Since as the 6th century AD. The

Since earliest
times, man has harnessed the power of the wind, with the first mill recorded as
long ago as the 6th century AD. The technology has diversified over the years
to include pumping water, grinding grain, powering sawmills and most recently
generating electricity, now the fastest growing energy sector worldwide.1

Today
there are various types of wind turbines in operation, (fig. 1 gives an
overview). The most common device is the horizontal axis wind turbine. This
turbine consists of only a few aerodynamically optimized rotor blades, which
for the purpose of regulation usually can be tumbled about their long axis
(Pitch-regulation). Another cheaper way to regulate it, consists in designing
the blades in such a way that the air streaming along the blades will go into
turbulence at a certain speed (Stall-Regulation). These turbines can deliver
power ranging from 10 kW to some MW.

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An LED lighting initiative is a common
attempt to reduce the energy consumption. By installing energy-efficient LED
lighting technology, we can lower energy consumption, decrease maintenance
costs, and lessen wear and tear on heating and cooling systems. As one of the
least risky sustainability practices with a rapid return on investment of less than
three years in many cases. LEDs have longer lifespans and lower energy
consumption levels than conventional bulbs. A major advantage of an LED is low
energy consumption and operation lifetime with no or minor maintenance when
compared to traditional lighting, such as HIDs, incandescent, fluorescent, etc.
The cost of LED lighting may be an issue when a major retrofit is planned on
campuses, but the payback will be around three or four years, depending on
capacity of the LED lighting deployed. LED lights are similar to typical light
bulbs, with the main difference being that they do not have a filament in
them—the reason why they burn for so long. Because LEDs do not use a filament,
they also do not get hot, and they run on less electrical power, making them
more energy-efficient

of interconnection. Small wind turbines
produce a variety of voltages and some produce DC power. Small wind turbines
generally require an inverter to match the power output with the load and/or
interconnection frequency and voltage.

Wind turbines produce electricity by
using the natural power of the wind to drive a generator. The wind is a clean
and sustainable fuel source, it does not create emissions and it will never run
out as it is constantly replenished by energy from the sun. Blades capture
energy in the wind and turn the turbines. Control mechanisms point the blades
into the wind (yaw control) and, on large wind turbines, adjust the pitch of
the blades (blade angle) as wind speeds change. Typically, a gearbox connects
the shaft from the blades (rotor) to the electrical generator. The electrical
generators used on wind turbines may either be induction generators or
synchronous generators. The electrical power from the generator is typical 60
Hz, AC power with 600V output for large wind turbines. A transformer may be
required to increase or decrease the voltage so it is compatible with the
endues, distribution or transmission voltage, depending on the type