Transgrid has recently published a Project Assessment Draft Report (PADR) for maintaining reliable supply to Bathurst, Orange and Parkes areas in Central West NSW.
As set out in Transgrid’s 2021 Transmission Annual Planning Report, the latest forecasts indicate that electricity demand is expected to increase substantially in the Orange and Parkes areas going forward. This is mainly due to expected demand growth associated with the expansion of some existing large mine loads in the area, the planned connection of new mine/industrial loads and general load growth around Parkes, including from the NSW government’s Parkes Special Activation Precinct.
Schedule 5.1.4 of the National Electricity Rules (NER) requires Transgrid to plan and design equipment for voltage control to maintain voltage levels within 10 per cent of normal voltage. The NER also requires the power system to be operated in a satisfactory operating state, which requires voltages to be maintained within these levels, both in normal operation and following any credible contingency event.
Transgrid has undertaken planning studies that show that the current Central West network will not be capable of supplying the combined increases in load in the area without breaching the NER requirements and that voltage-limited constraints will have to be applied in the 132 kV supply network if action is not taken, leading to substantial levels of unserved energy to end customers.
The Project Specification Consultation Report (PSCR) and accompanying non-network solution Expression of Interest (EOI) were released in March 2021. Transgrid subsequently received submissions from three parties to the PSCR and five parties to the EOI. All parties requested confidentiality, so none of the material has been reproduced in the PADR or on Transgrid’s website.
The credible options considered in the PADR assessment have been refined since the PSCR, to reflect:
- submissions to the PSCR and EOI, resulting in four new options being included that utilise non-network technologies (including Battery Energy Storage Systems (BESS) put forward by third-party proponents; and
- redcued demand forecasts since the PSCR, due both to a fall in Essential Energy’s general load forecasts as well as a decrease in several specific spot load forecasts, which has led to the network elements being resized and rescoped.
The results of the PADR assessment find that the options involving non-network solutions in the short-term coupled with the preferred network option in the long term are strongly preferred over the solely network options. This is due to these options being assumed to be able to be commissioned approximately two to four years before the network options, which allows them to avoid substantial additional unserved energy in those early years.
We will therefore be focussing, internally and with third party proponents of non-network solutions, to firm up the assumed commissioning dates (and costs) for all options between now and the Project Assessment Conclusions Report (PACR), and to ensure that the assumed option timing is realistic in all cases.
At this stage of the RIT-T, the preferred options are therefore the options involving non-network solutions in the short-term, coupled with the eventual build of a new 132 kV line between Wellington and Parkes.
Transgrid welcomes written submissions on this PADR. Submissions are due on 7 April 2022.
In accordance with the requirements of the Rules, a summary of the PADR is made available on the AEMO website. A copy of the PADR can be obtained from Transgrid’s website or by emailing regulatory.consultation@transgrid.com.au.