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.[2][3] 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.[4]
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.[4]
The power station has six vertical shaft generating sets, five Boving 51.6-megawatt (69,200 hp) Pelton-typeturbines 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,[1] 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,[4] 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.[5][6]
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.[7]
