Waking up in Geelong

On the outer eastern edge of Melbourne there is a curious piece of infrastructure – a high voltage power line to nowhere. So why was it built, and why is it currently sitting idle?

Running south-west from Coldstream to Templestowe, via Chirnside Park, Wonga Park and Warrandyte, I was first tipped off to the existence of the transmission line by someone who lives in the area.

The path taken was quite easy to see on the Melway – the eastern end is located at tower T293 in Coldstream.

While the western end terminates at tower T342 in Templestowe.

Eventually I paid a visit in person, and the dead-end nature of the transmission line was easy to see.

The northern end at Coldstream is located alongside two 500 kV transmission lines.

While the Templestowe end is located among the transmission lines that serve the Templestowe Terminal Station.

But unfortunately I was no closer to finding the reasons for the lines laying abandoned, until my recent post on transmission line crossovers. What started with an exploration of power lines in Sydney, expanded to Rowville Terminal Station in Melbourne, and then down a rabbit hole of State Electricity Commission of Victoria reports.

I eventually landed on a 1983 report on transmission lines serving Melbourne by the Natural Resources and Environment Committee. The purpose of the report was as follows:

This report specifically addresses the SEC’s proposal for a 500 000 volt transmission line from Coldstream to South Morang and in particular:

(i) The need for reinforcing transmission to the 500 000 volt terminal stations in the outer metropolitan area;
(ii) The feasible route to be subjected to detailed examination of environmental issues; and
(iii) The recommended process for assessment and approval of the route in this instance.

The report detailed the current state of the high voltage transmission lines linking the power stations of the Latrobe Valley to Melbourne.

The existing transmission system from the Latrobe Valley to the Melbourne metropolitan areas consists of three 220 kV double circuit lines and three 500 kV single circuit lines.

Two of the 500 kV lines were established in the late 1960s on a northern easement in conjunction with the Hazelwood Power Station and supply the western metropolitan area from the Keilor Terminal Station (KTS). The lines were routed via Coldstream and South Morang with one line being on a direct Coldstream to South Morang easement and the other routed via Templestowe to provide for later development of supply for the north-eastern metropolitan area. The easements from Coldstream to South Morang were each approved with capacity for a second circuit, thereby providing for the four incoming 500 kV lines to South Morang.

The third 500 kV line was established in late 1982 on a southern easement via Cranbourne, Narre Warren and Templestowe, in conjunction with commercial service of the completed Yallourn W Power Station and in preparation for service of the initial Loy Yang A units. The planning permission for the section of this line between Hazelwood and Cranbourne included easement provision for two further 500 kV lines. The section between Cranbourne and South Morang was established on an existing easement.

As well as how the SEC planned to add a fourth 500 kV transmission line into the system:

The further 500 kV line from Hazelwood to Melbourne is planned to be established on the southern 500 kV easement adjacent to the existing 500 kV line from Hazelwood to Templestowe. The section of the line between Narre Warren and Templestowe has already been constructed and the Rowville to Templestowe part of this section is temporarily in service at 220 kV.

And the interesting bit – the abandonment of the transmission line between Coldstream and Templestowe.

To achieve connection of the fourth 500 kV transmission line into South Morang, the SEC propose to take the existing second 500 kV line (the southern circuit on the northern easement) directly into South Morang from Coldstream, so as to free up the section between Templestowe and South Morang for inclusion as part of the fourth 500 000 volt line.

The short section on the northern easement between Templestowe and Coldstream would then be left out-of-service until the future establishment of new 500 kV switching stations at Templestowe and Coldstream.

If that wasn’t clear as mud, this diagram depicted the current state, as well as three proposals for adding a fourth 500 kV circuit between Hazelwood and Melbourne.

Abandoning a section of high voltage transmission line sounds like an odd thing to do – something which Mr. R.F. English, resident of the Bend of Islands Environmental Living Zone immediately adjacent to the proposed transmission line easement, pointed out in his submission to the Natural Resources and Environment Committee.

The decision to take the Coldstream to Templestowe 500 kV line out of service until at least the fifth 500 kV line is constructed and required – this would probably be in at least 25 years or more.

As the Coldstream to Templestowe line is approximately 20 kilometres long, and based on $470,000 per km, this would mean a $9 million asset would remain idle and depreciating for 25 years.

This appears to me to reflect a gross planning error in the SEC’s long term plans “to scar the landscape with 500 kV power lines”.

So what ended up happening?

And you guessed it – State Electricity Commission of Victoria got their way, with the fourth 500 kV transmission line being pushed through the Bay of Islands bushland along the “LV1: second Coldstream to South Morang line” route, and the transmission line from Coldstream to Templestowe abandoned.

But will it be used in the future?

Back in the 1980s the SECV believed that a fifth 500 kV transmission line would be required by 1990 to serve the increasing energy demand of Melbourne.

But this prediction was overly optimistic – development of the massive 4,00 MW Driffield Project west of Morwell was abandoned follwing a change of government, and the Loy Yang power station petered out at 3,250 MW of the 4,400 MW capacity originally planned.

In 2009 Victorian energy network operator VENCorp dusted off the old SEC plans, in their ‘Vision 2030’ document:

Development of eastern corridor distribution

A new (fifth) 500 kV power line from the Latrobe Valley to Melbourne via the Northern easement terminating at Templestowe via Coldstream, and establishment of new 500 kV switching stations at Coldstream and Templestowe (140 km). This line would incorporate the currently unused 500 kV line between Coldstream and Templestowe.

Cost: $460 million

But with the decommissioning Hazelwood power station, no new coal fired power stations on the horizon, and the rapid growth of distributed rooftop solar and battery storage, the need for additional capacity between Melbourne and the Latrobe Valley seems redundant.

And another example

Sent in by a reader – a dead end transmission line outside the Geelong Terminal Station.

The transmission line runs north towards the Moorabool Terminal Station, but terminates a short distance to the south.

My guess – the original 220 kV circuit to Geelong was replaced by parallel 220 kV circuits on a new set of pylons, with a 220 KV circuit to Terang taking over the northern-most part of the easement.

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