verified by the AEMC, and therefore may not be complete, accurate or up to date.