The Project Assessment Conclusions Report (PACR) has been published
Transgrid has completed the final stage of the Regulatory Investment Test for Transmission (RIT-T) for a new backup supply and after assessing multiple options, identified Hydrostor’s 200MW/1,500MWh compressed air storage as the preferred solution.
Transgrid’s analysis found the clean technology:
- Provides the highest net benefit for consumers and a reliable back-up supply for 17,000 people who live in Broken Hill
- Would be able to store up to 200 MW of renewable generation which could be made available to meet peak demand, benefiting existing generator customers and electricity consumers
- Aligns with the Federal Government’s Technology Investment Roadmap and Low Emissions Technology Statement, which specifically identifies electricity storage for firming as a priority low emissions technology.
- Aligns with the strategy of Broken Hill City Council to reach 100% renewable status by 2030, as outlined in their Sustainability Strategy 2018-2023 and Cities Power Partnership Pledge.
About 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 diesel-fired turbines owned by Essential Energy to avoid involuntary load shedding (these turbines each have a nameplate rating of 25 MW). Transgrid relies on these diesel-fired turbines to meet the NSW Electricity Transmission Reliability and Performance Standards 2017 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 diesel-fired 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 notified Transgrid of its decision to divest the diesel-fired turbines located at Broken Hill and that it would withdraw its provision of network support from 10 January 2022. 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.
We consider 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 light of Essential Energy’s notification that it would withdraw its provision of network support, we made the decision to purchase the existing turbines directly from Essential Energy. The continued use of the existing diesel-fired turbines is the only way for us to meet our supply reliability obligations at Broken Hill in the immediate term. The sale is expected to be completed by 31 May 2022. Essential Energy has agreed, as a condition of the sale, to continue to provide network support until the sale process has been completed. We consider this purchase to be a ‘no regrets’ decision, as the continued use of the existing turbines, at least in the near-term, was found to be a common feature across all three of the top-ranked options in the PADR assessment.