Highbank Power Station

This is the Highbank Power Station, a run-of-the-river hydroelectric station in New Zealand's South Island, owned by Manawa Energy. It uses water from the Rangitata Diversion Race, or RDR, which was originally built for irrigation, not power. The station generates electricity when there isn't much demand for agricultural water, usually in the winter, and then it discharges that water into the Rakaia River.

Work on the power station began in the early 1940s, starting with an access road. World War II caused delays due to manufacturing, material, and manpower shortages. There was even a ship carrying the generator's stator that was sunk by enemy action, which meant a new one had to be made in England. Flooding in February 1945 also caused significant damage, forcing the village of Highbank to move about 390 meters upstream from the powerhouse. The station was finally opened on June 16, 1945, by Minister of Works Bob Semple.

The powerhouse structure itself was finished in 1942. It's a reinforced concrete building, about 37 meters long, 16 meters wide, and 16 meters high. This height allowed for a 90-ton crane and a 10-ton auxiliary hoist to be installed. Both the generator and the turbine were made by English Electric, and they were installed between 1942 and 1945. At the time, the generator was the largest single generating unit in New Zealand. It's a 26.5 MW unit driven by a 36,000 bhp Francis turbine.

In the 1970s, the station's capacity dropped quite a bit due to sediment and wear, so the turbine runner was replaced, and they improved sediment control. More recently, in 2010, the station got an upgrade with a new pump station. This allows water to be pumped from the Rakaia River back up the penstock and into the RDR, which helps with agricultural irrigation during the summer. They've also been doing a major upgrade since November 2024, replacing the original turbine and generator with a new 29 MW unit, which should be done by May 2026. This is expected to increase output by 8 GWh per year.