Porcupines' quills, or spines, take on various forms, depending on the species, but all are modified hairs coated with thick plates of keratin, and embedded in the skin musculature.
Produce up to 400-Watt of power for free in your own back yard. The wind turbine will produce more power up to 400-Watts at 28 mph. If the wind dies down the turbine will continue to produce power in winds as low as 5.6 mph. This wind generator is used to charge 12-Volt batteries and mounts on any 1.5 in. Schedule 40 pipe.
The power a wind turbine can generate is proportional to the cube of the wind speed (until you reach the maximum power limit of the generator attached to the turbine). But even if you ask for the average of the cube of the wind speed, that really isn't all that useful either. Anyone wanting to build a wind turbine will look for sites where the wind speed is high a lot of the time. They won't put it where the winds are average.