Phys 471Phys 471Solar Energy Solar Energy II

WIND ENERGYWIND ENERGYByBy

ÇAĞRI İMİR ÇAĞRI İMİR

Instructor Instructor

Prof. Dr. AHMET ECEVİTProf. Dr. AHMET ECEVİT

METU METU

2004-12004-1

CONTENTSCONTENTS

1.1. IntroductionIntroduction2.2. History of History of WindWind Machines Machines3.3. Wind ResourceWind Resource4.4. Wind Energy TechnologyWind Energy Technology

– Horizontal Axis turbineHorizontal Axis turbine– Vertical Axis turbineVertical Axis turbine

5.5. Wind turbine UseWind turbine Use 6.6. Wind energy in TurkeyWind energy in Turkey7.7. EnvironmentEnvironment8.8. EconomicsEconomics9.9. ConclusionConclusion

ReferencesReferences

1-INTRODUCTION1-INTRODUCTION

Wind energy, the world's fastest growing Wind energy, the world's fastest growing energy source, is a clean and renewable energy source, is a clean and renewable source of energy that has been in use for source of energy that has been in use for centuries in Europe and more recently in the centuries in Europe and more recently in the United States and other nationsUnited States and other nations [11] [11]. .

And todays world wind is one of the And todays world wind is one of the cheapest and cleanest energy source.cheapest and cleanest energy source.

2-2-HISTORY of HISTORY of WWIND MACHINESIND MACHINES

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

Centuries later, the people in Holland improved the windmill. They gave it Centuries later, the people in Holland improved the windmill. They gave it propeller-type blades and made it so it could be turned to face the wind. propeller-type blades and made it so it could be turned to face the wind. Windmills helped Holland become one of the world's most industrialized Windmills helped Holland become one of the world's most industrialized countries by the 17th century.countries by the 17th century.

American colonists used windmills to grind wheat and corn, to pump water, and American colonists used windmills to grind wheat and corn, to pump water, and to cut wood at sawmills.to cut wood at sawmills.

LastLast century, people used windmills to generate electricity in rural areas that century, people used windmills to generate electricity in rural areas that did not have electric service. When power lines began to transport electricity to did not have electric service. When power lines began to transport electricity to rural areas in the 1930s, the electric windmills were used less and less.rural areas in the 1930s, the electric windmills were used less and less.

Then in the early 1970s, oil shortages created an environment eager for Then in the early 1970s, oil shortages created an environment eager for alternative energy sources, paving the way for the re-entry of the electric alternative energy sources, paving the way for the re-entry of the electric windmill on the windmill on the worldworld landscape landscape [1]. [1].

3-3-WIND RESOURCEWIND RESOURCE

WhereWhere Wind Energy ComeWind Energy Comess From From

All renewable energy (except tidal and geothermal All renewable energy (except tidal and geothermal power), and even the energy in fossil fuels, power), and even the energy in fossil fuels, ultimately comes from the sun. The sun radiates of ultimately comes from the sun. The sun radiates of 1.74 x 10 1.74 x 10 watts energy to the earth per hour. watts energy to the earth per hour.

About 1 to 2 per cent of the energy coming from About 1 to 2 per cent of the energy coming from the sun is converted into wind energy. That is the sun is converted into wind energy. That is about 50 to 100 times more than the energy about 50 to 100 times more than the energy converted into biomass by all plants on earth converted into biomass by all plants on earth [2].[2].

1717

What WindWhat Wind Is Is

Wind is simply air in motion. It is caused by Wind is simply air in motion. It is caused by the uneven heating of the earth's surface by the uneven heating of the earth's surface by the sun. Since the earth's surface is made the sun. Since the earth's surface is made up of land, desert, water, and forest areas, up of land, desert, water, and forest areas, the surface absorbs the sun's radiation the surface absorbs the sun's radiation differently differently [1].[1].

Wind ResourcesWind Resources

Global windsGlobal winds Local Winds Local Winds

– Land Breezes and Sea BreezesLand Breezes and Sea Breezes– Mountain BreezesMountain Breezes andand Valley BreezesValley Breezes

Global WindsGlobal Winds

The wind rises from the equator and moves north and south in The wind rises from the equator and moves north and south in the higher layers of the atmospherethe higher layers of the atmosphere as shown in figure 1 as shown in figure 1 [2].[2].

Around 30°; latitude in both hemispheres the Around 30°; latitude in both hemispheres the Coriolis force Coriolis force prevents the air from moving much farther. At this latitude there prevents the air from moving much farther. At this latitude there is a high pressure area, as the air begins sinking down again. is a high pressure area, as the air begins sinking down again.

