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.
Larger wind turbines are put on taller pillars, and the wind speed up there is usually somewhat higher. Nevertheless, the power production per unit area of land is not particularly impressive. Wind farms in the US produce power at the average rate of about 1.2 watts per square meter (about 5000 watts per acre).