Harnessing Wind Energy Hayley Norris Dept. of Chemical Engineering The University of Texas at Austin

Why Wind? Wind Power Wind Power No ambient air pollution No ambient air pollution No fuel needed No fuel needed Unlimited wind supply Unlimited wind supply Installed wind capacity sharply increasing Installed wind capacity sharply increasing 2002 – 4,685 MW 2002 – 4,685 MW 2005 – 9,149 MW 2005 – 9,149 MW U.S. % increase in 3 yrs = 95% U.S. % increase in 3 yrs = 95% Global capacity (2005) = 35,000 MW Global capacity (2005) = 35,000 MW

A Brief History of Wind Western wind technology begins 1180 with the first Dutch wind mill Western wind technology begins 1180 with the first Dutch wind mill Windmills seem to have fueled great social upheavals and thus social activism Windmills seem to have fueled great social upheavals and thus social activism Early English windmill pioneers Early English windmill pioneers 1970s 1970s Now?? Now?? Early windmills-lightened physical load Early windmills-lightened physical load Grind grain, shred tobacco, pump water Grind grain, shred tobacco, pump water

Modern Wind Turbines

Wind Potential - US Wind class of 3 or better for current technologies Wind class of 3 or better for current technologies Based on average wind speed and wind power density Based on average wind speed and wind power density 6% of US land area class 3 or better 6% of US land area class 3 or better Can supply 1 ½ current electricity consumption Can supply 1 ½ current electricity consumption US electricity consumption (2003) US electricity consumption (2003) billion kWh billion kWh If tapped all of US good wind potential If tapped all of US good wind potential billion kWh produced billion kWh produced

Texas Wind Potential Map Classes: Green-3, Yellow-4, Orange-5, Red-6

Texas Wind Potential Best regions for wind development Best regions for wind development Panhandle and W. TX Panhandle and W. TX Potential electrical generation of these regions Potential electrical generation of these regions billion kWh billion kWh Wind can generate 493% of current electrical consumption in TX Wind can generate 493% of current electrical consumption in TX

Wind Turbine Main Components Rotor Rotor Only part uniquely manufactured for wind power Only part uniquely manufactured for wind power Transmission system Transmission system Generator Generator Yaw system Yaw system Control system Control system

Blade Design Aerodynamic lift drives turbine Aerodynamic lift drives turbine Constant tip-speed ratio Constant tip-speed ratio Higher tip-speed, more noise Higher tip-speed, more noise Important concept: as radius Important concept: as radius increases, blade speed increases Taper and twist blades Taper and twist blades Twist – optimizes lift Twist – optimizes lift Taper – constant lift along length Taper – constant lift along length Better torque for self-starting Better torque for self-starting

Turbines Currently 3 blades 3 blades Best efficiency Best efficiency Aesthetically pleasing Aesthetically pleasing Minimal fluctuations Minimal fluctuations Self-starting Self-starting Fiberglass blades Fiberglass blades Strong, inexpensive Strong, inexpensive Good fatigue characteristics Good fatigue characteristics Carbon fiber if price decreases Carbon fiber if price decreases

Conclusions Plenty of wind energy around to support world’s electricity needs cleanly Plenty of wind energy around to support world’s electricity needs cleanly Horizontal-axis turbines most commercially viable Horizontal-axis turbines most commercially viable Blade design based on complex aerodynamics Blade design based on complex aerodynamics Current turbine design Current turbine design Taper and twist blades Taper and twist blades 3 blades 3 blades Fiberglass Fiberglass