I ran across this lightweight electricity-generating wind turbine at the Green Festival in San Francisco today.
Size:Blade/Ring Diameter: 7 feet/ Minimum clearance from roofline: 2 feet
Rated power output: 1.5kW @ 14 m/s / Annual Power Supplied: up to 2000 kWh
Electric power: 240VAC, 60Hz output voltage / can feed into grid
Noise: less than 35 decibels for all wind speeds
More info at: https://www.swiftwindturbine.com