wind energy

Wind Energy

Presented By: Ali Hassan Hafeez Anum Naz

Junaid Ahmad Joya Muhammad Usman

Wajiha Amjad Zia Ur Rehman

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What is Energy ?

Physicists, who are scientists who study force, motion and energy, say that energy is the ability to do work, and work is moving something against a force, like gravity. There are a lot of different kinds of energy in the universe, and that energy can do different things.

Energy can be found in many things, and takes many forms. There is a kind of energy called kinetic energy in objects that are moving. There is something that scientists call potential energy in objects at rest that will make them move if resistance is removed.

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Sources Of Energy

Sun

Water

Coal

Wind

Geo-Thermal

Bio-Mass

Tidal

Nuclear

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Introduction

All renewable energy (except tidal and geothermal power), ultimately comes from the sun

The earth receives 1.74 x 1017 watts of power (per hour) from the sun

About one or 2 percent of this energy is converted to wind energy (which is about 50-100 times more than the energy converted to biomass by all plants on earth

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Introduction contd.

Differential heating of the earth’s surface

and atmosphere induces vertical and horizontal

air currents that are affected by the earth’s

rotation and contours of the land WIND.

e.g.: Land Sea Breeze Cycle

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Introduction contd.

A typical 600 kW wind turbine has a rotor diameter of 43-44 meters, i.e. a rotor area of some 1,500 square meters.

The rotor area determines how much energy a wind turbine is able to harvest from the wind.

Since the rotor area increases with the square of the rotor diameter, a turbine which is twice as large will receive 22 = 2 x 2 = 4times as much energy.

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Introduction

contd.

To be considered a good location for wind energy, an area needs to have average annual wind speeds of at least 12 miles per hour.

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History

1 A.D. Hero of Alexandria uses a wind machine to power an organ

~ 400 A.D. Wind driven Buddhist prayer wheels

1200 to 1850 Golden era of windmills in western Europe – 50,000 9,000 in Holland; 10,000 in England; 18,000 in Germany

1850’s Multi-blade turbines for water pumping made and marketed in U.S.

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1882 Thomas Edison commissions first commercial electric generating stations in NYC and London

1900 Competition from alternative energy sources reduces windmill population to fewer than 10,000

1850 – 1930 Heyday of the small multi-blade turbines in the US midwast

As many as 6,000,000 units installed

1936+ US Rural Electrification Administration extends the grid to most formerly isolated rural sites

Grid electricity rapidly displaces multi-blade turbine uses

Historycontd.

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Historycontd.

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Increasingly Significant Power Source

coalpetroleumnatural gasnuclearhydroother renewableswind

Wind could generate 6% of nation’s electricity by 2020.Wind currently produces less

than 1% of the nation’s power. Source: Energy Information Agency

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Types of Wind Power

The major types of wind power are:

Utility-scale wind: wind turbines larger than 100 kilowatts are developed with electricity delivered to the power grid and distributed to the end user by electric utilities or power system operators;

Distributed or "small" wind: which uses turbines of 100 kilowatts or smaller to directly power a home, farm or small business as it primary use;

Offshore wind: which are wind turbines erected in bodies of water around the world, but not yet in the United States.

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Mechanism

When wind blows past a turbine, the blades capture the energy and rotate.

This rotation triggers an internal shaft to spin, which is connected to a gearbox increasing the speed of rotation.

The gearbox is connect to a generator that ultimately produces electricity.

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Construction & Equipment

Parts of a wind turbine:

1. Foundation2. Tower3. Nacelle4. Rotor blade5. Hub6. Transformer (this is not a part of the Wind Turbine)

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Tower and foundation

In order to guarantee the stability of a wind turbine a pile or flat foundation is used, depending on the consistency of the underlying ground.

The tower construction doesn’t just carry the weight of the nacelle and the rotor blades, but must also absorb the huge static loads caused by the varying power of the wind.

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Rotor and rotor blades

The rotor is the component which, with the help of the rotor blades, converts the energy in the wind into rotary mechanical movement.

Currently, the three-blade, horizontal axis rotor dominates.

The rotor blades are mainly made of glass-fiber or carbon-fiber reinforced plastics (GRP, CFRP).

The blade profile is similar to that of an airplane wing.

They use the same principle of lift. (on the lower side of the wing the passing air generates higher pressure, while the upper side generates a pull. These forces cause the rotor to move forwards, i.e. to rotate.)

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Nacelle

The nacelle holds all the turbine machinery.

Turbine machinery consists of gearbox, generator, coupling and brakes to the rotor.

It rotates to follow the wind direction.

It is connected to the tower via bearings.

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Gearbox

The gearbox converts the rotor motion of 18-50 rpm into the approx. 1,500 rpm which the generator requires.

