Transcript Slide 1
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 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 WinCharger – 1930s – 40s Smith-Putnam Turbine Vermont, 1940's 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 10 kW 400 W 50 kW 900 W (Not to scale) Orientation Turbines can be categorized into two overarching classes based on the orientation of the rotor Vertical Axis Horizontal Axis Vertical Axis Turbines Advantages Disadvantages • Omnidirectional • Rotors generally near ground where wind poorer • Centrifugal force stresses blades & components • Poor self-starting capabilities Windspire • 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) – 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 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 Wind Turbine Perspective Workers Blade 112’ long Nacelle 56 tons Tower 3 sections Turbines Being Tested 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! KidWind Project | www.kidwind.org US Capacity is Growing in fits and starts Wind Energy Industry Growth 1979: 40 cents/kWh 2000: 4-6 cents/kWh • Increased Turbine Size • R&D Advances • Manufacturing Improvements NSP 107 MW Lake Benton wind farm 4 cents/kWh (unsubsidized) 2004: 3 – 4.5 cents/kWh Wind Farms Off-Shore Wind Farms Middelgrunden Key Issues Fighting windmills has a long history! Don Quixote fighting “Giants” Costs & Benefits 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 28 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 29 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 30 KidWind Project | www.kidwind.org 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 KidWind Project | www.kidwind.org 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 – VXVXV • 20% increase in wind speed means 73% more power • Doubling wind speed means 8 times more power Calculation of Wind Power •Power the=wind Power in theinWind ½ρAV3 – Effect of swept area, A – Effect of wind speed, V – Effect of air density, Swept Area: A = πR2 Area of the circle swept by the rotor (m2). R Why do wind turbines need to be high in the sky?? Turbulent wind is bad wind Technology KidWind Project | www.kidwind.org How does a generator generate electricity? 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 Twist & Taper • Speed through the air of a point on the blade changes with distance from hub • To optimize angle of attack all along blade, it must twist from root to tip Fastest Faster Fast Tip-Speed Ratio Tip-speed ratio is the ratio of the speed of the rotating blade tip to the speed of the free stream wind. There is an optimum angle of attack which creates the highest lift to drag ratio. Because angle of attack is dependant on wind speed, there is an optimum tip-speed ratio ΩR TSR = V Where, Ω = rotational speed in radians /sec R = Rotor Radius V = Wind “Free Stream” Velocity ΩR R Performance Over Range of Tip Speed Ratios • Power Coefficient Varies with Tip Speed Ratio • Characterized by Cp vs Tip Speed Ratio Curve Betz Limit All wind power cannot be captured by rotor or air would be completely still behind rotor and not allow more wind to pass through. Theoretical limit of rotor efficiency is 59% Most modern wind turbines are in the 35 – 45% range Rotor Solidity Solidity is the ratio of total rotor planform area to total swept area R Low solidity (0.10) = high speed, low torque a A High solidity (>0.80) = low speed, high torque Solidity = 3a/A Over-Speed Protection During High Winds Upward Furling: The rotor tilts back during high winds Angle Governor: The rotor turns up and to one side Yawing – Facing the Wind • Active Yaw (all medium & large turbines produced today, & some small turbines from Europe) • Anemometer on nacelle tells controller which way to point rotor into the wind • Yaw drive turns gears to point rotor into wind • Passive Yaw (Most small turbines) • Wind forces alone direct rotor • Tail vanes • Downwind turbines Maintenance KidWind Project | www.kidwind.org Wind Energy in the Classroom Many Topics Addressed Use of Simple Tools & Equipment Forces Cause Change Energy Transformations (Forms of Energy) Circuits/Electricity/Magnetism Weather Patterns Renewable – Non Renewable Energy KidWind Project | www.kidwind.org Scientific & Engineering Practices New National Frameworks 1. 2. 3. 4. 5. 6. 7. 8. Asking questions & defining problems Developing & using models Planning & carrying out investigations Analyzing & interpreting data Using mathematics & computational thinking Developing explanations & designing solutions Engaging in argument from evidence Obtaining, evaluating & communicating information Elementary • • • • Engineering is Elementary Wind Chimes Wind Art Designing Simple Blades Upper Elementary/Middle balloon ~3m streamers Kite or balloon string • Building Wind Turbines • Assessing Wind Resource • Mathematics Secondary • • • • • Advanced Blade Design School Siting Projects Data Analysis Mathematics Download lessons Wind Turbine Blade Challenge • Students perform experiments and design different wind turbine blades • Use simple wind turbine models • Test one variable while holding others constant • Record performance with a multimeter or other load device • Goals: Produce the most voltage, pump the most water, lift the most weight – Minimize Drag – Maximize LIFT – Harness the POWER of the wind! KidWind Project | www.kidwind.org KidWind Opportunities & Resources KidWind and Wind Wise Web Sites Free Downloads -- Wind Wise – Math Lessons NEW On-Line Turbine Design Competition KidWind store – good prices: great stuff KidWind Competitions NEW Western Massachusetts Event May 5, 2012 KidWind Project | www.kidwind.org KidWind Project | www.kidwind.org Register On-Line at KidWind. See link below: KidWind Project | www.kidwind.org The KidWind Project www.kidwind.org Presenters: Susan Reyes Science & Sustainability Educator KidWind Wind Senator [email protected] Lynda Elie NYSERDA - Energy & Sustainability Educator KidWind - WindWise Curriculum Presenter [email protected]