Course Wind

8/2/2019 Course Wind

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WIND ENERGY SYSTEMS

Dr.L.Ashok KumarDept. of EEE

PSG College of TechnologyCoimbatore

www.ashokkumar.110mb.com 1


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Overview of Presentation

Introduction History of Wind Machines Wind Resource Assessment Wind Energy Technology

Horizontal Axis turbine Vertical Axis turbine

Wind Energy System Components Installation and Maintenance Environment Economics


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Electricity!

How much would it cost to run this

100 Watt bulb for a full day (24 hrs)? 100 Watts x 24 hours = 2400 Watt Hours(2400 Watt Hours = 2.4 Kilowatt Hours)

2.4 kWh x $0.08/kWh =$0.19

What about this 25 Watt CFL lightbulb, which produces the same

amount of light?

25 Watts x 24 hours = 600 Watt Hours(600 Watt Hours = 0.6 Kilowatt Hours)

0.6 kWh x $0.08/kWh =$0.05

More efficient light bulbs are great, but what isthe BEST way to conserve electricity and reduceour consumption of fossil fuels???

TURN IT OFF!!!

Be conscious of your energy choices!


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Where do we get our electricity?Where do we get our electricity?


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What is a Fossil Fuel???


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What is Renewable Energy?


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The wind blows day and night, which allows windmills to produce electricitythroughout the day. (Faster duringthe day)

Energy output from a wind turbine will vary as the wind varies, although the mostrapid variations will to some extent be compensated for by the inertia of the windturbine rotor.

Wind energy isa domestic, renewable source of energy that generatesno pollutionand has little environmental impact. Up to 95 percent of land used for wind farmscan also be used for other profitable activities including ranching, farming andforestry.

The decreasing cost of wind power and the growing interest in renewable energysources should ensure that wind power will become a viable energy source in the

United States and worldwide.

Advantages of Wind Power


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Major factors that have accelerated the wind-power technologydevelopment are as follows:

high-strength fiber compositesfor constructing large low-cost blades. fallingprices of the power electronics.

variable-speed operation of electrical generators to capture maximumenergy. improved plant operation, pushing the availability up to 95 percent. economy of scale, as the turbines and plants are getting larger in size. accumulated field experience (the learning curve effect) improving

thecapacity factor.


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Electricity for Central-grids

Isolated-grids Remote power supplies

Water pumping

but also

Support for weak grids

Reduced exposure to energyprice volatility

Reduced transmission anddistribution losses

What do wind energy systemsprovide?

San Gorgino Windfarm, Palm Springs, California, USA


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Utilisation of Wind Energy

Off-Grid Small turbines (50 W to 10 kW)

Battery charging

Water pumping

Isolated-Grid Turbines typically 10 to 200 kW

Reduce generation costs in remote areas:wind-diesel hybrid system

High or low penetration

Central-Grid Turbines typically 200 kW to 2 MW

Windfarms of multiple turbines

Off-Grid, 10-kW Turbine, Mexico


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INTRODUCTION

Wind energy, the world's fastest growing energy source, is aclean and renewable source of energy that hasbeen in use forcenturies in Europe and more recently in the United Statesand other nations.

And todays world wind is one of the cheapest and cleanest

energysource.


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HISTORY OF WIND MACHINES

Throughout history people have harnessed the wind. Over 5,000 years ago, theancient Egyptians used wind power to sail their ships on the Nile River. Laterpeople built windmills to grind their grain. The earliest known windmills were inPersia (the area now occupied by Iran). The early windmills looked like largepaddle wheels.

Centuries later, the people in Holland improved the windmill. They gave itpropeller-type blades and made it so it could be turned to face the wind.Windmills helped Holland become one of the world'smost industrialized countries

by the 17th century.

American colonists used windmillsto grind wheat and corn, to pump water, and tocut wood at sawmills.

Last century, people used windmills to generate electricity in rural areas that didnot have electric service. When power lines began to transport electricity to ruralareas in the 1930s, the electric windmillswere used lessand less.

Then in the early 1970s, oil shortagescreated an environment eager for alternativeenergy sources, paving the way for the re-entry of the electric windmill on theworld landscape .


