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Home My WebLink AboutWind Power, A Resource Booklet for Middle & High School Teachers 2007© Copyright 2007 Kotzebue Electric Associ Teacher’s Guide to Using The Wind Power Resource Materials Introduction This binder contains basic student readings on the history of wind energy and the math and science used in designing wind turbines. It also contains exercises, model plans and some other reference materials you may find useful in identifying appropriate additional readings or activities for students. : The core materials in this binder, “Wind Power: A Brief History,” “Wind Power: Math, Science and Technology,” and the model plans were originally created by Rollin Tait for Green Mountain Power in Vermont. Green Mountain Power gave Kotzebue Electric Association permission to adapt the materials for use in Alaska. The first KEA draft of these materials, produced in 2000, was slightly updated in 2007. Before using these materials, you may find it useful to have students review some of the standard curriculum materials available regarding electricity and magnetism. Such a review may help students understand the material presented here, which does not go into how electricity is produced, focusing instead on how wind energy is captured. While each section may be used as a stand-alone piece, students will likely find it motivating to read the history section first before tackling the formulas in the math and science section. Please consider this binder a start, and a place to organize additional information you may want to gather or develop for teaching about wind power. Summary of Binder Contents A short summary of what is behind each tab in this binder is listed below, as is a review of which State of Alaska curriculum standards may be met through using these materials. Section A: Wind Power: A Brief History. This section contains reading material that can be copied as a stand-alone section for a student handout. It reviews the uses people have made of wind power since ancient times and how technology for harnessing wind energy has changed and developed. It ends with a focus on the status of wind power generation in Alaska. It is followed by a tab behind which you can store exercises you may develop for this section. Section B: Wind Power: Math, Science and Technology. This section contains reading material that can be copied as a stand-alone section for a student handout. It reviews how winds are created, how geographic features and obstacles affect wind power, the relationship between wind power and wind speed, how to calculate the amount of power in the wind, and some of the basic features and calculations that go into designing rotors which are used to capture wind power. Teacher’s Guide to Wind Power Resource Materials — page 2 of 3 Glossary: Definitions of some wind power terms. Model Plans: Model plans compiled by Rollin Tait for the original Green Mountain Power version of this curriculum material. Students can use these plans to create different types of rotors. Wind at Work Activities. Copies of few of the exercises and activities included in Gretchen Woelfe’s excellent book “The Wind at Work.” You may wish to purchase a copy of this book. Web and Other Resources: There are tremendous educational resources available through the Internet. A number of websites have basic background information about wind power. Government, industry association and turbine manufacturer sites provide a great deal more detail about the matters covered in the readings that are included in this binder. Information is available about energy economics, marketing and other matters not covered here. Behind this tab, find: ¢ A listing of some of the major Web sites with information about wind power ¢ The bibliography for the original Green Mountain Power materials Alaska Education Standards In 2000, a former teacher and developer of middle school science curriculum materials reviewed the materials in this binder and suggested they had, at that time, the ‘ potential to address the following Alaska Education Standards: Math A2: Select and use appropriate systems, units, and tools of measurement, including estimation. Math A4: Represent, analyze and use mathematical patterns, relations, and functions using methods such as tables, equations, and graphs. Math B1: Use computational methods and appropriate technology as problem-solving tools. Math B2: Use problem solving to investigate and understand mathematical content. Math Cl: Express and represent mathematical ideas using oral and written presentations, physical materials, pictures, graphs, charts, and algebraic expressions. Math C2: Relate mathematical terms to everyday language. Teacher's Guide to Wind Power Resource Materials — page 3 of 3 Math E1: Explore problems and describe results using graphical, numerical, physical, algebraic, and verbal mathematical models or representations. Math E3: Use mathematics in other curriculum areas. Science AS: Understand the strength and effects of forces of nature, including gravity and electromagnetic radiation (Forces of Nature). Section A6: Understand that forces of nature cause different types of motion and describe the relationship between these forces and motion (Motion). Science A15: Use science to understand and describe the local environment (Local Knowledge). Science SB2: Design and conduct scientific investigations using appropriate instruments. Science C3: Understand that society, culture, history, and environment affect the development of scientific knowledge. Science D3: Recommend solutions to everyday problems by applying scientific knowledge and skills. Geography E1: Understand how resources have been developed and used. History D6: Create new approaches to issues by incorporating history with other disciplines, including economics, geography, literature, the arts, science and technology. Wind Power: A Breef History Wind Power: a Brief History Page A-2 TABLE OF CONTENTS WIND PowWER HiIsToRY TIMELINE Wind Power History Timeline... ccccecssssssssssssssssssssssssssssseeee Page A-4 CHAPTER 1—ANCIENT HISTORY (up 10 1200 AD) SATIS so cesensansscnsnsnsenenssesesssantstanvavarncosorsncnnnrestovusdonssiocvenssonborcssonasesssesvossessas Page A-7 WGCEG oc ccensesranssnsscssccsasconnnnezzsts suse easssssssssganenssnnssvFivanssststsssoseeresTvPwTavesoos000 Page A-7 Animal-powered machines... essssssssssssssssssssssssssssssssansnneseee Page A-8 Horizontal beam Mill .........ccccccecccssssssecsesessesseecseeeeeeeeeseeeeeeee Page A-8 BU re each rr i erersereneeneererereorecvorervvereteveeeseevenreececteeetsvorstersevsseeverereer7™ Page A-9 Water-powered Machines........esssssssssssesssssssssssssssssssesssesssnssee Page A-9 Undershot waterwheel 0.00.0... Page A-9 Overshot waterwheel .u.........ccccssssssssssssssssssssssssssssssnssnsesee Page A-9 Wind-powered machines .. ..Page A-10 Persian windmill... ..Page A-10 Chinese “Clapper” windmill ... ..Page A-11 Cretam Win drmllll 0... ssssesesnsnnsssssenscccsscssccssscscssccceseeseeececees Page A-12 CHAPTER 2—MIDDLE HISTORY (1200 to 1850 AD) Post Wind... eeeessssssssssssseeeseeessseeeesssssssssssssssssnssssssssssseeseneee Page A-13 (apy wien ch aa erescereeessereesceneenreencnenenessestesenernerteetrarreeeetreeoeerroeeeceea Page A-13 Rotor blade imMproveMentts ..............sceccesssssssssssssssssssssssseseseseenees Page A-13 Bear Cea GEV ACI ee cerre cee esecrectcecsretcrevceretceseesnogestrernereeesssesseetetoreereressset Page A-14 John Smeaton... eeesssssssssssseceeeeseeeeessnssnessnssnsnsnnenennesssesseeeeees Page A-14 Industrial REVOLUtION w.eeeeeceesessssscsssseseeseessesnsnneeseseecessssssnnnneess Page A-15 CHAPTER 3—MODERN HISTORY (1850 To 1950) First generation Wind Turbines. ............cessssseseescscsssssesnees Page A-16 Denmark: Professor P. La Cour ........ccccssssssssssseessesssssssssssneess Page A-16 FRUUSS Dea ecrsesssenecsecveccccsscerasesreevsveseetscccssssovatassonvacacatscevecessvnsssetinareeseviveseeress Page A-17 England: Golding and Stoddard... Page A-17 Germany: Ulrich Hutter .......ccssssssssssssssssscssssscsssssesseeeeeesseeee Page A-17 SavONiUS ANd Daxrrieus LOtOLS.........csecssssscccsccccccsscseseseseseseeeesseee Page A-18 Wind Power: a Brief History TABLE OF CONTENTS -— continued CHAPTER 4—USA History (1850 To 1990) Small wind turbime PUMPS .........ccceccsesssssssssssssssesssssesseseeseeeseeeee Page A-19 Small wind electricity gemerators 20.0... eeccceseeeesecsessstteeeesseeee Page A-20 Grandpa's Knob wind turbine ... ...Page A-20 EMeIgy CYISIS ......sccceeesssessssseesseeseeseseeceeeccsssssnneeeeeceeeeeesesssnnunnnsseeees Page A-21 Second generation wind turbines .0..0.... eee Page A-21 The California wirnd rush oo.......ccccccccccssssssssssssssseseseseceeeseeeeeeeeeetee Page A-22 CHAPTER 5—THE FUTURE OF WIND POWER Wind power has Come Of age .......ssessssssssssssssennseseeeeeeeeeeseeene Page A-23 National Energy Policy ACt........cccssssssssssessssseseecsesssnsnnnnesseeeees Page A-23 World Wind Energy Association .........cccsssssssssssssssssssssssssseeeseee Page A-24 United States Wind Resource Map ou... Page A-26 CHAPTER 6—WIND POWER IN ALASKA SVT AAU AS Ia reeceerenecceovarcencarneerevonconenvonnegsenrenrssnenenceessseccertvesnoraniv Page A-27 Reasons for exploring wind energy in Alaska................. Page A-27 History of wind energy in Alaska uuu... Page A-31 The first utility wind farm in Alaska uw... Page A-33 Wind energy development in Alaska uu... cessssssseseeeeeeen Page A-33 Page A-3 Wind Power: a Brief History Page A-4 WIND POWER HISTORY TIMELINE Year Pre 2000 BC 2000 BC 500 AD 1000 AD 1200 AD 1600 AD 1750's 1750 - 1850 1870 - 1900 1865 - 1950's Event Sails and kites are in common use throughout Eurasia. The Persian windmill is developed in the Middle East. The Chinese Clapper windmill is developed in Asia. The Persian windmill is brought to Europe. The Cretan windmill is developed in the Middle East. The Cretan windmill design spreads across Europe. The low-land European countries developed the Post and Cap windmills to do a wide variety of work. Shuttered wooden blades replace cloth on windmills. Englishman John Smeaton conducted the first scientific research on wind power and windmill design. The Industrial Revolution transforms everyday life. Coal-fired steam power becomes the dominant power Source. Windmill use and research stagnates. Electric generators, motors and lights are perfected. The internal combustion engine is invented. The first hydroelectric dam is built. Mechanical, modern-design wind powered water-pumps are widely used in the American west. Wind Power: a Brief History WIND POWER HISTORY TIMELINE Year 1890's 1910 - 1945 1910's 1920's 1937 1941 - 1945 1973 and 1980 1980 - 1990 1980's 1990's Event Dane P. La Cour researches modern windmill design. The first generation of large-scale wind turbine generators are built in numerous countries. Small-scale stand-alone wind turbine generators were widely used in rural USA, especially the west. The Danes build the first large-scale wind turbines. The Savonius and Darrieus rotors are invented. The Rural Electrification Act establishes national Electricity grids eliminating the market for small wind turbines. Grandpa's Knob turbine operates at Rutland, VT, USA. Oil shortage crises stimulate development of alternative energy sources: solar, wind, hydro, biomass. The second generation of large-scale wind turbine generators are built in the USA and western Europe. Experimental stand-alone turbines are installed separate from utility systems in Alaska. Most fail quickly. New legislation, government subsidies, improved designs and rising oil prices make wind-generated electric power cost competitive with traditional energy sources. The third generation of large-scale wind turbine generators are built in increasing numbers. Page A-5 Wind Power: a Brief History Page A-6 WIND POWER HISTORY TIMELINE — continued Year 1997 1998 1999 2000 2002 2003 2005 2006 2007 Event Kotzebue Electric Association (KEA) installs three Entegrity Wind Systems 15/50 turbines at Alaska’s first utility-run wind energy farm. 225 kW turbine installed on St. Paul island to serve Tanadgusix Corporation commercial complex. KEA installs seven additional Entegrity 15/50 turbines bringing its wind farm to 10 turbines and installed capacity of 660 kW. Wordwide installed wind energy generation capacity reaches 17,300 megawatts. KEA installs two Entegrity 15/50 turbines at Wales, Alaska with a total capacity of 132 kW. KEA installs one Northern Power Systems 100 kW Northwind 100 turbine. Alaska Village Electric Cooperative (AVEC) installs four Entegrity 15/50 turbines in Selawik, Alaska with a total capacity of 264 kW. KEA installs two additional Entegrity 15/50 turbines. KEA installs two additional Entegrity 15/50 turbines and one Vestas E-15 turbine at Kotzebue. Alaska Village Electric Cooperative (AVEC) installs three Northern Power Systems Northwind 100 turbines at Toksook Bay with a total capacity of 300 kw. KEA installs one additional Entegrity 15/50 turbine at Kotzebue for a total of 17 turbines and 1155 kW capacity, the first Alaska wind farm over one megawatt. Wind Power: a Brief History CHAPTER 1—ANCIENT HISTORY (up To 1200 AD) People all over the world have been har- nessing the power of the wind for a very long time — 4 millennium at least (since about 2000 BC). Many machines have been created to make use of the power of the wind. Some of these devices are for work, others are just for fun. This booklet will introduce you to some of these wind machines and to the people who made them. Sails: When people think of capturing the power of the wind most people think of sails and sailboats. Early sails were of the ‘parachute’ or ‘drag’ type, designed merely to be pushed along by the wind (figure 1). Later, sails of the ‘wing’ or ‘lift’ type were able to make better use of the wind (figure 2). These improvements in sail design foreshadowed windmill and airplane developments later on in history. Kites: The kite is another ancient device which makes use of the power of the wind. It has a long history in the Far East (China, Japan, etc.) and in the Pacific (Indonesia, Polynesia, Hawaii, etc.). While seen today as a Key IDEAS IN THIS CHAPTER e The power in the wind can be harnessed to do work. e Early uses included transportation, pumping and grinding. Te ep Foon Side figure 1 figure 2 Page A-7 Wind Power: a Brief History plaything, kites had strong cultural and reli- gious significance. They were thought to be able to contact the Gods and were seen as divine instruments, controlled by the Gods themselves. Kites have been used both for work as well as playthings. They have been used as aerial fishing rods, (figure 3), for observation in SSS ee Wartime (figure 4), to pull vehicles (figure 5), and figure 4 they have been instrumental in the development of the airplane (figure 6). = figure 5 / figure 6 Animal powered machines: Wind machines able to do work such as grinding or pumping water were developed from animal and water-powered machines in the 2000 years before Christ. Animal (or human) powered machines appear to have developed first. One of these early devices was the Horizontal beam mill aaa (figure 7). The animal pulled the beam which turned the axle with its attached grind stone which ground the grain. Page A-8 Wind Power: a Brief History The Treadmill was another useful machine (figure 8 ). Here, pushing on the treadmill paddles (or track) turned the axle with its attached water scoops which lifted (pumped) water. Both of these devices were simple, robust and low-tech. Water-powered machines: It seems probable that water-powered machines were in use before wind-powered ones. There were a couple of rea- sons for this. First, water was easier to harness than wind figure 8 because it flows in a well defined location and direction. Wind is less predictable. Second, water is denser than wind and so has more power in its flow. Wind doesn’t push as hard. The most common water-powered machines in the ancient world were developments of the treadmill design idea. The two basic types were the Undershot and the Overshot waterwheels (figures 9 and 10). figure 9 Water-power would appear to be the power source of choice. However, there are situations where wind-power is best. Areas which are flat, like open farmland, often did have enough running water for water-powered machines. In fact, getting water to these areas (or out of them) so crops can be grown was often what the machine is needed for in the first place. If there are steady, strong winds then wind power was the solution. Of course, any area with lots of wind had potential to be a good site for wind-powered machines. Page A-9 Wind Power: a Brief History Wind powered machines: The earliest wind-powered machines were developments of existing animal and water-powered models. Two families (types) of wind-machine emerged, each with its own design features and each from different areas of the world. From the Mid-East came the Persian Windmill and from the Far East came the Chinese "Clapper" Windmill. Both of these designs were developments of the Horizontal Beam Machine and, in the end, developed into modern Vertical Axis Wind Turbines (VAWT) such as the Savonius and Darrieus rotor turbines. From the Mediterranean region came the Cretan (or Greek) windmill, a development that combined the treadmill machine design a sail-rotor for motive power. This design evolved into the modern Horizontal Axis Wind Turbines (HAWT) which are the cur- rent standard design. The map below shows the origins of the windmills of the Middle and Far East. (figure 11). The World figure 11 Vertical axis windmills: The Persian windmill was developed in Persia (modern day Iran) and the Middle East around 2000 BC (figure 12). In this design an axle-sail assembly, like an up-ended paddle wheel, was placed inside a tower with windows in it that Page A-10 Wind Power: a Brief History allowed the wind to hit the sails on only one side of se the axle. The axle, connected to a grind stone, turned k and grain was ground. The tower was built to face the prevailing wind. If the wind came from a different direction then the windmill wouldn't work. This problem was solved by replacing the tower with a ie movable screen to block the wind (figure 13). These oe Persian windmills spread throughout the Middle East Tep View and were brought to Europe through Africa and Spain around 500 BC. ‘\ The Chinese “Clapper” Windmill (figure 14) need- ed no tower or shield because the sails ‘feathered’ or turned ‘edge-on’ to the wind for the return half of % their cycle. To do