Meeting System Strength Requirements
System strength is a general term encapsulating a number of specific technical issues. Maintaining adequate levels of system strength across the network is important for ensuring the power system can operate normally, especially following a fault.
The requirements for system strength can be significantly impacted by the connection of new wind and solar generators to the network. The way these technologies currently interact with and support the power system is fundamentally different to that of traditional synchronous generators, such as large coal or hydro machines.
TasNetworks is resolute in its commitment to power system security which underpins the delivery of safe and reliable services for our customers.
System strength is an evolving issue right across the National Electricity Market (NEM) as new technologies replace traditional generation. As a result, the Australian Energy Market Commission (AEMC) introduced changes to the National Electricity Rules (NER), which require System Strength Service Providers, such as TasNetworks, to proactively plan for and pre-emptively provide sufficient system strength services right across their networks.
TasNetworks will apply the Regulatory Investment Test for Transmission (RIT-T) process to determine which investments should be pursued to meet the new rule requirements.
Please refer to our Fact Sheet (PDF) for more information on what TasNetworks is doing to ensure sufficient system strength is available across the Tasmanian power system to meet Tasmania’s renewable energy targets.
The Regulatory Investment Test for Transmission (RIT-T) Process
The RIT-T is designed to help identify the most appropriate future investment(s) needed to meet our system strength obligations, while ensuring that costs borne by network users are transparent and justifiable.
We are initially seeking responses to our Project Specification Consultation Report (PSCR) to help inform what non-network solutions are likely to be available and their anticipated costs. We are particularly interested in identifying solutions that can address Tasmania’s inertia and system strength requirements simultaneously. This is to encourage the most technically efficient and cost effective outcome for our customers.
We anticipate that non-network solutions will be the most credible option in the short term for the period up to 2029. The need for accompanying network solutions is expected to become clearer following further network planning activities associated with the Tasmanian Renewable Energy Target. We will continue to monitor technological developments and mature our understanding of future system strength needs, with the broad objectives of avoiding over-procurement, minimising operational complexity and keeping network costs as low as possible.
We will pursue the solution that minimises the economic impacts on our customers, while still meeting our regulatory obligations. This requires TasNetworks to identify and implement the preferred solution to address the new system strength framework by 2 December 2025.
As part of this process, three main documents will be produced and consulted on:
- The Project Specification Consultation Report (PSCR) describes the need for investment, potential credible options to address the identified need, and technical information to encourage solutions from non-network proponents.
- The Project Assessment Draft Report (PADR) describes the results of the cost benefit analysis and identifies the preferred option.
- The Project Assessment Conclusion Report (PACR) confirms the preferred option and provides a summary of submissions and responses received during the PSCR and PADR.
Project Specification Consultation Report and Request for Expression of Interest
TasNetworks is seeking stakeholder submissions on the various issues and credible options that have been presented in the PSCR. We are particularly interested in receiving submissions from non-network service providers who are welcome to prepare written feedback, but must also respond to the Request for Expression of Interest (EOI) that has been published in parallel if intending to offer services to address the identified need.
Supporting templates have been released with the EOI for the provision of technical information. The templates have been developed to standardise the types of information to be submitted, which will ultimately be used as input data to the PADR modelling and analysis process.
While not administered under the RIT-T process, we are of the view that inertia and system strength services, whether they be procured in the form of non-network solutions or provided by network assets, should be considered together in parallel. Consequently, we have structured the EOI to address both system strength and inertia network services as part of the one submission, noting that potential service providers may elect to offer only one of the services if they so desire.
Although submissions to the EOI will be treated as confidential, stakeholders should be aware that submissions to the PSCR may be published by TasNetworks. Further information on this aspect of the submissions process is provided in the EOI.
TasNetworks is seeking written submissions to the PSCR and EOI over a 12 week period ending at 2PM Thursday 9 November 2023.
Submissions in relation to the PSCR can be sent directly to: firstname.lastname@example.org.
A copy of the PSCR can be found below.
Submissions to the EOI should be made through the TasNetworks E-Procurement Portal, Tenderlink (Reference: TASNET-1068758). A copy of the EOI and associated templates can be found below.
For further information, please contact: Chris Noye (Leader Regulation) at Chris.Noye@tasnetworks.com.au.
Next stepsWe intend to publish a PADR within 12 months of the PSCR consultation period ending including:
- A description of which credible options have been assessed.
- Indicative costs of each credible option.
- A description of the methodologies used to quantify costs and benefits.
- A net present value analysis for each credible option.
- A proposed preferred option, taking into account the net present value analysis as well as any other considerations deemed appropriate and allowable within the RIT-T framework.
- System Strength Fact Sheet (PDF)
TasNetworks hosted a stakeholder webinar on the 14th September 2023 to provide an overview of why system strength matters, what the potential options are to address it, and the assessment process. View the webinar presentation slides - Presentation-Stakeholder-Webinar-System-Strength (PDF)