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WORLD WIND POWER SCENARIO

(all data in MW)

as on January 2011


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Source: c-wet website


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INDIAN WIND POWER SCENARIO

STATE WISE INSTALLED CAPACITY OF WIND POWER IN INDIA

Sr.No StateInstalled Capacity

As on 31.03.2010

Installed Capacity

As on 31.03.2011

1 Andhra Pradesh 136.10 192.00

2 Gujarat 1863.70 2176.003 Karnataka 1472.80 1727.00

4 Kerala 27.80 35.00

5 Madhya Pradesh 229.40 276.00

6 Maharashtra 2077.70 2317.00

7 Rajasthan 1088.50 1525.00

8 Tamil Nadu 4906.80 5904.00

9 Others 4.30 4.00

Total 11807.1 14156

Source : MNRE


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Where Does Wind Come From?

The differential heating of earths atmospherecauses wind.


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The Jet Stream

The jet stream is responsible for the transportof heat and momentum in the mid latitudes


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Wind energy

Wind energy isactually aconverted form of solar energy.

The suns radiation heats different part of the earth at differentrates during the day and night, but also when different surfaces(e.g.,water and land) absorb or reflect at different rates.

Thisin turn causesportionsof the atmosphere to warm differently.

Hot airs rises, reducing the atmospheric pressure at the earthssurface, and cooler air isdrawn in to replace it.

Air hasa mass, and when it is in motion, it contains the kinetic frommassin motion.

Some portion of that energy can be converted into other formsmechanical force or electricity that wecan use to perform work.


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What is Wind?

Wind is simply air in motion. It is caused by the uneven heating of the

earth's surface by the sun. Since the earth's surface is made up of land,desert, water, and forest areas, the surface absorbs the sun's radiationdifferently.

All renewable energy (except tidal and geothermal power), ultimatelycomesfrom the sun

Theearth receives 1.74 x 1017 watts of power (per hour) from thesun

About 1%or 2% of thisenergy isconverted to wind energy (which isabout50-100 times more than the energy converted to biomass by all plants onearth)

Differential heating of the earths surface and atmosphere induces verticaland horizontal air currents that are affected by the earths rotation andcontoursof the landWIND.e.g.: Land SeaBreeze Cycle


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Winds are influenced by the ground surface at altitudes up to

100 m. Wind is slowed by the surface roughness and obstacles. When dealingwith wind energy, we are concerned with surface winds.

A wind turbine obtains its power input by converting the force of the windinto a torque(turningforce) actingon the rotor blades.

The amount of energy which the wind transfers to the rotor depends on the

density of theair, the rotor area, and the wind speed. The kineticenergy of a moving body isproportional to itsmass (or weight).

The kinetic energy in the wind thus depends on the density of the air, i.e. itsmass per unit of volume. In other words, the "heavier" the air, the moreenergy is received by the turbine.

At 15Celsius air weighs about 1.225 kg per cubic meter, but the densitydecreases slightly with increasing humidity.


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

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

Since the rotor area increases with the square of the rotor diameter, aturbine which is twice as large will receive 22 = 2 x 2 = four times as muchenergy.

To be considered a good location for wind energy, an area needs to haveaverage annual wind speedsof at least 12 miles per hour.


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Global Winds

The global wind patterns are created by uneven heating and the spinning

of the earth. The warm air rises near the equator, and the surface airmoves in to replace the rising air - two major belts of the global wind

patterns are created.

The wind between the equator and about 30north and south latitudes

move east to west. These are called the trade winds because of their use insailing ships for trades.

Two features of the wind, its speed, and the direction, are used indescribing and forecasting weather


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Local Winds

Land Breezes and Sea Breezes

Land massesare heated by the sun more quickly than the sea in thedaytime. The air rises, flows out to the sea, and creates a lowpressure at ground level which attracts the cool air from the sea.This is called a sea breeze. At nightfall there is often a period ofcalm when land and sea temperaturesare equal.

At night the wind blows in the opposite direction. The land breezeat night generally has lower wind speeds, because the temperaturedifferencebetween land and sea issmaller at night.


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Mountain Breezesand ValleyBreezes

Mountain breezes and valley breezes are due to acombination of differential heating and geometry. When thesun rises, it is the tops of the mountain peaks which receivefirst light, and as the day progresses, the mountain slopestake on a greater heat load than the valleys.

This results in a temperature inequity between the two, andas warm air rises off the slopes, cool air moves up out of thevalleys to replace it. This upslope wind is called a valleybreeze.

