CopperString is building at Flinders after a QIC reset that found $2.1 billion in savings

CopperString is planned as an 836-kilometre transmission line from Reid River, south of Townsville, to Mount Isa, connecting Queensland's North West Minerals Province and the Flinders region to the National Electricity Market in two stages. The first stage is now in the ground: ground was broken at the Flinders Substation near Hughenden in June 2026, and McCosker Contracting has been awarded the bulk earthworks.

It has also become one of the most instructive cost stories in Australian infrastructure — not because the number rose, but because of what was done about it.

The cost trajectory

The headline number rose almost eightfold, but the steps are not like-for-like. The last step is entirely connection assets that were added to the scope, and QIC's review attributes the growth to increased project scope, changes in sequencing and the project maturing from concept to detailed design — alongside rising transmission costs.

Then the direction changed. The government engaged the Queensland Investment Corporation in April 2025 to review the project, and on 10 October 2025, in its Energy Roadmap, announced that QIC would oversee delivery and that the Eastern Link would return to its original 330 kV design — Powerlink had since lifted it to 500 kV. Powerlink continues early works, easements and approvals on the Eastern Link.

The QIC review estimated savings to the State of up to $2.1 billion, measured against the Eastern Link's then-estimated cost of $5.8 billion — a 36 per cent reduction. The voltage change accounts for $0.8 billion (a $4.5 billion 500 kV backbone becomes a $3.7 billion 330 kV line). The larger part, $1.3 billion, comes from having spur lines and connection assets delivered by private capital under a commercially negotiated, unregulated model rather than funded by the Government.

The Western Link, from Hughenden to Mount Isa, reverts to the project's original sequence and follows the Eastern Link. In the meantime, a $200 million North West Energy Fund is backing lower-cost generation and storage in the North West Power System, with local generation and storage proposed for Julia Creek and Richmond.

The 2026-27 Queensland Budget lifted the State's CopperString commitment to a record $3.2 billion, an increase of $800 million on the previous Budget's $2.4 billion, with $420 million budgeted for 2026-27.

Why the voltage decision matters

Returning a transmission line from a 500 kV design to 330 kV is not a cosmetic saving. It changes towers, conductors, insulation and substation equipment — and it lowers the line's carrying capacity, from up to 2.6 GW at 500 kV to up to 1.7 GW at 330 kV.

That is the trade being made: lower cost now, less headroom later. QIC forecast transfer demand on the Eastern Link of around 1.3 GW, from new load in Townsville and along the corridor and transfers south of Townsville, and found a 500 kV specification was not necessary under all reasonable scenarios until at least 2050. The review kept the 120-metre easement, which can take a second 330 kV line if demand grows faster than forecast.

For contractors it is a live lesson in how cost control happens on Australian megaprojects. The public conversation is usually about efficiency and productivity. Here the mechanism was scope — the voltage — and who pays for the connection assets, and it arrived after early contractors had priced and mobilised on the earlier design.

What is being built

• Eastern Link: about 342 km of 330 kV transmission line from Reid River, near Townsville, to the Flinders Substation near Hughenden — targeted for completion by 2032, with main construction on track for 2028, pending federal approvals
• Flinders Substation: a $225 million substation near Hughenden, approved for construction in December 2025
• Workforce accommodation: construction of camps at Hughenden and Richmond began in 2024; Powerlink sought sites for further accommodation along the Eastern Link between Reid River and Hughenden in late 2025
• Western Link (later stage): about 494 km of 330/220 kV line from Flinders to Mount Isa via Cloncurry, now sequenced after the Eastern Link

Who holds the work

When the ECI contract was awarded in 2021, under the project's original private proponent, UGL and CPB Contractors were named preferred contractors for the delivery phase, subject to completion of the ECI contract and achievement of approvals and financing.

That is a conditional position, not an award. The project has since changed owner, voltage and delivery model, and QIC's review recommends formal market engagement with design and construction contractors and competitive procurement for the Eastern Link. Whether the 2021 preferred position carries through has not been publicly confirmed.

The delivery model is being rebuilt

QIC's review recommends delivering the Eastern Link backbone as a regulated asset, with a new regulated entity accountable for developing, constructing, operating and maintaining the Eastern Link. Powerlink is expected to support system operations after construction and to build a switching station connecting the line to its network.

That is a fundamental change. Under the previous model the Government would have funded the full cost. A regulated asset recovers its costs through network charges over decades. QIC recommends a modified version of the national regulatory framework under Queensland's Priority Transmission Infrastructure provisions, with the regulated asset base set by Ministerial direction and the Australian Energy Regulator providing independent oversight. How regulators treat transmission cost growth is a live question: on 1 September 2026 the AER published a preliminary position rejecting Transgrid's application to reopen its revenue determination to recover about $1.1 billion of additional Project EnergyConnect spending, leaving the costs to its standard review in the 2028–33 determination.

Funding on the public record:

• Queensland Government: $3.2 billion in the 2026-27 Budget; earlier, a $1.3 billion package for early and enabling works
• Federal Government: $11 million to the original proponent before 2021, and a share of a $134.7 million 2020-21 Budget allocation for transmission and generation capacity
• Private investment: a $17 million investment by Korea Zinc Company Limited, agreed with the original proponent, CuString, in January 2021

The Korea Zinc agreement is worth noting. Korea Zinc, owner of the Sun Metals zinc refinery in Townsville, backed the line while it was still a private project, two years before the Queensland Government took full ownership in 2023.

ANZIP records that it is unclear whether the $1.3 billion is grant funding, state-owned corporation borrowings, an equity injection, or retained dividends funded through user charges.

What to watch

1. How the Eastern Link's main construction contracts are procured, and whether UGL and CPB's 2021 preferred position carries through after the change in scope.
2. Establishment of the new regulated entity for the Eastern Link, and the regulatory process that follows.
3. Whether the $2.1 billion in identified savings is realised — identified and delivered are different things, particularly where $1.3 billion of it depends on private capital funding connection assets.
4. The North West Energy Fund, whose first project is a wind and battery development for MMG's Dugald River mine — a materially different construction program to a transmission line.
5. The 2032 Eastern Link completion date, which coincides with the Brisbane 2032 Games and Queensland's wider infrastructure build.

Published 28 September 2026 · Updated 30 September 2026