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The New Independent Home
by Michael Potts
from chapter 3 :
Generators:
Turning Spin Into Flow |
PV is magical, but most electricity is generated comparatively simply. Because electrons roam relatively freely in a conductor; large groups of them can be induced to flow by exposing them to the flux of a moving magnet. A generator is simply a magnet and a coil of wire, one held steady while the other is rotated, inducing electrons to flow through the coil. When the coil's output is connected to a circuit, electricity flows.
Wind power is a perfect example of transforming a linear flow -- wind -- into rotational power using a rotor. Hydro power transforms linear stream flow into rotational power using a turbine. Dirtier techniques convert combustion directly or indirectly into rotation using a piston-crankshaft arrangement. Rotational power is then harnessed to a generator, which produces a flow of electrons.
Wind power typically requires a "power wind" with minimum average speed of ten miles per hour (quite a windy site) to be economical. Wind and photovoltaic often make good partners, because wind frequently blows when the sun is not shining.
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