In response to Grange's request to be connected to the grid, Western Power investigated and discarded a number of line route options before deciding on the current alignments.
Western Power explored the option of going directly from Muja power station to Southdown. However, to secure future power supplies in the lower southwest, we were considering building a terminal substation in Kojonup. Routing the line through Kojonup would make it possible for us to connect the substation to the grid.
This option examines the possibility of undergrounding the 220 kV transmission line between Kojonup and Southdown. The cost of undergrounding 220 kV lines is approximately seven times greater than building overhead transmission lines pushing the cost of building the line well over the $1 billion mark, making the mine uneconomical.
This option includes a 220 kV line from Muja to Kojonup. From Kojonup a 132 kV line and a 220 kV line would run on the same set of towers (the 132 kV on the one side of the tower and the 220 kV on the other on what is called a dual circuit line) to Mount Barker. At Mount Barker the 132 kV line would continue south to Albany and the 220 kV would deviate east to Southdown.
This option was not chosen because this route requires the transmission line to run directly between the Stirling Ranges and the Porongurups and is a significantly longer line route.
This line route is similar to option 5. However, this option differs where the dual circuit line continues from Kojonup as far as Albany and does not deviate at Mount Barker. The deviation now runs east from Albany to Southdown.
This option was not pursued, as the line route is 60 km longer than the other options available, therefore significantly increasing the overall cost of the line.
Grange Resources explored the possibility of using onsite power generation. This option was discarded, as it is extremely expensive. Diesel-powered generators also emit significant green house gasses. Grange Resources can be contacted for more information on the process they followed in determining why wind power and bio fuel power were not chosen.
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Page update on 23 January 2007