The opposite effect takes place in the afternoon, as the valleyradiates heat. The peaks, long since cooled, transport air intothe valley in a process that is partly gravitational and partlyconvective and iscalled a mountain breeze.


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History of Wind Mills


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Early History 5000 BCE (before common era): Sailing ships on the Nile River were likely

the first use of wind power

Hammurabi, ruler of Babylonia, used wind power for irrigation

Hero (Heron) created a wind-pumped organ

Persians created a Vert ical Axis WT (VAWT) in the mid 7th Century

1191 AD: The English used wind turbines

1270: Post-mill used in Holland

1439: Corn-grinding in Holland

1600: Tower mill with rotating top or cap

1750: Dutch mill imported to America

1850: American mult iblade wind pump development; 6.5 million until1930; was produced in Heller-Allen Co., Napoleon, Ohio

1890: Danish 23-meter diameter turbine produced electricity


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Later History 1920: Early Twentieth Century saw wind-driven water-pumps commonly used in

rural America, but the spread of electricity lines in 1930s (Rural Electrification Act)

caused their decline 1925: Windcharger and Jacobs turbines popular for battery charging at 32V; 32V

dc appliances common for gas generators

1940: 1250kW Rutland Vermont (Putnam) 53m system (center)

1957-1960: 200kW Danish Gedser mill (right)

1972: NASA/NSF wind turbine research

1979: 2MW NASA/DOE 61m diameter turbine in NC Now, many windfarms are in use worldwide


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WIND ENERGY TECHNOLOGY

Horizontal Axis Turbine

Vertical Axis Turbine

Old-fashioned windmills


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DIFFERENT TYPES OF WIND TURBINES

Drag-type turbinesPersian windmillChinese wind wheelSaviounus

Lift-type turbinesVAWT, Vertical Axis Wind Turbine

Darrieus

HAWT, Horizontal Axis WindTurbine

The Danish concept American multiblade Grumman windstream


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DRAG-TYPE TURBINES

The Persian windmill

The Chinese wind wheel

Savonious


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DRAG-TYPE TURBINES

Ref: www.ifb.uni-stuttgart.de/ ~doerner/edesignphil.html


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Horizontal Axis Wind Turbine

HAWT (Horizontal Axis Wind Turbines) have the rotor spinning around ahorizontal axis

The rotor vert ical axis must turn to track the wind

Gyroscopic precession forces occur as the turbine turns to track thewind

The purpose of the rotor, of course, is to convert the linearmotion of the wind into rotational energy that can be used todrive a generator. The same basic principle is used in amodern water turbine, where the flow of water is parallel to

therotational axisof the turbine blades.


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Horizontal Axis Wind Turbines (HAWT)

1.8 m

75 m

AmericanFarm, 1854

Sailwing,

1300 A.D.

Dutch withfantail

ModernTurbines

Experimental Wind farm

Dutch postmill


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LIFT-TYPE TURBINES

HAWT, AMERICAN MULTIBLADE


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LIFT-TYPE TURBINES

HAWT, THE DANISH CONCEPT

The blades upwind the rotor

Constant speed on the rotor

Power output limitationStall control

BrakesMechanical

Aerodynamic


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LIFT-TYPE TURBINES

HAWT, GRUMMAN WINDSTREAM


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SPEED n 20 17 13 5 15 3 10 rpm

HEIGHT[M]

DEVELOPMENT OF HAWT


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HAWTHorisontal-Axis Wind Turbines

SMLA


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HAWT

Main Components

Foundation

Tower

Nacelle

Hub

Turbine blades

Ref. Wind Power Plants, R.Gasch, J.Twele


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Horizontal axis Turbine


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HAWT Examples

Charles Brush (arc light) home turbine of 1888 (center) 17 m, 1:50 step-up to drive 500 rpm generator

NASA Mod 0, 1, 2 turbines

The Mod-0A at Clayton NM produced 200kW (below left)


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VAWT

The only vert ical axis turbine which has ever been manufacturedcommercially at any volume is the Darrieusmachine, named after the Frenchengineer Georges Darrieus who patented the design in 1931. (It wasmanufactured by the U.S. company FloWind which went bankrupt in 1997).The Darrieus machine is characterized by its C-shaped rotor blades whichmake it look a bit like an eggbeater. It is normally built with two or threeblades.

