St. Thomas has landed on the province’s long-range power map. Ontario’s electricity system operator says the city could get a major new transmission line and a new transformer station by the late 2030s, the kind of infrastructure that decides how much more the city can grow.
The news came to city council on Tuesday, September 8th, in a short staff report called Long Term Hydro Supply. It walks through a study the Independent Electricity System Operator (IESO), the provincial agency that plans and oversees Ontario’s power grid, published on August 20th. The study, called the South and Central Bulk Plan, looks 20 years ahead at where the province needs new power lines and transformer stations to keep up with growth.
Most of the near-term work the study recommends is well outside St. Thomas. Over the next five to seven years, the plan calls for new or upgraded stations in Milton, Barrie, Vaughan, Puslinch and Guelph. But further out, the plan points here. It suggests a new 500/230 kilovolt transformer station in the St. Thomas area sometime around the late 2030s. That station would be fed by the high-voltage lines that already run through the city’s north end, plus new capacity from a new line running from Bruce County to the Longwood station west of London and on to St. Thomas. A separate link toward Windsor is already in development.
Justin Lawrence, who wrote the report for the City’s Industrial Development department, gave council the plain-language version. The new line would come down from the Bruce nuclear plant, he said, because generation is being expanded there. The transformer station would sit somewhere in the northeast of the city, on or very close to the existing 500 kilovolt line that passes the Tim Hortons on Highbury Avenue. He was also clear about who decides. St. Thomas does not build this infrastructure, and council cannot approve or reject it. The call is the province’s, through the IESO. The city’s role is to advocate for it.
Lawrence told council the study is really a map of where the IESO expects growth to happen, and the report is blunt about the stakes. St. Thomas is already home to the largest infrastructure investment in its history, the roughly $1 billion Yarmouth Yards industrial park being built around the PowerCo electric vehicle battery plant. The IESO’s own chart, reproduced in the report, has demand in the London region climbing from under 1,500 megawatts in 2025 to somewhere between 2,600 and about 4,000 megawatts by 2044. The high end assumes a faster shift from gas to electricity for things like home heating and cars. If the hydro system is not built out to meet that demand, power itself becomes the limit on growth, and on the city’s tax base. Built out, the report says, it supports residential, commercial and industrial growth alike.
There is a wrinkle buried in the report that is worth knowing about. Who actually supplies your power in this area is decided by old boundaries, not current ones. Local hydro utility territories, like Entegrus here, were locked in based on lines drawn back in 1999, and they do not shift when a municipal boundary changes. That mismatch is already causing headaches: new industrial development on the edges of the city, Yarmouth Yards included, sometimes has to sort out connection agreements with more than one hydro supplier just to get hooked up.
Asked whether the city would have to chip in, Lawrence told council there would be no direct cost to St. Thomas for the line or the station. The cost would be built into the hydro rates Hydro One charges to all users across the province. Council was not asked to decide anything. The report came forward to be received for information, and no one at the meeting spoke against it.
For now, the plan is exactly that: a plan. Lawrence told council the next step is more detailed plans from the IESO, and that council and the community can push to keep the project on track. It is not news you can act on today. But it is a sign of how far the city’s power needs have moved since 1999, the year the boundaries that still decide who supplies your electricity were locked in.
Sources: St. Thomas council agenda, September 8, 2026 (Report ID-08-26, Long Term Hydro Supply), IESO, South and Central Bulk Planning
By Anthony Zruna · About the LocVox Newsroom
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