Explainer: Why are wind turbines so big – and could smaller be better?

Everything is bigger in Texas, the saying goes, but for one thing: wind turbines. The US state is covered in many short wind turbines, thanks to a rush of development in the two decades before 2021, when turbines in general were much smaller than now.

In Australia, the trend is going in the opposite direction.  Project developers are opting for bigger and bigger turbines, in a bid to reduce project footprints – and impact on the environment.

But which approach is better: Fewer, much taller machines with massive windswept areas, or lots of small turbines that crowd the project area but can’t been seen from as far away?

Pushing for the biggest machine possible hasn’t always worked in developers’ favour in terms of social licence. In Victoria, Neoen’s proposed Kentbruck wind farm is the latest example of how turbine height can divide communities

Riled residents and holiday home owners have been sharing images comparing the future turbines with one of Melbourne’s tallest buildings, the Rialto Tower.

In the earliest days of wind, Aussie turbines were relatively small. On King Island in 1998, three of the earliest wind towers only generate 250KW each and have a 30m hub height.

Today, the biggest turbines have hub heights of 166m, tip heights up to 236m and power ratings of up to 7.2MW.

Behind wind turbine inflation is a trade off: communities want to be recompensed for hosting, no one wants large-scale environmental damage, and neighbours don’t want turbines on their doorstep.

But at some point, wind farms need to make money. This tension has led to bigger turbines that can wring more megawatt hours from fewer machines.

Sometimes turbines don’t need to be so big: developers often ask for the maximum possible number and size of machines to give them wiggle room if communities or regulators demand something smaller.

Community feedback is thought to be behind Neoen’s move to cut the height of turbines at its Tchelery wind farm in NSW by 15m.

Larger wind turbines are coming for Australia, as developers try to match size against what price their project will need to be able to sell electricity at to make money.

But greater and greater heights are also likely to make wind energy even more of a flash point.

And if communities do get their wish – to have more, smaller turbines – the question they will have to face is whether they are prepared for a trade off between height, or even higher power prices and a deeper impact on the environment they live in.

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