Manapouri Hydropower: Sustainable Awakening in New Zealand
Environmental champions managed to save Lakes Manapouri and Te Anau.
In this week’s Dispatch from New Zealand, I want to share a sustainability story from the fiordlands of the South Island about the power of environmental champions to protect our world. Although this story played out in the 1960s and 70s, it is still relevant today as we choose where and how to build the massive renewable power projects we’ll need to transition to a clean energy economy successfully.
Deep in the mountain at the end of Doubtful Sound is the 850 MW Manapouri Power Station—New Zealand’s largest. It takes advantage of the fact that Lake Manapouri, with a surface elevation 178 meters above sea level, is on one side of a mountain, with the sea at sea level on the other side. Dig a tunnel through the mountain, let a little lake water off the top drop down to the sea, and voilà, sustainable, clean power!
The thing about hydropower is that the further the water falls, the more power you get. One hundred seventy-eight meters is pretty good, but why not go for a full 200 meters or more? Build a dam, turn two large natural lakes (Manapouri and Te Anou) into one massive artificial lake, and get more power. That was the original plan: the Manapouri Power Station was designed to provide cheap power to smelt Australian bauxite into aluminum, so the more power, the better.
But then an unexpected thing happened: Forest & Bird, an environmental group, got wind of the plan and asked, “Why can’t we have a little less power, no dam, and keep our two beautiful natural lakes?” Thanks to the efforts of a colorful cast, including a Southland sheep farmer and former bomber pilot named Ron McLean, who gave a six-week speaking tour around the country with his high-school-age daughter handling the slide projector, by the end of the Save Manapouri campaign almost 10% of the entire population of the country had signed the petition.
Two accounts of this story I found full of particularly fascinating details: The Politics of Manapōuri and Manapouri Damning the Dam. The dam did not get built, but the power station did, and so did the aluminum smelter on Tiwai Point. The world now has millions of tons of aluminum produced from renewable power. But perhaps an even more durable legacy from how the power potential of Lake Manapouri was developed is the high regard for the natural environment that was awakened in New Zealand and the positive example it has set for other countries as they develop their own renewable resources.