TasNetworks has recently published a Project Specification Consultation Report (PSCR) to address system strength requirements in Tasmania from 2 December 2025.
System strength is becoming an increasing issue in Tasmania. The installed capacity of Inverter Based Resources (IBR) is already theoretically capable of supplying all of the state’s electrical energy needs at various times. With significant new wind and solar generation expected to connect in the foreseeable future, there is an increasing exposure to operating conditions whereby synchronous generation is not required to be online other than to provide essential security services.The Tasmanian power system has so far experienced instantaneous non-synchronous penetration levels of up to 92%, i.e. synchronous generation supplied only 8% of the state’s operational demand.
The Tasmanian Renewable Energy Target (TRET) requires the equivalent of 2,500 MW of new wind generation to be connected in Tasmania prior to 2040. The most recent Integrated System Plan (ISP) and System Strength Report published by the Australian Energy Market Operator (AEMO) forecasts much of this new capacity being installed within the next 10 years. Managing power system security and reliability under such circumstances will be challenging and require deliberate management of various technical issues including system strength and inertia.
As Tasmania’s System Strength Service Provider (SSSP), TasNetworks is already making system strength services available to AEMO to address shortfalls than have been previously declared, the most recent being 15 December 2022. Following the “Efficient Management of System Strength on the Power System” Rule change published by the Australian Energy Market Commission (AEMC) on 21 October 2021, the shortfall framework has been replaced with a System Standard and a network planning obligation for SSSPs. We are now required to proactively plan for and pre-emptively provide adequate system strength to maintain power system security at all times, as well as enable forecast levels of IBR to connect to the power system.
In response to these changes, TasNetworks is undertaking a Regulatory Investment Test for Transmission (RIT-T) to identify the preferred solution(s) to address our forward looking system strength obligations from 2 December 2025 onwards.
Our PSCR describes:
- The nature and timing of the identified need, including descriptions of necessary assumptions and calculation methodologies used to inform the quantum of need.
- The technical characteristics that non-network solutions would need to deliver to adequately address the identified need.
- Credible options that TasNetworks believe are capable of addressing the identified need, including non-network solutions (which we recognise as having significant potential based on our prior experiences with managing declared shortfalls).
- The relationship between system strength and inertia, specifically how TasNetworks might satisfy multiple NER obligations concurrently and at lowest cost for Tasmanian consumers.
- An overview of the analysis methodology intended to be applied during preparation of the Project Assessment Draft Report (PADR) to identify the preferred option(s).
TasNetworks welcomes submissions from industry in response to the PSCR, in particular from proponents who are in a position to offer credible non-network solutions capable of meeting the various requirements that have been defined.
To support the preparation of submissions from intending non-network service providers, TasNetworks has developed an Expression of Interest (EOI) document with supporting templates for the provision of technical information. As our existing Network Services Agreement for the provision of inertia network services and system strength services will expire on 1 December 2025, the Request for EOI has been tailored to address both sets of requirements. We are of the view that a number of potential credible solutions can address both requirements concurrently, and thus contribute to efficient and cost effective outcomes consistent with the National Electricity Objective (NEO).
Submissions to the PSCR and responses to the EOI close at 2 PM Thursday 9 November 2023.
A copy of the documentation, information on making a submission, and dates for planned engagement sessions can be obtained from TasNetworks’ website at www.tasnetworks.com.au/systemstrength or by emailing regulation@tasnetworks.com.au.