The Mysteries of Life with Tim and Moby:
Wind Energy
That’s a good question! First, some history…
It may seem strange to think of wind as a source of energy, but we’ve been harnessing it
for thousands of years. In ancient Egypt, people used wind to power their sailboats along the
Nile river. The first windmills were used in Persia - in today’s middle east region - about 1,500
years ago. Primitive windmills looked sort of like egg beaters and they were mainly used for
grinding grain and drawing water from wells. Later, people from Western Europe improved on
the technology by making propeller-style blades out of sails.
Ancient Egypt
Persia
Western Europe
Today, modern wind turbines are strong, sleek, and well-suited for
converting the force of wind into energy.
- - Beep?
Well, the rotor blades are aerodynamically shaped to make them
really efficient. The blades convert the wind’s energy into a rotational energy called “torque”.
How much torque is produced depends on three things:
1. Air density,
2. Wind Speed,
3. Length of the Rotor Blades
Torque = A twisting
force that tends to
cause rotation
Rotor Blade = Turbine Blade
As each of these factors increases, so does the amount
of power produced.
When strong winds blow against a turbine, the force
causes the rotors to turn pretty quickly.
Inside the turbine, a generator converts the movement
into electricity.
That electricity can be sent through power lines to light
up your house! - - Beep?
Actually, there are lots of places where you can see wind
turbines at work, but one of the most dramatic is called a
wind farm.
- - Beep!
No, they don’t grow wind in a wind farm, but it’s a place where electricity is made from wind.
Wind farm typically have at least a couple dozen
turbines that are positioned to take advantage of
local wind patterns.
- - Beep!
Good point! Many people think it’s a good
idea to invest in renewable energy sources
like wind, which is clean, and relatively
cheap to generate.
A renewable energy source is a source of energy that for all practical purposes never runs out
- like wind or solar energy. That’s in contrast to fossil fuels like coal and oil, which the earth
only has finite amounts of.
Right now, only about 1% of all the power we use is America is created
by wind. Even so, the United States is the second-highest producer of
wind energy in the world. And since North America has more sites
suitable for wind farms than any other continent, our wind power
output should have no problem growing!
- - Beep?
Yeah, there are a few drawbacks to getting electricity from wind. For one thing, some people
think turbines are ugly, and they don’t want to look at them all day. Other people worry that
wind turbines are dangerous to flying animals, like birds and bats. Some studies suggest that
the numbers of animals hurt by wind turbines is fairly small. But it is a real problem that the
wind energy industry is looking into.
-- Beep!!
Nah, it’s windy out here, but it’s not that . . . windy. . .
Wind Power Vocabulary Terms: These are the parts of a Wind Turbine
1. Rotor blades (Turbine) - capture wind's energy and convert it to rotational energy.
2. Hub (outside cover) and 4. Rotor hub (inside) - this is the center of the actual turbine,
where the wind shaft and turbine are connected
3. Nacelle - The structure that holds the gearbox and generator, plus the brakes for the system
5. and 8. Brakes - these will keep the speed of rotation within safe limits so the equipment
isn’t damaged.
6. Low Speed (“wind”) shaft - connects the turbine and gearbox
7. Gearbox - increases the speed of the wind shaft to make the generator turn faster.
9. High Speed (“generator”) shaft - connects the gearbox and generator
10. Generator - Generates electricity using copper wires and magnets.
11. Tower - supports the turbine and nacelle and lifts entire setup to higher a elevation so the
blades can safely spin
12. Transformer: Inside the transformer, the electricity from the turbine is converted to a
voltage that we can use for power.
Rotor Blades
Hub (outer cover)
Nacelle
Hub - Inside View
Brakes - Turbine Side
Low Speed (Wind Speed) Shaft
Gear Box
Brakes - Generator Side
High Speed (Generator Speed) Shaft
Generator
Tower (250 feet on average)
Transformer (increases the voltage
so the electricity can travel along power lines)
Axis - an
imaginary
line that runs
through the
center of a
turbine.
Gear Ratios:
In order to make wind power useful, we use gears. One gear is attached to the TURBINE
and so it rotates at WIND SPEED. The other gear is attached to the GENERATOR. It will
be smaller than the TURBINE GEAR, so it will be rotating FASTER!
Calculate the speeds for these gear sets…
1) Example: If Gear A is rotating at 10 miles an hour,
Ratio = 1:2
Gear B =
10 mph
x
2
=
20 mph
2) If Gear A is rotating at 18 miles an hour,
Gear B =
A
x
=
3)If GEAR B is rotating at 50 miles an hour,
B
(Every time A rotates1 time, B
rotates 2 times)
Gear A =
÷
=
1) Example: If Gear A is rotating at 10 miles an hour,
Ratio = 1:1.5
Gear B =
10 mph
x
1.5
=
15 mph
A
2) If Gear A is rotating at 24 miles an hour,
B
(Every time A rotates1 time, B
rotates 1.5 times)
Ratio = 1:5
A
Gear B =
x
=
3)If GEAR B is rotating at 75 miles an hour,
Gear A =
÷
=
1) Example: If Gear A is rotating at 10 miles an hour,
Gear B =
10 mph
x
5
=
50 mph
2) If Gear A is rotating at 45 miles an hour,
Gear B =
B
=
3)If GEAR B is rotating at 85 miles an hour,
Gear A =
(Every time A rotates1 time, B
rotates 5 times)
x
÷
=