I spent a morning last month going through the development application file for a tablelands wind project west of Glen Innes, the kind of paperwork nobody reads at a community barbecue. Forty-two turbines, a transmission easement running to a substation that doesn’t exist yet, and a connection date that had already slipped twice. Three hundred kilometres east, off Gippsland, Star of the South was still working through feasibility studies on a project that, on paper, would dwarf it. Same country, same grid, two completely different timelines. That gap is the whole story of onshore versus offshore wind in Australia right now, and almost nobody outside the industry understands how wide it actually is.
The public conversation tends to flatten the two into one category – wind is wind, more of it is good, pick whichever one the renders look nicer for. That’s not how AEMO’s connection queue works, and it’s not how the Clean Energy Regulator’s accreditation data reads either. Onshore and offshore wind in this country are at completely different stages of maturity, cost, and, this is the bit that actually matters, proximity to the wires that would carry their power anywhere.
Onshore wind: the known quantity, mostly
Australia has been building onshore wind since the Woolnorth and Challicum Hills days in the early 2000s. We know the turbine supply chains, we know the civil works, we know roughly what a planning overlay fight looks like in a shire council chamber. Goldwind, Tilt Renewables and Neoen have all built out portfolios at scale, and Goldwind’s shift from turbine supplier to developer tells you the model is mature enough that a manufacturer wants a piece of the development margin too.
The constraint isn’t the turbines. It’s the queue. New England REZ, where the wind-solar-storage build is still working through its own sequencing problems, shows what happens when generation capacity races ahead of the transmission that’s supposed to carry it. You can erect a turbine in under two years from a clean approval. Getting a firm, unconstrained connection into a REZ that’s still building its backbone line is the actual bottleneck, and it has been for several years running.
Onshore wind also carries the planning fights that offshore mostly avoids for now: visual amenity, noise setbacks, the state-based overlay regimes that differ between NSW, Victoria and Queensland. None of that is fatal to a project, but it adds months, sometimes years, that spreadsheets rarely account for when a developer first floats a capacity figure to the market.
Offshore wind: the unproven bet with better wind resource
Gippsland’s declared offshore wind zone is the furthest advanced in the country, and it’s still in feasibility. The feasibility phase there has run longer than most observers expected, which isn’t a criticism so much as a description of how offshore wind actually works everywhere it’s been tried for the first time: the UK’s early rounds took a similar amount of runway before steel went in the water.
The appeal is real. Offshore wind off southern Victoria and Tasmania runs at higher and steadier capacity factors than most onshore sites, and it lands closer to load centres than a REZ three hours inland. Victoria’s revived SEC has staked some of its credibility on offshore wind delivering, which tells you how much political weight is riding on a technology that hasn’t connected a single commercial turbine to the NEM yet.
Fixed-bottom turbines work in Gippsland’s shallower water; further south and off WA, the depth forces floating platforms, a technology that’s barely out of pilot stage anywhere in the world. I’ve written before about why depth is the variable that decides which foundation type you’re even allowed to consider, and it’s worth remembering that floating offshore wind adds cost and engineering risk on top of everything else offshore already carries: marine approvals, Commonwealth waters jurisdiction under the Offshore Electricity Infrastructure Act, specialist installation vessels that don’t queue up in Australian ports the way a standard crane fleet does.
The grid connection timing gap is the real comparison
I’ve gone through this in more detail elsewhere on which one actually connects first, but the short version bears repeating here because it’s the single fact that should anchor any comparison between the two technologies. Onshore wind projects with a clean planning pathway can be bidding into the NEM within a presidential term. Offshore wind in Australia, even on the most generous published timelines from the most advanced proponent, is looking at commissioning dates well into the 2030s.
That’s not a flaw in offshore wind’s engineering. It’s a function of starting from zero: no domestic supply chain, no local installation vessels, no precedent transmission connection into the Latrobe Valley network that offshore proponents keep citing as the advantage of building near old coal infrastructure. AEMO’s Integrated System Plan treats offshore wind as a real contributor to the 2040s generation mix, but what the ISP actually says is more cautious about near-term volumes than some of the marketing around Gippsland suggests.
Onshore wind’s advantage compounds here. Every REZ delay is frustrating, but it’s a delay measured against an established technology with a functioning supply chain. Offshore wind’s delay is measured against a technology still proving it can exist in Australian conditions at all.
Cost, and who actually carries it
Onshore wind is now one of the cheapest forms of new generation in the NEM on a levelised cost basis, and has been for several years according to the CSIRO’s GenCost work, produced jointly with AEMO. Offshore wind sits well above it: the UK and European experience puts offshore strike prices at multiples of onshore, even after a decade and a half of cost reduction driven by scale. Australia doesn’t have that scale yet, and won’t for a long while.
That cost gap matters for who ends up paying. Transmission build-out costs get socialised across the system one way or another, and offshore wind’s proximity to load is genuinely attractive on that front. It could, in theory, need less new transmission than a REZ three hundred kilometres from Sydney or Melbourne. But that theoretical saving only shows up on the ledger once a project is actually built, and right now none are.
The Clean Energy Finance Corporation and ARENA have both flagged interest in supporting early offshore wind projects precisely because the private cost of being first is so high relative to onshore, where the market now finances projects largely on its own. That’s a reasonable use of concessional capital. It’s also an admission that offshore wind in Australia isn’t yet commercial on its own terms.
A Novocastrian’s honest read on the politics
I swim off Newcastle’s Bar Beach most mornings I can manage it, and on a clear day you can just make out where a proposed offshore zone off the Hunter coast would sit. The local opposition there has been louder and more organised than almost anywhere else in the country: fishing fleets, the Port of Newcastle’s own concerns about shipping lanes, residents worried about sightlines from Merewether. None of that opposition is irrational, and I think the industry has underestimated how much community goodwill offshore wind needs to bank before a single turbine order goes in, especially compared to onshore projects that at least have twenty years of Australian precedent to point to when a council asks what to expect.
My honestly mildly contrarian view is this: offshore wind in Australia is being sold on its eventual scale and capacity factor before it’s earned trust on its basic ability to connect anything. That’s not an argument against building it: the resource is genuinely excellent and the Gippsland zone sits near a grid that badly needs new generation as Yallourn and Loy Yang wind down. But the industry’s own spruiking of multi-gigawatt zones well ahead of a single commissioned turbine has made the comparison with onshore wind look more lopsided in offshore’s favour than the facts on the ground currently support.
What the verdict actually looks like from here
If you need megawatts in the NEM this decade, onshore wind remains the answer, REZ congestion and council fights notwithstanding. It’s cheaper, faster, and backed by a supply chain and workforce that already exists in regional NSW, Victoria and Queensland. The state renewable target scorecards that matter for 2030 are almost entirely going to be met, or missed, on the back of onshore builds, not offshore ones.
Offshore wind’s case is a 2035-and-beyond argument, and it’s a legitimate one: better capacity factors, proximity to retiring coal infrastructure, and a resource that doesn’t compete with agricultural land the way onshore sometimes does. But anyone treating Gippsland’s gigawatt-scale zone as a near-term substitute for onshore capacity is reading the feasibility studies with more optimism than the documents themselves contain. I’d back onshore wind to still be doing the heavy lifting in the NEM’s generation mix well into the next decade, with offshore arriving as a genuinely useful addition rather than the headline act its own marketing keeps suggesting it already is.
– Callum Hayes, Wind & Offshore Correspondent