Endeavour Energy records a 2027 power constraint at Menangle Park

Endeavour Energy’s project page says the existing mobile substation on Fitzpatrick Road “does not have the capacity to meet anticipated demand beyond 2027”. The Review of Environmental Factors it commissioned from JBS&G, dated 11 September 2025, sets out the consequence: the mobile substation “will have load at risk from 2025 with the total capacity exceeded by 2027… This will result in customers not being able to connect to the network, which contravenes Endeavour Energy’s obligation to provide connection services.”

Its Distribution Annual Planning Report 2025, published in December 2025, is the regulator-facing version of the same thing: a Menangle Development Area network need of 28.2 MVA with a constraint timing of FY27, and non-network options assessed and found not feasible.

What supplies the estate today

One 66/11kV 15 MVA mobile substation on Fitzpatrick Road, commissioned in 2021. One transformer, one 66kV feeder from Transgrid’s Macarthur Bulk Supply Point. Endeavour’s Final Project Assessment Report of 5 May 2025 says that if it fails there is only 5.67 MVA of firm backup through the 11kV network from the Ambarvale and Nepean zone substations, that firm capacity was already insufficient from 2024/25, and that the 15 MVA total will be exceeded in 2026/27.

Why an estate this size is on a mobile substation

The same DAPR sets out the policy: for greenfield residential development Endeavour uses “a staged approach to provision of supply capacity including the use of distribution feeders, single transformers and temporary and mobile substations”, where “the minimum viable solution may involve a temporary mobile substation that can be moved on to the next greenfield development when its capacity has been outgrown”. It is a staged, least-cost sequence that avoids stranded assets, which means headroom in a greenfield estate is planned to be limited until the permanent asset arrives.

A 2019 Endeavour Energy submission put the mobile substation’s design capacity at “approximately 2000 homes”. Menangle Park is being built for roughly 4,000.

What is proposed

A permanent indoor 66/11kV zone substation on the same site — two 35 MVA transformers with space for a third, 35 MVA firm and 70 MVA installed — plus a new 66kV underground feeder, 85U, from the Macarthur Bulk Supply Point along Fitzpatrick and Glenlee Roads. The mobile substation would be decommissioned. This is the RIT-D preferred option, costed at $39.9 million, and the DAPR 2025 records the project as RIT-D complete with planned commissioning in FY28. A second substation at Moreton Park Road sits in the five-to-ten-year future needs list, estimated constraint date November 2031, and would need a fresh RIT-D of its own.

The status, precisely

This is not a development application, and Council is not the consent authority. It is a Part 5 (Division 5.1) activity under the Environmental Planning and Assessment Act 1979, assessed by a Class 4 Review of Environmental Factors under the NSW Code of Practice for Authorised Network Operators, with Endeavour Energy both proponent and determining authority.

On 30 August 2026 the project page said that “if approved, a Notice of Determination… will be issued by Endeavour Energy”. No determination is published. Endeavour’s works index lists this as a substation that “has been planned”; it describes South Leppington as under construction. The feeder REF said works would commence in late 2025 or early 2026, and that feeder and substation together would take 24 to 30 months — which would put completion somewhere between late 2027 and mid-2028. No Endeavour source confirms construction has physically started.

What it means for a household here

Endeavour publishes a forecast risk, not a freeze. No moratorium, queue or refusal on new connections is published, so do not read this as a connections ban. For an existing household nothing changes today: outages and electrical emergencies are 131 003, 24 hours, and that is also the number for registering life-support equipment, alongside Endeavour’s online form; a doctor-signed Medical Confirmation Form finalises the registration.

If you are buying a later stage or planning a 2028 build, this is the question to put in writing — to the developer, and to Endeavour Energy at environment@endeavourenergy.com.au. Ask what supply is committed for your stage, and when.

What to watch

A determination for either the feeder or the zone substation, and any confirmed construction start. The DAPR 2026, expected December 2026, is the document that will confirm or move the FY28 commissioning date. The project page is live and its status can change, so re-read it rather than relying on this item. See the tracker entry for the current status line.