AEMO, the Australian Energy Market Operator, wants about 6,000 kilometres of new high-voltage line by 2050, with about 13,000 steel towers up to 76 metres tall, and the seven major projects, with a first and a latest price, have gone from $11 billion to $35.5 billion between them.

The Scale

The grid today	About 44,000 kilometres of transmission line on the east coast. The plan adds about 6,000, a 14 percent extension. Two years ago it said 10,000.
In the register	34 major projects, about 5,020 kilometres of new line: 1,347 under construction, 756 committed, 110 approved, about 1,822 proposed, 490 paused, and 496 recently energised.
What a line is	Project EnergyConnect’s 700 New South Wales kilometres needed 1,508 towers and monopoles and 10,385 kilometres of conductor. HumeLink’s 365 kilometres need about 850 lattice towers, 50 to 76 metres tall, 300 to 600 metres apart. A 76 metre tower is more than half the height of the Harbour Bridge arch. At that spacing 5,020 kilometres is 11,000 to 12,000 towers and 6,000 kilometres is 13,000 to 14,000 (estimate).
What it costs	Seven projects have both a first estimate and a latest: $11.1 billion became $35.5 billion, 3.2 times. Without CopperString it is still 2.5 times. Seventeen projects in the register carry no published cost at all.
Who pays	Network costs are recovered from every electricity bill under the Australian Energy Regulator’s revenue determinations. The Commonwealth’s contribution is finance, not grants: $20 billion under Rewiring the Nation, $19 billion of it through the Clean Energy Finance Corporation, including up to $1.92 billion for HumeLink and $700 million of equity for VNI West.
The plan’s transmission bill	$16 billion up front in present-value terms for the plan’s own transmission projects, inside the $106 billion total.

What Is Being Built

Project EnergyConnect runs 700 kilometres of new line from Wagga Wagga to the South Australian border, with the second stage energised in June 2026 and completion in September. Transgrid’s original forecast was $2.1 billion; the cost is $3.6 billion. HumeLink, 365 kilometres at 500 kilovolts through the Snowy Mountains, was costed at $1.3 billion in 2020 and is now $4.895 billion. The Central West Orana zone’s 240 kilometres around Coolah and Uarbry were declared at $650 million and determined at $5.5 billion. First dirt turned at the Merotherie substation and the workers’ camp while access agreements were still being negotiated with landholders.

What Is Coming

CopperString, just under 350 kilometres of 330 kilovolt line east from Hughenden, Queensland, was announced in 2020 at about $1.8 billion. In April 2025 the Queensland government put it at $13.9 billion; in October it said $2.1 billion of savings had been identified, which leaves about $11.8 billion, a derived figure no document states. The western link towards Mount Isa is not in that scope. Marinus Link Stage 1, 345 kilometres of undersea and underground cable between Tasmania and Victoria carrying 750 megawatts, was approved by the Australian Energy Regulator in February 2026 at $3.47 billion, cut from two cables to one, for completion by 2030. The Hunter Transmission Project, 110 kilometres at 500 kilovolts from Bayswater to Olney, won state approval on 29 July 2026 at $1.364 billion, up from $900 million, for construction from mid-2027 and completion in late 2029.

What Remains Proposed

VNI West, 475 kilometres across two states, was estimated by AEMO at $3.9 billion; on 31 July 2025 it raised that to $7.6 billion and possibly $11.4 billion. The Western Renewables Link, 190 kilometres of 500 kilovolt line from Bulgana to Sydenham, was costed at $479 million in 2019 and $737 million in November 2022, and no figure has been published since. An Inquiry and Advisory Committee reported to the Victorian planning minister on 8 May 2026, and by 18 August 2026 AusNet was still awaiting the minister’s assessment. The New England zone’s network, about 305 kilometres, has no published cost and is not expected in service until 2034.

The Projects

Project	Network, new km, first estimate, latest, status
Project EnergyConnect (NSW)	Transgrid, 700 km, $2.1 bn, $3.6 bn, under construction
HumeLink	Transgrid, 365 km, $1.3 bn, $4.895 bn, under construction
Central West Orana REZ	EnergyCo NSW and ACEREZ, 240 km, $650 m, $5.5 bn, under construction
CopperString (Eastern Link)	Powerlink, 350 km, $1.8 bn, about $11.8 bn derived, committed
Marinus Link Stage 1	Marinus Link, 345 km, $3.47 bn, committed
VNI West	Transgrid and AusNet, 475 km, $3.9 bn, $7.6 bn, proposed
New England REZ	EnergyCo NSW, about 305 km, not published, proposed, 2034
Western Renewables Link	AusNet, 190 km, $479 m, $737 m (2022), awaiting decision
Hunter Transmission Project	EnergyCo NSW and Transgrid, 110 km, $900 m, $1.364 bn, approved

Reading the Numbers

The threshold here is a named project in AEMO’s plan, a zone network project, a line at 220 kilovolts or above with 50 kilometres or more of new route, or an interconnector. Local distribution upgrades are excluded. The register’s 5,020 kilometres and AEMO’s 6,000 are not comparable: one counts named projects now, the other models 2050. Tower counts are estimates from published spacing on three projects.

Technical material prepared for To Save a Beach and removed from the manuscript for length. Figures are as at August 2026. Where a figure is an estimate, the assumption is stated.

Australia’s New Transmission Lines