Why Wind Power Is Difficult — and Why Solar Usually Wins for Tasmanian Homes

Wind power does extraordinary work at grid scale, but as a way to power one home or business it’s far harder than it looks. We’re often asked in Tasmania whether a small wind turbine is worth it alongside — or instead of — solar. For the vast majority of properties, the honest answer is no.

The wind near your house isn’t the wind you imagine. A turbine’s output rises with the cube of wind speed, so a 6 m/s site yields more than double a 4 m/s site. But close to the ground — around houses, trees and sheds — wind is both slower and far more turbulent. The US Department of Energy recommends the bottom of the blades sit at least 9 m above anything within about 90 m, which in practice means a tall free-standing mast, not a rooftop.

Rooftop turbines barely generate anything. The two largest independent field trials ever run — the UK’s Warwick Wind Trials and the Energy Saving Trust’s national study — found building-mounted turbines performed dismally: Warwick measured an average capacity factor under 1%, with the worst site producing less than its own electronics consumed, and the Energy Saving Trust found none generated more than 200 kWh in a year (some were net consumers of power). Free-standing turbines on tall masts did about six times better — so the problem is location, not the machine.

Turbulence wears them out. Beyond cutting output an estimated 15–25%, the choppy air around buildings fatigues the blades and tower. An Australian study of a turbine in a built-up area found turbulence high enough to roughly double the blade fatigue load and exceed the international design standard for small turbines — shortening their life and adding maintenance to a machine that, unlike solar, has moving parts to service.

It’s not just theory in Hobart, either. In 2010, four rooftop wind turbines installed on Hobart’s Marine Board building made the news when a blade worked loose and police closed the streets below while it was made safe — a very public reminder that putting turbines on a city building is hard to get right. (ABC News, 11 August 2010.)

It costs more and pays back slower than solar. A 2019 University of Southern Queensland engineering dissertation modelled five small wind turbines against an equivalent rooftop solar system: four of the five had a payback longer than their own service life, every one cost between 30% and 400% more to buy and install than the solar system, and away from the coast their output fell to as little as 16% of what the solar array produced.

The official advice agrees. The Australian Government’s Your Home guide states plainly: “Wind generators are not suitable for most homes. Household wind systems are much more expensive than solar PV systems” — and it advises homeowners to prioritise solar, while warning people to be wary of anyone marketing turbines as suitable for urban or turbulent sites.

(Worth knowing: small wind systems under 10 kW can technically claim the same STC incentive as rooftop solar. But being subsidy-eligible doesn’t make it a good investment — the output, siting and maintenance realities above still apply.)

None of this means wind is bad — at utility scale, on exposed ridgelines and coastlines, it’s a workhorse of the grid. It just rarely makes sense bolted to a Tasmanian home. If your goal is to cut your power bill and shrink your footprint, rooftop solar (and increasingly a battery) will almost always deliver more energy, more reliably, for less money.

For an honest assessment of what will actually work on your roof and your block, contact Solar Generation Tasmania.

Published by Solar Generation Tasmania. General information current as at publication — rebates, tariffs and prices change, so confirm current figures before deciding.