VAWT (Vertical Axis Wind Turbines) have the rotor spinning around a verticalaxis

This Savonius rotor will instantly extract energy regardless of the wind

direction The wind forces on the blades reverse each half-turn causing fatigue of

the mountings

The two-phase design with the two sections at right angles to each otherstarts more easily


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Vertical Axis Wind Turbines (VAWT)

Savonius

Darrieuswith Savonius

Panemone,1000 B.C.

Giromill

This sample shows the diversity of VAWT over the years

ExperimentalSavonius


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LIFT-TYPE TURBINES

VAWT, DARRIEUS


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LIFT-TYPE TURBINES

VAWT, DARRIEUS


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Ref: www.ifb.uni-stuttgart.de/~doerner/edesignphil.html


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Vertical axis wind turbine.


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Advantagesof VAWTs

1) You may place the generator, gearbox etc. on the ground, and you maynot need a tower for the machine.

2) You do not need a yaw mechanism to turn the rotor against thewind.


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Disadvantages of VAWTs

Wind speedsare very low close to ground level, so although you may savea tower, your wind speeds will be very low on the lower part of your rotor.

Theoverall efficiency of thevertical axismachines isnot impressive. The machine is not self-starting (e.g. a Darrieus machine will need a

"push" before it starts. This isonly a minor inconvenience for a grid.


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Small Wind Turbines: American

In 1854, patented wind pumpers were popular across the US, laterspreading to other nations

By 1870, improvements made with sheet steel blades stamped to anaerodynamic contour

These turbines use 2 turns of the rotor to 1 stroke of the pump lift rodgear ratio to allow starting at a low wind speed

AEI states that there are some 30,000 farm wind pumps in the SouthernGreat Plains at 0.25 kW each, or some 5 MW total

S ll Wi d T bi


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Small Wind Turbine

Bergey produces small windturbines up to 50 kW


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Amateur or hobbyist wind turbines are often somewhat crude, butmany sourcesof construction information are available

Booksby Paul Gipe and Hugh Piggott are essential references Bladesare usually madeof fir, pine, fiberglass, or metal Turbine at right uses a bicycle front axle for strength, PVCblades, and

apermanent magnet servomotor asa generator

Small Wind Turbines: Homemade


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Large Systems: Size and Numbers

Rotor hub is high aboveturbulent ground wind layer

Production line assembly

660kW to 7 MW power models

Groups of 10 to 1000s of

turbines Attractive, modern appearance


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Large Systems

FPL Stateline and Vansycle Ridge Wind Farms in southeast WA andnortheast Oregon

Wasco ORshown; plowed fields for wheat underneath


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Offshore Wind Farms Wind farms are often placed offshore a few miles because the winds are

unimpeded (have a good fetch, or upwind distance, of the wind) Depthsof less than 60 feet are preferable

Undersea cablescarry power to shore terminals


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Types of Electricity Generating Windmills

Small (10 kW) Homes Farms Remote Applications

(e.g. water pumping,telecom sites,icemaking)

Large (250 kW - 2+MW)

Central Station Wind Farms

Distributed Power

Intermediate

(10-250 kW)

Village Power Hybrid Systems

Distributed Power


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Vertical Wind Speed Variation

At a given location, wind speed increases as we go above the earthsurface.

At the earth surface, the wind speed is zero due to the friction of air withthe surface.

As we go up, wind speed increases more rapidly at lower heights but less

rapidly at greater heights. At about 2000 m from the ground the change in the wind speed becomeszero.

The vertical variation in the wind speed depends on Roughness of the terrain Wind speed near the ground Represented by (0.01 to 0.3)

If wind speed for a given location and at a given height is known, the V atany other height at the same location can be estimated. V(at unknown ht) = V (at known ht) x (New ht/Ref ht)


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Kinetic Energy

Kinetic energy (KE) is the energy of motion

Air molecules have mass, and wind is moving air. Thus, windhas kinetic energy.

Wind turbines convert the winds kinetic energy intomechanical kinetic energy (spinning the rotor).

Mass = density * volume: What is the kinetic energy of a 1m cube of air moving at 5 m/s

in Colorado (r= 1 kg/m3)?