this the sails had special pivot axles SS and stop-pins. The noise made by the sails hitting their retaining pins gave this windmill its name. A figure 13 major advantage of this type gu of mill was that it worked no matter where the wind came from. gee Sipe b i i + it : SE DE cts figure 14 Page A-11 Wind Power: a Brief History Horizontal axis windmills: The Cretan (or Greek) windmill, developed on the island of Crete (part of Greece) and in Egypt, around 500 BC. (figure 15) This windmill was the forerunner of the modern propeller-style wind turbine. It had a rotor with 8 to 10 sail-blades mounted on top of a tower. The rotor and tower were positioned so they faced into the prevailing wind. At some point in its development, the windmill became able to be rotat- ed on its base (or tower), which allowed it to make use of winds from any direction. The Cretan windmill was not a direct-drive mill like the Persian and Chinese windmills. It had to have a power-transfer linkage to get the power of the turning rotor down to the ground where it could be used. This was done through a crank arm, | belts, or gears, etc. (figure 15). By the 11th century windmills were common in the Middle and Far-East. y | They were used for all types of work. It is thought that windmill technology moved to Western Europe with traders and the returning Crusaders (in the 12th and 13th centuries). Ask YOURSELF THIS... e How has the wind been used in this area? e How do you use the wind? Page A-12 Wind Power: a Brief History CHAPTER 2—MIDDLE HISTORY (1200 To 1850 AD) By the 13th c. windmills were common throughout lowland Europe: Holland, Germany, France, England, etc. The Dutch took the lead in improving windmill design and used them extensively to drain marshes to reclaim land for farming. Key IDEAS IN THIS CHAPTER e Refinements were made to windmill designs to solve operational problems. Postmill: The predominant type was based on the Cretan windmill. The Dutch developed two main models. In the Post Windmill, the whole body of the windmill was mounted on a huge pivot-post. The windmill could be turned into the wind by pushing a pole stuck out the back. (figure 16). Capmill: In the Cap Windmill, the tower body of the windmill was fixed on the ground and the ‘cap’ (top) of the mill could be turned into the wind on its own. This was easier to build and allowed the tower base to be used for storage (figure 17). e The intermittent availability of wind made it less attractive than water- powered machines and the internal combustion engine Rotor blade improvements: The Dutch also improved the design of the rotor blades. By the 16th century cloth sails-blades were replaced by more efficient and con- trollable shuttered wooden blades. (figure 18). Sipe Page A-13 Wind Power: a Brief History Fantail: In 1745 an Englishman, Edmund Lee, patented a device that automatically kept the windmill facing into the wind. This was the Fantail, a small rotor set perpendicular to the main rotor. When the windmill was head-on to the wind, the fantail didn’t turn TYPES OF SAIL: A. oldest type, double-sided (about 1600) B. normal old-fashioned Dutch type (one leading board taken away) C shuttered type with air brake D. shuttered type with sky scraper. Pe figure 18 because it was edge-on to the wind. When the wind shifted to the side, the fantail would then be turned by the wind. Through a series of gears, the fantail would turn the main rotor to face the wind again (figure 19). In the 1750’s John Smeaton, another Englishman, was the first to scientifically investigate windmill design and performance. He discovered some of the basics ‘laws’ of rotor and blade design. His propeller testing machine is shown (figure 20). Page A-14 These designs represented the height of windmill technology at the time. Windmills were built in America and other parts of the world. But, radical change was on the hori- zon ... The Industrial Revolution (roughly 1750 to 1900) changed the developed world. Attention was focused on new technologies (steam power, mass production of goods) and new ways of life (people moved from agricul- tural to factory work). The late 1800’s saw the arrival of electric power, the internal combustion engine, and many other laborsaving devices. Wind-powered machines could not compete head-to-head with steam and water powered ones and so the development of wind-powered machines stagnated. Do You REMEMBER? e What were some of the innovations made to make it easier to use windmills in shifting winds? e Why were water-powered and internal combustion machines chosen over wind-powered machines? Page A-15 Wind Power: a Brief History CHAPTER 3—MODERN HISTORY (1850 To 1950) Key IDEAS IN THIS CHAPTER e Electricity use became wide- spread because it provided power in a form that can be used to doa lot of different kinds of work. Wind machines were developed to produce electricity. e Aircraft propeller technology developed during World War I spurred a boom in wind energy development for farms and other remote areas. Page A-16 Up to this point in history, windmills were used to produce local, mechanical power. A new type of windmill was being born ... the wind turbine electric genera- tor. This type of windmill could produce power in one place to be used in another. Electric power generation was the wave of the future. First generation wind turbines: Many countries worked on developing the first generation of large-scale wind turbine generators, most notably Denmark, Russia, England, France, Germany, and the USA. In Denmark, Professor P. La Cour set up a research wind turbine in 1891 (figure 21). His work laid the foundation for modern wind turbine science. By 1910 several hundred large- scale wind turbines were in service. These turbines had 80-foot towers support- ing 75-foot diameter 4-bladed shuttered wood rotors driving 25 kW generators. (figure 22). The tower was a steel-lattice design. The generator was at the bottom of the tower, driven by a shaft coming down from the rotor. Wind Power: a Brief History In 1931, Russia built a large wind turbine near Yalta on the Black Sea. It had an advanced aviation-style rotor. The generator was now moved to the top of the 100 foot tall tower. The turbine produced 100 kW. Development was halted by the Second World War (figure 23). In the 1940’s and 50’s English wind-power pioneers E. Golding and A. Stoddard did research on wind and wind turbines. In 1950 a 100 kW turbine was built on the Orkney Islands (figure 24). Also during the 40’s and 50’s the Germans, under the direction of Professor Ulrich Hutter introduced a number of improvements in turbine design. They introduced lightweight, simplified components: rotors built with fiberglass or plastic blades, towers made of a single tubes figure 23 supported by guy wires, and direct-drive generators. They also continued the now-standard use of an aviation- style, variable-pitch, constant-speed, 3-bladed rotors. These are common features of the modern wind tur- bine, (figure 25) though not all wind turbines share these features. Despite these advances, engineers found that the cost of large-scale wind- generated power was high compared with that produced by conventional fossil-fuel power plants. Therefore, further ae a development of wind power was sporadic and slow. Page A-17 Wind Power: a Brief History Savonius and Darrieus Rotors: The Savonius Rotor was invented by S.J. Savonius of Finland, in the late 1920's. (figure 26). It XN operates like a cup anemometer, being dragged around by Or? the wind. It does produce some lift though and it can be made into a kite quite easily (figure 27). This turbine has fom applications for mechanical operations (like pumping water) but is not efficient enough for electrical generation. Cj SIDE “Ts The Darrieus Rotor was invented by Frenchman G.J.M. —_— oF Darrieus in 1929 (figure 28). It was also re-invented by two figure 26 Canadians, Raj Rangi and Peter South in 1964. The Canadian team only found out it had already been invented when they applied for a patent on it! It looks like a huge, up-ended eggbeater, with rapidly spinning D-shaped _ blades mounted on a vertical axle. The \ Canadian government did a lot of ‘research on these rotors but ‘\_ they have not been used -. in commercial-scale power production. figure 27 \ \, figure 28 CHECK YOUR KNOWLEDGE... e What design features from the 1940's and 1950’s have become the standard for rotors today? Page A-18 Wind Power: a Brief History CHAPTER 4—USA HISTORY (1850 To 1990) Small wind turbine pumps: In the USA small wind turbine pumps were developed after the Civil War (1865) to supply water in the new territories of the west. Two compa- nies, Halladay and Eclipse, manufactured turbines which could be moved and built more readily than traditional types (figure 29). Note that these windmills were built of metal. By the turn of the century hundreds of thousands of windmills were in use across the country. After World War I wind-electric generation really took off due to advances in aircraft propeller technology. These new propeller blade designs made wind turbines more efficient. At the same time people in rural areas like the Mid-West wanted to have electricity like people in urban areas. If rural folks wanted electric power, they had to produce it themselves. Key IDEAS IN THIS CHAPTER e Wind turbines were used broadly for pumping water in agricultural areas. plants. The energy crises of 1973 the early 1980s spurred Congress to encourage wind energy development. ments in the 1980s made a leader for awhile. Wind energy development declined when most of the country became interconnected in a large electricity grid and could tap efficient large-scale fossil-fuel and hydroelectric The “California Wind Rush” and other wind energy develop- and the U.S. Page A-19 Wind Power: a Brief History Page A-20 Small electric wind generators: Beginning in the early 1920’s a number of companies produced small electric wind generators for stand-alone operation on rural farms and homesteads. These gen- erators produced DC electricity and could charge up bat- teries for storage. One of the first of these turbine generators was the Aeroelectric (figure 30). Another pioneer turbine was the Jacobs Wind Electric designed and built by Marcellus Jacobs (figure 31). This was the Cadillac of turbines, simple and yet efficient. There are 60 year-old Jacobs turbines still in use! Another DC generator was the Wincharger (figure 32). Over the 30 year period from 1920 to 1950 over a million wind generators were installed in rural locations across the USA. This proliferation of wind power was to be cut short by The 1937 Rural Electrification Act. This act made low-cost, cen- trally distributed electric power available to rural areas. People didn’t need their wind generators anymore — the government brought electricity to their homes and farms on poles and wires. Grandpa's Knob wind turbine: In 1941 the USA joined European countries in developing a first-generation, large-scale wind turbine generator. The Smith- Putnam wind turbine was built on Grandpa's Knob near Rutland, Vermont (figure 33). This was the world’s largest wind turbine of the time. It produced 1250 kW (1.25 MW) of power. It operated off an : on until 1945 when one of its 85-foot ic blades broke off and it was shut down. Z I rt As in Europe, it was found that the cost _ of large-scale wind-generated power was MS high compared with that produced by con- z ventional fossil-fuel power plants. Despite Wind Power: a Brief History technological advancements, wind-power simply couldn’t compete with inexpensive, often government-subsidized fossil-fuel and nuclear power plants. Use of wind-power to generate electricity went into decline. Energy Crisis: In 1973, the first Oil Crisis hit. The USA and i : the rest of the industrialized world realized they couldn't count eas on cheap, readily available fossil fuels. In the early 1980’s there was another oil crisis. This prompted Congress to pass legislation providing federal funding to the Department of Energy (DOE) for research and development of commercial-scale wind-power systems. The National Renewable Energy Lab (NREL) was established and its wind-power section, The National Wind Technology Center (NWTC), carried out research on a wide variety of turbines. At the same time, California instituted state-level tax credits to stimulate development and use of alternative ass energy sources. In addition to funding for R & D, the legislation forced utility companies to buy the new wind-generated electricity even if it was more expensive than traditionally produced electricity. The stage was set for The California Wind Rush. Investors couldn't resist — first, get a subsidy to develop the product and then, have a guaranteed market for it. Second generation wind turbines: First generation commercial wind turbines were large (500 kW to 1.5 MW). In the 40’s and 50’s engineers learned that despite the theoretical advantages of large size, the big machines were not the way of the future at that time. They couldn't be made as efficient in practice as they were in theory. They had a bothersome number of Page A-21 Wind Power: a Brief History mechanical problems. They required a large, unobstructed site and were somewhat intrusive. It was found that smaller machines could do the job better. They were as efficient as the large machines. They were easier to build and repair. They lasted longer in service because of modern, light-weight materials and new, better construction techniques. The California Wind Rush: Smaller, advanced-design turbines were built in the thousands, mostly in California because of the tax incentive and market-guarantee program there. By 1986 there were over 17,000 turbines in California producing 90% of the world’s wind-generated electricity. Most of these were located in densely laid-out wind farms around San Francisco: Tehachapee (figure 34), Altamont Pass, and near Palm Springs. The US Windpower company’s model 56-100 was typical of these second generation wind turbines. It had a 56 foot rotor diameter and developed 100 kW of power. It was the “Jeep” of the California Wind Rush. The USA was dominant in the field of wind-power. However, in the next ten years the USA would lose its preeminent place in wind power. Government tax credits and other incentives dried up as the energy crisis eased. At the same time European governments stepped up their investment in wind power. By 1996, the US share of world wind-generated electricity had dropped to 30% (from 90% in 1986). CONSIDER THIS... e Why was wind energy popular with farmers in the United States? What changed? e How is the situation in Alaska similar and different than in other areas of the United States? Page A-22 Wind Power: a Brief History CHAPTER 5—THE FUTURE OF WIND POWER Wind turbine technology continues to advance, with various designs being developed for specific wind profiles, environmental characteristics and applications. Wind turbines come with power ratings ranging from 500 watts to 5 megawatts. Very small turbines are used to charge batteries for remote applications. Home-sized wind machines, often 10 kilowatts, have rotors between eight and 25 feet in diameter and reach 30 feet tall or more. There is strong growth in the use of wind turbines ranging from 1.5 megawatts to 3 megawatts to feed power grids that utilities use to deliver electricity to consumers. A large turbine may have blades that span more than the length of a football field and it may stand 20 stories high. A turbine of that size can produce enough electricity to power 1,400 homes. Wind power has come of age. The cost Key IDEAS IN THIS CHAPTER e Wind energy has come of age as a cost-competitive source of supplementary electricity. Environmental concerns are helping to push wind power development. Different types and sizes of wind turbines work better in different environments. Innovation is underway to identify the best types for different places. of fossil fuels continues to rise and, at the same time, wind-turbine technology continues to improve and get less expensive. These two factors have made wind power cost-competitive with traditional sources of energy. It will only get more so. The industrialized world has taken note and is installing new wind turbines at record rates, mostly in Western Europe (Spain, the Netherlands and Britain). There is also a huge market for wind turbines in the developing world. They are being installed in India and parts of Latin America. Wind energy development in the United States was given a boost when Congress passed the National Energy Policy Act in 1992, which gives a tax credit for production of electricity from alternative energy sources. Some utility companies will respond to this incentive and build “green” power plants. Page A-23 Wind Power: a Brief History Page A-24 Green Mountain Power's wind farm in Searsburg, Vermont. figure 35 Today many states have mandated “Renewable Portfolio Standards” that requires utilities to have a percentage of their power come from new renewable sources. State renewable portfolio standards, mandates, and renewable energy goals are all relatively new. It has been estimated that these new requirements for new renewable energy capacity in 15 States resulted in an estimated 2,335 megawatts of renewable energy by 2003. Most of the new energy comes from wind power, with smaller amounts of landfill gas, hydroelectricity, biomass, and solar photovoltaic technologies. Wind energy is the world’s fastest-growing energy source. Total worldwide capacity in 2007 reached 73.9 gigawatts. Installed capacity in the US reached 11,600 megawatts in 2007. The World Wind Energy Association (WWEA) predicts that by 2010, Wind Power: a Brief History 160 gigawatts will be installed worldwide. The American Wind Energy Association identified the leading states in terms of installed wind capacity in 2007 as Texas (2,768 megawatts (MW), California (2,361 MW), Iowa (936 MW), Minnesota (895 MW) and Washington (818 MW). Still the wind energy being tapped in the U.S. and worldwide is a small fraction of the potential, and in the United States is a sliver of the pie of total generation. According to the American Wind Energy Association, wind power capacity increased by 27% in 2006 and is expected to increase by an additional 26% in 2007. More than half of the nation’s electricity was produced using coal. Nuclear power, natural gas, and hydroelectric power, in that order, provided the next highest contributions to generation. Wind power is part of the future of the world energy market. How much it will dominate the market remains to be seen. DISCUSSION e Why is wind power development increasing? e How much of the nation’s electricity is produced using wind? e How can the use of wind power help address environmental concerns? Page A-25 9z-V o8eq 9g ainsi Source: “Wind Energy Resource Atlas of the United States”, 1987 Wind Power Classification Resource Wind Power Wind Speed® Wind Speed” Potential pensty at50m at50m at50m Wit Marginal 200 - 300 7 E if : Fair 300- 400 ik i 7 ; U.S. Department of Energy Good 400- 500 H A i 5 National Renewable Energy Laboratory Excellent 500 - 600 . . 