Fundamentals of Wind Energy. Paul Gipe, wind-works.org

Transcription

1 Fundamentals of Wind Energy

2 Power in the Wind P 1 AV 2 3 Where is air density (kg/m 3 ), A is area (m 2 ), and V is velocity (m/s).

3 Air Density p R* T Where p is air pressure (mb), R is the gas constant, and T is temperature (K)

4 Vegetative Indicators--Wind Throw Aude, France

5 Increase in Wind Speed Over Ridges

6 Seasonal Wind Distribution 18 Avg. Monthly Wind Speed (mph) Amarillo, Texas Erie, Penn. San Francisco, Calif. 0 Jan Feb March April May June July Aug Sept Oct Nov Dec Month

7 Rayleigh Wind Speed Distribution 0.16 Frequency of Occurrence % 5 m/s m/s 7 m/s Wind Speed Bin

8 Weibull Wind Speed Distribution For Same Average Speed Frequency (%) Power Density (W/m2) Tera Kora % 70 Tera Kora W/m2 60 Helgoland % Helgoland W/m Wind Speed (m/s)

9 Speed, Power, & Height V/V o = (H/H o ) α P/P o = (H/H o ) 3α Where α is the surface friction coefficient. 1/7 (0.14), Low Grass Prairies 1/4 (0.25), Suburbs 0.40, Urban

10 Increase in Wind Speed with Height V=V o (H/H o ) " Wind Shear Exponent (1/7) H/H o

11 Increase in Power with Height " P=P o (H/H o ) Wind Shear Exponent (1/7) H/H o

12 Change in Wind Speed & Power with Height 2 X Height 25 to 50 m 5 X Height 10 to 50 m Wind Speed Wind Power /7 (0.14), Low Grass Prairies

13 Wind Resources of Ontario

14 Wind Resources of the Dakotas

15 Energy in the Wind Annual Energy Output (AEO) Annual Energy Production (AEP) 3 AEO = 1/2 ρ A V ή (8,760 hrs/year)

16 AEO Estimating Methods Back-of-the-Envelope (Swept Area) Simple Approximation Power Curve & Speed Distribution Method Used by the Pros Accuracy Dependent Upon Data Manufacturers Tables Dependent Upon Honesty of Manufacturer Software Must Know Assumptions Used (RETScreen)

17 Rotor Dimensions

18 Medium-Size & Large Wind Turbines 5000 Swept Area (m²) Rotor Diameter (m) Diameter (meters)

19 Measured Efficiency of Small Wind Wulf Field Efficiency (%) Marlec LVM Air 303 Air 403 BWC 850 Ampair Wind Speed (mph)

20 AEO Small Wind Turbines

21 Conversion Efficiency 0.5 Medium Size Wind Turbines Measured Efficiency 0.4 Efficiency bk1/medturbeffic.wb Wind Speed (m/s) L 18/80 S31 E40 V47

22 California Annual Specific Yield 1,400 1,200 Annual Specific Yield (kwh/m2/yr) 1, Cal. Avg. San Gorgonio Farms '00 '01 '02 '03 Year

23 Tararua New Zealand Yields Tararua Wind Plant New Zealand Specific Yields Vestas V47 Diameter Swept Area Specific Yield kwh/yr m m 2 kwh/m 2 /yr Low 1,457, , Median 2,500, ,735 1,440 High 3,050, ,735 1,760 WindStats, Spring 2005, Vol. 18, No. 2, pg 13. Approximate 800 1,500 1,800

24 AEO Medium & Large Turbines

25 Estimating AEO Swept Area Method for 7 m/s* Turbine Swept Area (m2) Yield (kwh/m2/yr) AEO (kwh/yr) 36 m;.5 MW 1,000 1,000 1,000, m;.75 MW 2,000 1,000 2,000, m; 1 MW 3,000 1,000 3,000, m; 2 MW 5,000 1,000 5,000,000 *At Hub Height

26 Sample Power Curve Calculation Power Curve Kilowatts Wind Speed (mph)

27 Sample Power Curve Calculation Speed Distribution 600 Hours per Year Wind Speed (mph)

28 Sample Power Curve Calculation 100 kwh/year Annual Energy Production Wind Speed (mph)

29 Net Generation from Wind Plants Net Availability 98% Electrical 97% Array Interference 90%-95% Total 86%-90%

30 Measures of Productivity Capacity (Plant) Factor Misleading Indicator Used for Fossil-Fired Plants Not Suited for Wind Energy Use kwh/kw/yr (for Planning Purposes) When Sufficient Data is Unavailable Annual Specific Yield (kwh/m 2 /yr) The Only Measure Specific to Wind Energy

31 Measures of Cost $/kw of Installed Capacity Often a Misleading Indicator $/m 2 of Installed Swept Area Most Useful When Resource is Unknown $/kwh/yr of Annual Generation Most Important Criteria in the End

32 Wind Energy Software Spreadsheets Integrated (Tom Wind) Fully Integrated (RETScreen) Wind Farm Design Tools WAsP (Risø) WindFarm (ReSoft) WindFarmer (Garrad Hassan) WindPro (EMD) WindMap (Brower)

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34 Wind Turbine Standards Small Turbines Caveat Emptor (Buyer Beware) You Get What You Pay For Big Turbines Minimum Design Stds. (GL) Power Curve Field Tests Warranteed Power Curves Performance Guarantees Field Experience Best Guide

35 Trade Magazines Windpower Monthly WindStats WinDirections RE World New Energy Neue Energie North American Windpower Systèmes Solaires

36 Measured Performance Data Power Curves Noise Power Factor Flicker

37 Pricing Model Tower Transformer /kwh/annum /m 2

38 New Wind Books

39 WWW Sites Danish Manufacturers en français BWE, German Wind Turbine Owners wind-works.org Archive of Articles by Paul Gipe

40 Don t Be Afraid of Foreign Language Web Sites

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