TasNetworks has published the Project Assessment Draft Report (PADR) for Meeting Network Planning Requirements at George Town. Publication of this PADR represents the second step in the Regulatory Test for Transmission (RIT-T) process following publication of the Project Specification Consultation Report in November 2024.
George Town Substation is the sole substation supplying the George Town area. It is the connection point for Basslink, the High Voltage Direct Current (HVDC) interconnector which links the Tasmanian and Victorian networks. It also supplies transmission connected customers at Bell Bay, a major industrial area in Tasmania.
The Australian and Tasmanian Governments have agreed to develop Bell Bay as one of Australia’s first Hydrogen Hubs. This follows the Tasmanian Government publishing the Tasmanian Renewable Hydrogen Action Plan (TRHAP) in 2020 that envisions Tasmania as a major producer and exporter of hydrogen by 2030. In response, TasNetworks received a number of connection enquires from proponents seeking to establish hydrogen production facilities in Bell Bay, supplied out of the George Town Substation. TasNetworks has similarly received interest from other large load proponents, including data centres.
As new load connects at George Town, management of voltage stability is necessary to ensure secure operation of the power system. Specifically, Schedule 5.1.8 of the National Electricity Rules (NER) requires that the reactive margin (expressed as a capacitive reactive power in Megavolt-Ampere reactive (MVAr)) must not be less than one per cent of the maximum fault level (in Megavolt-Ampere (MVA)) at the connection point.
Under existing operating conditions, to ensure compliance with the NER, a constraint is applied to Basslink export to maintain acceptable voltage stability at George Town. However, following the connection of sufficient new load, without intervention, these constraints will severely limit Basslink export and may not fully mitigate voltage stability issues (including the risk of a black system) under all operating conditions.
Following the connection of sufficient new load, additional reactive power support is required to avoid non-compliance with NER Schedule 5.1.8, which if left unaddressed, could result in black system following one or more contingencies. Under Regulation 5 of the Electricity Supply Industry (Network Planning Requirements) Regulations 2018 (NPR), TasNetworks is required to plan the power system to avoid a single asset failure resulting in a black system.
A black system refers to loss of more than 60 per cent of regional load. Following the connection of 210 MW of new load at George Town, the maximum percentage of load connected to the George Town substation can reach this 60 per cent threshold.
Investment is therefore required to maintain voltage stability and ensure ongoing compliance with the NER and network planning requirements (making this a reliability corrective action RIT T). The investment will also ensure Basslink is not unduly constrained on an ongoing basis.
TasNetworks has identified one credible network option at a cost of $370.6 million to address the identified need that emerges as a result of new load connections. The option will enable full unconstrained operation of Basslink and accounts for uncertainty in the precise size and location of new connections. The option involves:
- establishment of a new air insulated switchgear substation;
- installation of 550 MVAr of reactive support in the new substation; and
- reconfiguration of the 220 kilovolt (kV) switchyard at the existing George Town substation.
As a reliability corrective action RIT-T, the aim of this RIT-T is to identify the least cost option to meet the identified need (i.e. ensure compliance with NPR and NER obligations). Although only one credible option has been identified, given the size of the investment, TasNetworks considered it prudent to undertake electricity market modelling (as part of the economic assessment) to understand market operation and development should Basslink export be indefinitely constrained.
The draft economic assessment undertaken by TasNetworks concludes that in weighted net present value terms, network investment to maintain voltage stability and ensure compliance with NER and network planning requirements following the connection of new load at George Town is expected to deliver $234 million in net market benefits.
TasNetworks is now seeking feedback on its draft assessment that has been presented as part of this PADR over a 12-week period ending 21 August 2026. TasNetworks also remains interested in hearing from any non-network service providers capable of addressing the identified need.
In accordance with the requirements of the NER, a summary of the Project Assessment Draft Report is made available on the AEMO website. A copy of the PADR can be obtained from TasNetworks’ website or by emailing [email protected].