First megawatt wind turbine
Smith-Putnam Wind Turbine, Palmer Cosslett Putnam
first first
United States (Grandpa's Knob)

The first wind turbine to generate more than 1 MW of electricity was the 1.25-MW Smith–Putnam wind turbine, erected on a hill called Grandpa's Knob in Vermont, USA, and synchronized with the local power grid on 19 October 1941.

The turbine was designed by American engineer Palmer Cosslett Putnam, whose design was inspired by the simple battery-charging windmills used by isolated homesteaders out in the Great Plains. It used manufacturing techniques developed for the aviation industry and featured two 66-ft (20-m) blades attached to a rotor hub some 120 ft (36 m) above the ground.

The turbine ran from October 1941 to February 1943, when a bearing failed. As this was at the height of World War II, no replacement bearing could be supplied, so the machine sat idle until 3 March 1945, when it was finally replaced. It ran for another three weeks before suffering a catastrophic failure on 26 March 1945. One of the blades failed on the site of an old repair (it wasn't possible to fix it properly, again because of wartime shortages) and was launched 750 ft (229 m) through the air.

The project won praise from influential technologist Vannevar Bush (who oversaw all US research and development projects during World War II) but following its public failure (and against a backdrop of low energy costs) Putnam was not able to attract investors to build a follow up.