5 ; Outstanding 600- 800 Superb 800 - 1600 "8-11. "7-24, peat ® Wind speeds are based on a Weibull k value of 2.0 20-MAR-2000 1.1.5 DISCLAIMER NOTICE. This GIS data was developed by the National Renewable Energy Laboratory ("NREL"), which is operated by the Midwest Research institute for the U.S. Department of Energy ("DOE"). The user is granted the right, without any fee or cost, to use, copy, modity, alter, enhance and distribute this data for ‘any purpose whatsoever, provided that this entire notice appears in all copies of the data. Further, the user of this data agrees to credit NREL in any publications or software that incorporate or use the data. Access to and use of the GIS data shall further impose the following obligations on the User. The names DOE/NREL may ‘ot be used in any advertising or publicity to endorse or promote any product or commercial entity using or incorporating the GIS data unless speciic written authorization is obtained from DOE/NAEL. The User also understands that DOE/NAEL shall not be obligated to provide updates, support, consulting, training or assistance of ‘any kind whatsoever with regard to the use of the GIS data. THE GIS DATA IS PROVIDED “AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DOE/NREL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER, INCLUDING BUT NOT LIMITED TO CLAIMS ASSOCIATED WITH THE LOSS OF DATA OR PROFITS, WHICH MAY RESULT FROM AN ACTION IN CONTRACT, NEGLIGENCE OR OTHER TORTIOUS CLAIM THAT ARISES OUT OF OR IN CONNECTION WITH THE ACCESS OR USE OF THE GIS DATA. ‘The User acknowledges that access to the GIS data is subject to U.S. Export laws and regulations and any use or transfer of the GIS data must be authorized under those regulations. The User shall not use, distribute, transfer, or transmit GIS data or any products incorporating the GIS data except in compliance with U.S. export regulations. If requested by DOE/NAEL, the User agrees to sign written assurances and other export-related documentation as may be required to comply with U.S. export regulations, Wind Power: a Brief History CHAPTER 6—WIND POWER IN ALASKA Alaska has abundant wind energy resources and a growing need for electricity. These are good reasons to develop wind power generation. There are two other pressing concerns, the need to lower the cost of energy, and the need to reduce pollution. Utilities are also exploring wind power generation as a way to meet consumer interest in purchasing “green” power, and to reduce the cost of energy. Key IDEAS IN THIS CHAPTER e Alaska has abundant wind energy resources, and a need for new sources of energy. e Early Alaska wind energy development failed in part due to inadequate design for cold-weather conditions and lack of maintenance. Wind resources in Alaska. Alaska has among the best wind resources for power generation in the world. Winds are often strong and steady in coastal areas, and Alaska has 33,904 miles of shoreline, twice the amount of the continental U.S. The Alaska Division of Energy once estimated that 70-90 communities in Alaska have strong enough wind resources to benefit from wind power generation. e Demonstration projects in Alaska are helping to develop viable wind energy systems for remote communities. Specific local conditions are extremely important in identifying possible sites for wind turbines. In recent years, the Alaska Energy Authority and many utilities in Alaska, both large and small, have invested in extensive wind monitoring to further assess wind energy options. These efforts are yielding good data that provide the foundation for successful wind energy development. Need to lower the cost of energy. Many of the communities with the strongest wind resources are the same ones with a critical need to reduce their cost of power. Rural Alaskans typically pay more than four or five times the electricity rates paid by consumers in urban areas of the state and other areas of the country. Page A-27 Wind Resource of Alaska 205000 705000 955000 1205000 1455000 1705000 1955000 2205000 r + t oe 1 _— + 4 ~—- . — n r- SCuW 17000 W SSCOW «STOW ISSOOW «STOW 0 usOOW «= TW tas COW woroow as0ow cow T T T T 205000 455000 705000 955000 1205000 1455000 1705000 1955000 2205000 Key to Features * city Federal Land Waterbody “7 Road 2) State / Local Park State Background —— Rairoad 2) Borough / Census Boundary [7] Canadian Province N River /Stream <3! Urban Area Projection: UTM, Zone 4N, WGS84 Spatial Resolution of Wind Resource Data: 200m This map was created by TrueWind Solutions using the MesoMap system and historical weather data. Although it is believed to represent an accurate overall —— picture of the wind energy resource, estimates at any location should be MUST confirmed by measurement Kilometers AWS Page A-28 figure 37 Wind Power: a Brief History These isolated communities cannot tap into distant large power projects that provide relatively low-cost electricity. It would be too expensive in most cases to run the sort of long transmission lines that allow residents of Fairbanks to use power produced from Cook Inlet gas at the state’s largest hydroelectric project at Bradley Lake, which is more than 500 miles to the south. Average annual wind speed (miles per hour at 10 meters) Wind Power Class Most small communities, ranging in size from less than 100 people to several thousand in a few larger rural centers, rely primarily on local diesel generators. Fuel represents about one-third to one-half of the cost of producing power. Fuel, equipment and other items must be transported hundreds, even thousands of miles. Larger diesel generators are usually more efficient, producing more Kotzebue winds are class 5, and figure 38 St. Paul has winds rated class 7. electricity for each gallon of fuel used. But small populations in villages often do not use enough electricity to be able to benefit from larger generators. Current wind energy projects in Alaska are helping to identify the costs and benefits of wind energy for these communities. Wind energy is a supple- mentary power source. Winds do not blow all the time or at the same force consistently. Also, there is currently no effective way to store the energy pro- duced by wind turbines for long periods of time. Short-term battery storage is common and is used in some areas for feeding consistent energy amounts through electrical systems as the wind fluctuates. ELECTRICITY GENERATION IN ALASKA Wind energy is just beginning to be used to produce electricity for Alaska’s communities. There are many other fuels currently in use. Combustion turbines fueled by natural gas produce most of the electricity in the populous Railbelt region, encompassing Fairbanks, Anchorage, and the Kenai Peninsula. About 10 percent of the power for that area is produced with water flowing through hydroelectric plants; some electricity comes from burning coal. Kodiak and some of the communities in Prince William Sound and Southeast Alaska (including the state’s capitol, Juneau) rely primarily on hydropower. Most of the rest of the state, particularly small communities in rural areas, currently have no cost-effective alternative to diesel generation. They bring in and store fuel to produce the electricity that lights and powers homes and businesses. Page A-29 Wind Power: a Brief History Diesel generators are the only or figure 39 main source of power in about 200 small Alaska communities. Photo courtesy AVEC. Because it is intermittent, wind energy will not fully replace diesel generation. But by providing supplementary power and replacing expensive imported diesel fuel with free local fuel, wind power might lower costs. In some communities, wind generation might be able to serve as the main source of power, with diesel generators kicking in only when there is not enough electricity generated by wind to serve community needs. Wind energy reduces pollution. Diesel generation creates many pollution dangers. Because the rivers and ocean freeze in many areas of Alaska, fuel must be barged in during the summer and stored for winter use. For instance—the 1.5 million gallons of fuel used in Kotzebue each year is transported over a thousand miles. In addition to the danger of spills during the transportation and storage of fuel, diesel generation produces air pollutants. As rural communities grow and their electricity use grows, continued reliance on diesel could cause air pollution problems. Urban utilities that use other types of generation are interested in wind power for similar reasons—lowering costs, reducing pollution, and providing consumers with clean “green” power. These interconnected urban systems face similar if somewhat different challenges in integrating wind power. Page A-30 History of wind energy in Alaska Wind energy has been used in many ways in Alaska, the most prominent use, perhaps, was for sailing. In rural areas, hunters use the signs of the wind on the land and snow to help guide them in finding animals. Travelers have used the dominant patterns on the snow created by prevailing winds to find their way home. Amid the California Wind Rush of the 1980s, when incentive programs spurred growth of the industry, the State of Alaska encouraged Alaskans to try wind ener- gy. The turbines available at that time were those constructed for use at individual homes and buildings in warmer climates, such as California. About 140 wind turbines were set up by government agencies at city offices, schools and other buildings around Alaska, including a few in Kotzebue. There was usually no involvement in the projects by local electric utilities. Wind Power: a Brief History CAPTURING WIND ENERGY FOR HEAT Using wind-generated electricity for heat has two benefits in rural Alaska communities that are interested in developing wind power. It can help maintain power quality and perhaps reduce heating costs. MAINTAINING POWER QUALITY In the normal electric utility system, the power being produced and sent into the system is matched to the amount consumers use on the other end. This steady matching of output and input helps to maintain constant voltages as electricity flows within the system. Flickering lights, television sets, and damage to computers are among the problems that can come from fluctuating voltage, because appliances are designed to run on the standard voltage provided through the electric system. In diesel generation systems, when there is a drop in the need for electricity, utilities can adjust the power output by burning less fuel. With modern systems and electronics, this can occur almost instantaneously. But utilities cannot speed up or slow down the wind, which is the fuel source for wind energy systems. So, other adjustments must be made. Using electricity to heat water that can then be used for space heating provides one outlet for this excess energy and a way to capture energy that might otherwise have to be wasted. This use of wind energy for heating is part of the wind energy projects in Wales and on St. Paul Island. LOWERING HEATING Costs Electric heating currently does not exist in most of Alaska’s rural communities because it would be inefficient. Most of the electricity used in these communities is produced by burning diesel fuel. It makes more sense to burn heating oil directly to create heat rather than burning it to create electricity and then heating with electricity. The fuel for wind systems is free. So, where the cost of heating oil is high and where extra wind energy is available beyond what is needed for other electricity needs, utilities may be able to provide cost-effective supplementary wind-powered electric heating for consumers who now rely on heating oil. These systems will likely take the form of using electricity to heat water which is then circulated to heat buildings. Page A-31 Wind Power: a Brief History Most turbines failed quickly, because they weren't built to withstand cold weather, or needed maintenance that was not available. The mostly small 4-10 kilowatt turbines produced direct current (DC) electricity instead of the alternating current (AC) used by utility systems. The Entegrity 15/50 (formerly AOC) wind turbines installed at the Kotzebue Electric figure 40 Association wind farm are modern-design Horizontal Axis Wind Turbines (HAWT) with a trailing rotor that has three blades. The turbines are set on 80 -foot towers. Each can produce up to 66 kilowatts of power. Photo courtesy KEA. Page A-32 Wind Power: a Brief History The failure of many of these installations dampened interest in wind energy, though there is recent renewed interest. Some small individual systems are being operated in remote areas, and some companies are using small, low-power wind systems to charge batteries for remote electronics. The first utility wind farm in Alaska New efforts by utilities to integrate wind as a part of the mix of generation sources is bringing greater harvesting of this resource in Alaska than ever before. In 1992, Kotzebue Electric Association (KEA), with assistance from the Alaska Division of Energy, began investigating local wind energy resources. Anemometers were installed to test wind-speed at various places and at varying heights above the ground. Over several years, tests and analyses were conducted to detail wind speeds, direction, power and other factors necessary to determining how much energy could be captured for electricity production. Tests confirmed good wind energy potential, with Kotzebue being ranked as a Class 5 wind site. At that time KEA entered into project partnerships with federal and state agencies to begin the Kotzebue Wind Energy Demonstration Project. The purpose of the project is to test and develop turbines for use in remote, northern communities. At first, it was difficult to find an appropriate U.S.-manufactured turbine built to withstand arctic conditions. However, more turbines are being built and as the project proceeds a number of different types of turbines will be tested in Kotzebue. The first utility wind farm in Alaska was begun as KEA installed three Entegrity 15/50 (formerly AOC) turbines in 1997. By January 2000, ten of these turbines were operating at the cooperative’s wind farm, about five miles south of Kotzebue. Each of these turbines can produce up to 66 kilowatts of power, and enough electricity each year to meet the needs of 20 homes. The turbines are HAWTs with three-blade trailing rotors. They have special features for use in arctic conditions, such as cold- weather metallurgy and heaters. Special braking mechanisms help stop the turbines and prevent damage in high winds. Page A-33 Wind Power: a Brief History Wind turbine on St. Paul Island in Alaska where KEA has also installed two other types of turbines and plans to continue to develop its wind farm. Ultimately, the utility plans to install 2- to 3-megawatts of wind energy capacity, enough that it could, at times of good wind, meet the entire electricity needs of the community by harvesting wind energy. It hopes to eventually reduce use of diesel fuel by 300,000 gallons a year. In addition, the cooperative is planning to provide options for heating using wind-generated electricity. That could reduce the need for purchase and storage of heating fuel used in the community. Wind Energy Development in Alaska Since KEA’s installation of the first utility wind farm in Alaska, interest in wind energy has been growing in the state. Utilities and other companies have been exploring projects both large and small. Alaska Village Electric Cooperative is developing wind power. In 1998 KEA, working with the Alaska Village Electric Cooperative (AVEC), initiated a high penetration project in Wales, Alaska. figure 41 The main goal of the Wales project was to demon- winds are excellent for power strate that is possible to effectively incorporate a development. Photo courtesy TDX Power. large proportion of wind energy into an isolated Page A-34 electrical system. The Wales High Penetration Wind System utilizes a system controller, wind turbines and short-term energy storage to displace diesel fuel used to produce electricity. This project was the prototype for numerous installations throughout Alaska. This project is important in that an electric system can only accept a certain proportion of wind energy before it becomes unstable, unless certain steps are taken to avoid problems. The proportion of wind power on a system is referred to as the penetration level. Wind Power: a Brief History The Wales project wind system was commissioned in July 2001. PENETRATION LEVELS The wind portion of the project Low Penetration — Diesel generators are always on. was primarily financed and maintained by Kotzebue Electric Association and the energy was sold under agreement to the Alaska Village Electric Cooperative. High Penetration — Little or no diesel power needed — thermal energy, battery storage and electronics keep the system stable with a high proportion of wind power. Medium Penetration — Diesel generators are always on, but electronics keep the system stable with a higher proportion of wind power. High penetration wind-diesel technology is important for rural Alaska because of the large number of villages which are located on the coast and could benefit from this technology. AVEC has since installed wind turbines in several of the other villages it serves. In 2006 it had systems operating in Selawik, Kasigluk and Toksook Bay and was looking at putting up systems in Savoonga and Gambell, Chevak, Hooper Bay and possibly Mekoryuk. Kotzebue Electric Association was the field project manager for the wind system in Selawik. Four of the same sort of turbines originally installed in Kotzebue (the Entegrity 15/50, formerly AOC) were set up in 2003. In 2006 three 100 kW Northwind 100 turbines were installed in Kasigluk to supplement a diesel power system that serves Kasigluk, Old Kasigluk and Nunapitchuck. This system was expected to displace 52,000 gallons of fuel each year. The new system includes upgrades to the diesel system as well, and a system for using excess heat to warm a community build- 4 Northwind 100 turbine at Toksook Bay, Alaska. igre 