It is a still in Sydney town, the trees show no movement, as I walk for the paper and a coffee on this Saturday morning. Mind you, it is sunny, so there’s that. No doubt the grid is being fed by households with subsidised rooftop solar panels and by the solar blots strewn across the landscape. Methinks, have they thought about putting solar panels offshore? No, silly, they put turbines offshore to capture extra wind and to avoid paying rent for land. But it’s got to be expensive. Hasn’t it, I ponder?

When I googled, the first source atop the page, said that a 12MW offshore turbine costs up to $400 million to make and install. Seems much too much, so I put it aside. A Statista analysis puts the cost in 2022 as being USD 3,461 per kW. In Aussie dollars that translate to about $5.2 million dollars per MW. Or over $62 million for a 12MW turbine. Two things, it seems that per-MW, capital costs increase as the size of turbines increase. And, second, note that the turbines that Chris Bowen in a wet dream imagines being built off the Illawarra coast are supposedly 15MW giants.

The plan, or, more correctly, the wild aspiration, is to install turbines 268 metres tall – at the tip of the blade – across an area of 1,022 km², 20 kms offshore at the nearest point. The cost has been officially estimated at $10 billion. Apparently, they will have a capacity to produce 2,900 MW. Arithmetic (2900/15) therefore points to there being 193 turbines at a capital cost of $52 million each. Already this seems optimistic, to say the least.

I am going to take a wild guess at this point. I don’t think this thing will be built but if it were it would cost a lot more than $10 billion. Call me a realist, but I think Snowy 2.0 provides a better guide to madcap-project costs. Recall costs have jumped sixfold from $2 billion to $12 billion, on the way to $20 billion and more once the wires and poles are included. Apply that modelling to Illawarra and the sky’s the limit. Which is why it will never be built.

Announcements are cheap – apparently over fifty offshore Australian wind projects have been proposed – thankfully, none are within cooee of being actually built. Let’s face it, projects are being cancelled overseas right, left and centre; e.g., here, here and here. Why? Simple, they are too costly. Ah, the bane of those with dreams aplenty – cost.

Back to my start. Wind turbines work better offshore. Still, even offshore, the wind is fickle. Aye lads, we be becalmed. Coleridge is instructive in The Rime of the Ancient Mariner:

Day after day, day after day / We stuck, nor breath nor motion / As idle as a painted ship / Upon a painted ocean.

Offshore wind averages about 40 percent of its capacity. Thus the 193 (15MW) turbines will churn out an average of 1,160 megawatt hours. Over a year this comes to a total of a little over 10,000,000 megawatt hours. Ignoring maintenance costs, which will be substantial, a return on capital of 10% per annum (very low considering the risky project), and on just an optimistic $10 billion of capital cost, requires that each megawatt hour be charged at a rate of $100.

That figure is, I suppose, within the current ups and downs of wholesale prices. According to AEMO the average wholesale price of electricity was $83.83 per megawatt hour in the fourth quarter of 2023 (U.S. prices are about AUD50 by the way). However, plug in a more realistic capital cost, running and maintenance costs, the costs of disposal and replacement of turbines in, say, twenty years, and the problem that dare not speak its name – that is, the need to fill the gaps when the wind don’t blow – and you have some very, very expensive electricity. Full of risk, full of cost, full of intermittency.

Do the climate whippersnappers who envision these madcap schemes ever do any sums? Maybe they can’t do sums; their formative school years being spent on all things Aboriginal and gender queer.