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.
An average onshore wind turbine with a capacity of 2.5â3 MW can produce more than 6 million kWh in a year â enough to supply 1,500 average EU households with electricity. An average offshore wind turbine of 3.6 MW can power more than 3,312 average EU households. In 1985, wind turbines were under 1 MW with rotor diameters of around 15 metres. In 2012, the average size is 2.5 MW with rotor diameters of 100 metres. 7.5 MW turbines are the largest today with blades about 60 metres long â over half the length of a rotor diameter of over 120 metres â longer than a football field.