2

2

1mvKE

Vm r


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Energy Conservation andEnergy Conversion

When the turbine extracts kinetic energy from the wind, thespeed of the wind is reduced.

Some of the winds kinetic energy is converted intomechanical kinetic energy, i.e., the rotation of the turbinerotor.

Some of the winds kinetic energy remains in the wind(conservation of energy).

2

2

1mvKE

outwindturbineinwind KEKEKE


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Speed and Power Relations The kinetic energy in air of mass m moving with speed V is given by the following

in SI units:

The power in moving air is the flow rate of kinetic energy per second.Therefore:

The volumetric flow rate is AV, the mass flow rate of the air in kilograms persecond isAV, and the power is given by the following:


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Power Extracted from the Wind

The actual power extracted by the rotor blades is the difference between theupstream and the downstream wind powers


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The mechanical power extracted by the rotor, which is driving the electrical

generator, is therefore:

Cp is the fraction of the upstream wind power, which is captured by the

rotor blades. The remaining power is discharged or wasted in thedownstream wind.

The factor Cp is called the power coefficient of the rotor or the rotorefficiency.


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Betz Limit All wind power cannot becaptured by rotor or air

would be completely stillbehind rotor and not allowmore wind to passthrough. Theoretical limit of rotor

efficiency is 59%

Most modern windturbines are in the 35 45% range


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Rotor Swept AreaThe output power of the wind turbine varies linearly with the rotor swept area. Forthehorizontal axis turbine, the rotor swept area isgiven by:

For the Darrieusvert ical axis machine, determination of the swept area is complex,as it involves elliptical integrals.


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Power Coefficient

Power coefficient Cp is a measure of theaerodynamic efficiency of the wind turbine

Q = turbines aerodynamic torque

W= rotor rotational speed

Betz limit - theoretical maximum

32

1 Av

Q

P

P

C wind

rotor

aerop r

5926.027

16BetzpC


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Cp for Various Configurations


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Air Density The wind power varies linearly with the air density sweeping the blades. The

air density varies with pressure and Temperature in accordance with the gaslaw:


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Wind Speed Distribution

Having the cubic relation with the power, the wind speed is the most

critical data needed to appraise the power potential of a candidate site. The wind is never steady at any site. It is influenced by the weathersystem, the local land terrain, and the height above the ground surface.

The wind speed variesby the minute, hour, day, season, and year.Therefore, the annual mean speed needs to be averaged over 10 or moreyears.

Such a long term average raises the confidence in assessing the energy-

capture potential of a site. However, long-term measurements are expensive, and most projects

cannot wait that long. In such situations, the short term, say one year, data is compared with a

nearby site having a long term data to predict the long term annual windspeed at the site under consideration.

Thisisknown asthe measure, correlate and predict (mcp) technique. The wind-speed variations over the period can be described by aprobability distribution function.


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Why do windmills need to be high in the sky??


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Importance of Wind Speed

No other factor is moreimportant to the amount ofpower available in the windthan the speed of the wind

Power is a cubic function ofwind speed

VXVXV

20% increase in wind speedmeans 73% more power

Doubling wind speed means8 times more power


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Wind Speed DistributionWeibull Distributions

0.000

0.050

0.100

0.150

0.200

0.250

0 2 4 6 8 10 12 14 16 18 20

Wind Speed Bin (m/s)

ProportionofTim

e

AWS = 5.0 m/sk = 2.0PD = 146 watts/m^2

AWS = 5.0 m/sk = 3.0PD 108 watts/m^2

AWS = 6.0 m/sk = 2.0PD = 253 watts/m^2


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Weibull Probability Distribution

The variation in wind speed are best described by the Weibull probabilitydistribution function h with two parameters, the shape parameter k, andthe scale parameter c.

Effect of Height

The wind shear at ground surface causes the wind speed increase withheight in accordance with the expression


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Energy Distribution

It is advantageous to design the wind power to operate at variable speeds inorder to capture the maximum energy available during high wind periods.


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Wind Turbine DesignWind Turbine Design

Lift & Drag

TheLift Forceisperpendicular to thedirection of motion. Wewant to make this forceBIG.

TheDrag Forceis parallelto the direction of motion.We want to make thisforce small.

= low

= medium


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Airfoil

Just like the wings of an airplane,wind turbine blades use theairfoil shape to create lift andmaximize efficiency.


