Option 4:
New Jacks Point substation + double circuit line

Construct a new Jacks Point substation, a 110kV double circuit line from Roxburgh with an interconnection to the Frankton substation.

This double circuit will be rated to approximately 2 x 180MW. This new line plus the existing line (rated 108/108MW) will increase the N-1 capacity to the Queenstown region from 108MW to 300MW. The Roxburgh substation will be upgraded to support the new line.

Cost: approx. $270-$460 million

Estimated programme timeline: 6-8 years        

Pros Cons
  • Will support midpoint and maximum electricity growth to 2050 and beyond
  • Will provide the best resilience of four options, with two circuits from Cromwell (existing line) and two new circuits from Roxburgh
  • Reliability and security increased with four circuits to Queenstown
  • Most expensive option, with highest cost uncertainty
  • Longest construction timeframe due to length of approximately 105kms (location factor, terrain). New lines will be installed at the base of the Remarkables Range
  • Construction risk is high and there is a larger potential for the project going over budget
  • Major Distribution Network upgrades will be required to connect to the network and pickup load
  • Getting construction materials to site and supporting worker accommodation will be more challenging as the route is more remote
  • Longest construction timeframe
  • Creating an interconnection circuit to the existing Frankton substation will be more challenging
  • Would still need to navigate fault lines and AF8 could potentially still impact

More information

This option provides an uplift of approximately 190MW to Queenstown, which provides enough additional capacity for (at 110kV):

  • ~26,600 homes (5kW) 70%

  • ~760 small and medium businesses (25kW) 10% and 

  • ~152 larger commercial loads. (500kW) 20%

Estimated Cost to the Customer per year
Based on midpoint population growth scenario and current Electricity Pricing Methodology.

2032 - $730 to $1,240 per year

2050 - $540 to $920 per year

Option 1: New Arrow Junction substation + single circuit line
Option 2: New Arrow Junction substation + double circuit line
Option 3: New Arrow Junction substation (220kV capacity) + double circuit lines