HumeLink reaches peak construction at five towers a week

Main works construction on HumeLink commenced in late September 2025, and by 2026 more than 10 per cent of the transmission towers for HumeLink West had been erected, with crews assembling around five towers a week. Conductor stringing is now underway, and HumeLink West has reached peak construction. With nearly all towers between Gugaa Substation and Keajura erected, crews began aerial stringing in mid-2026, working the 140-kilometre alignment from the Wagga Wagga end.

The stringing is being done from the air — helicopters and drones running conductor between towers, rather than ground-based pulling. It is the same method now appearing on the Hunter–Central Coast network upgrade, and it is becoming the default on long regional alignments where ground access is the binding constraint.

At $4.9 billion, HumeLink is the largest transmission project undertaken in Australia. It carries power from Snowy 2.0 and the South West Renewable Energy Zone to Sydney, Wollongong and Newcastle, and it is one of eight projects sharing the combined Federal and New South Wales transmission funding package.

What is being built

HumeLink is approximately 360 kilometres of 500 kV transmission running from Wagga Wagga and Maragle to Bannaby, connecting Snowy 2.0 and the South West Renewable Energy Zone to demand centres in Sydney, Wollongong and Newcastle.

Transgrid awarded $2.9 billion of construction contracts to two joint ventures: HumeLink East to ACCIONA Construction Australia and Genus, and HumeLink West to UGL Engineering and CPB Contractors. Each contract runs in two stages — Stage One covering early works, detailed design, investigations, procurement and mobilisation, and Stage Two main works construction.

Note the access tracks. Roughly 700 kilometres of them across the two contracts — more than the transmission line itself. On linear infrastructure through difficult country, access is a substantial civil work in its own right and is frequently underestimated by contractors pricing the line and treating the tracks as an incidental.

Transgrid is separately procuring key long-lead items — reactors, transformers and conductors — outside the two main contracts. Given global lead times on transformers, that is a sensible unbundling, and it means the head contractors are not carrying that supply risk.

Where the rest of the money goes

The two contracts total $2.9 billion. The project is $4.9 billion.

The $2 billion difference sits in Transgrid's own scope — long-lead equipment procurement, land, easements, approvals and the project's own costs. It is a useful reminder when reading transmission numbers: the head contracts are often little more than half the project.

How transmission costs are recovered

Transmission is a regulated asset, and the way costs are recovered is worth understanding if you work on one.

Transgrid does not absorb a cost increase or pass it to a client. It applies to the Australian Energy Regulator to recover the additional cost through network charges, which appear on electricity bills. The AER has a contingent project process for exactly this, and HumeLink Stage 2 is before it.

A recent decision shows how that process works in practice. On 1 September 2026 the AER published a preliminary position on Transgrid's application to recover more than $1 billion of additional cost on Project EnergyConnect, the $3.6 billion South Australia–New South Wales interconnector and a separate project from HumeLink. After a six-month review the regulator was not satisfied the additional cost was unforeseeable, and declined to approve the recovery. Transgrid attributed the increase to the failure of its contract with Clough and Elecnor, along with flooding and COVID-19. ElectraNet delivered its part of the same project on time and on budget in December 2023.

Australia's transmission build-out is substantial — Infrastructure Australia projects utilities investment more than doubling to $36 billion over five years — and these decisions set how cost increases are treated across the programme.

For contractors, the practical point is about timing rather than outcome. A cost increase on a regulated asset is not settled commercially between principal and contractor: it goes to a regulator, in public, and that shapes how quickly variations are resolved and how much appetite the client has for scope growth.

Funding and approvals

• Federal Government: $4.7 billion from Rewiring the Nation, and NSW $3.1 billion from the Transmission Acceleration Facility — though these cover eight critical transmission and REZ projects, not HumeLink alone
• Federal debt finance: A$66 million in underwriting
• November 2024: NSW planning approval
• December 2024: Federal planning approval, followed by Transgrid Board Final Investment Decision
• March 2025: included in the Federal Government's inaugural Renewable Energy Priority List
• August 2025: granted considered project status under the National Electricity Rules

Expected construction completion is late 2027.

What to watch

1. The AER determination on Transgrid's $1.1 billion application — the precedent matters for every transmission project behind it.
2. Whether late 2027 holds, given main works commenced in September 2025 on around 360 kilometres of line.
3. Tower erection rate. Five a week is the current pace; the schedule depends on it rising.
4. Snowy 2.0 timing. HumeLink exists substantially to connect Snowy 2.0, whose completion date currently sits between December 2028 and December 2029.

Published 23 September 2026