Wind turbines have been pumping water and powering machinery for over 2,000 years, but have only been used to generate electricity since the 1980s. Today, millions of people throughout the world use electricity generated by wind turbines, with Australia’s first wind farm being established near Esperance in Western Australia in 1993.
Wind energy is the least expensive large-scale renewable-energy source. One 600-kilowatt wind turbine at a reasonable site can produce enough electricity to meet the annual needs of 375 households. Wind-powered electricity does, however, need back-up from more traditional electrical generating methods such as the hydro-electric system, because batteries can only store a limited amount of wind-powered electricity.
The siting of wind farms takes into consideration topography, elevation, distance from the sea and vegetation, all factors that affect the amount of wind available for generating electricity. In general, wind is stronger at the coast and at on the top of elevated ridges and hill tops. It tends to be less strong inland, because vegetation and landscape restrict its flow. However, on elevated sites the wind can be accelerated as it is forced to rise over the ridge or hill. Wind speeds of between about 15 and 90 km/h are needed to operate a wind turbine, with the optimum wind speed for peak efficiency being 55 to 90 km/h.
Tasmania is located south of the 40th parallel in the path of prevailing westerly winds, the Roaring Forties, which ensure that Tasmania has conditions that are ideal for producing electricity through wind power. Hydro Tasmania’s research shows that 1,000 MW of wind energy could be generated by utilising these winds; enough energy to supply electricity in Tasmania and to mainland Australia. With Basslink, Tasmania could potentially sell excess wind-powered electricity to Victoria and other southern mainland states during their peak-load periods.
At May 2003, there are four wind farm sites or potential sites in Tasmania: Woolnorth, King Island's Huxley Hill, Heemskirk and Musselroe.
WOOLNORTH WIND FARM
The Woolnorth wind farm is on the far north-west tip of Tasmania. The farm will eventually reach an electrical capacity of 130 MW, producing enough energy to power every home in Launceston.
The wind towers at Woolnorth are the result of a partnership between Hydro Tasmania and Vestas, a Danish wind turbine manufacturer. They are the largest commercial turbines yet installed in the southern hemisphere, with the towers reaching a height of 60 metres and the turbine blades measuring 66 metres in diameter.
The Woolnorth wind farm project is proceeding as a staged development. The 10.5 MW stage one with six Vestas 1.75 MW wind turbines was completed in August 2002 along with the 22 kV transmission line to Smithton. Construction of the Bluff Point stage began in September 2002 and will be completed in late 2003. This stage will have a capacity of 54 MW with 31 wind turbines. Construction of the remaining stages of the full 130 MW wind farm will be considered in conjunction with other planned wind developments.
Information on the Woolnorth wind farm be found on the Hydro web site.
KING ISLAND'S HUXLEY HILL WIND FARM
Wind is now the source for about 20% of the electricity generated on King Island. Emissions of carbon dioxide have been reduced by up to 2,000 tonnes a year on the pre-1998 figures because of wind power and Hydro Tasmania saves hundreds of thousands of dollars each year in diesel fuel costs for the island’s thermal power station.
Several different locations were studied on King Island, but the best site was determined to be the crest of Huxley Hill. There, the axles of the turbine blades, sitting on top of their 30-metre-tall towers, are about 130 metres above sea level. This location has an average annual wind speed of 33 km/h (an excellent speed for generating electricity from the wind), ensuring the three turbines that make up the farm generate up to 750 kw of electricity.
The wind farm at Huxley Hill began operation in February 1998. It was the nation's second commercial wind farm.
Information on King Island's Huxley Hill wind farm can be found on the Hydro web site.
HEEMSKIRK WIND FARM
The licence area for the proposed Heemskirk wind farm lies between the tiny coastal settlements of Trial Harbour and Granville Harbour, west of Zeehan. It is expected that the initial stage will consist of up to 10 wind turbines generating about 20 MW, and the completion of all stages could involve up to 80 turbines and a capacity of about 160 MW.
Two wind-monitoring towers have been erected at Heemskirk to assess the available wind power resource. The data collected from these monitoring sites will enable a better estimate of the viability of a wind farm and help to determine the optimum locations for wind turbines. Other feasibility studies being undertaken include foundation, road assessment, power line and transport options.
Depending on the results of the feasibility studies, construction of the Heemskirk wind farm could proceed as a staged development in 2004.
Information on the Heemskirk wind farm can be found on the Hydro web site. For further information on Heemskirk, email david.wilson@hydro.com.au.
MUSSELROE WIND FARM
Little Musselroe Bay is on Tasmania’s far north-east coast, close to the eastern entrance to Bass Strait. Hydro Tasmania has been monitoring the wind in the Musselroe area since the early 1980s and has chosen a privately owned grazing property at Cape Portland as the best location for constructing wind turbines. A land agreement was put in place between the Cape Portland landowner and Hydro Tasmania in 2000.
Stage one of the wind farm could have 5 to 25 turbines generating from 10 to 50 MW and will require a transmission line to be constructed to connect the wind farm to Transend Network’s substation at Derby. In the future there may be potential for the Musselroe farm to receive a significant upgrade to a total of 70 to 80 turbines producing 150 MW of electricity.
If the feasibility study proves the project's viability, this development will begin late in 2003 or in 2004.
Information on the Musselroe wind farm development can be found on the Hydro web site. For further information on Musselroe, telephone Ron Steenbergen on (03) 6230 5212 or email him at ron.steenbergen@hydro.com.au.
FURTHER INFORMATION
For more information about wind farms visit http://www.hydro.com.au, http://www.auswea.com.au or http://www.vestas.com.
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