Transcript What is Electricity?

Wind Energy
Basics
The Kidwind Project
www.kidwind.org
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
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Faraday Effect
• Faraday Effect
• Basic Concepts
• Voltage – V – Potential to Move Charge (volts)
• Current – I – Charge Movement (amperes or amps)
• Resistance – R – V = IxR (R in =ohms)
• Power – P = IxV = I2xR (watts)
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How Does a Generator Work?
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Electricity!
More efficient light bulbs are great, but what is
the BEST way to conserve electricity and reduce
our consumption of fossil fuels???
• How much would it cost to run this
100 Watt bulb for a full day (24 hrs)?
• What about this 25 Watt CFL light
bulb, which produces the same
amount of light?
• 100 Watts x 24 hours = 2400 Watt Hours
(2400 Watt Hours = 2.4 Kilowatt Hours)
• 25 Watts x 24 hours = 600 Watt Hours
(600 Watt Hours = 0.6 Kilowatt Hours)
• 2.4 kWh x $0.08/kWh = $0.19
TURN IT OFF!!!
• 0.6 kWh x $0.08/kWh = $0.05
Be conscious of your energy choices!
Where do we get our electricity?
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What is a Fossil Fuel???
Fossil fuels come from the fossilized
remains of plants or animals: coal,
oil, natural gas. They will eventually
be used up.
What is “Renewable Energy?”
Renewable energy sources
can’t be “used up”: solar, wind,
geothermal
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KidWind Project | www.kidwind.org
KidWind Project | www.kidwind.org
Early “Windmill” in Afghanistan (900AD)
Jacobs Turbine – 1920 - 1960
WinCharger – 1930s – 40s
Smith-Putnam Turbine
Vermont, 1940's
Modern Windmills
Orientation
Turbines can be categorized into two overarching
classes based on the orientation of the rotor
Vertical Axis
Horizontal Axis
Vertical Axis Turbines
Advantages
Disadvantages
• Omnidirectional
• Rotors generally near ground
where wind poorer
• Centrifugal force stresses
blades
• Poor self-starting capabilities
• Requires support at top of
turbine rotor
• Requires entire rotor to be
removed to replace bearings
• Overall poor performance
and reliability
• Have never been
commercially successful
(large scale)
– Accepts wind from
any angle
• Components can be
mounted at ground
level
– Ease of service
– Lighter weight
towers
• Can theoretically use
less materials to
capture the same
amount of wind
Horizontal Axis
Wind Turbines
• Rotors are usually Up-wind
of tower
• Some machines have
down-wind rotors, but
only commercially
available ones are small
turbines
• Proven, viable technology
Modern Small Wind Turbines:
High Tech, High Reliability, Low Maintenance
• Technically Advanced
• Only 2-3 Moving Parts
• Very Low Maintenance
Requirements
• Proven: ~ 5,000 On-Grid
• American Companies are the
Market and Technology
Leaders
10 kW
400 W
50
kW
900 W
(Not to scale)
Over-Speed Protection During High Winds
Upward Furling: The rotor tilts
back during high winds
Angle Governor: The rotor turns up and to one side
Carnage!
Wind Turbine Destruction
Yawing – Facing the Wind
• Active Yaw (all medium &
large turbines produced
today, & some small turbines
from Europe)
• Anemometer on nacelle tells
controller which way to point
rotor into the wind
• Yaw drive turns gears to point
rotor into wind
• Passive Yaw (Most small
turbines)
• Wind forces alone direct rotor
• Tail vanes
• Downwind turbines
Wacky Designs out there…
Large Wind Turbines
•
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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
Wind Turbine Perspective
Workers
Blade
112’ long
Nacelle
56 tons
Tower
3 sections
Types of Electricity Generating Windmills
Small (10 kW)
Intermediate
(10-250 kW)
• Homes
• Farms
• Remote Applications
• Village Power
• Hybrid Systems
• Distributed Power
(e.g. water pumping,
telecom sites,
icemaking)
Large (250 kW - 2+MW)
• Central Station Wind Farms
• Distributed Power
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Parts of a Wind Turbine
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Calculation of Wind Power
•Power
inWind
the wind
Power
in the
= ½ρAV3
Effect of air density, 
– Effect of swept area, A
– Effect of wind speed, V
R
Swept Area: A = πR2
Area of the circle swept
by the rotor (m2).
Importance of Wind Speed
• No other factor is more
important to the amount of
power available in the wind
than the speed of the wind
• Power is a cubic function of
wind speed
– VXVXV
• 20% increase in wind speed
means 73% more power
• Doubling wind speed means
8 times more power
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Jobs in the Wind Industry
Construction
Public Relations/Organizing Support
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Operations/
Maintenance
Maintenance
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Engineering/
Design
Environmental Impact Assessment
Wind Power is Fun!
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Wind Turbine Project
• Each table group will design and build the blades for one hub
• Hubs will be mounted on each of three different towers, and the
electrical output will be measured and recorded
• Each table group will get three pieces of tag board, 7.5 x 23 cm,
which can be cut and shaped in any way that the group members
wish
• The three pieces of tag board will form three blades on one hub
• Your group must decide on the shape and sizes of the blades, and
the pitch (angle) of the blades
• On a age in your notes, create two scale drawing of your group’s
blade design
– Show both front and side view of the hub and three blades
– Give the pitch of the blades as part of the side view
Questions???
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