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Wind Energy Educators’ Workshop. The Kidwind Project and WindWise. What is KidWind?. The KidWind Project is a team of teachers, students, engineers and practitioners exploring the science behind wind energy in classrooms around the US.
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Wind Energy Educators’ Workshop The Kidwind Project and WindWise
What is KidWind? The KidWind Project is a team of teachers, students, engineers and practitioners exploring the science behind wind energy in classrooms around the US. Our goal is to introduce as many people as possible to the elegance of wind power through hands-on science activities which are challenging, engaging and teach basic science principles. KidWind Project | www.kidwind.org KidWind Project | www.kidwind.org
Wind Power • Yesterday & Today • Key Issues • The Wind Resource • Technology • Wind in the Classroom • Resources & Opportunities KidWind Project | www.kidwind.org
Yesterday & Today Holland & Colonial America First documented windmill: Afghanistan (900AD) Greece
Jacobs Turbine – 1920 - 1960 Smith-Putnam TurbineVermont, 1940's WinCharger – 1930s – 40s
50 kW 10 kW 900 W 400 W Modern Small Wind Turbines: • Technically Advanced • Minimal Moving Parts • Very Low Maintenance Requirements • Proven: ~ 5,000 On-Grid • American Companies are the Market and Technology Leaders (Not to scale)
Orientation Turbines can be categorized into two overarching classes based on the orientation of the rotor Vertical AxisHorizontal Axis
Advantages Omnidirectional Accepts wind from any angle Components can be mounted at ground level Ease of service Lighter weight towers Can theoretically use less materials to capture the same amount of wind Disadvantages Rotors generally near ground where wind poorer Centrifugal force stresses blades & components Poor self-starting capabilities Requires support at top of turbine rotor Requires entire rotor to be removed to replace bearings Overall poor performance and reliability/less efficient Have never been commercially successful (large scale) Vertical Axis Turbines Windspire Savonious
Horizontal Axis Wind Turbines • Rotors are usually Up-wind of tower • Some machines have down-wind rotors, but only commercially available ones are small turbines • Proven, viable technology
Large Wind Turbines • 450’ base to blade • Each blade 112’ • Span greater than 747 • 163+ tons total • Foundation 20+ feet deep • Rated at 1.5 – 5 megawatt • Supply at least 350 homes
Workers Blade 112’ long Nacelle 56 tons Tower 3 sections Wind Turbine Perspective
Wind Energy is a Growing Industry • 50% growth rate! • US total installed wind energy capacity now over 43,635 MW as of Sept 2011 per WindPoweringAmerica.com • Enough electricity to power the equivalent of over 7 million households!
Wind Energy Industry Growth 1979: 40 cents/kWh 2000: 4 - 6 cents/kWh NSP 107 MW Lake Benton wind farm 4 cents/kWh (unsubsidized) • Increased Turbine Size • R&D Advances • Manufacturing Improvements 2004: 3 – 4.5 cents/kWh
Fighting windmills has a long history! Don Quixote fighting “Giants”
Where do we get our electricity? KidWind Project | www.kidwind.org
What’s in Common Here? • Nitrous oxides, sulfur oxides leading to sulfuric and nitric acid formation • Toxic heavy metals including mercury, arsenic and others • Volatile organic compounds • Surface ozone pollution • Soot particles • Hydrocarbons • Greenhouse gases
And linked to… • Asthma & breathing troubles • Cancer & other health problems • Damaged lakes and forest ecosystems • Damaged monuments • Injury to trees and other plants • Injury to animals • Haze, smog and poor visibility • Oil spills • Poisoned water supplies • Strip mined mountains • Conflict among people
Burning fossil fuels contributes to many serious issues impacting our health, environment, society and security…including global warming 4 in 10 adults cannot name a fossil fuel. 6 in 10 adults cannot name a renewable energy source. -Public Agenda
Accidents & Troubles “So far no evacuation zone has been declared. There are no threats to sea life, and the fallout from the disaster was not detectable thousands of miles away. Cleanup efforts are in progress, and will not include covering the area in a giant concrete dome. No workers have been asked to give their lives in order to save their countrymen from the menace of this fallen wind turbine.” – Christopher Mims KidWind Project | www.kidwind.org
1980’s California Wind Farm • Older Technology • + Higher RPMs • + Lower Elevations • + Lattice Towers • + Poorly Sited • = Bad News!
In the November-December Audubon Magazine, John Flicker, President of National Audubon Society, wrote a column stating that Audubon "strongly supports wind power as a clean alternative energy source," pointing to the link between global warming and the birds and other wildlife that scientist say it will kill.
Impacts of Wind Power:Noise • Modern turbines are relatively quiet • Rule of thumb – stay about 3x hub-height away from houses
The Transmission Challenge • Where is the wind? • Where are the population centers? • Where are the wind farms? • How do we get wind energy from the wind farms to the population centers?
Importance of Wind Speed • No other factor is more important to the amount of power available in the wind than the speed of the wind • Power is a cubic function of wind speed • V X V X V • 20% increase in wind speed means 73% more power • Doubling wind speed means 8 times more power
Calculation of Wind Power • Power in the wind • Effect of swept area, A • Effect of wind speed, V • Effect of air density, Power in the Wind = ½ρAV3 R Swept Area: A = πR2 Area of the circle swept by the rotor (m2).
Airfoil Shape Just like the wings of an airplane, wind turbine blades use the airfoil shape to create lift and maximize efficiency. The Bernoulli Effect
Lift & Drag Forces • The Lift Force is perpendicular to the direction of motion. We want to make this force BIG. • The Drag Force is parallel to the direction of motion. We want to make this force small. α = low α = medium <10 degrees α = High Stall!!
Pitch Control Mechanisms KidWind Project | www.kidwind.org