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Twist & Taper Twist from blade root to the tip is used

to optimize the angle of attack all alongblade and result in a constant inflowalong the blade span

Taper is used to reduce induced dragand increase the L/D ratio


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Tip-Speed Ratio

Tip-speed ratio is the ratio of the speedof the rotating blade tip to the speed ofthe free stream wind.There is an optimum angle of attackwhich creates the highest lift to dragratio.Because angle of attack is dependant on

wind speed, there is an optimum tipspeed ratio

R

VTSR =

Where,

= rotational speed in radians /secR = Rotor Radius

V = Wind Free Stream Velocity

R

R


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Power Coefficient vs Tip Speed Ratio

Power Coefficient Varies with Tip Speed Ratio

Characterized by Cp vs Tip Speed Ratio Curve

0.4

0.3

0.2

0.1

0.0

Cp

121086420

Tip Speed Ratio


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Rotor Solidity

Solidityis the ratio of total rotorplanform area to total swept area

Low solidity (0.10) = high speed, low torqueHigh solidity (>0.80) = low speed, high torque

A

R

aSolidity= 3a/A


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Tip-Speed Ratio

Ratio of the linear speed of the tip of the blade to the windspeed

Linear speed of a rotating object is angular speed t imesdistance from center of rotation

l= tip-speed ratio R = rotor radius w= angular speed

v = wind speed What is the tip-speed ratio of a 20 m

diameter rotor rotating at 6 rad/s in10 m/s wind?

v

Rwl


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150 m2

250 m2

800 m2

1,800 m2

3,700 m2

19801985

1990

19952000

A= 12,000 m2

2005How big will wind turbines be?

2010

Slide courtesy NREL


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Elements of Wind Energy Projects

Wind resourceassessment

Environmental

assessment Regulatory approval

Design

Construction

Roads

Transmission line

Substations


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Wind Turbine Components


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Wi d T bi D i i


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Wind Turbine Description

Components

Rotor

Gearbox

Tower

Foundation

Controls

Generator

Types

Horizontal axis

Most common Controls or design turn

rotor into wind

Vert ical axis

Less common

Schematic of a Horizontal Axis Wind Turbine


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Large Turbine Components


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Large Turbine Components

Note railing

SECTIONALVIEW


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SECTIONAL VIEW


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Partsof a Wind Turbine


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Parts of a Wind Turbine


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IMAGE OF A TYPICAL WIND TURBINE


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Wind Turbine Perspective

Nacelle56 tons

Tower3 sections

Workers Blade112 long

Small Turbine Components


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Small Turbine Components

A small turbine has a free-spinning assembly that the wind turns inazimuth by pushing on the tail


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LARGETURBINES:

Able to deliver electricity at lower costthan smaller turbines, because foundationcosts, planning costs, etc. are independentof size.

Well-suited for offshore wind plants.

In areas where it is difficult to find sites,one large turbine on a tall tower uses thewind extremely efficiently.

SMALLTURBINES:

L l l i l id b bl h dl h l l i l


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Local electrical gridsmay not be able to handle the large electricaloutput from a large turbine, so smaller turbines may be moresuitable.

High costs for foundations for large turbines may not beeconomical in some areas.

Landscape considerations


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Wind Turbines: Number of Blades


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Most common design is the three-bladed turbine. The most important reason is

the stability of the turbine. A rotor with an odd number of rotor blades (and at leastthree blades) can be considered to be similar to a disc when calculating the dynamicpropert ies of the machine.

A rotor with an even number of blades will give stability problems for a machinewith a stiff structure. The reason is that at the very moment when the uppermostblade bends backwards, because it gets the maximum power from the wind, the

lowermost blade passes into the wind shade in front of the tower.

