Download Harnessing the Wind`s Energy How It Works

Harnessing the Wind’s Energy
How It Works
Anatomy of a Typical 1.5 MW Wind Turbine
• Turbine Weight: 480,500 lbs
• Tower: Tubular steel
• Tower Height: 255 ft 7 in
• Tower Diameter (base): 15 ft
• Tower Weight: 276,000 Ibs
The Blades
Typical 1.5 MW Wind Turbine Blades
• Composite fiberglass
• Length: 135 Ft.
• Diameter: 6 Ft.
• Weight: 14,000 (each blade)
The Rotor
Typical 1.5 MW Wind Turbine Rotor
A rotor is composed of three
blades and has a diameter of
approximately 270 feet
25% longer than the wingspan of
a Boeing 747-400 jumbo jet.
The Hub
Typical 1.5 MW Wind Turbine Hub
• Weight: 37,000 Ibs
• Diameter 10ft
The Nacelle
• Sits on top of the tower and houses the power train
• The nacelle is approximately 13 ft wide, 13 ft tall and 26 ft long.
Tracking the Wind
• A wind turbine continually tracks the wind
through an on-board computer which
monitors the wind direction sensor and an
anemometer for measuring wind speed.
• Once the wind reaches (approximately
3.5m/s or 8 mph), known as cut in speed,
the blades will pitch, to full power position,
and the turbine will begin generating
electricity.
• The nameplate rating of a modern turbine
is typically between 1,500 kW and 3,000
kW.
• A typical 1.5 MW turbine annually
produces enough electricity to meet the
average annual demand of about 750 U.S.
homes.
Understanding Wattage
What is a megawatt (MW) and how many homes can one MW of generation really serve?
•
Watts (W) are the yardstick for measuring power. A one hundred watt light bulb, for example,
is rated to consume one hundred watts (or 0.1 KW) of power when turned on. If such a light bulb were on
for four hours it would consume a total of 0.4 WKh of energy. Watts, therefore, measure
instantaneous power while watt-hours measure the total amount of energy consumed
over a period of time.
•
A megawatt (MW) is one million watts and a kilowatt (kW) is one thousand watts.
Residential Electricity Consumption
•
Amount of electricity consumed by a typical residential household varies by region of the country, as
well a other factors.
•
According to 2001 Energy Information Administration (EIA) data, New England residential customers
consume the least amount of electricity, averaging 650 kilowatt hours (kWh) per month per household,
while the East South Central region, which includes states such as Georgia and Alabama and
Tennessee, consumes nearly double that amount at almost 1,200 kWh per month per household.
Catching the Wind
• Wind turbine blades typically rotate between 12-20 revolutions per
minute (RPM), depending upon wind conditions.
• When the cut in wind speed is reached, the blades pitch to “full power”
position.
• This then turns the gearbox through a mainshaft.
• The gearbox takes the 12-20 rpm rotation from the hub/mainshaft and
ramps it up to 1400 to 1800 rpm, depending on the turbine, as input to
the generator.
Generating Power
• Once the generator speed is met,
power flows from the generator to a
step-up transformer typically at the
base of each tower.
• The generator voltages range from 575
to 690 volts. The step up transformer
increases the voltage to 34.5kv or
34,500 volts.
• The power then typically gets further
stepped up in voltage at a substation
and is then exported into the utility grid.
A Snapshot of the U.S.
Wind farms are typically sited in regions that have annual average wind
speed of at least 11-13 miles per hour with proximity to existing high
voltage transmission lines.
Map of the Average Annual Wind Power
The Electrical Grid
Environmental Benefits
Wind power is environmentally sustainable.
•
Wind turbines don’t produce CO₂
emissions, so they do not contribute to
climate change.
•
Wind power helps preserve our finite
supplies of fossil fuels.
•
Wind power plants do not consume water
•
Wind power is compatible with existing
agricultural land uses
•
Wind power is renewable because it is
generated from daily solar radiation and
cannot be depleted.
Glossary of Terms
Anemometer
an instrument for measuring wind speed
Cut In Speed
the lowest wind speed at which a wind turbine begins producing usable power
Electrical Grid
an interconnected network for delivering electricity from power plants to consumers
Gearbox
converts the slow, high-torque rotation of the rotor into much faster rotation for the electrical generator
Generator
a device that converts mechanical energy to electrical energy, generally using electromagnetic induction
Hub
the blades of the turbine are attached to the hub
Main Shaft
the rotor is bolted to a mainshaft – which runs to the gearbox
Nacelle
the structure that houses all of the power train and generating components
Padmount Transformer
mounted on the ground to step up the voltage
Pitch
the angle of the blades
Rotor
all blades attached to the hub
Substation
a subsidiary station of an electricity generation, transmission and distribution system where voltage is
transformed from high to low or the reverse using transformers
Tower
the tower that supports the wind turbine nacelle
Transmission Lines
the structure and circuits that transport electricity from one place to another.
Turbine
a rotary engine that extracts energy from a fluid flow
VAC
Volts Alternating Current
Wind Vane
an instrument for measuring the wind direction
Yaw Drive
a device used to keep the rotor facing into the wind as the wind direction changes