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.
Small and intermediate turbines make up the bulk of the older installed turbine base, but new turbines installed in the late 1990s are generally 600 kW and larger. Utility-scale wind farms are generally located in areas with average annual wind speeds of at least 13 miles per hour.