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Location
The original Vales Point A station was built in the 1960s as a four-unit station in what is now a populous region and favourite holiday district. There are lakes, beaches and other nearby tourist attractions as well as abundant bird and sea life, so it is especially vital to maintain the strictest standards of environmental performance. The power station is at the southern end of Lake Macquarie, about 35 km south of Newcastle. Vales Point was one of the first stations to be built at the site of its fuel source, with local mines supplying coal. Two additional units were installed in 1978-79, and the original four units were decommissioned in 1989.
Turbo-Generators
Vales Point now operates two 660 MW generating units. Installed in the late 1970s, these were the first of their type in Australia. High-pressure steam passes through four cylinders and spins the shaft of each generator. The steam turbine spins the magnetised rotor at 3,000 rpm. The spinning magnetic field of the rotor induces alternating current in the stationary coils of the stator.
Boilers
Electricity is produced using pulverised coal-fired boilers. For best combustion, coal is ground to the consistency of talcum powder in pulverising mills before being blown into the boiler in a stream of pre-heated air. Pulverised coal burned in the boiler furnace chamber produces great heat to convert water circulating in the boiler tubes into high-pressure steam. A boiler for a 660 MW turbo-generator evaporates over 2,000,000 litres of purified fresh water to steam each hour in 450 km of boiler tubes lining the furnace walls and superheaters. After use this steam is condensed back to water and is recycled.
Cooling Water
Water for cooling is drawn from and returned to Lake Macquarie. Rigorous water treatment processes ensure that no contaminants are discharged into the lake system.
Transmission
The output from Vales Point is stepped up in voltage by generator transformers before passing to the adjacent station switchyard and transmitted at 330 kV into TransGrid's interconnected high-voltage supply system. (Vales Point was the first power station to be connected to the main 330 kV transmission system.)
Coal Supply
Raw coal flows from the local mines to the pulverising mills and subsequently to the boilers and is measured and regulated by coal feeders. Bunkers above the coal feeders hold enough coal for up to eight hours' supply to the boilers. The power station achieves a very high thermal efficiency in excess of 36% in converting the energy in coal into electrical energy transmitted into the grid.
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