Evaluation of global wind power Cristina L. Archer Stanford University 5 October 2005 San Jose State University
Outline Introduction on wind energy Least Square (LS) Methodology Global wind maps at 80 m Validation Statistics Calculation of global wind power potential Benefits of networking
Introduction Wind turbines are: reliable non invasive Wind energy is: clean inexpensive abundant scalable increasingly popular More info: Archer and Jacobson (2003)
Some Examples of Wind Turbines 32 m rotor blade of a 1.5 MW turbine (~54 m) Vindeby (DK) Copenhagen (DK)
Problems with wind power Intermittency Unreliability Noise Aesthetics Animals and birds Solutions: Siting Networking frequency of low wind speeds standard deviation of wind speed
Least Squares (LS) methodology Power law:Log law: Friction coefficient (1/7) Roughness length (0.01 m)
Least Squares (LS) methodology Power law:Log law:
LS methodology: examples
Mean 80m Wind Speed at Sounding Locations
Mean 80m Wind Speed in North America
Mean 80m Wind Speed in Europe
Validation: KSC towers
Four-level towers
Statistics: Global Frequencies ClassN. of stations Percent Total Total ≥
Statistics: Global Mean 80m Speeds Station TypeMean V80Mean V80 for Class ≥3 (m/s) Surface over land Buoys Soundings All
Calculation of Global Wind Power P global = 72 TW =53,898 Mtoe P global = f x A land x x P turb 12.7%1.3x10 8 km 2 6 km x /77 2 P turb = P rated x CF = P rated x (0.087V-P rated /D 2 )
Calculation of Global Wind Power
Problems with wind power Intermittency Unreliability Noise Aesthetics Animals and birds Solutions: Siting Networking frequency of low wind speeds standard deviation of wind speed
Methodology for hourly 80m- trends
Methodology for hourly 80m- patterns
The shear function ( )
The shear function ( ) at KSC
Networking – The arrays
Networking – Frequency Distributions
Networking - Statistics
Conclusions 1)~13% of world’s stations are in class ≥3 2)Mean wind speed is steady and reliable at “windy” locations 3)Data from KSC support LS methodology 4) Networking several wind farms virtually eliminates intermittency and reduces backups 5) Global wind power potential is 72 TW 6) More results at: