The transmission line connects the Southern Terminal substation in Bibra Lake to one of Western Power's major distribution points, the Cannington Terminal substation. The lines feeding into the Cannington Terminal substation reached capacity in the 2004/05 summer and additional supplies are needed so that Western Power can cope with the forecast increased demand in the metropolitan area supplied from Cannington.
Without the transmission line from the Southern Terminal substation, the quality and reliability of power supplies out of the Cannington Terminal substation would have been compromised.
A number of possible routes were considered, including the Roe Highway. Discussions with Main Roads WA reached agreement to run the transmission line within the road reserve and the median strip of the highway to Beckenham.
This route minimises the impact on the environment and the community while fulfilling the requirement for extra power supplies to meet the increasing demand.
In its current format, the transmission line cost about $23 million. To bury the line would have increased that cost at least 10- fold, to about $250 million.
This level of expenditure could not be justified and would mean severe cut backs to many other programs around the State, designed to keep pace with demand for electricity as well as maintaining the existing system.
The only way Western Power could fund a project of that magnitude would be to increase the cost of electricity for consumers across the State.
There is no clear link between transmission line electromagnetic fields (EMF) and human health after more than 25 years of research and studies around the world.
Nevertheless, Western Power observes a stance of 'prudent avoidance'. It adopts guidelines for human exposure to EMF as recommended by the National Health and Medical Research Council of Australia and the World Health Organisation. Hence, this transmission line will be designed, built and operated in compliance with these exposure guidelines.
It's worth noting that people are exposed to more EMF from domestic appliances and wiring in their house and place of work than they would be by living in proximity to this powerline.
Wherever possible Western Power follows existing service corridors, such as highways, freeways, reserves and railways, which were gazetted in the past for this and similar community infrastructure purposes. This keeps the number of service corridors to a minimum while maintaining services into all parts of the metropolitan area as it continues to grow.
Page update on 7 December 2007
