Hydro-Electricity at Tarraleah

Take a walk to the lookout next to Wildside Restaurant.

The views of the hydro-electric pipes as they plunge down the hill are spectacular.

The six steel pipes drop 584 metres to the power station below. The pipes get narrower as they descend, forcing the water at higher pressure onto the turbines. At the top, the pipe diameter is 1525mm and at the bottom it's 1220mm. Each pipe – or penstock, as they are called – is fitted with a butterfly valve. These valves will close off automatically if the velocity in the penstock reads 30m per second above the normal operating velocity of 45m per second.

The water which powers the Tarraleah power station covers 26km overland (via canal, syphons and pipe) from the Butlers gorge, and ends in the Nive River. The first three generators were commissioned in 1938. Three more generators were commissioned between 1943 and 1950, bringing the capacity to 90 megawatts.

The River Derwent begins its journey at Lake St Clair and flows down to Hobart. Tarraleah isn’t the only power station to harness its power, there are 10 power stations within the catchment area with six below Tarraleah. So the same water is used to generate electricity six more times after leaving Tarraleah. Altogether, the 10 power stations of the Derwent catchment have a capacity of 515mw.