Wind Energy Educators’ Workshop This slide show is a basic outline. We often make changes to this template depending on the time and location of the event. 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

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 First windmills were found in Persia. They were vertical axis and were used to grind grains and seeds. Reeds form blades. They were kind of like a waterwheel turned on its side. Most of the paddles were covered by a wall and wind would run through a narrow opening to push the blades. Many have seen the Dutch windmills. Used to grind grains, seeds, pump water, saw lumber…these were fairly sophisticated devices. Used to cover much of New England coastline.

Water pumpers were (and still are) a common site on farms in the Midwest and West. These devices pump water into a pond or cistern when it is windy and can be used at any time. Notice the blades on this device and compare them to electrical generating wind turbines are they the same or different?

Smith-Putnam Turbine Vermont, 1940's Jacobs Turbine – 1920 - 1960 Smith-Putnam Turbine Vermont, 1940's WinCharger – 1930s – 40s In 1888, Charles F. Brush invented a large wind turbine which created electricity. This enormous windmill produced enough electricity for about 10 homes. Brush’s invention was soon adapted and copied all over the world. Electricity generating wind turbines spread throughout Europe in the early 1900’s, and they soon appeared in the United States as well. In the 1930s Marcellus Jacobs producing an affordable small turbine called the Jacobs that provided electricity for homes and farms throughout rural America. However, these small American turbines faded away with the widespread installation of power lines through the end of the 1930s.

Modern Small Wind Turbines: 50 kW 10 kW Technically Advanced Minimal Moving Parts Very Low Maintenance Requirements Proven: ~ 5,000 On-Grid American Companies are the Market and Technology Leaders 400 W 900 W When teachers build their Basic PVC Turbines they are more like a small wind turbine, simple direct drive systems. Emphasize high RPM…these things spin fast 300-600 RPM. Many of these are sent to villages offshore as they can provide power for an entire village…here in the US is hard to justify the cost for one household. $$ on small wind turbines 10K-100K (Not to scale)

Various small HAWTs 1. Southwest Skystream 2. Bergey 3. ARE (now Xzeres) Check out http://www.smallwindcertification.org/index.html

Orientation Turbines can be categorized into two overarching classes based on the orientation of the rotor Vertical Axis Horizontal Axis Turbine can spin on a vertical axis or a horizontal axis

Vertical Axis Turbines 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) Windspire See testing on early Mariah Windspire at NREL – test was discontinued due to failures. Spire seen swaying in the wind. Beware “Hope & hype” hucksters 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 Ask what is upwind and what is downwind. Explain how small turbines can turn into or away from wind with

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

At right – world’s largest turbine Enercon E-126 near Emden, Germany 6MW to be adjusted to 7+ Over 20,000,000 kW produced – enough to power 5000 European families of four

Wind Turbine Perspective Workers Blade 112’ long Nacelle 56 tons Tower 3 sections

Turbines Being Tested One “ballast” model is being tested right now off the coast of Norway. Search “hywind” for some cool info and images. Commercial application of this technology is still a long way off… Imagine one of these in a 10 year storm event. Yikes!

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!

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US Capacity is Growing in fits and starts

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 The rapid growth in wind power can be attributed to two things….reduction in cost of the electricity produced and more interested in Green Power. I usually ask people here what they pay for their electricity by kwh….typical # are 7-20 cents. Wind has come way down in terms of cost over the last 40 years. The cheapest power out there is coal and wind cannot compete with that…Natural Gas and coal are comparable. The costs for wind listed above are the wholesale rate…do not include transmission etc. On this slide I often ask the crowd how we generate most of our electrical power in the US. Coal 50% Nuclear 20% Natural Gas 17% Hydro 7% Oil 3% Renewables 3% Wind less than 1% 2004: 3 – 4.5 cents/kWh

Wind Farm in the MidWest. Farmers and landowners are paid by wind developers to lease land for turbines. Not a bad cash crop!

