Transcript Document

By Hana Bull
&&
Jennii Derry
• We chose Wind Energy because it is a
renewable energy re-source.
• England doesn’t have the best weather
conditions and we have a lot of rainy… and
windy conditions… this is very helpful.
• Wind && Rain are both re-newable sources
making them both perfect choices.
• When the wind blows over the blades of a wind turbine,
their aero-dynamic shape makes them turn.
• When air passes over an aero-dynamic part, it travels
faster over the top of the blade than it does below. This
makes the air pressure above the blade lower than it is
below. Due to the unequal pressures the blade
experiences a lifting force. You can see this if you hold a
thin sheet of paper to your lips and blow over the top of
it. This will make the paper rise more than if you blow
underneath it. The opposite force is drag, due to surface
friction and turbulence. Wind turbine designers use these
forces generated by the wind to make the rotor blades
turn.
• This rotational energy is transmitted either
to an electrical generator or to a machine for
mechanical work, such as a water pump.
With electricity generating turbines, a
gearbox is used to speed up the rotation,
about 30 times. In mechanical turbines a
shaft connects the turbine to the working
machine.
• Energy is extracted from the wind as it
moves through the 'swept area' of the
turbine's blades. On the down wind side of
the turbine the wind moves more slowly, as
some of its kinetic energy has been lost.
Every unit (kWh) of electricity produced by the wind displaces a unit
of electricity which would have been produced by a power station
burning fossil fuel. This is a fact used by many organisations
including Government in their environmental calculations.
Wind turbines produce electricity by using the natural power of the
wind to drive a generator. The wind is a clean and sustainable fuel
source, it does not create pollution and it will never run out. Wind
energy technology is developing fast, turbines are becoming
cheaper and more powerful, bringing the cost of renewablygenerated electricity down. Europe is at the hub of this high-tech
industry.
Some people say that wind turbines are ugly, but
this could easily be resolved by designing new
styles of wind turbines.
If you have a small garden or live in a small town
which is cramped all ready. You wont want a
huge wind turbine on your roof or In your town.
They need lots of space.
They need wind and if you have a wind turbine in
a country that hardly has any wind this will not be
the ideal solution for you!
The Most Common methods of generating electricity burn fuel to
provide the energy to drive a generator, usually by using the heat to
provide steam to drive a turbine. These technologies may use fossil
fuels, - coal, oil or gas - or nuclear fuel. Using fossil fuels creates
pollution, such as oxides of sulphur and nitrogen which contribute to
acid rain, and carbon dioxide which contributes to global climate
change.
Although these sources of power dominate the energy needs of
European countries, wind energy is growing rapidly. Renewable energy
sources currently provide nearly 5.4% of the European Union's
primary energy needs and have the potential to provide much more.
Rotor diameters range up to 80 metres, smaller machines
(around 30 meters) are typical in developing countries
Wind turbines can have three, two or just one rotor
blades. Most have three.
Blades are made of fibreglass-reinforced polyester or
wood-epoxy.
The blades rotate at 10-30 revolutions per minute at
constant speed, although an increasing number of
machines operate at a variable speed.
Power is controlled automatically as wind speed varies and machines are
stopped at very high wind speeds to protect them from damage.
Most have gearboxes although there are increasing numbers with direct drives.
The yaw mechanism turns the turbine so that it faces the wind. Sensors are
used to monitor wind direction and the tower head is turned to line up with the
wind.