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Professor Quester Answers
Questions on Wind Energy
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Dear Dr. Q:
I am doing a science report on wind energy and I have looked at your sight under this
subject. The only thing that I don't think was made clear was exactly how the wind energy
was turned into electricity in the generator located inside the wind turbine. Does the
high speed shaft create heat that somehow turns into electricity? Please explain! Thank
you. (Alexandra, 8th grade, New York City.)
The Professor Answers:
Good observation ...actually the shaft does create some heat however that's
not what makes electricity. A generator (attached to the shaft) produces
electricity using electromagnetism. When metal moves through a "magnetic
field," a voltage is produced. Voltage is a measure of electric energy.
These types of generators (also known as dynamos) have a huge magnet
surrounding many coils of wire. The shaft spins this coil of wire at very
high speeds between the poles (positive and negative) of a magnet
generating an electric "field" or current. The first dynamo was invented by
Zenobe Gramme in 1870. Good luck on your science report.
Dear Dr. Q:
How and when did someone figure out that they could use wind as a type
of energy? (Connor, 5th grade, Lafayette)
The Professor Answers:
I don't think it was a particular person that thought of using the wind as
an energy source. Well, maybe it was someone particular but we don't know
his or her name. Ancient people (we're talking several thousand years ago)
could see that there was tremendous force in the natural motion of wind and
water. Although they had no scientific understanding of energy, they
realized they could harness these natural forces to do some heavy work.
Early civilizations used "mechanical energy" to do work like lifting,
grinding grain, building and transporting people and goods. This mechanical
energy was from wind or water.
One of the earliest forms of wind power was used to move boats with cloth
sails as long ago as 3500 BCE. On land, the first windmills seem to have
been used in Persia (that's Iran and Iraq today) around 700 Common Era.
Wind power was also used for irrigating dry land and draining wet land.
More recently wind is used as an alternative energy source to generate
electricity.
Dear Dr. Q:
How many lights can one wind mill light up?
The Professor Answers:
Wind turbines (people in the wind business like to call them wind turbines instead of
windmills) usually produce about 50 to 300 kilowatts of electricity each. A kilowatt is
1,000 watts (kilo means 1,000). You can light ten 100 watt light bulbs with 1,000 watts.
So, a 100 kilowatt (100,000 watts) wind turbine could light up 1,000 light bulbs that use
100 watts. More than are in your home.
Thanks for asking and check out more wind information from
The Energy
Story.
Dear Dr. Q:
How do windmills work? (Nicole, 5th grade, Lafayette, CA)
The Professor Answers:
Very simply, blowing wind spins the blades on a wind turbine -- just like a
large toy pinwheel. The spinning blades turn a generator that makes electricity.
Check out
The Energy Story (Chapter 16 on Wind Energy) for some pictures and more
details on how a wind turbine makes electricity.
If YOU have a question about energy, send your question by e-mail to
"Professor Quester."
Ask your parents or teacher first before sending an e-mail. Please tell us your grade level, the name of your school and your city. We will usually respond within
four or five days.
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