Powering up for tunnelling operations
Work has started to construct a dedicated electricity substation at Tonsley to power the tunnel boring machines (TBMs) which will excavate the first two tunnels for the T2D Project.
The Tonsley East Substation – to be built, owned and run by SA Power Networks – is being established on the site of a recently demolished former Mitsubishi building fronting South Road and will constitute part of the Project’s Southern Laydown Area.
Work on the new facility – which will supply electricity to the tunnel boring machines (TBMs) and then to the two parallel 4km Southern Tunnels once they are completed in 2030 – is the first construction to occur in direct relation to the T2D Project and will be undertaken by SAPN and its subsidiary Enerven.
Following clearance of the site, and completion of ground investigations and detailed design of the substation, construction began in March 2023 and is expected to take about one year to carry out.
As part of construction of the substation, two 66,000-volt transformers were installed at the Tonsley East Substation in early August 2023.
The substation will be fully operational well ahead of the expected start of TBM works on the Southern Tunnels, with a similar one to be established in the Richmond area to power the TBMs that will build the 2km Northern Tunnels.
The substations are being set up to ensure TBM operations have a reliable and dedicated source of electricity.
The 10.5km T2D Project will enable motorists to have a nine-minute journey from West Hindmarsh to Darlington, and complete the North-South Corridor’s 78km of non-stop motorway between Gawler and Old Noarlunga.