1,100 kilometres. That’s roughly the length of 275kV transmission line Powerlink now has to build between Townsville and Mount Isa, give or take the final route adjustments still being worked through with landholders. It’s longer than the distance from Sydney to Melbourne, strung through some of the emptiest country in the National Electricity Market, to connect a handful of mines and a mid-sized city to a grid most of them have never touched.
I’ve spent a chunk of the last fortnight going back through Powerlink’s public filings and AEMO’s north Queensland work to get a clean read on where CopperString 2032 actually sits, because the project has a habit of appearing in press releases looking slightly different each time. The name itself tells you the ambition: it’s meant to be energised by 2032, which is also the year Brisbane hosts the Olympics, a coincidence the Queensland government has not been shy about mentioning.
What CopperString actually is #
Strip away the branding and CopperString 2032 is a single-circuit 275kV transmission line running from the existing grid near Townsville out to Mount Isa, with 500kV-capable towers built in from the start so it can be upgraded later without starting again. Along the way it picks up a string of mine sites and towns in the north-west minerals province – places like Cloncurry and Hughenden – that currently run on diesel and gas generation because there’s never been a wire long enough to reach them economically.
Powerlink took over the project from the original private proponent, CuString, in 2022, after years of the concept sitting on various drawing boards going back to the 1980s. That handover matters. A state-owned transmission business with a regulated asset base and access to government underwriting can carry a project like this in a way a standalone developer chasing merchant returns generally can’t. It’s the same logic that sits behind Queensland’s energy plan built around pumped hydro and public ownership – big, long-dated infrastructure that the state has decided is worth carrying on its own balance sheet rather than waiting for the market to price it correctly.
The cost number, and why it keeps moving #
Let’s be careful with that number, because CopperString’s price tag has shifted more than once and it’s worth being precise about which figure you’re looking at. Early cost estimates sat in the $1.7–1.8 billion range. By the time Powerlink’s business case work was further advanced, the figure being discussed publicly had moved past $5 billion, reflecting more detailed route surveys, updated steel and labour costs, and the decision to build to a higher voltage standard than originally scoped. Anyone quoting a single fixed cost for this project without a date attached to that quote isn’t being precise.
That kind of escalation isn’t unique to CopperString. It’s the same story playing out at VNI West, stuck in its own paddock dispute in Victoria, and at Marinus Link under Bass Strait. Long linear transmission projects in Australia have a near-universal pattern: the first public number is the planning estimate, and the number that survives contract execution is routinely double or more. The Australian Energy Market Commission and the AER have both flagged cost escalation on major transmission builds as a structural problem for the sector, not a one-off.
Who’s actually paying for it #
The funding stack for CopperString is a genuine mix. The Queensland government has committed equity and underwriting through Powerlink, the Commonwealth has put money in via its rewiring-the-nation style arrangements administered partly through the CEFC, and there’s an expectation that mining customers connecting along the route will contribute through connection charges once the line is operating. That’s a different funding model to a straight regulated-asset-base recovery through Queensland electricity bills, and it needs to be, because the customer base at the far end is small and concentrated rather than the millions of households that normally absorb transmission costs.
This is the same question that sits underneath every major transmission build in the country right now, and I’ve written before about who really pays for the transmission build-out more broadly. CopperString is a useful test case precisely because it isn’t a renewable energy zone feeding household demand. It’s industrial load, which changes who should logically be asked to stump up.
The minerals province case for building it #
Mount Isa Mines, Glencore’s copper and lead-zinc operations, and a run of newer critical minerals projects chasing copper, vanadium and rare earths all sit in a pocket of Queensland that currently generates its own power off gas and diesel, mostly through the isolated Mount Isa system. That’s expensive, it’s emissions-intensive, and it caps how big new projects in the region can get because self-generation doesn’t scale the way grid connection does.
Connect that province to the NEM and two things happen. First, existing operations get access to cheaper, more reliable bulk power, with the option to bring in wind and solar generation that’s currently stranded because there’s nowhere for the electrons to go. Second, and this is the bit that tends to get the most airtime in government messaging – new critical minerals projects get a viable energy pathway that doesn’t require them to build their own power station before they can build a mine. Federal and state critical minerals strategies lean on this logic heavily, and it’s not unreasonable. Copper and rare earths are genuinely strategic inputs, and north-west Queensland has genuine known deposits.
Where I’d push back a little is on how tightly the region’s future demand has been forecast. A lot of the economic case for CopperString rests on mining and minerals processing projects that are themselves at feasibility stage, not under construction. If even half of the flagged new loads don’t proceed on the timeline assumed, the line still gets built, but the utilisation that justifies the spend takes a lot longer to materialise. That’s not a reason not to build it. It is a reason to be sceptical of the rosier load-growth slides in the investor presentations.
What’s actually holding it up #
Three things, in practice. Route finalisation across pastoral leases and native title areas is still working through, and in a corridor this long that process doesn’t move fast no matter how much political will sits behind it – landholder negotiation and cultural heritage assessment under Queensland’s own planning framework take the time they take. Construction workforce availability is the second constraint; Queensland has several large transmission and pumped hydro projects – Borumba pumped hydro among them – competing for the same linesmen, surveyors and civil crews at the same time, and that labour market is tight enough that sequencing matters.
The third is the one that gets less attention: the connection agreements with the actual mining customers at the far end haven’t all been locked down. A transmission line is only as valuable as the load it serves, and some of the larger prospective customers are still working through their own feasibility studies in parallel with Powerlink’s build schedule. That’s a reasonable commercial position for them to take, but it means CopperString carries a bit of chicken-and-egg risk that a REZ connecting established generators to established demand, like the New England REZ, simply doesn’t have.
Why it matters beyond Mount Isa #
CopperString is also a data point in the broader argument about Renewable Energy Zones and whether government-led transmission is the right tool for opening up new generation and demand corridors: a debate I’ve covered in Renewable Energy Zones: the plan behind the pushback. Queensland’s approach here is distinct from the NSW and Victorian REZ model because the primary driver isn’t renewable generation seeking a path to market, it’s industrial demand seeking cheaper, cleaner power. If it works, it becomes a template other states might use for connecting remote minerals and processing hubs, think of parts of WA’s Pilbara or South Australia’s Eyre Peninsula, without waiting for a generation cluster to justify the wire first.
I’ll admit there’s something almost old-fashioned about the project, in a good way. Most of what I cover involves firming intermittent generation or managing distributed rooftop solar at the margins. CopperString is closer to the classic nation-building transmission story: build the wire, open the country behind it. Worth remembering that the Snowy Scheme was sold on similarly long horizons, and nobody now asks whether that was worth the wait.
For readers wanting the primary source rather than my summary of it, Powerlink’s project updates sit on its own CopperString website, and AEMO’s Integrated System Plan documents the north Queensland transmission context this line sits inside – worth cross-checking against what the AEMO Integrated System Plan actually says if you want the full grid picture rather than just the north-west corner of it.
The 2032 energisation date lines up neatly with an Olympics deadline that has nothing to do with electricity. Whether a 1,100-kilometre transmission line across pastoral country, native title land and some of the harder industrial relations territory in the state actually lands on that date is a different question, and it’s the one I’ll keep tracking.
– Anjali Rao, Grid & Storage Correspondent
Photo by Ernest Brillo on Unsplash