42 ing and the power plant. Photo courtesy AVEC. Page A-35 Wind Power: a Brief History Page A-36 AVEC also installed three 100 kW Northwind 100 turbines in Toksook Bay in 2006. The wind-diesel system in Toksook also provides power to Tununak and Nightmute. St. Paul Island Commercial Complex. In 1999, Tanadgusix Corporation installed the largest turbine ever placed in Alaska, a 225 kW Vestas wind turbine on St. Paul Island, which has among the best wind energy resources in Alaska. The island has a documented average annual wind resource in excess of 18 mph. Tanadgusix (TDX) is a shareholder-owned Aleut village corporation with primary offices in Saint Paul and Anchorage. The turbine works in conjunction with two diesel generators to provide electricity needed by the company’s commercial building complex. The hybrid system incorporates a full waste-heat hot water system to handle excess electricity generated by the wind turbine. This is expected to reduce the corporation’s annual purchase of 30,000 gallons of diesel heating fuel. TDX Power plans to expand this system and is working on projects for other communities as well. Kodiak has good wind resources. In 2006, Kodiak Electric Association was planning a 3- to 5 megawatt wind farm on Pillar Mountain behind the city of Kodiak. The utility produces electricity using diesel generation and also gets power from a hydroelectric plant at Terror Lake. The utility was expecting that wind generation would save diesel fuel, reduce polluting emissions, lower generation costs, stabilize fuel costs, and allow efficient use of the hydroelectric plant, which could serve as a sort of battery to help maintain voltage amid shifting winds. Kodiak was exploring the use of up to eight 600 kW turbines. Urban utilities explore larger wind projects. Golden Valley Electric Association, based in Fairbanks, has pledged to use renewable energy for 20 percent of its peak generation by 2014. In 2006 it was evaluating the possibility of a major wind project near Healy, Alaska and had begun a program called SNAP (Sustainable Natural Alternative Power). SNAP links local people who want to produce renewable power, such as wind or solar, with members of the cooperative who want to buy renewable power. Wind Power: a Brief History Chugach Electric Association, Alaska’s largest producer of electric power, is exploring the possibility of a large wind farm on Fire Island, perhaps as large as 50 to 100 megawatts. These projects across the state represent just part of the explosion of interest in wind power generation in Alaska. For each of these and other project to begin operation, utilities and other companies must carefully assess wind resources, find the appropriate generation, plan for integration and operation with existing systems, evaluate potential environmental impacts, find ways to pay for the equipment, find skilled employees to operate wind systems, and deal with many other issues. The math section of this curriculum provides a better understanding of some of the technical factors that wind energy developers must consider. Wuat Do You THINK? ¢ Where are the best wind energy resources in Alaska? ¢ What is the average wind speed for a Class 5 rating? ¢ What are some of the challenges of developing wind power in Alaska Page A-37 Wind Power: Math, Science & Technology TABLE OF CONTENTS CHAPTER 1—THE NATURE OF WIND The wind is solar-powered World Wind patterns 00... .csesesecsceesssssssssssssssssneesesseessssssssnssnnes Local Wind patterns .......cccsssssssssssssssssnnesesseseeeeceecesssnsseeeeseseeeeee Wind speed and ground friction ......ccsssssssssssseesseseeeeeeeesseeseee Page B-5 Wind flow and obstacles wi eecccsssssssssssssssssecssssesssesssssessees Page B-7 Wind-enhancing geographic features ........... eee Page B-7 Summary: Wind turbine siting. eecsssssseecesseeneeeeeeeeeeenees Page B-8 CHAPTER 2—THE PHYSICS OF WIND TURBINES Energy, WOrk and DOWEL ws ssssessssssssssssssssssesesustssseseseeceeseeeeeeeeeeees Page B-9 Power in the Wind 00... eeesescsssssssssssneseeeseessnneseccessesnsneceesnnneeseeeessesnnes Page B-9 Capturing the power in the wind............... ..Page B-10 Two types of wind devices (lift and drag) ......... eee Page B-11 How lift devices WOK ...eeiceeccccsssssssessessssneeessceesssneesssnsneeeeesees Page B-12 Summary: Wind turbine PHYSICS ee ssssesssssssssseseeeees Page B-13 CHAPTER 3— DESIGNING MODERN WIND TURBINES Selecting and designing modern wind turbines...........Page B-15 Wind turbine design flow chart 0.0... Page B-17 The big question: HAWT or VAWT 2 ou... eesessssssessessseeeceeeeeeee Page B-18 Horizontal Axis Wind Turbines (HAWT)...........csscseeeee Page B-18 Leading vs trailing LOtor .........seccsscccsesssessseseecceeeeeeeeeeteee Page B-19 YAW CONTLOL waceceeececsssssssessseseseeeeeeeceeeeseesssnnnsusunneeeeseessesssesnsenees Page B-19 The fartail eee cesssssssssssssssesssssesssseeeessesesessesseceeeeeeees Page B-20 Vertical Axis Wind Turbines (VAWT) .....ccssscscsessssssssceeseeees Page B-20 SAVONIUS (S-LOCOT) ooceececscesssessesssecsesstessecsecscseeseesesesessncenses Page B-21 Darrieus (D-rotor) ou. eeeseessecccsccsssessesssssnneessesseeeeeeenses Page B-22 Hybrids (H-TrOtor) o...e.eeeeceessssssssesssssssssseeseesccesssneeeessssssnseesecs Page B-22 Page B-2 Wind Power: Math, Science & Technology TABLE OF CONTENTS -— continued Rotor and blade design issues .........eccessssssseseesscesesessssssnneeess Page B-23 ROtOr Cesign Steps | srecsestsscerceeecseescestcassssaassrnsavourseesueercosartnenesaaey Page B-23 1 - Use, Power and Wind. o.......c.ceecessesssssssesssesssesseeessessees Page B-23 2 - ROOT design uu... .Page B-24 Be eee eer eee reeset sat tssMHtaddstenabeeanaasazanenelantatatane Page B-24 4 — TIP Speed rai een ssesecsouatasscaeseneronsostssasuasuaezsea reer Page B-26 5 - Rotor solidity and Blade area .............csssseeeeeeee Page B-27 Bea eo CO oe ee eee ced etdettatedltedbabateeaMadbsstebaMedb aM Page B-30 Over speed and high wind protection .... Page B-32 Generating thee HICCHrichty .......ssssecssssessecesecessecensensseessesesesee Page B-32 Constant vs variable speed rotors ...........ecccssssssseeeeeeeseenees Page B-32 Direct drive Vs tramsMisSiOn ...........eccccccsssssssesessseseeseesnsssssseee Page B-33 How a Wind Turbine WofFkS ...0......cceccccecsssssssssssssssssssssnssesssnnssnnee Page B-34 Page B-3 Wind Power: Math, Science & Technology CHAPTER 1—THE NATURE OF WIND Key IDEAS IN THIS CHAPTER ¢ Wind is a form of solar energy. ° Geography affects wind patterns. ¢ Wind speed increases with height above the ground. Early wind machines were simple devices. (see the "Wind Power: History" booklet). Modern wind turbines, in con- trast, are highly refined, complex machines. This booklet will introduce the basic concepts and mathematics involved in designing wind turbines. The Wind is solar-powered: Wind ener- gy is a form of solar energy. Without the Sun, there would be no wind. When the Sun strikes the Earth it heats it and the atmosphere around it. Because of the Earth’s round shape, uneven surface, ellip- tical orbit, and clouds in the atmosphere, this solar heating is uneven. Some areas get warmer than others. These areas of warmer air become less dense and therefore rise. Cooler air fills in from the sides. So, wind is merely air moving around in an attempt to equalize the temperature and pressure differences caused by this uneven solar heating (figure 1). World wind patterns: Although the solar heating of the Earth is uneven, predictable global wind patterns have developed (figure 2). These ‘prevailing’ or ‘trade’ wind routes have long been taken advantage of by sailors. The more regular and powerful the wind is, the better it will be for wind turbines. suN Lud WARM Vlivadly voor We FRI Cooe Ang ——eaeteo Page B-4 figure 1 Wind Power: Math, Science & Technology sw Trdewinds NE Tradrewinds Se Trade winds NW Trade wuds figure 2 Local wind patterns: Local areas often have predictable daily wind patterns caused by solar heating of uneven geography like coastlines, hills and valleys (figure 3). Wind speed and ground friction: There is friction between the wind and the ground. It causes wind near the ground to slow. So, the higher you go, the stronger the wind is. (figure 4). Page B-5 Wind Power: Math, Science & Technology HEIGHT — figure 4 The Wind Speed — Ground Friction Rule gives the speed of the wind at any chosen altitude. To use it you need to know the wind speed at another known height: V =V. x (H/H.)* Where: H = height at which wind speed is wanted Ho = height at which wind speed is known Vv = wind speed you want to know (at H) Vo = wind speed at Ho (which is known) F = Friction Coefficient of the ground ... .10 for smooth, hard ground or water .15 for foot high grasses .20 for high crops, hedges, few trees = .30 for wooded country and towns 7 .40 for cities with tall buildings Example ‘ i VL = lo mph ak He = lol é F=.20 then V= lo x ( rs ys 12.8 mpl. (at H=5So f+) Page B-6 Wind Power: Math, Science & Technology DSSS 7x HEIGHT Substantial turbulence occurs on the downwind side of buildings. The turbulence is greater figure 5 for buildings with sharp edges. If the building is 100 feet tall, the air turbulence downwind extends about 700 feet and the turbulence upwind extends about 100 feet. Wind flow and obstacles: Wind turbines need smooth wind flow to operate efficiently. Any obstacle in the path of the wind will dis- turb its smooth flow. Obstacles create turbulence both up and down wind. One rule of thumb states that for an obstacle of height H, the wind will be turbulent 1 x H upwind and 7x H downwind (figure 5). If the building is 100 feet tall, the air turbulence downwind extends about 700 feet and the turbulence upwind extends about 100 feet. _—_— —— Wind-enhancing geographic features: Certain land formations will actually increase the speed of the wind. One formation that does this Acceleration of Wind Over Hill is a gradual, smooth hill (figure 6). figure 6 Another is a narrow valley with a smooth, gradual entrance and exit (figure 7). The phenomenon which causes these speed-increasing effects is called the Bernoulli Effect, the same effect that gives wings their lifting properties. Proposed Type of Terrain Modification for the Purpose of Augmenting Average Wind Speeds figure 7 Page B-7 Wind Power: Math, Science & Technology Summary: Wind turbine siting: So, here are some guidelines for siting a wind turbine to take advantage of the best winds: © Choose a high wind speed region (check a wind map). e Choose high altitude and mount the turbine on a tower. e Choose open sites with few obstacles. © Choose a site with wind-enhancing geographic features. e Above all, take wind speed and direction measurements over a substantial period of time to ensure your site is in fact a good one for a wind turbine. CONSIDER YOUR COMMUNITY ¢ From what direction do the winds usually blow in your community? Does the direction change depending upon the time of day or time of year? ¢ What local geographic features affect wind patterns in your community? ¢ What obstacles exist to wind flow in your community that create friction or turbulence? ¢ Where do you think the best place might be to try to harness the wind in your community? Why? Page B-8 Wind Power: Math, Science & Technology CHAPTER 2—THE PHYSICS OF WIND TURBINES Energy, work and power: Energy is the capacity to do work. Work is done when a force moves an object. Power is the rate at which energy is used (or made) or work is done. ¢ The energy in the wind increases Here is an example: The gasoline dramatically as wind speed in a car’s fuel tank has a certain amount of energy in it (ability to do work). When I drive fast, the car uses Only part of the energy of the wind more power (works harder) and emp- ties the tank more quickly than if I drive more slowly, using less power. Wind energy is harnessed with Energy is what you have, work is using it, power is how fast you use it (or make it). Expressed as a formula: Key IDEAS IN THIS CHAPTER e Energy = Power x Time increases. can be captured. drag or lift devices. Energy = Power xTime E=PxT_ (kilowatt hours = kWh) or Power = Energy/Time P=E/T (kilowatts = kW) Power in the Wind The power in the wind is essentially the force its moving mass exerts on objects it hits. In other words, wind has power to move things it hits. It is this inertial force we can capture and use. The power of moving air is given by the Formula: Power = $ xpxV?xA_ (watts) Where: p = density of air (about 0.0023 slugs / ft3) ad* — areaofacircle (1 slug = 32.2 lb @ sea level) Y where — speed of the wind (mph) d = diameter of the rotor A = area of wind captured (ft?) Page B-9 Wind Power: Math, Science & Technology Page B-10 Wind power is proportional to the cube of the wind speed. For example: if wind speed goes up 2x, then wind power goes up 8x(27=2/x2 x2) Wind power is proportional to the area of wind captured. This means a bigger turbine catches lots more energy. For example: if you double the rotor diameter of a HAWT, then wind power quadruples. 2 Since: ad =A . aD] — ww (2) (a7) = Thus: re = Z 4A Wind power is proportional to the density of the air running past the blades. Air density ( p ) is directly related to air pressure and temperature by the following equation. P iT ea Where: P = air pressure i = air temperature Ry = universal gas constant From the wind power equation Power = 4 xpxV°xA_ we see that power will increase if the air density increases. From the air density equation we see that p will increase if air pressure increases or temperature decreases. Therefore, wind turbines will produce more power in the winter than in the summer. Capturing the power in the wind: Of course, wind turbines are not 100% efficient. The designs vary widely but, as a rule, they lose between 50 and 90% of the wind’s power before it can be used. So, here's the adjusted formula: Wind Power: Math, Science & Technology Useful Power = 4 xpxV?xAxE (watts) Where: E = efficiency of power extraction (.10 to .50) E = .10 to .20 for a Savonius rotor E 7 .15 to .30 for a Darrieus rotor E 7 .20 to .45 for a HAWT (Horizontal Axis Wind Turbine) Two Types of Wind Devices: Draggers and Lifters Drag devices use the direct ‘pushing’ power of the wind. Their efficiency is low, about 10 to 20%. Examples of drag devices are parachutes, spinnaker sails, cup-anemometers, Persian windmills, Chinese ‘clapper’ windmills, and Savonius rotors (figure 8). figure 8 commute x Wind “Clapper” mill, e cup- anemometer | | Page B-11 Wind Power: Math, Science & Technology Lift devices make use of aerodynamic lift and capture much more of the wind’s power than drag devices of the same area. Their efficiency is about 30 to 50%. Examples of lift devices are: bird wings, modern sails, kites, airplane wings, helicopter rotors, Darrieus rotors and modern windmills. dé Turbine rR J Win Darrieus Rotor rt How lift devices work: Here is how ‘Lift’ devices capture more of the wind’s power than ‘drag’ devices. ‘Drag’ devices like parachutes lose most of their power to turbulence (which takes power to make) (figure 10). ‘Lifting’ devices like wings allow the wind to maintain its lami- nar (smooth) flow, so little power is lost to turbulence. Also, Page B-12 Wind Power: Math, Science & Technology because the wind has to travel farther on the _—— ‘top’ of the wing than wa es the ‘bottom’ (and there- 7 CE BD fore gets less dense or _! > thinner) the wing gets $$. ‘lifted’ along by the D _ 3 Ss” lower pressure there o~> (figure 11). figure 10 Summary: Wind turbine physics: Let’s look at what we know: e Wind energy is proportional to the cube of wind speed. For example: if wind speed goes up 2x, then wind energy goes up 8x (23 =2x2x 2) © Wind energy is proportional to the area of wind captured. This means...a bigger turbine catches lots more energy. For exam- ple: if a HAWT rotor diameter goes up 2x, The flow of wind about a wind turbine blade. Then wind energy goes up 4x (2? = 2 x 2) Lift forces act perpendicular to the local wind . direction, while drag forces act parallel to it. ¢ These two facts would lead us to believe The rotor blades of KEA’s Entegrity turbines that the bigger the turbine, the better. This are designed to make use of the lift forces. is exactly what designers thought in the figure 11 30’s and 40’s. The Smith-Putnam turbine eu on Grandpa's Knob near Rutland, Vermont was an example of this thinking. (See “Wind Power, A Brief History” booklet) e However, other factors, such as which turbine is most produc- tive with a particular wind profile and whether the equipment needed to install large turbines is available may also need to be considered. So the size of turbine to be used must be evaluated for each site to determine what is best. Page B-13 Wind Power: Math, Science & Technology ¢ What is the difference between energy and power? If wind speed doubles, how much greater is the energy in the wind? Why? How does air density affect wind power? Name a drag type wind device; now name a lift type. How much of the power in the wind can be captured by modern wind turbines? Why is the area a rotor sweeps important to the amount of power that can be captured? Why would you want to put a turbine high in the air if you are trying to harness the wind? Page B-14 Wind Power: Math, Science & Technology CHAPTER 3— DESIGNING MODERN WIND TURBINES Selecting and Designing Modern Wind Turbines The key thing to remember in either choosing or designing a wind turbine for electric power generation is that it must be matched to the wind profile and operating realities where it will be installed. So, in other words, know your wind, and know your electric system! The first step in deciding ona turbine is to do detailed wind energy assessments to identify average wind speeds, duration, fluctuations and other characteristics. These help identify the actual wind energy potential. Additionally, wind assessments will help in choosing or designing a turbine. For instance, different types of turbines are able to begin producing power at different wind speeds, and produce their maximum power at different wind speeds. You want to find the best fit for specific circumstances. Because the wind does not blow at the same force all the time, wind energy is an intermittent energy source and so must be coupled with Key IDEAS IN THIS CHAPTER ¢ Turbine design must match specific use. ¢ Design elements balance issues of cost, ease of use, efficiency, conditions within which the turbine will operate, and other considerations. ¢ Design elements: — Horizontal or vertical axis — Leading or trailing rotor — Rotor area and diameter — Tip-speed