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.
1 In 2007, average cost per kilowatt hour of electricity generated by utility-scale wind turbines was 4â7Â¢ per kilowatt hour.  One 10 kilowatt wind turbine system, operating at a site where the average wind speed is at least 12 mph, can generate around 10,000 kilowatts per year.