As the wind rises from the equator there will be a low pressure As the wind rises from the equator there will be a low pressure area close to ground level attracting winds from the North and area close to ground level attracting winds from the North and South. South.

At the Poles, there will be high pressure due to the cooling of the At the Poles, there will be high pressure due to the cooling of the airair [3]. [3].

Figure 1 Figure 1 Global windsGlobal winds..

Local Winds Local Winds

Land Breezes and Sea BreezesLand Breezes and Sea BreezesLand masses are heated by the sun more quickly Land masses are heated by the sun more quickly than the sea in the daytime. The air rises, flows than the sea in the daytime. The air rises, flows out to the sea, and creates a low pressure at out to the sea, and creates a low pressure at ground level which attracts the cool air from the ground level which attracts the cool air from the sea. This is called a sea breeze. At nightfall there sea. This is called a sea breeze. At nightfall there is often a period of calm when land and sea is often a period of calm when land and sea temperatures are equal. temperatures are equal. At night the wind blows in the opposite direction. At night the wind blows in the opposite direction. The land breeze at night generally has lower wind The land breeze at night generally has lower wind speeds, because the temperature difference speeds, because the temperature difference between land and sea is smaller at night between land and sea is smaller at night [2].[2].

Mountain BreezesMountain Breezes and and Valley BreezesValley Breezes Mountain breezesMountain breezes and and valley breezesvalley breezes are due to a are due to a combination of differential heating and geometry. combination of differential heating and geometry. When the sun rises, it is the tops of the mountain When the sun rises, it is the tops of the mountain peaks which receive first light, and as the day peaks which receive first light, and as the day progresses, the mountain slopes take on a greater progresses, the mountain slopes take on a greater heat load than the valleys. This results in a heat load than the valleys. This results in a temperature inequity between the two, and as warm temperature inequity between the two, and as warm air rises off the slopes, cool air moves up out of the air rises off the slopes, cool air moves up out of the valleys to replace it. This upslope wind is called a valleys to replace it. This upslope wind is called a valley breezevalley breeze. The opposite effect takes place in the . The opposite effect takes place in the afternoon, as the valley radiates heat. The peaks, afternoon, as the valley radiates heat. The peaks, long since cooled, transport air into the valley in a long since cooled, transport air into the valley in a process that is partly gravitational and partly process that is partly gravitational and partly convective and is called a convective and is called a mountain breezemountain breeze [4].[4].

4-4-WIND ENERGY TECHNOLOGYWIND ENERGY TECHNOLOGY

Horizontal Axis TurbineHorizontal Axis Turbine Vertical Axis TurbineVertical Axis Turbine Old-fashioned windmillsOld-fashioned windmills

Horizontal Axis Wind TurbineHorizontal Axis Wind Turbine

Most of the technology described in this project is related to Most of the technology described in this project is related to horizontal axis wind turbines (HAWTs,) horizontal axis wind turbines (HAWTs,) as shown in figure as shown in figure 2. 2.

The reason is simple: All grid-connected commercial wind The reason is simple: All grid-connected commercial wind turbines today are built with a propeller-type rotor on a turbines today are built with a propeller-type rotor on a horizontal axis (i.e. a horizontal main shaft). horizontal axis (i.e. a horizontal main shaft).

The purpose of the rotor, of course, is to convert the linear The purpose of the rotor, of course, is to convert the linear motion of the wind into rotational energy that can be used motion of the wind into rotational energy that can be used to drive a generator. The same basic principle is used in a to drive a generator. The same basic principle is used in a modern water turbine, where the flow of water is parallel to modern water turbine, where the flow of water is parallel to the rotational axis of the turbine blades the rotational axis of the turbine blades [5].[5].

Figure Figure 2 2 Horizontal axis Turbine Horizontal axis Turbine [6].[6].

Vertical Axis Vertical Axis Wind Wind Turbine Turbine As you will probably recall, classical water As you will probably recall, classical water

wheels let the water arrive at a right angle wheels let the water arrive at a right angle (perpendicular) to the rotational axis (shaft) (perpendicular) to the rotational axis (shaft) of the water wheel. of the water wheel.

Vertical axis wind turbines (VAWTs) are a Vertical axis wind turbines (VAWTs) are a bit like water wheels in that sense. (Some bit like water wheels in that sense. (Some vertical axis turbine types could actually vertical axis turbine types could actually work with a horizontal axis as well, but they work with a horizontal axis as well, but they would hardly be able to beat the efficiency would hardly be able to beat the efficiency of a propeller-type turbine). of a propeller-type turbine).

