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Hydro One Project, Downtown

I have just been informed that the tunnel has reached Terualey!

Hydro One plays an important role in delivering electricity to your community by supplying power to Toronto Hydro and its customers. We are currently upgrading existing underground transmission cables that provide power to Toronto's downtown core from our Esplanade Transformer Station (TS) to Terualey TS. We anticipate work will be complete in 2026.

Originally built in the 1950s, the underground cables located between our Esplanade Transformer Station (TS) and Terauley TS are reaching their end of life and will be replaced to ensure that we continue to energize the city's most crucial institutions. The map below shows the tunnel route selected for the new cables through the Class Environmental Assessment (EA) process completed for the project in June 2020. The new underground tunnel will run between the stations at a depth of approximately 25 metres below ground in bedrock within existing road allowances.

In addition to the installation of the new tunnel, new tunnel access shafts will be constructed at both Esplanade TS and Terauley TS. During the Class EA process, we communicated that a mid shaft would also be required near the intersection of Sherbourne Street and Shuter Street. We have now completed the design process and determined that the mid shaft is no longer required and will not be built.

Map showing new underground tunnel route:

Map of the Power Downtown Toronto Project preferred route
 
Power Downtown Toronto – 2024 Project Update
Good morning,

With 2024 well underway, we are sharing an update on our Power Downtown Toronto project, which includes upgrading underground cables between our Esplanade Transformer Station (TS) located at The Esplanade and Lower Sherbourne St. and Terauley TS located at Bay St. and Foster Pl. The existing underground cables have served the downtown core since the 1950s and need replacing. As part of this, we are building an underground tunnel for the new cables along with entry points at each station (click here for the route). We anticipate the project will be complete and in-service in 2026.
What’s new
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Photo of tunnel boring machine at Esplanade TS before it was lowered underground in January 2023.​
Crews have made steady progress since the start of our construction in 2022, which included site preparation and building entry points at each TS followed by underground tunnelling. The tunnel is approximately 25m underground, 3m in diameter and 2.5km long. The machine allows most construction to take place underground along the route, which helps minimize disruptions to residents and businesses by reducing noise and road closures.
What’s next

Photo of the new tunnel near the mid-point.​
We anticipate the tunnel boring machine will reach Terauley TS over the next few weeks. Once the 2.5 km journey is complete, crews will then need to remove the machinery from the tunnel and entry point using a crane. The tunnel boring machine is slow yet mighty as it has been moving approximately 10 metres a day. Once the machine is removed, crews will continue tunnel construction followed by cable and other equipment installation in 2026.
Stay in touch
We are pleased to have an on-site Construction Ambassador who is available to meet with residents during construction. If you have any questions, please contact Rick Parnell at (647) 969-5744.
To be added or removed from this contact list, please email Community.Relations@HydroOne.com.

 
I wonder if these spools, stored between the Gardiner and tracks, are the new feeders?
230KV noted on the inside of the spool.
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Lower Sherbourne looking SE
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Interesting, but I suspect that these cables are to be put in the new Hydro One conduits they are currently installing beside the rails on top of the berm. If they were for the new tunnel I guess they would be stored in the Hydro One yards at each end of the new tunnel. They announced this recently:

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The 2.5 km tunnel line operate or designed at 115KV and after some digging, on the internet, they are supplying 230KV cables.
Maybe the spools were delivered by train? Maybe they don’t have enough room in The Esplanade TS Yard? I counted over 40 spools. Maybe @globalexpress has a better view on the count? Then I found four spools in the TS yard with one matching/similar to the ones by the tracks.

I can’t imagine they are installing 230KV lines in ducts near the tracks unless they are replacing the overhead lines. Are there any existing buried HV lines underground in this area? Maybe the new Gardiner or the OL Line or the Don flood protection work requires a tower or two to be relocated and they are burying the main feed?

After some more digging, I found this
From the USCR TPAP Environmental Project Report of 2018.

I guess we have more fun stuff to watch.

Edit - some typos.
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The 2.5 km tunnel lines operate at 115KV and after some digging, on the internet, they are supplying 230KV cables.
Maybe the spools were delivery by train? Maybe they don’t have enough room in The Esplanade TS Yard? I counted over 40 spools. Maybe @globalexpress has a better view on the count? Then I found four spools in the TS yard with one matching the ones by the tracks.

I can’t imagine they are installing 230KV lines in ducts on/near the tracks unless they are replacing the overhead lines. Are there any existing buried HV lines under ground in this area? Maybe the new Gardener or the OL Line or the Don flood protection work requires a tower or two to be relocated and they are burning the main feed.

After some more digging I found this
From the USCR TPAP Environmental Project Report of 2018.

I guess we have more fun stuff to watch.

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Great sleuthing, Dr Watson!
 
^ Tagging @smallspy in case he can shed light on whether the spools were delivered by train.
they were delivered by flatbed truck, I got held up by one for 15 minutes going west on Lakeshore while it backed into a driveway. As you might expect in Toronto, this was during rush hour instead of at an off peak time like, say, the middle of the night.
 
The tunnel boring machine has completed its underground journey and will be removed from within Terauley TS with the use of a crane. As we prepare for the removal and for the safety of the public and our crews, intermittent restrictions are required on Foster Pl. and Elizabeth St. due to the size of the equipment assisting in the removal. Crews will re-direct traffic and pedestrians as needed during this time. Additional details can be found in the attached notice that was mailed to properties near Terauley
What’s next
Crews will continue work inside the underground tunnel over the next year, followed by cable installation and completion of the tunnel entry/access points. We anticipate the upgrades will be complete and in-service in 2026.





TS.CONSTRUCTION UPDATE
Power Downtown Toronto
April 2024
Hydro One proudly energizes life for homes and businesses across Ontario. As part of our commitment to energizing life, we are completing upgrades to underground cables between our Esplanade Transformer Station (TS) at The Esplanade and Lower Sherbourne St. and Terauley TS at Bay St. and Foster Pl. that have served the area since the 1950s and need replacing. We anticipate these upgrades will be complete in 2026.
Tunnel construction started at Esplanade TS last year with the use of a tunnel boring machine, which allows most construction along the route to take place underground. As the tunnel boring machine nears the end of its underground journey, a crane and other equipment will be brought into Terauley TS for its safe removal.
 

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