ratio and rotor solidity — Blade pitch — Overspeed and high wind protection batteries or other types of generation in order to assure a constant source of power. Understanding in what way a wind turbine will be used and contribute to the overall need for power is important to choosing a design. Page B-15 Wind Power: Math, Science & Technology Page B-16 Will it be used to charge batteries that feed electricity to a home? Will it be used as one of many generators feeding a large utility grid where most of the power comes from other sources? Will it occasionally be used as the main power source for a small hybrid system using diesel or other generators? Within integrated systems, what is the ideal goal for how much of the total energy produced will come from wind power? What is the most cost- effective mix of generation options? All of these questions are important. It is also important to understand the conditions under which the turbine will operate. Is the weather very hot, or very cold? Is the equipment needed for installation available? These and many other factors must be considered. Modern wind turbines are being designed to combine a variety of technical features that will make turbines effective in specific circumstances. The rotor of a wind turbine is what is used to capture the energy of the passing winds, and therefore is of great importance. In the rest of this section, we'll learn about some of the major technical choices regarding rotors that face a wind turbine designer. Entegrity 15/50 rotor. Wind Power: Math, Science & Technology Wind turbine design flow chart: Below is a generic planning flow chart for the design of wind turbine systems. Evaluate wind resources Evaluate energy needs == Select wind turbine type | Estimate overall system efficiency | other factors Calculate rotor size Develop Airflow, airfoil, blade aerodynamic design [~<—— twist, performance (rotor shape) coefficients Develop Rotor and tower loads stryguiral peter ~~ blade construction : (strength, durability) Revise Evaluate design 7 performance Evaluate Legal, environmental |< costs, conservation options | Build and test wind system figure 12 The wind machine design process. Page B-17 Wind Power: Math, Science & Technology The big question: HAWT or VAWT ?: The biggest decision facing a designer is the type of rotor. There are two main groups of tur- bine rotors. They are defined by the orientation of their rotor axles: horizontal and vertical. Horizontal Axis Wind Turbines (HAWT): HAWTs are the most common type of wind turbine. They are the most efficient type (up to 45%) and can oper- ate at high speeds. This makes them good for lots of applications, especially generating electricity. They do require a mounting tower which can make instal- lation and maintenance more challeng- ing than VAWTs. Some modern HAWTs are shown below (figure13). figure 13 Page B-18 Wind Power: Math, Science & Technology Leading vs Trailing Rotor: HAWTs are designed with either leading or trailing rotors. Leading rotors are positioned in front of the nacelle (and tower) to catch the cleanest wind (figure 14). Because the wind wants to push the rotor around behind the tower, they > require mechanical yaw (side-to-side) control which adds cost and com- ————— a plexity to the design. Trailing rotors have their rotors Wrap behind the nacelle and tower i (figure 15). Because of this they don't need yaw control. However, the air — hitting the blades is disturbed by the nacelle and tower. This is simpler and cheaper but it lowers efficiency. §£§—<-———————=— > The Entegrity 15/50 turbine used in Kotzebue has a trailing rotor. fpUrESTS Yaw control: HAWTs with leading rotors need yaw control. A number of mecha- nisms have been designed to do this job. The tail-fin Wap (figure 16) is the ultimate B in simplicity. It drags in the wind, keeping the rotor (which has less drag) forward. figure 15 Page B-19 Wind Power: Math, Science & Technology The fantail (figure 17) was an early (1745) mechanical solution. The fantail was a small rotor set perpendicular to the main rotor. When the windmill was head-on to the wind, the fantail didn’t turn because it was edge-on to the wind. When the wind shifted to the side, the fantail would then be turned by the wind and, through a series of gears, it would turn the main rotor to face the wind again. Most modern HAWTs use hydraulics —_— a fantail controlled by computers which monitor Ww 3 en > the wind. Te 7 Hee Vertical Axis Wind Turbines (VAWT): VAWTs, while not as a as common as HAWTs, are being built in substantial numbers. figure 17 | They are generally less efficient than HAWTs but have the advantage of being simpler to build and maintain. The tower can be short and the generator is on the ground. Examples of modern VAWTs are shown below (figure 19). r Darrieus Rotor A straight-bladed Darrieus Rotor Savonius Rotor figure 19 Page B-20 Wind Power: Math, Science & Technology Savonius (S-rotor) : It operates like a cup anemometer, being dragged around by the wind. The basic design is shown below with some variations (figure 20). It has high starting torque but low operating efficiency (10 to 20%). This turbine has applications for mechanical operations (like grinding grain and pumping eater) but is not efficient enough for electrical generation. (see plan 16 for a model windmill to build). > yD —” eft ~~ d Although it is primarily a drag device, it does figure 20 produce some lift and it can be made into a kite quite easily (figure 21). Page B-21 Wind Power: Math, Science & Technology Darrieus (D-rotor): The Darrieus rotor is a lift device and is much more efficient (15 to 30%) than the Savonius rotor and comes close to the efficiency of the HAWT rotors. It has very low starting torque and early models were not self-starting. Modern designs are good for gen- erating electricity and are competitive with HAWTs. The basic design is shown below (figure 22). (see plans 17a, b, c, for models you can build) Darrieus rotors work like other airfoils, on the princi- ple of lift. It appears more complex than other types because of the circular path of the blades. Darrieus rotors depend on high speed operation for their efficiency. Because of the high speed of the blades, the relative wind, while constantly changing, stays in front of the blade, allowing it to pro- duce lift (figure 23). Hybrids (H-rotor): Hybrid rotors are modifications of Savonius and Darrieus rotor |, designs. In combination, they " can produce good starting torque and good high speed efficiency (figure 24). figure 22 Page B-22 Wind Power: Math, Science & Technology This can also be accomplished with variable pitch blades. Rotor and blade design issues: An important part of any wind turbine project is the design of the rotor and its blades. There are many issues to consider. The major steps involved in the design of a turbine are: 1. Know the facts. . Choose the rotor design to suit its use. . Calculate rotor area and diameter. 2 3 4. Choose appropriate tip-speed ratio and rotor solidity. 5. Calculate blade area and proportions. 6 . Calculate blade pitch. 1. Know the facts: The first thing to do is to know what the turbine will be used for, how powerful it needs to be, and what kind of winds it will operate in. Most turbines are used for either mechanical or electrical power generation. Different types of turbines are better suited to each application. You also need to know what the average wind speed and direction will be at you site. To learn this you will need to take measurements over a substantial period of time. Page B-23 Wind Power: Math, Science & Technology Page B-24 2. Choose the rotor design to suit the use: Here are some basic rules of thumb for finding a rotor design to suit you intended use. An HAWT design is assumed: Mechanical Applications pumping, milling needs high torque speed less important “Fan” Rotor Design lower wind speed required Low tip-speed ratio High rotor solidity High blade pitch Electricity Generation turning an electric generator needs high speed torque less important “Propeller” Rotor Design requires higher wind speed high tip-speed ratio low rotor solidity low blade pitch figure 26 3. Rotor Area: The first design element to tackle is the area of the rotor. In other words, “How big should it be?” I n order to size the rotor you need to know: E = the efficiency of the rotor (see figure 27) Vv = speed of the wind F = the power factor (see figure 28) Wind Power: Math, Science & Technology The formula is: Rotor area = A = P/ (E x F) (P= power) Model wind turbine example: Let’s calculate the rotor area for a model wind turbine. It will have four blades, operate in 10 mph winds, turn a 3 Watt bicycle electricity generator and have an Rapid Efficiency Estimator Wind System Muttibladed farm water pumper Saitwing water pumper Darrieus water pumper Savonius windcharger ‘Small prop-type windcharger up to 2 kW) Medium prop-type windcharger (2 to 10 kW) Large prop-type wind generator (over 10 kW) Darrieus wind generator efficiency of 20%. So ... 1o “= [ee x 173) To calculate the diameter of the rotor: p= 2x| A = 2y\2-84 = T 2.1415 u Qe b . 24. 12" 2. “a —— 0.2 KITS - 2,69 feash! Tee 3.1415 Page B-25 Wind Power: Math, Science & Technology Page B-26 figure 29 Tip-speed ratio: In order to be efficient the blades of a turbine rotor need to spin at a certain speed. The best speed Tip-Speed Ratio | Number of Blades is different for each type of rotor. Wind turbine operating speed are defined in terms of tip-speed ratios instead of simple RPM. This allows designers to compare turbines of different sizes. Tip-speed ratio =TSR = blade tip-speed wind speed Look at the graph at left (figure 29). A modern three-blade HAWT, for example, is most efficient at a TSR of between 3 and 5. ™ ideal efficiency 8 & rieus rotor = Rotor efficiency (percent) 8 8 Expressed as a formula, Tip-speed ratio (TSR) is: 0 1 2 aj 4 5 6 7 8 Tip-speed ratio Typical performance curves for several wind machines. Rotor efficiency is the percent of available wind power extracted by the rotor blade tip-speed fa il wind speed i _ 2xpixRx RPM 1 | TSR = ae or, solving for R: TSR x 60 x kx V , l R = 2 x 7t x RPM or, solving for RPM: TSR x 60 x kx V it 2xIxR Where: TU = 3.1415 R 7 rotor radius (ft) RPM = rpm of rotor Vv wind speed (mph) k = 1.47 for Vin mph Wind Power: Math, Science & Technology Rotor solidity and Blade Area: Rotor solidity tells of how much of the rotor-swept-area is occupied by the blades. (figure 30 shows high, medium and low solidity rotors) Rotor solidity needs to match the figure 31 rotor’s intended tip-speed ratio. The graph below correlates the two (figure 31). 80 — For example, our four-blade rotor with a TSR of 3 should have a rotor solidity of 70 + about 20%. 60 Solidity (percent) & 8 _ H 0 2 4 6 8 10 12 Tip-speed ratio, TSR Typical performance curves for several wind machines. Rotor efficiency is the percent of available wind power extracted by the rotor Page B-27 Wind Power: Math, Science & Technology Page B-28 Blade Area and Proportions: Once you know your rotor solidity you can then calculate the total blade area of the rotor and the area of each blade. Here's the formula: Total blade area Single blade area Where: swept-rotor-area ll solidity x swept-rotor-area solidity x 7 x R? total blade area Number of blades 1 x R* for a HAWT HxW _ fora Savonius rotor 1.33xRxH _ fora Darrieus rotor Wind Power: Math, Science & Technology For our four-blade rotor example, it’s rotor solidity would be about 20% so, 2 ae Total blade Area= .20 X Se | 961) ||| | = 0.62 te ba G05 ia A Single blade area= O. 602 = OV/E5 er pelle gaeae ae rf 24 jn> Page B-29 Wind Power: Math, Science & Technology Blade pitch: The pitch of a blade is the angle it makes with rotor’s plane of rotation. A blade with 0 degrees of pitch is in-line with the plane of rotation. A blade with 90 degrees pitch is perpendicular to the plane of rotation. Most blades have a pitch of between 5 and 20 degrees (figure 34). ‘ > BLADE MOTION A A figure 34 Blade pitch allows the wind to spin the rotor in the same way a screw spins its way into a piece of wood. Ancient wind mills had a fixed pitch for the whole length of the blade. (in other words, the pitch near the hub was the same as that at the tip) Modern tur- bines vary the pitch along the length of the blade to compensate for the differences in speed. This is called blade-twist. Near the hub the pitch is high (20 degrees), at the tip it is low (5 degrees). (figure 35). Page B-30 Wind Power: Math, Science & Technology Most modern HAWT can also vary the pitch of their blades by rotating the blade at the hub. In this way, they can adjust to differ- ent wind speeds in order to maximize their efficiency. (figure 36). Calculating the correct pitch and twist for a turbine blade is very complicated. For our purposes t he following angles will suffice (these are from Professor P. La Cour) : Position on blade _ pitch (angle of attack) o 1/3 to tip 20° 2/3 to tip 15° at the tip 10° see the graph below: Page B-31 Wind Power: Math, Science & Technology Page B-32 Over speed and high wind protection: Turbines have to be designed to protect themselves from self-destruction by spinning too fast when wind speed rises above their designed operating speed. There are a number of methods used to accomplish this function. One simple method is to have a spring in the turbine which turns the rotor out of the wind (figure 38). Another is to ‘feather’ the blades of the rotor (figure 39). Some machines use air brakes to slow the rotation of the blades (figure 40). Turbines may also use mechanical friction brakes on the axle to slow the rotor down. Wind Turbine Generates Electricity x It is not within the scope of this booklet Air Brake v to explain how an electric generator works. Suffice it to say that they do. There are 7 however a some important factors that Se han relate to generator operation that affect the design of a wind turbine. Electricity produced for commercial ft figure 40 use is 60 Hz AC (alternating current) electricity. Wind turbines that are intended to pump electricity into the commercial grid must match the standard 60 Hz AC format. Constant vs variable speed rotors: Fixed speed rotors turn at a fixed RPM. Most mod- ern turbines are fixed-speed turbines. This Wind Power: Math, Science & Technology allows them to match their electricity with the 60 Hz frequency of the grid. To do this requires brakes or blade feathering or other methods to control the rotor RPM. This adds cost and complexity, limits operation in light winds, and adds stress to parts. Variable speed turbines rotate at wind-dictated RPM. They are free to spin fast or slow. This reduces cost, complexity and stress on parts but it requires converting the electricity produced (which is of variable frequency) to the standard 60 HZ. This adds cost. Direct drive vs transmission: Direct drive turbines are simpler and mechanically more efficient but require specially designed low-speed generators which are generally less efficient. Turbines with transmissions to step-up the rotor RPM are mechanically more complicated but they can use higher efficiency high-speed generators. Most modern turbines use a transmission. Page B-33 Wind Power: Math, Science & Technology Page B-34 Summary: How a Wind Turbine Works: Here is a quick run down on the power-train in a modern wind turbine. The Zond Z-40 turbine will be used as an example. This system is drawn in (figure 41). Wind: The wind blows, its moving mass pushes against the turbine rotor. (8 mph will turn the turbine, 27 mph is ideal, 65 mph will shut unit down, 150 mph is max survival speed) Rotor: The force of the wind pushing against the rotor causes it to spin. The rotor in turn spins a drive shaft. (the Zond unit has a fixed RPM of 29) Drive Shaft 1: The drive shaft turns the transmission (gear box). (at 29 RPM) Transmission: The transmission raises the RPM speed of the drive shaft to a level appropriate for the generator. (1200 RPM) Drive Shaft 2: This drive shaft turns the generator. (1200 RPM) Generator: The generator produces electricity. (550 kW at 440 V) Plant Electricity: This is usually lower voltage power. (12 kV) Sub Station: The voltage is raised to grid level. (69 kV) Power Grid Electricity: The electricity enters the regional electricity grid and goes out to customers on demand. Wind Power: Math, Science & Technology How a Wine Torame Woerns figure 41 8 poe DB Ss | Awe HAPT W 2 Tres emission it v GeNneRaroR. ———_—_—_—_=—_ Other Turbines Page B-35 Wind Power: Math, Science & Technology CHECK YOUR KNOWLEDGE... ¢ What are some things you should know before choosing a wind turbine design? Explain the difference between HAWT and VAWT rotors. Give an example of each. What are the advantages and disadvantages of leading and trailing rotors? The tip speed ratio defines what about a wind turbine? Where is blade pitch greatest on modern rotors, at the hub or the tip? Why? Page B-36 Glossary (Term definitions and explanations from the U.S. Department of Energy) Anemometer: Measures the wind speed and transmits wind speed data to the controller. Blades: Most turbines have either two or three blades. Wind blowing over the blades causes the blades to "lift" and rotate. Brake: A disc brake which can be applied mechanically, electrically, or hydraulically to stop the rotor in emergencies. Controller: The controller starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 65 mph. Turbines cannot operate at wind speeds above about 65 mph because their generators could overheat. Gear box: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speeds from about 30 to 60 rotations per minute (rpm) to about 1200 to 1500 rpm, the rotational speed required by most generators to produce electricity. The gear box is a costly (and heavy) part of the wind turbine and engineers are exploring "direct-drive" generators that operate at lower rotational speeds and don't need gear boxes. Generator: Usually an off-the-shelf induction generator that produces 60-cycle AC electricity. High-speed shaft: Drives the generator. Low-speed shaft: The rotor turns the low-speed shaft at about 30 to 60 rotations per minute. Nacelle: The rotor attaches to the nacelle, which sits atop the tower and includes the gear box, low- and high-speed shafts, generator, controller, and brake. A cover protects the components inside the nacelle. Some nacelles are large enough for a technician to stand inside while working. Pitch: Blades are turned, or pitched, out of the wind to keep the rotor from turning in winds that are too high or too low to produce electricity. Rotor: The blades and the hub together are called the rotor. Tower: Towers are made from tubular steel (shown here) or steel lattice. