With more wind farms proposed in Tasmania, bush fire brigades need to plan for the increased fire hazard, particularly when wind turbines are proposed to be sited near forest or timber plantations.
Lake Echo is the western boundary of the proposed Cattle Hill Wind Farm and east is predominantly cleared, open grazing land, but north of the wind farm is a rugged area with forested gullies. To the southeast of the site the forested areas have been logged and are being established as plantation forests.
Eucalyptus forests are typically fire-prone, but the Central Highlands is only susceptible to bushfire for a few months of the year due to the relatively cold and wet climate. However, other sites in Tasmania, including Spring Hill, are being assessed for wind farms.
Last October, fire destroyed a turbine at the Starfish Hill Wind Farm ( south of Adelaide) and fire-fighters could do little but watch the blaze because burning bits of the blades were flying off the structure. The situation was considered too dangerous to get closer than one kilometre.
From ground to blade tip the turbines can be more than 100m tall and fire units simply do not have pumps capable of directing water up that high.
But even if they could be reached, water cannot be used to extinguish a turbine fire because the turbines hub contains a large electrical network.
There are also restrictions on the operation of aerial water bombers in the vicinity of wind turbines. With smoke reducing visibility, high towers pose a hazard to low-flying aircraft.
Modern wind turbines are lightning protected and are said to meet the highest possible standards for electrical safety. However, a fire risk always exists when electronics, flammable oils and hydraulic fluids exist in the same enclosure.
This risk is heightened on high fire danger days and, in the event of a turbine fire, strong winds could carry embers, burning oil and burning debris over a wide area.
If fire crews are unable to approach a turbine fire, spot fires may spread quickly to form large fronts and dangerous conditions for fire crews.
Typically, wind farms are built in open pasture land such as at Woolnorth, and access roads help as firebreaks.
Considering the high combustibility of eucalyptus, dry summer pastures and stubble, substantial setbacks from national parks, plantations and the like should be mandatory.
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