Number of Blades: One


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Number of Blades: One

Rotor must move more rapidly tocapture same amount of wind

Gearbox ratio reduced Added weight of counterbalance

negates some benefits of lighterdesign

Higher speed means more noise,

visual, and wildlife impacts

Blades easier to install because entirerotor can be assembled on ground

Captures 10% less energy than twoblade design

Ultimately provide no cost savings

Number of Blades: Two


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Number of Blades: Two

Advantages & disadvantagessimilar to one blade

Need teetering hub and or shockabsorbers because of gyroscopicimbalances

Capture 5% less energy than threeblade designs

Number of Blades: Three


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Balance of gyroscopic forces

Slower rotation

increases gearbox &

transmission costs More aesthetic, less noise,

fewer bird strikes

Bl d M i l W d


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Blade Material: Wood

Wood Strong, light weight,

cheap, abundant, flexible Popular on do-it yourself

turbines

Solid plank Laminates Veneers Composites

Blade Material: Metal


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Blade Material: Metal

SteelHeavy & expensive

Aluminum

Lighter-weight and easy to

work withExpensive

Subject to metal fatigue

Blade Material: Fiberglass


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Blade Material: Fiberglass

Lightweight, strong, inexpensive,good fatigue characteristics

Variety of manufacturing processes

Cloth over frame

Pultrusion

Filament winding to producespars

Most modern large turbines usefiberglass


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Wind Turbine


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A wind system transforms the kinetic energy of windto mechanical or electrical energy.

Wind turbines are mounted on a tower to capture

the most energy. Turbines catch the winds energy with their

propeller-like blades.

Usually two or three blades are mounted on a shaft

to form a rotor. A blade acts much like an airplane wing.


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Wind Turbine Generators


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Wind power generatorsconvert wind energy(mechanical energy) toelectrical energy.

The generator is attached atone end to the wind turbine,

which provides the mechanicalenergy.

At the other end, thegenerator is connected to theelectrical grid.

The generator needs to havea cooling system to make surethere isno overheating.

SMALL GENERATORS:


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Require less force to turn than a larger ones, but give much lower poweroutput.

Less efficient

i.e.. If you fit a large wind turbine rotor with a small generator it will beproducing electricity during many hours of the year, but it will capture onlya small part of the energy content of the wind at high wind speeds.

LARGE GENERATORS:

Very efficient at high wind speeds, but unable to turn at low wind speeds.

i.e.. If the generator has larger coils, and/or a stronger internal magnet, itwill require more force (mechanical) to start in motion.


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Large Wind Turbines


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g

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


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Wind Amplified Rotor Platform


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Wind Amplified Rotor Platform (WARP) is a different kind of windsystem that is designed to be more efficient and sue less land thanwindmachinesin use today.

The WARPdoes not use large blades; instead it looks like a stack ofwheel rims.

Each module is a pair of small, high-capacity turbines mounted toboth of itsconcave wind amplifier module channel surfaces.

Wind Turbine Capacity


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p y

Diameter Capacity

60 ft 0.10 MW

164 ft 0.75 MW216 ft 1.5 MW

279 ft 2.5 MW

328 ft 3.5 MW

394 ft 5.0 MW

Average Turbine Size


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g

1980 0.25 MW

1995 0.50 MW

0998-1999 0.71 MW

2000-2001 0.88 MW

2002-2003 1.19 MW

2004-2005 1.44 MW

2006 1.60 MW2007 1.65 MW



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p y

The output of a wind turbine depends on the turbines size and thewindsspeed.

Wind speed isa crucial element in projectingturbineperformance.

A siteswind speed is measured through wind resource assessmentprior to awind systemsconstruction.

Generally, an annual average wind speed greater than 10 mph isrequired for small wind turbines while larger utility scale windplants need a slightly higher minimum average wind speed of 13

mph.



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p y

The power available in the wind isproportional to thecube of itsspeed.

Doubling the wind speed increases the available power by a factor ofeight.

For example, a turbine operating at a site with an average wind speed of11 mph could in theory generate 33%more electricity than the one at 10mph.

Therefore, a small difference in wind speed can make a big difference inthe capacity.


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Garden State OffshoreEnergy (GSOE) will employ a propietary deep water foundation technology which enables wind turbines to be located in deep waters far from shore.

Thanks to these deep water foundations, the GSOEproject will be located more than 16milesoffshore, making it virtually invisible from New Jersey'sbeaches.

From the Music Pier in Ocean City, NJ- the location closest to GSOEproject the windturbines will be virtually invisible from shore.


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Design of wind turbines and windfacilities


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facilities

Wind turbine technical features


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Wind turbines consist of four main componentsthe rotor, transmission

(gearbox), generator, yaw system, and control systems. Turbines canbe direct drive (no gearbox) as well.

The nacelle rotates (or yaws) according to the wind direction.

Turbines can vary rotational speed, blade pitch, or both.

