Our Electricity System

Western Australia’s publicly owned electricity system can be thought about as being comprised of two different, but related, components.

The South West Interconnected System (SWIS) comprises power stations and transmission poles and wires in the southwest of WA. It extends from Kalbarri in the north to Albany in the south. It includes the Perth metropolitan area and extends east to Kalgoorlie.

Western Power is the publicly owned corporation that builds, maintains and operates the poles and wires that connect power stations on the SWIS to more than one million households and businesses.

Synergy owns five major publicly owned power stations at Kwinana, Cockburn, Pinjar, Muja and Collie, as well as three smaller power stations at Mungarra, West Kalgoorlie and Geraldton.

Synergy has a joint venture power station at Worsley Alumina, and has an agreement with Kemerton Peaking Plant to buy electricity during peak demand.

Synergy also has wind farms at Albany, Esperance and Kalbarri, with wind-diesel energy systems at Bremer Bay, Coral Bay, Denham and Hopetoun.

In addition to generating electricity, Synergy is also responsible for retailing electricity on the SWIS, meaning Synergy manages billing and customer service for all electricity consumers in southwest.

Outside of the SWIS, Horizon Power is the publicly owned corporation that generates, procures, distributes and retails electricity to almost 50,000 households and businesses in the Pilbara, Kimberley, Gascoyne, Mid West and southern Goldfields (Esperance) regions.

Horizon Power manages 38 electricity systems, including the North West Interconnected System (NWIS) in the Pilbara, the connected network between Kununurra, Wyndham and Lake Argyle, as well as 34 stand-alone systems in regional towns and remote communities.

Western Australian residential electricity prices are uniform for both Synergy and Horizon customers. This is achieved by charging all customers the Tariff Equalisation Charge, which subsidises the higher cost of producing and delivering electricity in regional areas.