Business South April 2022

38 | Meridian Energy - Manapōuri Power Station REGIONAL DEVELOPMENT Milestone for iconic power station Richard Loader Manapōuri is New Zealand’s largest hydroelectric power station, with its seven 125-megawatt generating units housed in a cavern 200 metres below the lake surface. As with so many special events over the last couple of years, celebration of Meridian Energy’s Manapōuri Power Station’s 50th anniversary in 2020 was put on hold due to the impact of Covid-19. The event was to have included a large gathering and special dinner in Te Anau, with those who worked on the construction of the station, or worked at the station during the past five decades, and their families on the invitation list. In its place anniversary tours were run over three weekends in May of 2021 and included a tour of the underground power station and a coach tour to Deep Cove. Of the 1800 men who endured the harsh conditions working on the station construction from 1963 to 1972, about 30 attended the event and were awed by how regenerating natural bush now covered the piles of spoils extracted during tunnelling, leaving no trace of the work that had been done, other than the power station itself sited deep within a cavern at West Arm. Hugging the edge of Lake Manapōuri’s West Arm in the Fiordland National Park, which has UNESCO World Heritage status, Manapōuri is New Zealand’s largest hydroelectric power station, with its seven 125-megawatt generating units housed in a cavern 200 metres below the lake surface. Primarily designed to power the Aluminum smelter at Tiwai Point, the electricity goes into the national grid. With an operating maximum station output of 800 megawatts, on average Manapōuri generates enough electricity each year to power 619,000 Kiwi homes. Commencing in 1963 with three construction phases costing $135.5 million, the original construction of the hydro station was a significant engineering achievement. Over the eight to nine years the project took to complete it consumed eight million work hours in extremely harsh conditions. Sadly, sixteen workers lost their lives during the project. The project involved constructing the power station 200 metres below a granite mountain in an underground cavern. Several access and service tunnels were built and the 10-kilometre tailrace outflow tunnel was excavated to take the water that flows out of the station into Deep Cove in Doubtful Sound. The first power was generated in September 1969, with the installation of two generating units. The station became fully operational in 1972 when the seventh and final generating unit was commissioned. Site Manager Blair Falconer paints an insight into what it would have been like for those hardy souls working on the power station. “It would have been cold, dark, wet and loud. There were no sophisticated boring machines in those days and no PPE gear. Tunnelling was completed using drill and blast excavation methods to carve through hard Fiordland rock. “Working in a very remote location the workers faced transport and logistics challenges and had to stay in hostels or a boat in Deep Cove without family for long periods of time. They would’ve endured the constant irritation of sandflies and very wet weather. They say West Arm normally gets four metres of rain a year and Doubtful Sound gets eight metres.” Construction of a second tailrace outlet tunnel commenced in 1997 and was completed in 2002, increasing capacity to 850MW, although it is limited to 800MW due to resource consent conditions. Before the new tailrace outflow was complete, Meridian embarked upon a $98m project to refurbish, upgrade and automate the plant equipment to maximise the benefits of more available head. The head is the height difference between where the water enters the intakes and where is leaves it. The plant was automated and the station operates remotely from Wellington at night. Reflecting on what it is like to work in such an iconic piece of New Zealand infrastructure and engineering achievement, Blair says the power station speaks of the of the resilience and mental toughness of the 1800 souls who did the hard mahi under extraordinary conditions. “But it’s a great place to work in a National Park and World Heritage area. “We have a boat trip every day out to the station — people pay good money to do the same trip we do every morning.” OWNER / OPERATORS • GRANT & ANGIE NEWTON Phone 03 249 6644 After Hours 027 352 1689 Proud to be associated with Meridian Energy Telfer Electrical Timaru Ltd, 10 Barnard St, Timaru |