Tuesday, October 6

Wind power and dam water

Our nearest major settlement is Crookwell, in the Southern Tablelands. In the 2006 Census, Crookwell had a population of 1,993 people. The town is at a relatively high altitude in Australian terms, over 900 metres, and there are heavy frosts and snowfalls during the winter months. Most employment is based around the local agriculturally based economy. The district is renowned for potato farming so residents are often referred to as 'spud diggers'.

Crookwell is also home to NSW's first wind farm. The wind farm consisting of 8 600 kW wind turbines is located 8 minutes south of Crookwell on the Goulburn road. The "windmill" operates automatically when there is 15 km/h wind and shuts off when wind speed reaches 72 km/h. Locals either love it or hate it. I like it and it is a curious sight with sheep safely grazing beneath the turbines.

It has a capacity of 4.8 MW and was the first grid-connected wind farm in Australia when built by Pacific Power in 1998. It is now owned by Eraring Energy, and currently supplies electricity to Country Energy's "GreenPower" customers of which we are most definitely one. Each year it saves 8,000 MT of CO2 and powers 3,500 homes. Planning approval has been received for phase two of the Crookwell Wind Farm, which will have an installed capacity of 92 MW.

It will be located near to Pejar Dam, constructed to supply water for the city of Goulburn. It is one of three water storage facilities serving the city, and is used to augment the water supply when Sooley Dam is unable to maintain enough water in Rossi Weir, from which Goulburn's water filtration plant is supplied.

The dam can store 9,000 megalitres over 1.55 sq kms collected from a catchment of 142 sq kms. The dam wall is 25 metres high. In theory Pejar Dam represents 60% of Goulburns’ water, because of its size in proportion to the total storage. In practice Pejar Dam does not perform near this level because it is not catching and then delivering that amount of water to Goulburn because Pejar Dam has no engineered link to the City nor to the river. It has become evident that Pejar Dam doesn’t yield as much water as it was originally estimated to yield, particularly in drought years. Pejar Dam was last full in November 2000. Five years later, in May 2006, it was empty.

With some recent rains it is fuller and at Daramalan even the new Archie's dam is filling nicely and the Tarlo River is flowing audibly. Long may it rain!!

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