The only vertical axis turbine which has ever The only vertical axis turbine which has ever been manufactured commercially at any been manufactured commercially at any volume is the Darrieus machine, named volume is the Darrieus machine, named after the French engineer Georges Darrieus after the French engineer Georges Darrieus who patented the design in 1931. (It was who patented the design in 1931. (It was manufactured by the U.S. company FloWind manufactured by the U.S. company FloWind which went bankrupt in 1997). The Darrieus which went bankrupt in 1997). The Darrieus machine is characterized by its C-shaped machine is characterized by its C-shaped rotor blades which make it look a bit like an rotor blades which make it look a bit like an eggbeater. It is normally built with two or eggbeater. It is normally built with two or three bladesthree blades As shown in figure 3 [5]. As shown in figure 3 [5].

FigureFigure 3 3 Vertical axis Vertical axis wind turbine.wind turbine.

AdvantagesAdvantages of VAWT’sof VAWT’s

1) You may place the generator, 1) You may place the generator, gearbox etc. on the ground, and you gearbox etc. on the ground, and you may not need a tower for the machine. may not need a tower for the machine.

2) You do not need a yaw mechanism 2) You do not need a yaw mechanism to turn the rotor against the wind to turn the rotor against the wind [5].[5].

Disadvantages of VAWT’sDisadvantages of VAWT’s

1) Wind speeds are very low close to ground 1) Wind speeds are very low close to ground level, so although you may save a tower, level, so although you may save a tower, your wind speeds will be very low on the your wind speeds will be very low on the lower part of your rotor. lower part of your rotor. 2) The overall efficiency of the vertical axis 2) The overall efficiency of the vertical axis machines is not impressive. machines is not impressive. 3) The machine is not self-starting (e.g. a 3) The machine is not self-starting (e.g. a Darrieus machine will need a "push" before Darrieus machine will need a "push" before it starts. This is only a minor inconvenience it starts. This is only a minor inconvenience for a grid for a grid [5].[5].

Old-fashioned windmillsOld-fashioned windmills

Figure 4 Old-fashioned windmills.Figure 4 Old-fashioned windmills.

Why turbines not look like old-Why turbines not look like old-fashioned windmillsfashioned windmills

The old-fashionedThe old-fashioned, as seen in figure 4,, as seen in figure 4, windmill is windmill is viewed with nostalgia, and some people prefer the viewed with nostalgia, and some people prefer the look of them to that of their modern counterparts. look of them to that of their modern counterparts. Just because wind turbines are modern, it does Just because wind turbines are modern, it does not mean that they are less aesthetically pleasing. not mean that they are less aesthetically pleasing. A modern wind turbine is simply an improved A modern wind turbine is simply an improved windmill. Every aspect of their design has been windmill. Every aspect of their design has been optimized, and they are hundreds of times more optimized, and they are hundreds of times more efficient than old-fashioned windmills. To make efficient than old-fashioned windmills. To make them look more old-fashioned would result in them look more old-fashioned would result in much more expensive electricity [7]. much more expensive electricity [7].

5-5-WIND TRIBUNE USEWIND TRIBUNE USE

Electricity for homes and farmsElectricity for homes and farms Electricity for communitiesElectricity for communities Electricity in industryElectricity in industry Supplying electricity for a nationSupplying electricity for a nation Remote communitiesRemote communities Energy to drive pumpsEnergy to drive pumps

Electricity from turbinesElectricity from turbines

As shown in figure 5As shown in figure 5 aa wind turbine consists of six major wind turbine consists of six major components :  components : 

A rotor that aerodynamically converts the wind energy into A rotor that aerodynamically converts the wind energy into mechanical energy on a slowly turning shaftmechanical energy on a slowly turning shaft..     

A gearbox that increases the rotor-shaft speed for the A gearbox that increases the rotor-shaft speed for the generator. Some specially designed generators run at rotor-generator. Some specially designed generators run at rotor-shaft speed and do not need a gearboxshaft speed and do not need a gearbox..     

A generator that produces electricityA generator that produces electricity..      A control and protection system that optimizes performance A control and protection system that optimizes performance

and keeps the machinery operating within safe limitsand keeps the machinery operating within safe limits..      A tower that raises the rotor high off the ground where the A tower that raises the rotor high off the ground where the

wind speed is greater and the effects of local obstructions wind speed is greater and the effects of local obstructions are lessare less..     

A foundation that supports the wind turbine system, A foundation that supports the wind turbine system, sometimes with the aid of guy wiressometimes with the aid of guy wires [7].[7].

Figure 5 Figure 5 Major components of horizontal Major components of horizontal and vertical axis wind turbinesand vertical axis wind turbines..

