Manapouri Power Station, New Zealand
There’s just one slight difference between the Hoover Dam and this power plant in New Zealand: the latter is located below ground in the middle of New Zealand’s Fiordland National Park. Housed in a 364-foot-long, 128-foot-high cavern excavated from a solid granite mountain, the station sits nearly 700 feet below the surface of Lake Manapouri.
Manapouri’s initial capacity was to be 700,000 kilowatts. But due to a design problem, the station’s operators risked flooding the powerhouse if they ran the station at so great an output. This went on for 30 years, until the construction of a new tunnel in 2002 pushed the station’s maximum generating capacity to 850,000 kilowatts. Today, Manapouri generates enough electricity each year to power 591,000 homes.
Looking out at the lake, no one would know there was a massive generator churning away in the depths of the water. The only visible hints include a nearby control center building, a switchyard and a pair of transmission lines looping across the lake to link up with the country’s power grid. To reach the cavern for a four-hour-long tour, visitors are ferried 22 miles across the lake to its eastern end. There, they have two options to reach the heart of the plant: They can board a car that zooms down a 1.2-mile spiraling tunnel, or take a two-and-a-half minute elevator ride that descends a distance equivalent to a 70-story building.