Turgo Turbine

The Turgo turbine is an impulse water turbine designed for medium head hydropower sites, typically those with a net head between 15 and 300 meters, that reaches efficiencies of about 87 percent in the field and up to 90 percent under laboratory conditions. The British engineering firm Gilkes developed the design in 1919 as a direct modification of the Pelton wheel, angling the jet of water to strike the runner buckets from one side so the water can pass through and exit on the other, which lets a Turgo runner handle a greater flow of water than a Pelton wheel of the same diameter. Because its runner costs less to manufacture than a Pelton wheel and it does not need the airtight housing a Francis turbine requires, the Turgo turbine fills the cost and performance gap between those two established designs, occupying the medium head range where their operating ranges overlap. The design has since become especially popular for small scale hydroelectric projects, where its lower generator and installation costs make marginal sites economically viable.