The gearbox thus takes on the task of matching the rotation speeds of the slow-moving rotor and the fast-moving generator, and generally has several steps to cover for various wind conditions.

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Generator

For high power wind turbines, doubly-fed asynchronous generators are most frequently used.

The operating rotation speed can be varied somewhat, unlike when using conventional asynchronous generators.

Another concept uses synchronous generators. A grid connection of synchronous generators is only possible via transformers, due to the fixed rotation behavior.

The disadvantage of requiring complicated control systems is countered by the overall efficiency and better grid compatibility.

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Coupling and brake

Because of the enormous torque, the coupling between the main shaft and the transmission is a rigid one.

The type of brake depends on the control mechanism for the blades.

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Electronic equipment

These are composed of the generator, the system for the grid in feed of the electricity, and various sensors.

Sensors include: Temperature Sensor

Wind Direction Sensor

Wind Speed Sensor

Fault Sensor in nacelle

Control and Monitoring

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Other components

The wind turbine contains components for following the wind direction, for cooling, heating and lightning protection, as well as lifting gear (e.g. winches for spare parts) and fire extinguishing equipment.

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Working of Turbines

Wind Blades Rotate

Rotor Rotates

Generator Shaft Rotates

Produces Electricity

Step-Up Transformer

3 Phase High Voltage/Low

Current

Transmission Lines

To Grid Station

Distribution Lines

Step-Down Transformer

For Home Use

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Typical Wind Turbine Operation

0-5 m/s Wind Speed is too low for generation power. Turbine is not operational. Rotor is locked.

5-15 m/s 5 m/s is the minimum operational speed. It is called “Cut-in speed”. In 10-25 mph wind generated power increases with the wind speed.

15-25 m/s typical wind turbines reach the rated power at wind speed of 15 m/s.

>25 m/s Turbine is shut down when speed is higher than 50 mph (called “Cut-Out” speed) to prevent structure failure

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Wind Power Advantages

Environmental

Economic Development

Fuel Diversity & Conservation

Cost Stability

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Environmental Benefits

No air pollution

No greenhouse gasses

Does not pollute water with mercury

No water needed for operations

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Pollution from Electric Power

Toxic Heavy Metals

Particulate Matter

Nitrous Oxides

Carbon Dioxide

Sulfur Dioxide

0% 10% 20% 30% 40% 50% 60% 70% 80%

23%

28%

33%

34%

70%

Electric power is a primary source of industrial air pollution

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Economic Development Benefits

Expanding Wind Power development brings jobs to rural communities

Increased tax revenue

Purchase of goods & services

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Fuel Diversity Benefits

Domestic energy source

Inexhaustible supply

Small, dispersed design reduces supply risk

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Cost Stability Benefits

Flat-rate pricing hedge against fuel price volatility risk

Wind electricity is inflation-proof

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Power in the Wind (W/m2)

= 1/2 x air density x swept rotor area x (wind speed)3

A V3

Density = P/(RxT) P - pressure (Pa) R - specific gas constant (287 J/kgK) T - air temperature (K)

Area = r2 Instantaneous Speed(not mean speed)

kg/m3 m2 m/s

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Siting a Wind Farm

Winds Minimum class 4 desired for utility-scale wind farm (>7 m/s at hub height)

Transmission Distance, voltage excess capacity

Permit approval Land-use compatibility Public acceptance Visual, noise, and bird impacts are biggest concern

Land area Economies of scale in construction Number of landowners

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Wind Disadvantages

Siting Avian

Noise

Aesthetics

Intermittent source of power

Transmission constraints

Operational characteristics different from conventional fuel sources

Financing

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Wind Energy and the Grid

Pros

Small project size

Short/flexible development time

Dispatch ability

Cons

Generally remote location

Grid connectivity -- lack of transmission capability

Intermittent output

Only When the wind blows (night? Day?)

Low capacity factor

Predicting the wind -- we’re getting better

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Birds - A Serious Obstacle

Birds of Prey (hawks, owls, golden eagles) in jeopardy

Altamont Pass – News Update – from Sept 22 shut down all the turbines for at least two months each winter

eliminate the 100 most lethal turbines

Replace all before permits expire in 13 years

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Wind Energy- The need of Pakistan

Now-a-days Pakistan is suffering from a great downfall of energy that is causing a great loss in all walks of life.

Now Pakistan need a permanent and reliable source of energy, i.e. THE WIND ENERGY

There are many sites in Pakistan that are compatible for installing the Wind Turbines.

In future, if Pakistan work on this permanent source of energy, In Sha ALLAH, we will overcome this shortfall of energy.

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Questions &

Answers

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