Wind Farms

Off-Shore Wind Farms Many developers would like to move windfarms offshore because the wind are faster, smoother and they can be close to major population centers on the coast. This is very controversial in the US….we have a few planned offshore farms…CapeWind and Long Island…but nothing installed. Major complaints about offshore are related visual impact, navigation impact and lack of history. Check http://www.capewind.org/

Middelgrunden There are quiet a few offshore wind farms in Europe near Holland, England, Ireland, Sweden and the Denmark. This one is off the coast of Copehagen.

Key Issues

Fighting windmills has a long history! Don Quixote fighting “Giants”

Costs & Benefits We also need to change students perceptions about what the future may look like and the limits of this technology. Wind will never be “base load” for the grid. The wind farm above is capable of generating 15-20Mw of electricity at full capacity. The oil fired facility below is at 300Mw. Most Nuclear plants are at 600-1000Mw… Must keep the scale in mind….a very aggressive wind program can generate 10-20% of our power needs. To move towards a green future we are going to need mix of sources and also a great deal of energy efficiency….Wind cannot do it all.

Where do we get our electricity? KidWind Project | www.kidwind.org 27

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 Pass around coal

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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! Altamont Pass Wind Farm in California… This wind farm was built in the 1980’s. Without doing an Environmental Impact Assessment, they built the wind farm in a raptor migration path. This wind farm had a major problem with avian mortality, and scarred the industry. Today this farm is being repowered. This means they are taking down the old turbines and replacing them with new. With one new turbine, they can replace 10 old turbines. Still poorly sited, but this is an improvement.

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. National Audubon Society endorses wind power…

It is a common complaint that wind turbines kill birds It is a common complaint that wind turbines kill birds. While it is true that turbines kill birds, this graph puts that in perspective with other human technologies.

Impacts of Wind Power: Noise Modern turbines are relatively quiet Rule of thumb – stay about 3x hub-height away from houses Many people think wind turbines are noisy. While this may have been true in the past (it is still somewhat true on older smaller devices)…newer larger devices are much quieter.

KidWind Project | www.kidwind.org Note the Wind Belt 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? Probably the largest issue facing Commercial Wind Energy is transmission. It is typically windy where people don’t want to live so how will you get the power from where it is generated to where the people live? Most people oppose new power line construction vehemently….so this will be a touchy issue for a very long time. Quick Fact: 1 mile of High Voltage transmission line can cost upwards of $1 million!

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 This is the equation for the power in the wind. (Don’t fear – there are only 2 equations in this presentation.) Each of the terms in this equation can tell us a lot about wind turbines and how they work. Lets look at wind speed (V), swept area (A), and density (Greek letter “rho,” ) one at a time. First, let’s look at wind speed, V. Because V is cubed in the equation, a small increase in V makes for a increase in power. (illustrated on next slide) (Click on the links at the bottom to get the values of both k and .) Swept Area: A = πR2 Area of the circle swept by the rotor (m2).

Why do wind turbines need to be high in the sky?? The higher we get the more faster and cleaner the wind are. As you move closer to the earth the friction with the surface of the earth causes the wind to slow down and to become more turbulent…bad things if you want to generate energy from the wind. The nacelle of most commercial wind turbines is around 100 meters.

Turbulent wind is bad wind “Micro-Siting” refers to how a wind turbine is placed on a given property. Trees and buildings are significant obstacles to the wind. We can’t see it, but the region of disturbed flow downwind of an obstacle is twice the height of that obstacle and quite long. For example, a 30-ft tall house creates a region of turbulence that is 60 ft high and 600 ft long (2 football fields!). This turbulence reduces power output from a wind turbine, and increases the stress and wear on that turbine. THE SOLUTION  Place the turbine upwind of obstacles (in the prevailing wind direction), or use a tower twice the height of the obstacles, or both.

Technology Part of a turbine…all turbines from our little models to the biggest in the world have these parts.

