Grandpa’s Knob, Vermont (43° 38' 4.99"N, 73° 10' 50.02W), the 1,976-foot summit, at Castleton near Rutland, where the first large-scale electricity-producing windmill in the United States began operating on October 19, 1941. The 1.25 megawatt turbine was financed by the Pennsylvania firm Morgan Smith Company and built by Palmer Coslett Putnam. It supplied energy to the New England power grid for a brief period during World War II, generating enough electricity to power about one thousand Vermont homes.
The turbine was a downwind machine with two 75-foot-by-11-foot pitchable blades, each weighing eight tons, and a synchronous generator. With the prospects of the United States entering into war ever-looming, the nation looked towards securing its electrical generating facilities, and scattered wind turbines on top of hills were less vulnerable to air attack. The blades churned out electricity in winds of 70 miles per hour and withstood gales of 115 mph. In February 1943, power generation ground to a halt as a main bearing failed. Since the country was in the midst of war, a replacement part took more than two years to manufacture and install. Operators restarted the turbine after its long hiatus on March 3, 1945. Later that month, a metal connector cracked causing one of the eight ton blades to be tossed over 700 feet, landing on its tip.
The blade failure would mean the end of the project since wartime shortages made steel a luxury. Replacing the blade would not have been possible at the time. With coal prices substantially cheaper than the price of electricity produced by the wind turbine, the will to continue the project was not adequate and the project was dismantled. Nevertheless, the experiment at Grandpa’s Knob was a success in the sense that it demonstrated the feasibility of generating power from a large scale turbine that fed power to the local electrical grid.
- Breezin' through history: Vermont pioneered wind energy atop Grandpa's Knob in 1940s, Rutland Herald, November 4, 2004.