TransGrid has published a Regulatory Investment Test for Transmission (RIT-T) Project Specification Consultation Report (PSCR) for maintaining reliable supply to Broken Hill.
Broken Hill is located in the far west of New South Wales and is part of TransGrid’s south western transmission network. It is currently supplied by a single 220 kV transmission line, ‘Line X2’, from Buronga which spans approximately 260 km.
When Line X2 is out of service due to a planned or unplanned outage, electricity supply to Broken Hill is supported by two gas turbines owned by Essential Energy to avoid involuntary load shedding (these turbines each have a nameplate rating of 25 MW). TransGrid relies on these gas turbines to meet the NSW Electricity Transmission Reliability and Performance Standards 2017 (the ‘reliability standards’) set by the NSW Energy Minister and regulated by the NSW Independent Pricing and Regulatory Tribunal (IPART). In accordance with these standards, Essential Energy’s gas turbines allow TransGrid to operate its network so as not to expect more than 10 minutes of unserved energy (EUE) per year at average demand.
Essential Energy has notified TransGrid of its decision to divest the gas turbines located at Broken Hill. If no action is taken by TransGrid, this will result in the required reliability of supply to Broken Hill not being maintained, and involuntary load shedding when Line X2 is on planned or unplanned outage.
TransGrid considers this a ‘reliability corrective action’ under the RIT-T as the identified need is to ensure that the externally-imposed reliability standards for Broken Hill continue to be met.
In order to efficiently avoid involuntary load shedding and meet the reliability standards TransGrid has adopted a two-step approach.
- Step 1 – Establish a short-term non-network support solution, via an Expression of Interest (EOI) process. The EOI was issued in October 2019 with responses due in November 2019. This short-term non-network support solution will be required to be available:
– immediately, and
– until the long-term solution, which will be identified under this the RIT
T process is operational. This could be up to three years.
- Step 2 – Establish a long-term solution via the RIT-T. This document is the first step in the RIT-T process, which will consider all credible long-term options including traditional network, innovative, and non-network solutions. It may take up to three years for the long-term solution identified under the RIT-T process to be operational.
TransGrid’s revenue determination for the 2018-2023 regulatory control period includes a contingent project for the reliability of supply to Broken Hill. This contingent project is to provide additional capacity to supply Broken Hill in an event that the total 220 kV and 22 kV load at Broken Hill exceeds the capacity of the back-up gas turbines owned by Essential Energy and EUE exceeds the allowance.
The PSCR details the need to identify the long-term option to maintain the required reliability of supply at Broken Hill, in light of the existing gas turbines no longer being available to provide back-up capacity.
TransGrid has also released an EOI for technology solutions to be considered as options in the RIT-T. Options may include generation, storage, demand management and other technologies, as either network or non-network solutions. Submissions to the EOI close on the same date as submissions to the PSCR and will be considered in the assessment of options in the RIT-T.
The consultation process
In order to assess all network and non-network solution options from a technical and economic perspective, we are using the Australian Energy Regulator's Regulatory Investment Test for Transmission (RIT-T). The RIT-T is a formal consultation process designed to:
- Inform stakeholders of investment need and proposed options to address it
- Test the market for alternative and more efficient solutions
- Explain to stakeholders the basis on which the preferred option has been selected.
The RIT-T consultation process has three stages:
We are now at the first stage of the process, having published the Project Specification Consultation Report (PSCR). The second stage will involve a full quantitative analysis of the proposed options and expected market benefit across a range of scenarios and sensitivities. This will be reported in the Project Assessment Draft Report (PADR).
Submissions and next steps
TransGrid welcomes written submissions on materials contained in this PSCR and the accompanying EOI. Submissions are due on 31 January 2020.
At the conclusion of the consultation process, all submissions received will be published on the TransGrid’s website. If you do not wish for your submission to be made public, please clearly specify this at the time of lodgement.
The next formal stage of this RIT-T is the publication of a PADR. The PADR will include the full quantitative analysis of all credible options and is expected to be published in early 2020.