wind 101-half-5 fundamentals - wind-works: welcome€¦ ·  · 2013-08-06wind turbines @ wulf...

Fundamentals of Wind Energy

Paul Gipe, wind-works.org

Power in the Wind

321 AVP

Where is air density (kg/m3),A is area (m2), andV is velocity (m/s).

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Air Density

TRp*

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Where p is air pressure (mb),R is the gas constant, andT is temperature (K)

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Vegetative Indicators--Wind

Throw

Aude, France

Increase in Wind Speed Over Ridges

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Seasonal Wind Distribution

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Jan Feb March April May June July Aug Sept Oct Nov Dec

Month

0

2

4

6

8

10

12

14

16

18Avg. Monthly Wind Speed (mph)

Amarillo, TexasErie, Penn.San Francisco, Calif.

Rayleigh Wind Speed Distribution

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Wind Speed Bin

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16Frequency of Occurrence %

5 m/s6 m/s7 m/s

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Weibull Wind Speed DistributionFor Same Average Speed

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0 2 4 6 8 10 12 14 16 18 20 22 24

Wind Speed (m/s)

0

0.05

0.1

0.15

0.2

0.25Frequency (%)

0

10

20

30

40

50

60

70

Power Density (W/m2)

Tera Kora %Tera Kora W/m2Helgoland %Helgoland W/m2

Speed, Power, & Height

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V/Vo = (H/Ho) α

P/Po = (H/Ho) 3α

Where α is the surface friction coefficient.• 1/7 (0.14), Low Grass Prairies• 1/4 (0.25), Suburbs• 0.40, Urban

Increase in Wind Speed with Height

1 1.5 2 2.5 3 3.5 4 4.5 51

1.1

1.2

1.3

1.4

1.5

1.6

Wind Shear Exponent0.1 0.14 (1/7) 0.2 0.25

V=Vo (H/Ho)"

H/Ho

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Increase in Power with Height

1 1.5 2 2.5 3 3.5 4 4.5 51

1.5

2

2.5

3

3.5Wind Shear Exponent

0.1 0.14 (1/7) 0.2 0.25

P=Po (H/Ho)

H/Ho

"3

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Change in Wind Speed & Power with Height

2 X Height 25 to 50 m

5 X Height 10 to 50 m

Wind Speed 1.1 1.25

Wind Power 1.35 1.99

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1/7 (0.14), Low Grass Prairies

Wind Resources of Ontario

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Wind Resources of the Dakotas

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Energy in the WindAnnual Energy Output (AEO)

Annual Energy Production (AEP)

AEO = 1/2 ρ A V ή (8,760 hrs/year)3

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AEO Estimating Methods

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• Back-of-the-Envelope (Swept Area)Simple Approximation

• Power Curve & Speed DistributionMethod Used by the ProsAccuracy Dependent Upon Data

• Manufacturers’ TablesDependent Upon Honesty of Manufacturer

• SoftwareMust Know Assumptions Used (RETScreen)

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Rotor Dimensions

Medium-Size & Large Wind Turbines

01020304050607080

Rotor Diameter (m)

250

1500

1000

500

50

15 25 40 60 70 80Diameter (meters)

0

1000

2000

3000

4000

5000

Swept Area (m²)

2000

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Measured Efficiency of Small Wind Turbines @ Wulf Field

0 5 10 15 20 25 30 35Wind Speed (mph)

0

0.05

0.1

0.15

0.2

0.25

0.3Efficiency (%)

MarlecLVMAir 303Air 403BWC 850Ampair

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AEO Small Wind Turbines

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Conversion Efficiency

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0

0.1

0.2

0.3

0.4

0.5

Effi

cien

cy

0 2 4 6 8 10 12 14 16 18 20 Wind Speed (m/s)

L 18/80 S31 E40 V47

Medium Size Wind TurbinesMeasured Efficiency

bk1/medturbeffic.wb3

California Annual Specific Yield

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86 87 88 89 90 91 92 93 94 95 96 97 98 99 '00 '01 '02 '03

Year

0

200

400

600

800

1,000

1,200

1,400Annual Specific Yield (kWh/m2/yr)

Cal. Avg.San Gorgonio Farms

Tararua New Zealand Yields

Tararua Wind Plant New Zealand Specific YieldsVestas V47

Specific YieldSwept AreaDiameterApproximatekWh/m2/yrm2mkWh/yr

8008401,735471,457,901Low1,5001,4401,735472,500,000Median1,8001,7601,735473,050,622High

WindStats, Spring 2005, Vol. 18, No. 2, pg 13.

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AEO Medium & Large Turbines

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Estimating AEOSwept Area Method for 7 m/s*

Paul Gipe, wind-works.org *At Hub Height

Turbine Swept Area (m2)

Yield (kWh/m2/yr)

AEO (kWh/yr)

36 m; .5 MW 1,000 1,000 1,000,000

50 m; .75 MW 2,000 1,000 2,000,000

62 m; 1 MW 3,000 1,000 3,000,000

80 m; 2 MW 5,000 1,000 5,000,000

Sample Power Curve CalculationPower Curve

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8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

Wind Speed (mph)

00.10.20.30.40.50.60.70.80.9

11.11.2

Kilowatts

Sample Power Curve CalculationSpeed Distribution

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8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

Wind Speed (mph)

0

100

200

300

400

500

600Hours per Year

Sample Power Curve CalculationAnnual Energy Production

Paul Gipe, wind-works.org

8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40Wind Speed (mph)

0

20

40

60

80

100kWh/year

Net Generation from Wind Plants

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Net

Availability 98%

Electrical 97%

Array Interference 90%-95%

Total 86%-90%

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Measures of Productivity

• Capacity (Plant) FactorMisleading IndicatorUsed for Fossil-Fired PlantsNot Suited for Wind Energy Use

• kWh/kW/yr (for Planning Purposes)When Sufficient Data is Unavailable

• Annual Specific Yield (kWh/m2/yr)The Only Measure Specific to Wind Energy

Measures of Cost• $/kW of Installed Capacity

Often a Misleading Indicator

• $/m2 of Installed Swept AreaMost Useful When Resource is Unknown

• $/kWh/yr of Annual GenerationMost Important Criteria in the End

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Wind Energy Software• Spreadsheets

Integrated (Tom Wind)Fully Integrated (RETScreen)

• Wind Farm Design ToolsWAsP (Risø)WindFarm (ReSoft)WindFarmer (Garrad Hassan)WindPro (EMD)WindMap (Brower)

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Paul Gipe, wind-works.org

Wind Turbine StandardsSmall Turbines

Caveat Emptor (Buyer Beware)You Get What You Pay For

Big TurbinesMinimum Design Stds. (GL)Power Curve Field TestsWarranteed Power CurvesPerformance GuaranteesField Experience Best Guide

Trade Magazines

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• Windpower Monthly• WindStats• WinDirections• RE World• New Energy• Neue Energie• North American Windpower• Systèmes Solaires

• Power Curves• Noise• Power Factor• Flicker

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Measured Performance Data

Pricing

• Model• Tower• Transformer• €/kWh/annum• €/m2

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New Wind Books

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2002 20012002

2005

WWW Sites

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• www.windpower.dkDanish Manufacturers

• www.eole.org/ en français

• www.wind-energie.deBWE, German Wind Turbine Owners

• wind-works.orgArchive of Articles by Paul Gipe

Don’t Be Afraid of Foreign Language Web Sites