TransGrid has recently published a Project Specification Consultation Report for improving stability in south-western NSW.
The main power system in south-western NSW consists primarily of one 330 kV transmission line from Darlington Point to Wagga Wagga (Line 63) and 220 kV transmission lines west of Darlington Point (including Line X5). Smaller underlying 132 kV transmission lines supply regional towns.
This area has seen significant growth in renewable connections to the transmission network as part of the wider energy market transition. Approximately 560 MW of renewable generation has connected in the area since December 2015, with a further 800 MW expected to connect by 2021. This is having an impact on how this part of the power system operates. In particular, while power has historically primarily flowed west from Darlington Point to supply rural and mine loads, this is expected to reverse with the increase in renewable generation in the area, particularly during daytime when there is an abundance of solar generation.
These changes in power flows are expected to lead to an increasing risk of power system instability going forward. Currently, the only way of managing this risk is to constrain generation in south-western NSW. In recognition of the risks to future power system stability, the Australian Energy Market Operator (AEMO) recently implemented an operational constraint in the NEM Dispatch Engine (NEMDE) to limit power flows and prevent this occurring.
TransGrid has identified the opportunity to strengthen the transmission network to relieve this constraint and realise net market benefits. This RIT-T has therefore been initiated to progress and consult on the assessment of investment options. The investments considered in this RIT-T are not expected to form part of AEMO’s final 2020 Integrated System Plan (ISP), and so are being progressed outside of the ISP framework.
TransGrid’s revenue determination for the 2018-2023 regulatory control period includes a contingent project to support south-western NSW for renewables. This contingent project is to reinforce the transmission network in the area to enable additional renewable generation and provide net market benefits to NSW as well as the wider National Electricity Market.
TransGrid has put forward four credible options for consideration in this Project Consultation Specification Report:
Option 1A: Establish a new Darlington Point to Dinawan 330 kV transmission line
Option 1B: Rebuild the existing 99T Darlington Point to Coleambally and 99L Coleambally to Deniliquin as 330 kV to Dinawan
Option 2: Establish a new Wagga Wagga to Darlington Point 330 kV transmission line
Option 3: Implement a static synchronous compensator solution (STATCOM)
TransGrid welcomes written submissions on materials contained in the PSCR. Submissions are particularly sought on the credible options presented and from potential proponents of non-network options that could meet the technical requirements set out in the PSCR. Submissions are due on 26 October 2020.
In accordance with the requirements of the Rules, a summary of the Project Specification Consultation Report is made available on the AEMO website. A copy of the Project Specification Consultation Report can be obtained from TransGrid’s website or by emailing firstname.lastname@example.org