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity. Wind direction: This is an "upwind" turbine, so-called because it operates facing into the wind. Other turbines are designed to run "downwind", facing away from the wind. Wind vane: Measures wind direction and communicates with the yaw drive to orient the turbine properly with respect to the wind. Yaw drive: Upwind turbines face into the wind; the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. Downwind turbines don't require a yaw drive, the wind blows the rotor downwind. Yaw motor: Powers the yaw drive. Wind Power — 3D view. Paper Model Plan Kook Wind Turbine Science and Technology Acknowledgements This unit was developed as part of a school-business internship during the summer of 1997 with Green Mountain Power Company of Montpelier, Vermont. During the year I teach 5™ and 6" grade at East Montpelier Elementary School in East Montpelier, Vermont. IT am grateful to GMP for sponsoring me and providing resources and support for this project. Special thanks go to Cynthia Russell, my supervisor at GMP. Copyright 1998 - Green Mountain Power Introduction ‘the plans presented in this booklet are designed to be built by students with a minimum of tools and skills. Most are designed to be duplicated on a photocopier and worked on directly. Others are scale drawings to be used as building plans. Here is a list of tools you will need to have a successful experience: pencil, ball-point pen, markers, scissors, exacto- knife, board to cut on,ruler, compass, photocopier, hot glue gun (and glue), wire cutters, pliers, saw. Materials: paper, oak tag, heavy card stock, cardboard, white glue, tape (scotch, masking and duct), pins, paper clips, paper fasteners, coat hanger wire, bendy wire, straws, tongue depressors, popsicle sticks, trash bag plastic, toilet paper and paper towel roll tubes, wood dowels. Note Well: not all models require all or even most of these things - look at the models you intend to build and take it from there. Each model has been built and works. However, as these designs were done and tested, improvements may have been made which are not shown on the designs. So, be prepared to tinker if things don't work perfectly. Jam confident that it will all work - so be patient! Good luck and have a great time building and flying’ your creations, : Foe Q Ve /, Rollin : Wind Power aver Model Plan Kook ‘lable of Contents Utle Plan# Keaufort Wind Scale if Wind Measurement Devices 2,5,4,5,6 Anemometer (Cup rotor) 7 Sun - faced and Blank Kite 8 Sled kite 9 Savionus Rotor Kite 10 Paper Helicopter 17 Parachutes 12 Persian Windmill is Chinesef Clapper Windmill 14 Cretan Windmill 12 Savionus Rotor 16 Darrieus Rotors ta Pinwheel Turbine 18 Dutch 4-blade Windmill 19 8-blade Wind Turbine 20 Up-wind Rotor HAWT 21 (horizontal axis wind turbine) Home made Wooden Propeller Rotor 22 Enjoy! = I +1 = b \/ Beaufort Wind Scale windstrength |Beaufort | wind description | effects thatcan be seen (for home-made | number speed onland anemometers) (m.p.h) oe fe Below 1 | calm smoke rises vertically wind direction shown by smoke, but vanes donot move 2 len | light breeze |leaves rustle, wind felton face, vanes move leaves and small twigs move, light flags extended moderate moderate winds dust raised, small branches sway, flags flap [Ff freee fmatoeresey rengwnat [a _ [3-81 [sree reise arbrnsieneay | ear |e waa—rreraon ja [se-46 Joate | twigs broken off trees, very hard to walk into wind 9 fa7—s4 | stronggale | slight damage to houses [ie [sore rveuaronstousdamaseshaus = 1 [ea—72_| violent storm | widespread damage n2 [above 72| hurricane cutfrom nylon stockings or tights . Sellotape upturned flower pot head and tail cutfrom a polystyrene ceiling tile brick with holesin point of balance drinking straw two cotton reels taped together strip of plastic Meccano wooden knitting needle = 1 card letters 7 tapedon long stick wind sock curved card |/ af for scale strong wire metal rings painted cup fixed to wood with drawing pin pointer vane card, metal foil or polystyrene C. In an early pressure-tube anemometer, wind pressure induces a height differ- ence between the fluid levels in a U- shaped tube. A “sandpile” anemometer, first used Apressure-plate anemometer. Wind pres- in the 1830's. This simple but crude sure forces the plate to swing up along a method of recording windspeed pro- graduated scale, providing a rough meas- vided only qualitative estimates. ure of the windspeed. -- Wines MedAsutement— Devices ( speed WIND SPEED INDICATOR MATERIALS: Wood (approx. one metre); Cardboard ; Strips of washing-up liquid bottle; Glue; Sticky tape; Tissue paper. TOOLS: Junior hacksaw Rolled up wash r 1d, boHle MATERIALS: Wood (approx. 42 an.); Cardboard; Strip of washing-up liquid bottle; Glue; TOOLS: Junior hacksaw monofila' wind nylon 0.08 Ae O.2mm 4 iment SK S “ through ball and is atlached at bottom with small amount of cement A do-it-yourself, hand-held wind gauge with calibration data (based on C.L. Strong, Scientific American, October 1971). mee stand away to minimize ai disturbance sprit level cemented to protractor calibration data nylon line goes =— Spee “a SPSS eS f| te enna ee™ Pete) LT PpeizontAe Axis Wind ee ei | uonepunog uoIs25463 StatV LEAL ® : Construction . First, scale the kite based on the design shown in Illus. 168. Establish your module unit by dividing the height by 4. For a 36” kite: 36 + 4 = 9; multi- ply each module by 9 for a 36” version of the kite. For a 16” kite, multiply modules by 4. A kite with 16” or 24” longerons makes efficient use of both standard 48” dowels (a %” dowel for 24” and smaller) and large-size trash bags. 2. Make the kite half-pattern template (Illus. 164). . Two 24” kites may be cut from an unopened trash bag. Trim the sealed bottom end and the top as required to lay the trash bag completely flat. Align the straight sides of the templates along the bag’s fold lines (Illus. 165). . Cut out a half-pattern for a complete kite (Illus. 166). Illus. 162. The Hornbean Sled Kite Mark I. 1.25 RADIUS HALF —- PATTERN TEMPLATE Illus. 164. Step 2. LARGE TRASH BAC FOLOED FLAT Illus. 165. Step 3. COMPLETED Illus. 167. Step 5. RUVTE S ”) middle of the bridle and attach the flying line. (See Illus. 168.) Note: Adding crepe paper streamers to POSITIONS the aft tips of kites 24” and under makes the kites Illus. 166. Step 4. more stable in higher winds. 5. Use 8” strips of Scotch transparent tape to secure + the longerons in position as shown in A of Illus. BRIDLE LES » i. Two strips of tape, fore and aft, are sufficient * for 16” kites that can be flown from heavy carpet - thread for buttons. Larger kites need additional _ tape to keep the longerons in position. “The kite shown here illustrates taping (9’ apart) a 36” kite with %” dowels for longerons. Reinforce * the bridle connect points with an overlapping sec- - tion of strapping tape; punch holes 3 in the keel tips ©. for the bridle. : Optional detail: (See B of Tus. 167.) The tape + Will hold the longeron tips more securely if the Illus. 168. Step 6. '- dowel ends are sanded flat as shown. Add strap- ~ -ping tape to prevent the dowel from poking s: :through the transparent tape. . . 7. Keel tip option: (See the steps in Illus. 169.) Use 6. The bridle should be three times the height of the - strapping tape to secure a %”" x %” dowel in place ¥ekite, For a 36” version, tie the ends of 18' of 30 to absorb the stress of the bridle. Punch a %" hole %Ib.—test line to the keel tips. Form 4 loop at the for the bridle line. IN FLIGHT ri 4: 1 a LL ° 7 2 y 3 5 * i ‘Sces” Kire Paarl % Foun Tar 7:16:97 kg. fulacge to Ul’ 17" Pape to use “a pp) "Scen Kite (Fal | Size) =r - Mate Rais Lise “Tooes List ia is. Tyver TheeR | Scissors | re: aos 4 2 stringers | Cmbe knife te _Doer Tee Ol & Pencil vi —Kite. Strin . . Hole Fone. Te Ze % 86 Yarw 7 \ tol 1% 3 if Re Yarw Ta'l hogs fom ay sree i* | plow lOg IMAI Wee A Rotor Kite Design: Courtesy of W. D. (Red) Braswell Rotating Lift from the Wind The rotor, shown in Illus. 303, is one of the eight generic kite forms. This kinetic kite manifests lift through an autorotating action induced by the motion of the surrounding air currents. With its dynamic surfaces blinking ever faster at the sun, the rotor must be in constant motion to stay aloft. While pas- sive rotors, like windmills and kites, rely solely on available wind for their power, other rotation-lifting surfaces, like airplane and helicopter ee ae motorized. The lift principle occurring in a spinning body mov- ing through a fluid or air, as in this case, is known as the Magnus effect, after G. Magnus, a mid-nine- teenth-century physicist, who observed and recorded the phenomenon. However, nature's use of the Mag- nus effect predates Magnus’ discovery by countless millions of years. Many of us have observed maple seedlings, for example, twirling and gliding earth- wards—often catching the winds to travel great dis- tances. On the official side, while patents for rotor and related gyration-lifting airfoils date back to 1911, in- terest in rotor kites remains esoteric—though a spin- ning rotor continues to amaze us. 198 Materials To make this kite you need: ¢a +%c” x 8” x 12” expanded polystyrene (foam) meat tray, ¢two +10%" foam picnic plates, * one %e" x 48” dowel—cut to the length of the rotor plus 6”, ¢ two round head pins, ea plastic lid from a yogurt cup, coffee can, or mar- garine tub—for bridle connectors, ¢ Elmer's Glue-All (white glue), ° 20 lb.-test line—for bridle, ¢ a hobby knife, ¢ sandpaper or an emery board, * wax paper, ¢ nylon thread, * super glue like Elmer’s Wonderbond Plus, and * (optional) a Dremel Moto-tool and router. Details * (Detail 1 in Illus. 302.) Main view. * (Detail 2 in Illus. 303.) In flight. 8’ length of 20 Ib. test: Connect to plastic bridle points, tie the loop in the exact center, and then attach the tether (flying line) to the loop. (Option: Try flying and maneuver- ing the rotor from dual lines as with a stunt kite.) Illus. $02. Detail 1. 2° LENGTH OF 20 LB. TEST. CONNECT TO PLASTIC BRIDLE POINTS, THEN 116 LOOP (N EXACT CENTER 5 ATTACH TE MER CFLYING UNE) TO LOOP, OPTION: TRY FLYING AND MANEUVERING ROTOR FROMM DUAL LINES, AS WITH A STUNT KV7E. Mus. 808. Detail 2—in flight. \ Flight Data: Wind range: 8-20 mph Line: 20 Ib. test AE: +55° Construction Cutting: 1. Use a sharp hobby knife to cut the expanded poly- styrene (foam) meat tray. Smooth the rough edges with light sandpaper or an emery board. Trim the edges of the meat tray as shown in Illus. 304. Mark the horizontal centerline X and the vertical cen- terline Y. Tip: Use a flexible straightedge, like a business envelope, as guide in marking lines over the tray’s curved edges. eu Y EE Ll—| Ke te St FF Mus. $04. Step 1. 2. Cut the tray along centerline X to form vanes #1 and #2. Reverse the position of vane #2 as shown in Illus. 805. Illus. $05. Step 2. Gluing: 5. 6. See Illus. 306. Cut %e” dowel to the length of the vane (L) plus 6” and mark the middle. Drill a %" pilot hole (pin diameter) in the middle of both ends. Wrap the ends with nylon thread and glue them to prevent splitting. Align the centerline of vane #1 with the middle of the dowel and glue in position. Align vane #2 (facing the opposite direction) with vane #1 and glue to form a rotor assembly. Option: For a precision join, use a Dremel Moto- tool with a router attachment to uniformly rout the edges of vanes #1 and #2 that meet at the dowel. See Illus. 307. Place a sheet of wax paper between the rotor assembly and a flat surface to prevent glue from sticking to your work area; make sure the rotors are aligned and flat. Allow to dry over- night. See Illus. 308. Locate the middle of both plates and drill a %e” hole in each. See Illus. 309. Sandwich the rotor assembly be- 199 plow (De. SIDE V/EW OPTION t DRILL + PLOT fe HOLE IN ADDL ae VANE ST O VANE BZ ON BOTH ENDS. FE" Dower Illus. 806. Step 8. . tween the two plates; mark the positions where vane e1 Te DOWEL the rotor meets the plate. Check for gaps and trim the rotor ends for a flush fit. Remove the plates SWEET OF WAX and lightly sand the area where the rotor will be PACER BETWEEN ae Saen Ge Lace FLAT SURFACE glued. Glue and sandwich the rotor assembly between Illus. $07. Step 4. the plates. Let it dry overnight. 7. See Illus. 310. Cut two plastic bridle connectors to size (1" x %"). Use a darning needle or other thin, strong, sharp point to make a pin hole. Use a € 2 = cenzERuUNE sharp paper punch for both a %” hole and a notch i | at the tip. sos iP nou. : 8. See Illus. 311. Take two round head pins and cut F both to %" lengths. Make pin holes large enough to ¢— _ : allow free movement of the bridle connector. Place a dab of glue in the holes on the dowel ends. Insert the pins through the bridle-connector pin holes born rosiawoll and %" into the dowel ends. ered A fe HOLE IN 9. To make the bridle knot, fix the bridle line to the Illus. 808. Step 5. connector as shown in Illus. 312. MARK POSITION WHERE ROTOR MEETS PLATE. DIRECTION OF REFERENCES ROTAT] ON SIDE VIEW MATE? OF PLATE yowe =, Illus. 309. Step 6. ROTOR ASSEMBLY SANDWICHED AND GLUED BETWEEN PLATES. enol GLUE PREVENTS. = PIN-ROUSH BRIDLE PLASTIC BRIDLE CONNECTOR. END Aeon conmecroe and §° iNT + “ Aceow FREE MOVEMENT OF PIN a Tri GRiOLE CONNECTOR: woe + I Fides = - USE #4; AP MOE ~ US ES tote *__‘Tllus. $11. Step 8. connae AND NOTCH TO SEULRE GRIDLE U/NE- ons Tilus 310. Step 7 paras Illus. $12. Step 9. “*?7 pou Il _ ewer Notes te hold juss ES a _ad 5 e heli- iM spi i caper mill Spin hell here A Y SS it on | + - a] “2 A wv! > : a a | 3 w S + c E iv, V s } A ; E a. 3 ef i A ee a > = Strplkes - Teast Bre Floshe about /2° x 12° ~ Bestan ~BxY maddie Wheel Frome Ft (x2) ! lies Eo € as ize to axle ( roar hanger wire) ull size lau* 134 How to build the “Persian” Windmill r Materials: cardboard coathanger wire tape hot glue 7 k- Bs) Study the sample model! before you start to build !! fe" “ ot The box - tower + cut out a piece of cardboard to the design shown. —————*~ <2 * fold into a box and staple / glue together. 4N | * poke holes at each side of the open end of the box (with a piece of wire) to accept the axle. The top and bottom plates * cut 2 squares of cardboard (5" x8”) to form the top and bottom plates of the rotor. + draw diagonals and mark the center. + poke a hole in the center (with a pencil) big enough for a straw to ‘just’ fit snugly. * poke a hole in each corner (with a piece of wire) about 1/4” in from the edge. * draw two more lines so that the cardboard looks like it has 8 equal pieces. *draw a "diameter circle on the cardboard. * cut out the cardboard to the circle. * cut narrow slots (1” long) into the cardboard along each radiating line. (these slots should be just big enough for a piece of cardboard to fit into them snugly) The paddies 6 * cut 8 pieces of cardboard (6" x 2") [Tite Tbe slots The axle lo” + cut a piece of wire 10" long ae feo * cut a straw 7" long —Ee Assemble it | * glue the paddles into the slots you cut in the top and bottom plates. + insert the straw into the center holes of the top and bottom plates so that it sticks out about 1”. Glue in place. * Pu the rotor and the tower together and feed the wire axle through it all. * Bend the wire over at top and bottom so it stays. Bottow Plate Wive Treces OGRE wire) Tee a 7 Side View Lee = shan (F >) oe pag card beard _ washoar pen*™ J4b " A " Materials: cardboard coathanger wire tape glue Study the sample model before you build it ! Go The top and bottom plates C 4 - cut 2 squares of cardboard (6" x 6") to form the top and bottom plates of the rotor. - draw diagonals and mark the center. - poke a hole in the center (with a pencil) big enough for a straw to fit snuggly. - poke a hole in each comer (with a piece of wire) about 1/4" in from the edges. - poke a hole in each diagonal about half way out from the center towards the corner. The paddles - cut 4 pieces of cardboard &" xi". - cut 4 straws’7" long for the paddle axle-collars. - tape the paddles onto the axle collars like this ---------> The axles and rods - cut one piece of wire 12" long for the central axle. - cut one piece of straw 4" long for the central axle-collar. - cut 4 pieces of wire 8" long for the paddle axles. (e - cut 4 stra 8" long for the paddle stop-rods. {2 samp wires iad \ one mo € Assemle it 4 - insert the q" straw axle-collar into the center hole in the top and bottom plates (it should stick out about 1/2" at each end) - insert the g" straw stop-rods into the holes in the diagonals of the top and bottom plates (they should stick out about 1/2" at each end) - feed the g" wire paddle-axles through the paddle axle-collars (on the paddles) and insert them into the holes in the corners of the top and bottom plates. (they should stick out about 1/2" at each end) - square everything up and glue it with hot glue (be sure the paddles are free to rotate!) The handle - cut a piece of cardboard 6" x 3" (with the corrogations running the 6" way). - insert the | 2" wire axle into the corrogations of the handle about 3" and hot glue. - cut a small washer of cardboard and put it on the axle just above the handle. Final assembly - put the windmill on the handle You are done ! ce =< ry —.———YIND.... =f eadis; + - ep IS i f: fess -pt+ Washer _ (exe row Yoguct pot Vee hot give +o assembler axle, Fotr blades and eud caPS. ow straw axle Se eee’ wee ase + PL 7-78-37 | fe] FO ji] Foor size ee) 4 - Folding the Blade / ot tape: Inside. = ; a pees outs e ES } i Frnt t Finished Blade nr Sty ro fone ox see ay eet ell i ; +7 ah 7 Gore rage fecyey i f° = 3 bP E + + £ z es = x* fy 4+=- BLADES -.. WINBM Ite sandwich herweenr turo lay ers 12°x/2 a oer dades — @ Id° pitch so Masver Coupliara , | GENERAL CONSTRUCTION TIPS Stert at tips bringing wood down on airfoil side of prop with drawknife (or resp when it starts getting close) until template for station A will fit on prop in the right place (7" from tip)— then go to template 6B until it fits (7” from A)—and so on toward the center. The flat side made in Step 3 is your refer- ence for positioning the templates. Sand well, varnish (several costs), and balance both horizon- tally and vertically. Balancing cen easily be accomplished by adding small weights to the edge (vert. balance) and front (horiz, balance). NOTE: This prop can be made 10 feet long by extending the distance between stations from 7” to 10”, making the 3” x 4” sections both 5”. All other dimensions, the same. S DRAW DOTTED LINES ON EDGES (FIGURE FOR STEP 2 SHOWS RIGHT-HAND EDGE OF FIGURE IN STEP 1). TRAILING EDGE (3/32" THICK) LEADING EDGE DIMENSIONS ARE "Xx" +"°2" FOR EACH STATION STEP 2 DIMENSIONS ARE “y" +"'2" FOR EACH STATION 7 X 2” X 6" (REDWOOD, STRAIGHT- LEADING EDGE HOLD DOWN — WITH VICE OR C-CLAMPS FLAT SIDE BEGINS TO CURVE A BIT ATSTA.E AS IT BECOMES FLAT AGAIN TOWARD CENTER STEP 3. GRAINED FIR, OR SPRUCE) TRAILING EDGE be TRAILING EDGE fra LEADING EDGE CUT ON DOTTED LINES. BRING DOWN TO FLAT SIDE OF PROP WITH * DRAWKNIFE. WATCH TRAILING AND LEADING EDGE LINES DRAWN IN STEP 2. DRAW CROSS SECTIONS FOR EACH STATION FULL SIZE ON CARDBOARD AND CUT OUT WITH RAZOR TO MAKE TEMPLATE MEASURED FROM PROP AT EACH STATION AFTER STEP 1. ast EVESALL THESE CURVES. LOOK AT SOME AIR. PLANE WINGS. 