Electricity from windmills
|Grandpa's Knob in Vermont was the site of a large
(1.5 megawatt) electricity-producing windmill just before World War-II.
It was finished on October 19th, 1941, and produced electricity for 16
months before a blade failure disabled the windmill.
In a total of 695 hours of operation, it produced just under 300,000 kilowatt-hours of electricity.
In 16 months, there are over 11,000 hours, of which the windmill actually operated for 695, about 6% of the total hours.
The electrical production was about 300,000 kWh. A true 1.5 megawatt producer of electricity working for the same 695 hours would produce over 1,000,000 kWh, so when the windmill was actually operating, its output was about 30% of capacity.
Overall, the output was 6% of 30% of capacity, namely about 2% of the output one should expect from a 1.5 MW unit operating around the clock at full capacity.