Distribution infrastructure capacity is a current and ongoing concern for summer peak loads (every house turning on air conditioners at once) even with the large government subsidies that have existed for residential solar panels, residential batteries, reverse cycle heat pump cooling/heating and insulation. The cost to rebuild every distribution substation, change every pole-top transformer and rewire suburbs would be much higher if these subsidies never existed.

For most of Australia's population you can look up an annual report that each transmission and distribution operator is required to publish annually for their predicted demand on substations, transmission lines and distribution lines. For example in Victoria this report is the TCPR, an example available at [1]. For many distribution substations, the 10th percentile maximum demand is predicted to occur in the early 2030's, meaning that at least transformers at substations would need upgrading, or the substation rebuilt or expanded. The reasons include higher density development in urban areas, electric vehicle charging and for winter, electrification of gas heating.

As an example of the impact of residential solar generation, [2] states that for an urban growth corridor of Melbourne being built largely in the era of residential solar panels being a standard housing feature, a distribution substation ATS West has 2x 150MVA transformers operating at combined peak of 200MVA, also with 125MW of embedded residential solar generation. Without that 125MW embedded residential solar generation, this substation and feeders perhaps would have had to be replaced years earlier to allow import of ~325MVA rather than ~200MVA. Also not mentioned explicitly in this report is residential battery storage which may be reducing maximum demand from predictions made before residential batteries were widely installed.

As a side note, perhaps Australia perhaps has the most open and transparent electricity market in the world? I don't know any other country where the entire electricity grid down to 230/400VAC distribution lines running on poles in every residential street is available publicly on a map, including serial numbers of poles and ratings of pole-top transformers. And substation schematics and constraint reports, etc are all available through various public reports. I think the transparency demonstrates a great deal of confidence in the electricity grid and how it is managed.

[1] https://www.powercor.com.au/network-planning-and-projects/ne... -- refer to the PDF document in the TCPR zip file download for a substation-by-substation analysis in easy to read format.

[2] https://media.powercor.com.au/wp-content/uploads/2025/06/121...