3 | i : i i TRAILING EDGE LEADING EOGE SHARP. From The Wind at Work, © 1997 by Gretchen Woelfle. Used with permission of Chicago Review Press. The Wind at Work can be ordered by calling (800) 888-4741 or by visiting www.chicagoreviewpress.com. Harnessing Wind Power Through Time COMPARE ELEMENT TEMPERATURES Goal Understand temperature patterns that affect the wind. Materials 2 plastic buckets of the same size Water Earth 3 outdoor thermometers Notebook Pencil 1 piece of graph paper 3 different color markers Ruler Directions Fill one bucket with earth and the other bucket with water. Place a thermometer in each buck- et. Place the buckets side by side. Place the third thermometer on the ground nearby to measure the air temperature. Make sure you place the buckets and thermometers some- place where the sun can shine on them for part of each day. Day Monday morning Water Use the notebook to record your observa- tions three times a day. For each observation, record the day of the week, time of day, the name of the element (water, earth, or air), the temperature reading on the thermometer, and the weather conditions at the time of your observation. Record your observations for three days. Time Element Temperature Condition 76 degrees sunny but cloudy Monday morning Earth 78 same Monday morning = Air 77 same Monday afternoon Water 82 sunny and soon... At the end of your three days of observation, create a chart like the one shown above. Write in a temperature range on the vertical axis and the days of observation on the horizontal axis leaving enough room to record your three daily observations. Use a different color marker to record your observations for each element. Place a dot in the spot where the day of the week and time intersect with the recorded tem- perature. Once you’ve recorded all your obser- vations, use a ruler to connect these dots. The Wind at Work Results Which element shows the least temperature What element has the highest temperature— change during the day? water, earth, or air—in the morning? What does this tell you about the relative Afternoon? Evening? temperature of the oceans, earth, and atmos- Which element heats up the most during the phere? How might these temperature differ- day? ences affect wind patterns? Which element cools down the most at night? MONDAY TUESDAY WEDNESDAY Morning Afternoon Evening Morning Afternoon Evening Morning Afternoon Evening Harnessing Wind Power Through Time LEARN HOW TEMPERATURE AFFECTS WIND Goal Observe the flow of air in a warm and cool environment. Materials 1 2-foot piece aluminum foil 1 small piece molding clay 1 thick candle, 4 inches tall Matchbook 2 small wooden blocks, 1 or 2 inches thick 1 empty soup can, label and both ends removed 1 sharp knife 1 piece heavy cotton string, 3 inches long (Don't use nylon string!) Directions (Adult help suggested.) Spread the aluminum foil on top of a table. Secure the candle to the tabletop with clay. Light the candle. Place 2 wooden blocks on opposite sides of the candle. Carefully place the can over the candle and resting on top of the 2 blocks. The candle flame should not show above the can. (If the candle is too tall, blow it out and cut it at the bottom so it will fit inside the can.) Light the end of the string over the sink, then quickly blow out the flame. The string should smoke. Hold the smoking string 2 inches above the candle flame. Notice the temperature above the candle. What happens to the smoke? 10 The Wind at Work While the string continues to smoke, hold it beside the candle, about a foot away. Notice the temperature now. What happens to the smoke? Finally, hold the string near the table top, about ’2 inch from the edge of the can. What happens to the smoke? How can you explain this? Results If our atmosphere were all the same temper- ature, air wouldn't move. However, sunlight warms our atmosphere just like a candle pe warms the air around it. The warm air rises, and the cooler air moves in to take its place. So, when you hold the string directly above the candle, the smoke rises. When you hold the string a foot away from the heat source, the smoke drifts because the air surrounding the string is not as warm. Finally, when you hold the string close to the bottom of the tin can, the smoke is drawn up under the can and rises because the smoke moves in the direction of the warmer air. | MoM SF _|_ Ancient Wind Machines 15 MAKE A WIND SOCK AND WIND VANE Wind socks are used in airports to show which direction the wind is blowing. Goal Make a wind sock and wind vane and:learn how they work. Materials 1 nylon knee sock or 1 knee-high hosiery 15-18 inches long 1 12 ounce Styrofoam cup 1 %s inch wooden dowel, 3 feet long 2 straight plastic straws, 8 inches long (not the flexible kind) 1 % inch washer 1 push pin 1 sheet construction paper Tools Scissors Pencil Masking tape White glue Ruler Compass Directions WIND SOCK (Adult help suggested.) 1. Use the scissors to cut off the toe of the sock or the knee-high hose, so that it is open at each end. 2. Cut out the bottom of the Styrofoam cup. Using a sharp pencil, bore a hole in the cup, just below the raised rim. This hole should be big enough for the 1 %6 inch dowel to fit through. Bore another hole directly opposite the first one. Use a sharp pencil to bore a hole in the Styrofoam cup just below the raised rim. Make a second hole directly across from the first one. 16 Pull sock or hose over the cup, from the bottom/nar- rower end up, and Secure with tape. This is your wind sock. Use scissors to rip holes in the sock or hose where the cup holes are located. to p e tape The Wind at Work Slide the wind sock onto the dowel through the 2 holes. Place the washer directly below the cup. Wrap tape around the pole directly above the cup and just below the washer to Secure. . Stretch the wide (knee-end) of the sock or hose over the bottom of the cup up to the raised rim. Tape the sock or hose onto the rim by securing it with 1 long piece of tape. Reinforce it with 4 small pieces of tape around the rim. . Use scissors to snip holes in the sock or hose where the cup holes are located. WIND SOCK POLE . Push the pushpin through the top end of the dowel, as far as it will go. Then twist and remove the pushpin. (This hole will be needed for the next stage when you make your wind vane.) . Slide the wind sock onto the dowel through the 2 holes, leaving 1 inch free at the top. . Place the % inch washer on the bottom of the dowel and push it up the pole until it rests just below the Styrofoam cup. Wrap a piece of tape around the pole several times, just underneath the washer, until it is thick enough to hold the washer in place. The washer will prevent the wind sock from sliding down the pole. . Wrap another strip of tape around the top end of the dowel, just above the wind sock, to keep it from sliding off the top of the pole. Ancient Wind Machines 17 WIND VANE 1. Carefully cut %-inch slits in each end of the straws. Cut 4 small 1 by 1-inch squares of con- struction paper. Mark each square of construc- tion paper with a compass direction N, S, E, or W. Dab a drop of white glue on each side of the paper and slip one piece between each pair of slits on all 4 ends of the 2 straws. Place N and S on the 2 ends of 1 straw; E and W on the other, just like the compass points. Be sure that the paper is horizontal. Dab more glue on the spots where the paper meets the straw to secure. Allow this to dry. Allow the glue to dry ~washer before taking your wind sock and wind tape — | vane outside to con- duct your experi- ments. 2. Measure the straws and find the middle of each. Pierce the middle of each straw with the Cut 14-inch slits in each straw pushpin. Then dab the following surfaces with end —— i re of white glue: the top of the dowel with the push- construction paper tha Fs . ° compass direction between pin hole, the middle of each straw, and point of each pair of slits. the pushpin. 18 The Wind at Work 3. Insert the pushpin through both straws and into the top of the dowel, loosely secured with the pushpin. Be certain the straws form a cross, with each arm 90° apart. Wipe off excess glue. Allow glue to dry before trying the experi- ments. Experiments 1. Take your wind sock outside and watch it fill with wind. Wind speed increases with altitude, so use the highest (safe) location you can find to test your wind sock. Walk to the top of a nearby hill or climb to the top of the slide in a playground. If you can’t find any place higher than the level ground, hold the wind sock above your head. Try to stay clear of trees and buildings. These will block the wind. 2. Use a compass to find North. Point your N straw vane in that direction. Your wind sock will turn until it faces into the wind. The wind vane will show you the direction of the wind. In the next activity, you can use your wind sock to determine how fast the wind is blowing. MEASURE THE WIND WITH ADMIRAL BEAUFORT Young Francis Beaufort joined the British Royal Navy and went to sea when he was twelve years old. For more than twenty years he learned the ways of the wind. In 1805 he devised a scale to determine the wind speed by looking at things around him—trees, flags, smoke. In later years he became Admiral Sir Francis Beaufort. Today, sailors, meteorologists, and others continue to rely on the Beaufort scale. You can find the wind speeds in your neighborhood by using your wind sock and wind vane from the previous activity and by following the Beaufort scale. Goal Observe and measure wind patterns at different times of the day. Calibrate (adjust) your wind sock and wind vane to the Beaufort scale. Materials Beaufort scale (see pg. 19) Notebook Pencil Wind sock and wind vane (see Make a Wind Sock and Wind Vane activity above) Compass Experiment Take your wind sock to your backyard, school yard, or a nearby park. Find an open area, away from trees and buildings. Observe the wind in Beaufort Number — Name of Wind 0 calm 1 light air 2 light breeze 3 gentle breeze 4 moderate breeze Si: fresh breeze 6 strong breeze 7 moderate gale or near gale 8 fresh gale or gale 9 strong gale 10 whole gale or storm 11 storm or violent storm 12 hurricane Ancient Wind Machines BEAUFORT SCALE | Signs/Description ' calm; smoke rises vertically . smoke drifts, indicating wind direction | wind felt on face; leaves rustle; flags stir leaves and small twigs in constant motion small branches move; wind raises dust and loose paper » Small-leaved trees begin to sway; crested wavelets form on inland water . overhead wires whistle; umbrellas difficult to control; large branches move whole trees sway; walking against wind is difficult twigs break off trees; moving cars veer slight structural damage occurs such as signs and antennas blown down ° trees uprooted; considerable structural ’ damage occurs : widespread damage occurs widespread damage occurs *The United States uses 74 mph as speed criterion for a hurricane. Wind Speed/mph <1 1-3 4-7 8-12 13-18 19-24 25-31 32-38 39-46 47-54 55-63 64-74* 74+* 19 20 The Wind at Work the same place in the morning, afternoon, and evening for five days. Watch how the wind moves different things: the tops of trees, a tall flagpole, your wind sock. Using the Beaufort scale, estimate the wind speed and record in your notebook. Recopy the Beaufort scale in your notebook but leave room to record your own observa- tions under the description column. Observe how your wind sock reacts to different wind speeds. Add this information to the description column on your Beaufort scale. Find North using your compass. Point the N arm of your wind vane North. Find the wind direction using your wind sock and record in your notebook. Results You will probably memorize the Beaufort scale after a few days and then you'll always know how hard the wind is blowing! How could this be useful to you? When does the wind blow strongest in your neighborhood? When is it weakest? Do you notice any wind speed pattern? Try this experiment during different seasons. Do you see the same wind patterns in summer and winter? In the rainy season and the dry season? What sort of geographical area do you live in—plains, valley, mountains, desert, seaside, or lakeside? How does this help to explain the wind patterns you find? Windmills in Europe Across the Centuries 31 WRITE ABOUT THE WIND You can do these writing exercises alone or, with a group of people, with everyone contributing words and ideas. If you work in a group, try writ- ing your story, legend, or journal as a play with different people acting out each role. Goal Use your imagination to experience the wind from different points of view and express this experience in words. Materials Pen or pencil Paper Directions EXERCISE 1: IMAGINE A COOL WIND ON A HOT DAY Use your eyes and think about riding a bicycle, skateboard, or roller skating on a hot, sunny day. What does the wind feel like blowing on your face? Think of words to describe this physical feeling. Open your eyes and write down your words. Close your eyes again and get back on your imaginary bicycle, skateboard, or skates. Think of words to describe the sound of the wind. Open your eyes and write down your words. Repeat this process for seeing, tasting, and smelling the wind. After you have compiled these lists of words describing the wind through your five senses, look at your list of words. Now write a para- graph or a poem using some of these words to describe exactly how you experienced the wind while on your bike, skateboard, or skates. (Hint: If you write a poem, try writing one that does not rhyme. You can choose from a greater vari- ety of words this way.) Read your paragraph or poem to someone else. Ask them if they could feel the sensations about which you wrote. EXERCISE 2: IMAGINE A COLD WIND IN A RAINSTORM Repeat Exercise 1 while you imagine walking against a strong wind on a cold, rainy after- noon. Close your eyes and imagine each of the following senses, one at a time: sound, touch, sight, taste, and smell. Write down your descriptive words for each sense. Choose the words that best describe walking through the cold, windy rainstorm, and write a paragraph or poem about it. (Hint: Again, if you write a poem, try writing one that does not rhyme so that you can choose from a greater variety of words.) Read your paragraph or poem to someone else. Ask them if they could feel the sensations about which you wrote. 32 The Wind at Work EXERCISE 3: WRITE A STORY ABOUT THE WIND Think of a friendly sort of wind that flies kites, pushes sailboats and windsurfers, makes waves on the water, pollinates plants, moves clouds across the sky, turns windmill 'sails, or makes the trees sway. Close your eyes and pre- tend you are a bird, a kite, a windmiller, a sailor, or a child lying on your back on the grass. A gentle wind is moving some of the things that surround you. After a few minutes, open your eyes and begin writing a story by describing who you are, what you are doing, and what you see, hear, smell, taste, and touch. Remember that you are inventing a story, not just writing a list of words. Now imagine that the wind is growing stronger and stronger until it turns into a storm, a hurricane, or a tornado. Perhaps it starts raining, or snowing, or a raging wind sweeps a fire toward you. Think about what you might see, hear, smell, taste, or touch. (Remember, you are still a bird, sailor, child, or whatever you originally imagined.) Write about what is happening around you now. You might use parts of a true experience or you might make up the whole story. Now imagine that the wind finally dies down. What has happened to you? What has happened to the world around you? Write a conclusion to your story. Read your story to another person. Ask them if they could feel some of the same things that you wrote about in your story. EXERCISE 4: WRITE A LEGEND ABOUT HOW THE WIND CAME TO BE Many cultures have legends about how the earth was made or how the first people were created. Think up a legend about how the wind came to be. Perhaps it resulted from an argu- ment between the moon and the sun or the earth and the ocean. Perhaps the wind was the child of an unusual mother and father. Use your imagination and make your legend as fan- tastic as you like. Begin your story this way: A long time ago, before there were any books or storytellers, or any humans at all, there was no wind. Then one day... Read your legend to someone else and use different voices and movements to tell your story like a traditional storyteller would do. EXERCISE 5: RECORD A DAY IN THE LIFE OF THE WIND Pretend you are the wind. Write a journal about a day in your life. You might make it funny or serious or both. Begin writing about this day as if it is an hour before sunrise. Where are you? Are you asleep or have you been traveling in disguise all night? Windmills in Europe Across the Centuries 33 Write down your activities all through the day. Where do you go? What and who do you see? What do you do? Still pretending to be the wind, allow yourself to talk to the trees, the mountains, the ocean, or the people you meet. ‘Record these encounters. Do you ever take a rest? Do you become angry, sad, or happy? What happens if you do? Continue your journal into the evening of your day and through the night, finally ending 24 hours after you started. Read your journal to someone else using sound effects, different voices, and body move- ments to make your story dramatic. Take your imagination with you next time you're outside on a windy day. See how you can experience the day from a different point of view. A New Kind of Windmill 83 MAKE AN ELECTRIC INVENTORY OF YOUR HOUSE One hundred years ago most people didn’t have electricity in their home. When their houses were finally wired, they installed electric lights. Other inventions came later. Today we depend on electricity for dozens of activities. Goal Discover all the ways you use electricity by making an electrical survey of your home. Materials