Wind turbine generators produce a range of Wind turbine generators produce a range of electricity. Rotors that have diameters of electricity. Rotors that have diameters of about 1m produce a few hundred watts of about 1m produce a few hundred watts of electricity. Rotors that have diameters that electricity. Rotors that have diameters that approach 75approach 75 m can produce over one m can produce over one megawatt [7].megawatt [7].

Electricity for Homes and FarmsElectricity for Homes and Farms

Small and medium wind turbine generators at Small and medium wind turbine generators at homes, farms or small industrial sites can be homes, farms or small industrial sites can be used with diesel generators or connected to used with diesel generators or connected to the electrical supply grid. By connecting to the the electrical supply grid. By connecting to the electrical grid, the user of the electrical supply electrical grid, the user of the electrical supply pays only for the electricity they use from the pays only for the electricity they use from the electrical utility companyelectrical utility company [7]. [7].

Electricity For CommunitiesElectricity For Communities

Small numbers of medium/large wind Small numbers of medium/large wind turbine generators can be installed by turbine generators can be installed by groups of individuals wishing to contribute groups of individuals wishing to contribute pollution-free energy to their electricity pollution-free energy to their electricity networks [7].networks [7].   

Electricity in IndustryElectricity in Industry

Medium systems (10 to 100 kilowatts) can be used Medium systems (10 to 100 kilowatts) can be used by large farms, process industries, and groups of by large farms, process industries, and groups of individuals to offset costs of electricity from the individuals to offset costs of electricity from the grid network, or by remote communities to offset grid network, or by remote communities to offset fuel costs and pollution of diesel power plants.   fuel costs and pollution of diesel power plants.   Large systems (100 kilowatts to 1 megawatt) can Large systems (100 kilowatts to 1 megawatt) can be used either individually or in small clusters to be used either individually or in small clusters to provide electricity toprovide electricity to industries, large farms, or industries, large farms, or groups of dwellingsgroups of dwellings. When used in arrays of . When used in arrays of multiple units, they can supply significant amounts multiple units, they can supply significant amounts of electricity to provincial or national networks of electricity to provincial or national networks [7][7]..

Supplying Electricity For A NationSupplying Electricity For A Nation

Arrays of large wind turbine generators can Arrays of large wind turbine generators can be connected to electricity supply grids and be connected to electricity supply grids and can provide significant amounts of provincial can provide significant amounts of provincial and national electrical demand. In Denmark, and national electrical demand. In Denmark, for example, wind-generated electricity now for example, wind-generated electricity now provides about 10 % of national needs and provides about 10 % of national needs and is scheduled to provide 50 % of the need by is scheduled to provide 50 % of the need by 2030 [7].2030 [7].

Remote CommunitiesRemote Communities

Small wind turbine generators that are Small wind turbine generators that are connected to batteries can provide sufficient connected to batteries can provide sufficient electricity for rural dwellings, electricity for rural dwellings, communications relay stations, navigational communications relay stations, navigational aids, and other needs in isolated areas. aids, and other needs in isolated areas. Small and medium wind turbines may also Small and medium wind turbines may also be used for pumping, either by direct drive be used for pumping, either by direct drive or by powering electric pumps [7].or by powering electric pumps [7].

Energy To Drive PumpsEnergy To Drive Pumps

A wind turbine can be used to drive a A wind turbine can be used to drive a rotating or reciprocating pump. Like a wind rotating or reciprocating pump. Like a wind turbine, a wind pump has a rotor, a tower, turbine, a wind pump has a rotor, a tower, and foundations. However, the hydraulic and foundations. However, the hydraulic pump replaces the generator. Often, the pump replaces the generator. Often, the rotor shaft drives the pump directly, which rotor shaft drives the pump directly, which eliminates the need for a gearbox. eliminates the need for a gearbox. 

As shown in figure 6As shown in figure 6 tthe pump can be he pump can be located in the following places: located in the following places: 

on top of the tower at the turbine rotor on top of the tower at the turbine rotor shaft     shaft    

at ground level, in which case shafting or at ground level, in which case shafting or pulleys are used    pulleys are used   

at the bottom of the well, in which case a at the bottom of the well, in which case a reciprocating pump with a long "dipper rod" reciprocating pump with a long "dipper rod" is used [7].is used [7].

Figure 6 Mechanical and wind-electric water-pumping Figure 6 Mechanical and wind-electric water-pumping wind systems.wind systems.

