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 A little napkin math tells us that a modern wind turbine will power roughly 232 homes. 2  A little bit more math tells us that it will cost around $12,900 per home to erect the wind turbine. 3  A little bit more math tells us that this works out to around $646 per year of life.  So that's it.