Notebook Pencil Directions Make a chart in your notebook like the one shown below. Room __ Electrical Equipment How often used Importance Kitchen Refrigerator 24 hours/day necessity Garbage disposal as needed ____ light bulbs as needed convenience more important at night Ventilator fan... Walk through each room of your house and write down everything that uses electricity. Look carefully—some items may be stored in cupboards and closets. Remember to include battery-operated watches, toys, and so on. (Be sure to ask permission to inspect other peo- ple’s rooms first.) Don’t forget the garage and the basement. What about heating and cooling systems for your house? Are they electric, do they use electric fans, or starter motors? Ask your family to help estimate how much time they use each electrical item. Some are used every day, all the time (such as a refrigerator) and others may be used only once a month (such as a crock pot). Mark down their answers next to each item. During a day at home, record on another sheet of paper each time you use something electrical. Mark down each item and how many times you use it. This includes looking at an electrical watch or a clock, answering the tele- phone, and counting all the light bulbs that are on in the rooms you enter. At the end of the day, review the electrical equipment you used. Rewrite this list in your notebook, putting the items in three categories: necessity, convenience, or luxury. (Be certain to leave room for one more column for the next activity.) Now add all the electrical equipment from your first list. How often do you use the items in this list? Could you live without many of your electrical items? In the next activity you'll have a chance to try. 84 The Wind at Work LEARN WHAT LIFE WAS LIKE BEFORE ELECTRICITY Some electrical inventions have been around for a long time such as lights and radios. Others were not invented when your parents were chil- dren such as computers. Perhaps they heard sto- ries from their parents and grandparents about how people lived without the electrical equip- ment we have today. Goal Research the past and discover old ways of doing things. Materials Notebook Chart from “Recording Household Electricity Usage” Pencil Directions Add an “alternate” category to your final list from the “Make an Electric Inventory of Your House” activity. Show the list to your parents, grandparents, and other adults. Ask them how people did things without the electrical equip- ment you found in your house. Write their responses in this column. Try to discover a non-electrical alternative for everything on your list. You might remember books you've read or movies you've seen about life long ago. Discuss all your alternatives with your family or classmates. Did you find alternatives for everything? How did the alternatives make people’s lives different from yours? Was life better in any way? Was it worse? Which electri- cal inventions would you miss most? Which would you not miss very much? SPEND A DAY WITHOUT ELECTRIC POWER Plan this activity when you don’t have school so you can spend the whole day without electricity. Talk to your family about doing this activity together so that you'll experience the full impact of using no electricity around the house. Even if they don’t all agree to do it, do your best to stay away from those watts! (Note: Leave your elec- tric refrigerator or freezer running, or the food will begin to spoil. But try to eat food that needs no refrigeration.) Goal Experience what life was like before electricity. Materials Notebook Pencil A New Kind of Windmill 85 Directions Unplug your electric clock the night before and take off your battery watch. (Remember, bat- tery-powered items use electricity, even though they’re not plugged into a wall socket.) Use a wind-up clock or watch, or try to tell time by the sun. Pay attention to everything you do. Don’t turn on the lights and don’t cook toast in the toaster. Try not to eat food from the refrig- erator. (Discuss this with your parents first.) Keep a diary during the day. Write about everything you do. Was it fun or hard work? Did it take longer to accomplish tasks without electricity? Which ones? Choose some non- electrical activities for part of the day—playing sports, riding your bike, reading by daylight. See how many non-electrical alternatives you can use (see “Learning What Life Was Like Before Electricity”). Bake cookies (if you have a gas oven) using a hand beater. Wash the dish- es by hand. Try some hand sewing. (See the activities in chapter 5). Do some household chores without electricity. Wash your clothes by hand and hang them out to dry or clean your room without a vacuum cleaner. What can you do after dark without electrici- ty? Will you go to bed at sunset or light can- dles? (Check with your parents about using candles safely.) Make your own music or tell your own stories instead of listening to a radio or watching television. Play non-electronic games such as checkers or chess. On the following day, discuss how the day went with other members of your family who participated in this activity. Write down every- one’s answers to the following questions. Was it hard to live without electricity for a day? What parts were the most fun? Most difficult? Could you live comfortably without electricity for very long? How would your life change if you did? What things would be better or worse? In the next chapter, you’ll learn to measure the electricity your family uses, and find ways to conserve or use less electricity. Windmills Today 95 LEARN HOW MUCH ELECTRICITY YOU USE Goal Read your electric bill and meter to understand how much energy you use. Energy used or energy charged will tell you how many kilowatt- hours (kWh) you used during this time period, the basic charge per kilowatt-hour, and the total cost of your electricity. Metropolitan Electric Company The meter number on your bill will match the number on your electric meter. Account # ——Fr Customer and Service Address Jane Consumer 410-66823-01153-0008 ane Anema Billing period or service dates refer Sun Valley, CA 91234 27 | to the time that you were charged for electric power. Each bill may cover Dates of Service. 8/1/97-8/31/97 one or two months. Current Electricity Rate Service charge -60 Energy used 553 kWh x $0.07288 40.30 _ City and state taxes and other charges City tax 10% 4.03 may be added to your bill. State tax 553 kWh x $0.00020 oad Total Meter Usage Information Meter Number Current Reading 6-8953125 21230 Previous 20677 Usage 553 The usage comparison section tells you how many kilowatt- hours your family used this year and last year during the same months. Also, it will give the average daily use and the sea- sonal average for both years. Usage Comparison Usage Daily Average Seasonal Average This year Last year This year Last year Summer Winter 553 kWh 699 kWh 9 kWh 12kWh 10.4 kWh 19.6 kWh The Wind at Work Materials Electric bills during the past year, one for each season Notebook Pencil Calculator Stool Flashlight (optional) Directions Look at your family’s electricity bills from the previous year. (If necessary, you can probably order duplicate copies from your electric com- pany.) The categories on your bill may not have the same names as those illustrated above, but you should find the same informa- tion. How much electricity—in kilowatt-hours— does your family use each year? Find out a daily average by taking the total monthly read- ing and dividing it by the number of days in that month. Draw a graph in your notebook, like the one shown here, to record your family’s use of kilo- watt-hours. Mark a range of kilowatt-hours on the vertical axis and the names of the months on the horizontal axis. Do you use more elec- tricity in different seasons? Why? Look at your list of electrical equipment in the activity called “Make an Electric Inventory of Your House” in the previous chapter to see what might make the difference. Find your electric meter. It may be outside, in the basement, or in a hallway. You may need a stool or a flashlight to see the meter. If you live in an apartment building, there may be many meters, one for each unit. Check the number on the meter to see that it matches the meter number on your electric bill. An electric meter has a wheel in the center. The faster the wheel rotates, the more electrici- ty you are using at that moment. Watch how fast the meter turns. Walk through your house and see how many electrical items are on (lights, television, and so on). Turn off anything’ that is not needed. Look at your meter again and see if the wheel spins more slowly. The five dials on the meter turn at different speeds and show the number of kilowatt-hours used. Create a chart like the one below. Read your meter then write down the numbers on the dials from /eft to right (counter clockwise). Look at the one on the extreme left. Is the dial pointing directly to a number? Write down that number. If the pointer is between two num- bers, write down the /ower number. Read the dial to the right in the same way, and record it to the right of the first number. Continue read- ing the dials and writing the numbers. Windmills Today 97 Look at your latest electricity bill. How many days have passed since the last official meter reading? What was the kilowatt-hour reading 32 kWh / then? Subtract this amount from your reading. Find the daily average electricity usage in that 30 period by dividing the number of days into the 28 kilowatt-hour reading. Is it more or less than the last billing period? Can you explain the 26 change? kWh January February March April May June July August Sept. Oct. Nov. Dec. 98 The Wind at Work SAVE ENERGY AT HOME Goal Monitor your electricity use and change your energy habits to conserve electricity. Materials Notebook Pencil Directions Make a chart like the one below. Read your electric meter each day for a week. Try and determine why you used more or less electrici- ty during different days of the week. Call a family meeting and talk to members of your family about using less electricity. Ask your electric company for information about energy conservation programs. Their phone Date Current meter reading Previous meter reading 11/4 16698 16685 11/5 16723 16698 11/6 16739 16723 117 16747 16739 11/8 11/9 11/10 number should be on your bill. Share these conservation ideas with your family. Create a plan for your family to modify their electricity use, such as turning off lights when leaving a room, turning off the television, and more. You may save a few dollars a month on your elec- tricity bill. Each family’s energy habits do make a difference. After putting this energy-saving plan into action, read the electric meter each day for a week and record the results. Call another fami- ly meeting and review your findings. Are you using less electricity? Does everyone agree that you are as energy-efficient as you can be? If the answer to both questions is yes, congratu- late yourselves. If you think you can be more energy-efficient, review your conservation plan and keep trying. The following ideas may help. kilowatt-hours used Special Activities 13 25 portable heater on 8 hours 16 . lights and TV on all day 8 away all day HINTS FOR CONSERVING ENERG ¢ In the winter, lower your thermostat a few degrees to save heat and put on a sweater instead. If you use air conditioning in the summer, keep your house a few degrees warmer than usual to save energy. Do you need to heat or cool every room in the house all day long? Is it possible to close some air vents in rooms you aren’t-using? ¢ Insulate your home (walls, windows, doorways) and your hot water heater to save on heating and cool- ing costs. (Your power company may pay part or all of the costs of these conservation measures.) ¢ Turn your refrigerator dial to a warmer setting to - Save energy. ¢ Turn lights and electronic equipment off when no one is in the room. * Don’t use the heated drying setting on your dish- washer. This doubles the amount of energy it takes to do the dishes. ¢ Many new models of electrical equipment—includ- ing that energy hog, the refrigerator—use much less electricity than older models. When it’s time to buy a new appliance or piece of electronic equip- ment, compare the energy use of different models. (Some appliances offer energy cost/savings charts affixed to their exterior.) * Try compact fluorescent light bulbs. They cost more to buy, but they use much less electricity and last ten- to twenty-times longer than ordinary incandes- cent light bulbs. In the long run, they are much cheaper and more energy-efficient. Also, your elec- tricity company may give special rebates for com- pact fluorescent bulbs. Windmills Today NY Anemometers, or wind-measuring instruments, measure wind patterns for a year or more before wind turbines are installed on a site. Computer programs can also predict the wind, but are not as accurate as measuring the wind directly. Zond Systems, Inc. Web Resources for Wind Power Education There are many good websites with information about wind power. A good place to start is the U.S. Departments of Energy’s wind energy site, http://www] .eere.energy.gov/windandhydro/, Two other must-see sites include the American Wind Energy Association (AWEA) website, Wwww.awea.org, and the wind research website for the National Renewable Energy Laboratory, http://www.nrel.gov/wind/. AWEA offers a Wind Web Tutorial at http://www.awea.org/faq NREL has an education site at http://www.nrel.gov/education The Franklin Institute Museum of Science has wind energy materials and a “hotlist” linking to other sites with that information at http://www.fi.edu/tfi/hotlist/wind.html The Danish Wind Turbine Manufacturers Association offers a “Wind with Miller” curriculum online at http://www.windpower.org/en/kids/index.htm The Alaska Energy Authority provides a listing of wind projects in Alaska at http://www.akenergyauthority.org/programwind.html Utilities actively involved in wind energy development activities in Alaska include Kotzebue Electric Association, http://kea.coop/home/ Alaska Village Electric Cooperative, www.avec.org Chugach Electric Association, www.chugachelectric.com Golden Valley Electric Association, www.gvea.com Kodiak Electric Association, www.kodiakelectric.com Alaska Power Association, www.alaskapower.org _ Capturing ~~ the Power of — theWind , NOTES & NEWS rea we N ar ATIC ISTSIST VI BIOS BOSOM CT AT ANY NY V4 Rs Sa SERIE OP LL Se x NY é EAN Z\ Tid ALY, 4 AUGUST 2001 Korzesue $- Ruralite Auguet 10:29 AM 7/10/01 Page 2 KOTZEBUE EL E-ODR EC ASSOCIATION > e The 80-foot Tower raises the rotor into stronger, more con- sistent winds. The turbine assembly rotates on the Yaw Bearing like a weather vane, orienting the rotor so that it faces downwind. Anemometers measure the wind speed. At 11 miles per hour, electronic controls automatically release the Parking Brake. The Rotor begins to spin. Each of the blades on the rotor measures 23.7 feet. The wind’s force is transferred to the rotor as it sweeps an area of about 1900 square feet. Wind turbines have different characteristics. Here is a look at how the AOC 15/50 turbine produces electricity to light homes and power businesses in Kotzebue. Co) When the rotor reaches 64 revolutions per minute, a Gearbox increases the turning speed of a generator shaft. The Generator shaft begins to turn at 28.3 times the rotor speed. When the generator speed reaches 1800 revolutions per minute (or the equivalent of 60 Hz frequency) a signal is sent through the Tower Junction Box. At the Control House, a computer program relays commands that automatically control system operations. A Main Connector Switch is activated, sending elec- trical power into the main power grid. At 50 mph, when the wind is strong enough to blow down signs and antennas and cause other damage, the automatic controller deploys brakes to stop the retor in order to protect the turbine and gener- ator from damage. Kotzesue AUGUST 2001 5 — Bibliography for original GMP version of Wind Power Curriculum Butler, J. George. How to Build and Operate your own Small Hydroelectric Plant, TAB books, Blue Ridge Summit, Pennsylvania, 1982 California Office of Appropriate Technology, Common Sense Wind Energy, Brickhouse Publishing Company, Andover, Massacgusetts, 1983 The Concise Columbia Encyclopedia 34 edition), Columbia University press, New York, 1994 Eden, Maxwell. Kiteworks (Explorations in kite building and Slying), Sterling Publishing Co., New York, 1989 Eldridge, Frank. Wind Machines, U. S. Government Printing Office, Washington, D.C., 1975 Golding, E.W. The Generation of Electricity by Wind Power, E. & F. Spon Ltd., London, 1976 Grun, Bernard. The Timetables of History (34 edition), Simon & Schuster, New York, 1991 Hackleman, Michael. The Homebuilt Wind-Generated Electricity Handbook. Peace Press, Culver City, California, 1976 Hackleman, Michael. Wind and Windspinners (A nuts and bolts approach to wind-electric systems), Peace Press, Culver City, California, 1976 Landt, Dennis. Catch the Wind: a book of windmills and windpower, Four Winds Press, New York, 1976 Leckie, Jim; Masters, Gil; Whitehouse, Harry; Young, Lily. Other Homes and Garbage (Designs for self-sufficient Living). Sierra Club Books, San Francisco, 1975 McDonald, Lucile. Windmills: an old-new energy source, Elsevier / Nelson Books, New York, 1981 Mar, Jon. The New Wind Power, Penguin, New York, 1982 Marier, Donald. Wind Power for the Homeowner, Rodale Press, Emmaus, PA, 1981 Mother Earth News, The Mother Earth News Handbook of Homemade Power, Bantam Books, New York, 1974 New Age Access. Wind worker (24 edition), Tyneside free press workshop, Hexham, England, 1979 Park, Jack. The New Wind Power Book, Cheshire Books, Palo Alto, California, 1981 Prenis, John (editor). Energybook #1 (Natural sources and backyard applications), Running Press, Philadelphia, 1975 Rickard, Graham. Wind Energy Gareth Stevens Childrens Books, Milwaukee, 1991 Ridgeway, Harold. Kite making and Flying, Gramercy Publishing Company, New York, 1962 Szczelkun, Stefan, A. Survival Scrapbook #3 (Basic ways to decrease energy dependence- making solar, wind, tidal, bio- gas, animal ... power), Schoken Books, New York, 1974 Stockley, Corinne; Oxlade, Chris; Wertheim, Jane. The Usborne Illustrated Dictionary of Science (Physics, chemistry & biology facts), EDC Publishing, Tulsa, Oklahoma, 1988 Uvarov, E. B; Isaacs, Alan. The Penguin Dictionary of Science, Penguin Books, London, 1986 The World Almanac and Book of Facts 1995, Funk and Wagnall’s, Mahwah, New Jersey, 1994 Yole, Will. The Complete Book of Kites and Kite Flying, Simon & Schuster, New York, 1976