6-WIND ENERGY IN TURKEY6-WIND ENERGY IN TURKEY

Turkish wind energy association was founded Turkish wind energy association was founded in 1992. by the help of energy ministry first in 1992. by the help of energy ministry first turbines built at İzmir- Çeşme-Alaçatı by ARES turbines built at İzmir- Çeşme-Alaçatı by ARES –GÜÇ BİRLİĞİ co. This turbines produces 7,2 –GÜÇ BİRLİĞİ co. This turbines produces 7,2 MW energy. In the same years DEMİRER MW energy. In the same years DEMİRER HOLDİNG built turbines at Çanakkale-HOLDİNG built turbines at Çanakkale-Bozcaada which produces 10,2 MW. Today Bozcaada which produces 10,2 MW. Today working is still going on to built new turbines working is still going on to built new turbines at İzmir- Çeşme, Çanakkale- Karacaören, at İzmir- Çeşme, Çanakkale- Karacaören, Muğla–Datça, Balıkesir- Bandırma [12].Muğla–Datça, Balıkesir- Bandırma [12].

7-7-ENVIROENVIRONNMENTMENT

Wind energy is considered a green power Wind energy is considered a green power technology because it has only minor impacts technology because it has only minor impacts on the environment. Wind energy plants on the environment. Wind energy plants produce no air pollutants or greenhouse produce no air pollutants or greenhouse gases. However, any means of energy gases. However, any means of energy production impacts the environment in some production impacts the environment in some way, wind energy is no different way, wind energy is no different [8].[8].

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

Birds and Other living ResourcesBirds and Other living Resources

Preconstruction surveys can indicate Preconstruction surveys can indicate whether birds or other living resources are whether birds or other living resources are likely to be affected by wind turbines. likely to be affected by wind turbines.

Noise Noise Like all mechanical systems, wind turbines Like all mechanical systems, wind turbines produce some noise when they operate. In recent produce some noise when they operate. In recent years, engineers have made design changes to years, engineers have made design changes to reduce the noise from wind turbines. reduce the noise from wind turbines.

TV/Radio Interference TV/Radio Interference In the past, older turbines with metal blades In the past, older turbines with metal blades caused television interference in areas near the caused television interference in areas near the turbine. Interference from modern turbines is turbine. Interference from modern turbines is unlikely because many components formerly made unlikely because many components formerly made of metal are now made from composites.of metal are now made from composites.

Global WarmingGlobal WarmingWind energy can help fight global warming. Wind energy can help fight global warming. Wind turbines produce no air emissions or Wind turbines produce no air emissions or greenhouse gasesgreenhouse gases [9] [9]. .

8-8-ECONOMICSECONOMICS

Ecomomics of wind energy based on Ecomomics of wind energy based on followings as shown in figure 7 followings as shown in figure 7

Wind source.Wind source. Capital cost.Capital cost. Wind energy market.Wind energy market. Technology [10].Technology [10].

Figure 7 Economics of wind energy.Figure 7 Economics of wind energy.

The cost of electricity from utility-scale wind The cost of electricity from utility-scale wind systems has dropped by more than 80% over the systems has dropped by more than 80% over the last 20 years last 20 years as seen in figure 8 and graph 1.as seen in figure 8 and graph 1.

GraphGraphicic ((11)) kwh cost kwh cost ($/kwh) ($/kwh) vsvs year graphic [10]. year graphic [10].

A simple tribune cost inA simple tribune cost in

Figure 8 cost of wind energy [11]Figure 8 cost of wind energy [11]

Wind energy is one of the Wind energy is one of the cheapest energy sourcecheapest energy source

We can compare wind We can compare wind energy source with another energy source with another sources in graphic 2 [10].sources in graphic 2 [10].

Graphic (2) cent/kwh&energy sourcesGraphic (2) cent/kwh&energy sources..

CONCLUSIONCONCLUSION

This is true that today's world need more This is true that today's world need more clean and more cheap energy. As I try to clean and more cheap energy. As I try to mentioned in this project wind energy is the mentioned in this project wind energy is the one of the best way of clean and cheap one of the best way of clean and cheap energy. And also it is understood that in the energy. And also it is understood that in the future most of our energy source will based future most of our energy source will based on wind energy.on wind energy.

ReferencesReferences

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http://www.german-renewable-energy.com/downloads/pdf/wwec/ecohttp://www.german-renewable-energy.com/downloads/pdf/wwec/economics_wind.pdfnomics_wind.pdf

11.11. http://solstice.crest.org/wind/index.htmlhttp://solstice.crest.org/wind/index.html12.12. http://www.meteor.gov.tr/2003/sorucevap/ruzgaren/http://www.meteor.gov.tr/2003/sorucevap/ruzgaren/

ruzgarenergel.htmruzgarenergel.htm