A wind turbine converts the kinetic energy of wind into rotational shaft energy using blades or sails to spin a generator that produces electricity. Wind turbines come in small, intermediate, and large sizes to provide power for homes, farms, villages or large centralized wind farms. The key components of a wind turbine are the blades, shaft, generator, tower and foundation. Wind speed, air density, and the surface area swept by the turbine blades determine the amount of power that can be captured from the wind.
4. A windmill is a mill that converts the
energy of wind into rotational energy by
means of vanes called sails or blades.
Centuries ago, windmills usually were used
to mill grain, pump water, or both.
5. wind turbines operate on a
simple principle. The
energy in the wind turns two
or three propeller-like
blades around a rotor. The
rotor is connected to the
main shaft, which spins a
generator to create
electricity.
6. The purchase and installation of very small (<1
kW) off-grid turbines generally cost $4,000 to
$9,000, and a 100-kW turbine can cost $350,000.
The federal government and many states have
rebate or tax credit programs in place to
encourage investment in small wind.
7. What is Electricity?
Electricity is energy
transported by
the motion of electrons
**We do not make electricity, we CONVERT
other energy sources into electrical energy**
Conversion is the name of the game
9. • Wind power generators
convert wind energy
(mechanical energy) to
electrical energy.
• The generator is attached at
one end to the wind turbine,
which provides the
mechanical energy.
• At the other end, the
generator is connected to the
electrical grid.
• The generator needs to
have a cooling system to
make sure there is no
overheating.
11. Types of Electricity Generating Windmills
Small (≤10 kW)
• Homes
• Farms
• Remote Applications
(e.g. water pumping,
telecom sites,
icemaking)
Large (250 kW - 2+MW)
• Central Station Wind Farms
• Distributed Power
Intermediate
(10-250 kW)
• Village Power
• Hybrid Systems
• Distributed Power
15. Large Wind Turbines
• 450’ base to blade
• Each blade 112’
• Span greater than 747
• 163+ tons total
• Foundation 20+ feet deep
• Rated at 1.5 – 5 megawatt
• Supply at least 350 homes
16. Calculation of Wind Power
•Power in the wind
Effect of air density, ρ
– Effect of swept area, A
– Effect of wind speed, V
R
Swept Area: A = πR2
Area of the circle swept
by the rotor (m2
).
Power in the Wind = ½ρAV3
This is the equation for the power in the wind. (Don’t fear – there are only 2 equations in this presentation.) Each of the terms in this equation can tell us a lot about wind turbines and how they work. Lets look at wind speed (V), swept area (A), and density (Greek letter “rho,” ) one at a time.
First, let’s look at wind speed, V. Because V is cubed in the equation, a small increase in V makes for a increase in power. (illustrated on next slide)
(Click on the links at the bottom to get the values of both k and .)