Turbines deployed in multiple groups, called arrays, are arranged to avoidshadowing the wind from turbine to turbine.

Turbines can be turned on and off remotely by an operator at a centralcontrol station.

Turbines dont spin unless the winds are sufficient to generate electricity, orin extreme winds associated with severe storms.

Other important wind power terminology

Turbine power rating --the maximum instantaneous power output of the wind turbine


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Turbine power rating --the maximum instantaneous power output of the wind turbine,quoted in Watts. Typical value is 1.5 Megawatts (1.5 million Watts).

Turbine energy production --a cumulative amount of energy produced by the windturbine for a given period, usually a year. Quoted in kilowatt-hours (kWh) or megawatt-hours (MWh).

Capacity factor --the average power output of the wind turbine, as a fraction of itspower rating. A typical value is 28 percent. This reflects both the variability of the windat a site and the efficiency of the turbine.

Average wind speed --the long-term average speed of the wind, usually quoted inmeters per second. (1 m/s = 2.24 mph). Typical value is 6 m/s.

Tower height --the height of the turbine to the hub of the rotor, usually quoted inmeters (1 meter = 3.28 feet). Typical values are 80 meters.

Wind shear --the speed-up of wind with height, given as the exponent of a power-lawequation. Typical low value--.15; high value--.30.

Turbulence intensity --the roughness of the wind at a site. This is a dominant criteriafor specifying a wind turbine. Typical low value--.15; high value--.30.


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Nacelle


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Nacelle and Yaw system


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Ref. www.windpower.org

Nacelle


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Nacelle Design


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Nacelle Drive Trains


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Yaw system


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Ref. www.windpower.org

YawingYawing Facing the WindFacing the Wind


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Active Yaw (all medium &large turbines producedtoday, & some small turbinesfrom Europe) Anemometer on nacelle tells

controller which way to pointrotor into the wind Yaw drive turns gears to point

rotor into wind

Passive Yaw (Most smallturbines) Wind forces alone direct rotor

Tail vanes Downwind turbines


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TowersLattice tower Tubular steel towers


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Guyed Pole Tower

att ce to e Tubular steel towers,

Concrete tower

Tower designs


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The 7.5 MW Jersey-Atlantic Wind Farm


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Wind Energy Cost Trend


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1979: 40 cents/ kWh

Increased TurbineSize

R&D Advances

ManufacturingImprovements

OperatingExperience

NSP 107 MW Lake Benton wind farm4 cents/kWh (unsubsidized)

2004:3 - 5 cents/ kWh(no subsidy)

2000:4 - 6 cents/ kWh

(no subsidy)

Atypical 600 kWturbine costs about $450,000.


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Installation costsare typically $125,000. Therefore, the total costs will be about $575,000.

The average price for large, modern wind farms is around $1,000 per kilowattelectrical power installed.

Modern wind turbines are designed to work for some 120,000 hours of operationthroughout their design lifetime of 20 years. ( 13.7yearsnon-stop)

Maintenance costs are about 1.5-2.0percent of the original cost, per year.


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ENVIRONMENT Wind energy is considered a green power technology because it has only

minor impacts on the environment. Wind energy plants produce no air


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minor impacts on the environment. Wind energy plants produce no air

pollutantsor greenhouse gases. However, any meansof energy productionimpacts the environment in some way, wind energy isno different .

Aesthetics and Visual ImpactsElements that influence visual impacts include the spacing, design, anduniformity of the turbines.


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Birds and Other living ResourcesPreconstruction surveys can indicate whether birds or other living resourcesare likely to be affected by wind turbines.

NoiseLike all mechanical systems, wind turbines produce some noise when theyoperate. In recent years, engineers have made design changes to reduce thenoise from wind turbines.

TV/ Radio InterferenceIn the past, older turbines with metal blades caused television interference inareas near the turbine. Interference from modern turbines is unlikely becausemany components formerly made of metal are now made from composites.

Global WarmingWind energy can help fight global warming. Wind turbines produce no airemissions or greenhouse gases .

Impacts of WindPower: Noise


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oModern Turbines arerelatively quiet

oRule of Thumb: Stayabout 3 times a hubsheight away from houses

Bird Kill?


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Carnage!


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Carnage!

Jobs in the Wind Industry


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Construction


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Operations/


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Operations/Maintenance

Documents

Course Wind