A look inside. Things to note as compared to Small Wind Turbines Blades can be actively pitched by hydraulics. Spin at 12-20 RPM --- much slower than a small wind turbine Large driveshaft attached to a gearbox….must go from 12-20 RPM to 1600 RPM for the generator. Generator creates electricity. Small Wind Turbines use vanes (typcally) to track the wind…they uses and anemometer and hydraulics to move the turbine. Highly computerized and automated….senses conditions and can turn itself off if there is a problem. Often connected by computers to one location and run from there.

KidWind Project | www.kidwind.org The “guts” of a wind turbine 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 Fast Faster Fastest

Tip-Speed Ratio ΩR TSR = V R Ω = rotational speed in radians /sec 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 R ΩR V TSR = Where, Ω = rotational speed in radians /sec R = Rotor Radius V = Wind “Free Stream” Velocity

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 Low solidity (0.10) = high speed, low torque High solidity (>0.80) = low speed, high torque R a A 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

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In addition to teaching about wind power because of it’s growth in the US I find it to be an elegant source of power as do students when they try to build their own spinning devices. Solar boring….just sits there;-) I will often tell a story about the Research done by Smart Power SmartPower research is based on the fact that studies continue to show consumers are willing to switch and pay more for renewable energy, yet there is minimal market activity to date. SmartPower wanted to understand what are the emotional barriers which prevent people from purchasing clean energy and what are the most powerful emotional hooks that could make clean energy important and desirable to the American public?   SmartPower brought together focus groups to explore how the public perceives current energy choices. Participants were charged to write an obituary. Respondents were asked to imagine fossil fuels on earth have died. Their task is to then to write an obituary including: What was the cause of death? What will it be remembered for? Who will take its place? Who will miss it? They found that many people were far less critical of fossil fuels than you might have imagined. Many felt it was scary to imagine our world without fossil fuels.  While many participants clearly recognized the problems of pollution, health and energy independence, they see fossil fuels as a necessary evil because it can be relied on to power our world. They also did not know about reliable alternatives. While they were all comfortable discussing clean energy and know how it’s made -- they don’t see it as “being up to the job” and is viewed as “eccentric” with “kinks to work out.” Next, they asked respondents to draw what their “clean energy” world would look like and to name their “worlds” and date them. The pictures reinforced the prior findings; fossil fuels are viewed as a necessary evil -- bad for health, bad for the environment, bad for national security. But at the end of the day, it keeps my house warm. Some other findings were that: Clean energy is simply not seen as up to the job Using clean energy would require sacrifices Clean energy is just too far in the future to be useful now As the obituaries and the drawings tell us we need to convince people that clean energy is strong enough to take the place of coal, oil and nuclear. They also found that we need to inform consumers that these sources are available and happening now. From this research came an advertising campaign that tries to convince people that clean energy is viable and available. The slogans, ads and radio spots created by this research is called Clean Energy: Its Real. It’s Here. It’s Working. Let’s Make More. Now SmartPower is doing research to see if this campaign changes any peoples mind about renewable energy choices.

Wind Energy in the Classroom

KidWind Project | www.kidwind.org 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 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 63

Upper Elementary/Middle Building Wind Turbines Assessing Wind Resource Mathematics balloon ~3m streamers Kite or balloon string 64

Secondary Advanced Blade Design School Siting Projects Data Analysis Mathematics - Download lessons Math lessons – free downloads on topics such as gear ratios, tip speed ratio & tower height estimation. 66

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!

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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 Download Wind Energy curriculum at www.windwiseeducation.org Individual lessons are FREE to download KidWind Project | www.kidwind.org

KidWind Project | www.kidwind.org JOIN US! Register On-Line at KidWind. See link below: KidWind Project | www.kidwind.org http://learn.kidwind.org/workshops_events/state/massachusetts/event/2821

The KidWind Project www.kidwind.org Presenters: Susan Reyes Science & Sustainability Educator KidWind Wind Senator sreyes7@mac.com Lynda Elie NYSERDA - Energy & Sustainability Educator KidWind - WindWise Curriculum Presenter lynda@kidwind.org