Poatina Hydroelectric Power Station
Technical details
Located in the Great Lake and South Esk catchment area, Poatina makes use of a 900-metre (3,000 ft) descent from the Great Western Tiers to the Norfolk Plains in Tasmania's northern Midlands. Water from Great Lake is diverted via a tunnel to the edge of the Great Western Tiers where it plummets down a viable penstock line, which enters the ground again near the power station. The Poatina Power Station is located 150 metres (490 ft) underground in a massive artificial cavern hence the name Poatina, Palawa for "cavern" or "cave". The headrace tunnel and penstocks were bored through mudstone with the aid of a Robbins Mole. Water leaves the power station via a roughly 4-kilometre (2.5 mi) long tailrace tunnel and discharges into the Macquarie River via Brumbies Rivulet.
Poatina was commissioned in 1964, and replaced the Waddamana and Shannon power stations. The small construction village of Poatina sits perched on top of a low plateau, 3.5 kilometres (2.2 mi) from the stations subterranean location.
The power station has six vertical shaft generating sets, five Boving 51.6-megawatt (69,200 hp) Pelton-type turbines of which three are upgraded Andritz turbines and one Fuji 54.5-megawatt (73,100 hp) Pelton-type turbine with a combined generating capacity of 300 megawatts (400,000 hp) of electricity. The station output, estimated at 1,255 gigawatt-hours (4,520 TJ) annually, is fed via underground circuit breakers to two 16 kV/110 kV and four 16 kV/220 kV generator transformers located in the switchyard above, and then to TasNetworks' transmission grid at the Palmerston Substation 4-kilometre (2.5 mi) to the east. Two grid batteries at a combined 380 MW / 860 MWh are scheduled for the substation by 2027.
2016 Tasmanian energy crisis
The Poatina output in early 2016 had dropped to one-fifth of capacity due to ongoing water shortage in Tasmania's hydro system.
