Key facts
- Fact 01
Meridian says Manapōuri, in Fiordland National Park, is the largest hydro power station in New Zealand.
- Fact 02
By capacity, Genesis Energy says Huntly (1200MW) is New Zealand's largest power station.
- Fact 03
Manapōuri's generating units are in a cavern about 200 metres below the surface of Lake Manapōuri, Meridian says.
- Fact 04
Construction of Manapōuri Power Station began in 1964, and the project took 1,800 workers eight years.
- Fact 05
Manapōuri first generated power in September 1969 and was fully operational in 1972.
Manapōuri Power Station sits on the edge of Lake Manapōuri's West Arm in Fiordland National Park, part of the Te Wāhipounamu World Heritage Area. Meridian Energy, which runs it, says it is the largest hydro power station in New Zealand, with its generating units in a cavern excavated from rock 200 metres below the surface of the lake. It is not the biggest power station of any kind: Genesis Energy says that by capacity Huntly, at 1200MW, is Aotearoa's largest power station.
Meridian lists seven 128 megawatt units. Since a second tailrace tunnel was finished in 2002, the station has a maximum continuous rating of 850 megawatts, though resource consent conditions limit generation to 800 megawatts. Meridian says the station generates enough electricity for about 619,000 average New Zealand homes.
Engineering New Zealand says the site uses the 178 m drop between Lake Manapōuri and Deep Cove in Doubtful Sound, where two 10 km tailrace tunnels carry the water. Construction began in 1964. Meridian says the project took 1,800 workers eight years, building the station 200 metres below a granite mountain by drill and blast; Engineering New Zealand records almost eight million work hours and 18 workers killed. Power was first generated in September 1969, and the station was fully operational in 1972 when the seventh unit was commissioned.
It was built to supply the Tiwai Point aluminium smelter, which Engineering New Zealand puts more than 150 kilometres away. The original plans would have raised Lake Manapōuri by up to 30 metres. A 1970 petition against raising the lake gathered 264,907 signatures, and in 1972 the Government confirmed the lake would not be raised; in February 1973 it created the Guardians of Lakes Manapōuri, Monowai and Te Anau. Engineering New Zealand says many consider the project the birth of New Zealand's environmental movement.
On the way to Doubtful Sound, RealNZ's boat crosses the lake to West Arm in about 45 minutes; there the station sits inside the mountain, and guides explain its history. The coach then crosses the Wilmot Pass Road, built in the 1960s to carry equipment for the station.
Our Milford Sound vs Doubtful Sound guide compares the fiords, and our Queenstown to Milford Sound planner covers the road through Te Anau.
Questions visitors are asking
Is Manapōuri New Zealand's biggest power station?
No, but it is the biggest hydro station. Meridian says Manapōuri in Fiordland is the largest hydro power station in New Zealand, with a maximum continuous rating of 850 megawatts. Genesis Energy says that by capacity Huntly, at 1200MW, is Aotearoa's largest power station of any kind.
How deep underground is Manapōuri Power Station?
Meridian says the generating units at Manapōuri Power Station in Fiordland sit in a cavern excavated from rock about 200 metres below the surface of Lake Manapōuri. Engineering New Zealand says the machine hall is reached by a 2 km spiralling road tunnel, or by a lift that drops 193 m from the control room.
When was Manapōuri Power Station built?
Construction began in 1964, and Meridian says the project took 1,800 workers eight years in extremely harsh Fiordland conditions. Power was first generated in September 1969, and the station became fully operational in 1972 when its seventh generating unit was commissioned. Engineering New Zealand says 18 workers died on the project.
Why does Manapōuri matter to New Zealand's environmental movement?
The original plans for Manapōuri Power Station in Fiordland would have raised Lake Manapōuri by up to 30 metres. A 1970 petition against raising the lake gathered 264,907 signatures, and in 1972 the Government confirmed it would not be raised. Engineering New Zealand says many consider the project the birth of New Zealand's environmental movement.
Can visitors see Manapōuri Power Station?
Not inside, as far as we could confirm: none of the sources we read offers public tours of the underground station, so check with Meridian Energy, which runs it. Visitors to Doubtful Sound do pass it. RealNZ says its boat crosses Lake Manapōuri to West Arm, where the station sits inside the mountain and guides explain its history.