Deriaz Turbine

The Deriaz turbine, presented by the engineer Paul Deriaz and patented in 1957 after being described in the technical literature in 1955, was the first diagonal flow hydraulic pump turbine ever designed, moving water along a path that combines axial and radial flow diagonally rather than purely along one axis or the other. Like a Kaplan turbine it has runner blades that can be adjusted for efficiency as the flow rate changes, and combining that adjustable runner with moving guide vanes lets it perform well across a wide range of operating conditions in both pumping and generating modes; a more modern fixed blade variant instead varies runner speed electronically through an inverter rather than adjusting the blades mechanically. Its versatility under partial load makes it well suited to pumped hydro energy storage and to any system with fluctuating demand, and an installed example runs at the Sir Adam Beck Pump Generating Station at Niagara Falls.