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Wind 101

Wind 101. Jerry L. Hudgins Electrical Engineering Department University of Nebraska-Lincoln. Course Goals.

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Wind 101

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  1. Wind 101 Jerry L. Hudgins Electrical Engineering Department University of Nebraska-Lincoln

  2. Course Goals • This broad multidisciplinary course will combine introductory principles of both the mechanical (aerodynamics) and electrical components and systems, along with economic and environmental considerations for siting, and associated public policy to appropriately cover the relevant topics for all scales of wind energy implementation. • This course is intended as an introduction to wind energy and will provide the necessary background for persons wanting to pursue further education or certification to become a small-wind installer/dealer, or move into segments of the large-wind industry.

  3. Career Pathways • Students completing this course are well positioned to pursue further training from turbine manufacturers to become a licensed or certified dealer or installer, OR • Pursue further training as a certified installer for small wind through the North American Board of Certified Energy Practitioners (NABCEP), OR • Obtain further training through the trades such as the International Brotherhood of Electrical Workers (IBEW), OR • Continue into an Associates Degree program for Wind Technicians at a regional community college.

  4. Learning Objectives • Students will: • Acquire an understanding of wind resource assessment and the skills to process wind data for projected energy production, • Acquire an understanding of basic aerodynamic limitations involved with wind turbines including lift- and drag-type machines, • Acquire an understanding of the basic operational characteristics of wind generators, power converters and transformers, • Acquire an understanding of grid connection issues • Acquire an understanding of siting issues • Acquire an introductory understanding of wind energy economics, economic impact of commercial wind farms, and public policy issues • Acquire an understanding of issues related to the environmental impact of wind turbines

  5. Course Outline • WIND CHARACTERISTICS, DATA ANALYSIS, AND RESOURCE ESTIMATION • AERODYNAMICS OF WIND TURBINES • WIND GENERATORS • 3-phase ac circuits • Magnetics and Transformers • Induction Machines • PM (synchronous) Machines • POWER CONVERTERS • dc/dc converters • Inverters • Power electronics and converter systems • Generator Systems • Control of Wind Turbines • TOPOLOGIES OF WIND FARMS • SITING • Environmental Impacts • Technical Considerations • INTEGRATION INTO THE ELECTRIC POWER GRID • WIND VALUE AND ECONOMICS • Avoided Costs • Net Metering • Renewable Portfolio Standards, RPS (or Renewable Energy Standards, RES) • Green Tags • Jobs and Economic Development Impact (JEDI) Models • PUBLIC POLICY ISSUES • ENERGY STORAGE • FURTHER TRAINING AND CERTIFICATION

  6. Section 0Background and Context

  7. The electric power system is composed of 4 layers: Generation, Transmission, Distribution, and the Load. The “Supply Side” is the generation and transmission systems. The “Demand Side” is the distribution and load. Transmission Distribution Generation Load

  8. We can divide resources into 2 categories: Non-sustainable Resources Sustainable Resources can be replenished or sustained over a short time frame takes much longer than a human lifetime to replace

  9. Sustainable Resources Non-sustainable Resources Sun Wind Water Fossil fuels Nuclear?

  10. Wind Energy • There are two major drivers for increasing use of wind energy systems: • Wind is a sustainable form of energy input to produce electricity. • Small local generators (called Distributed Generation, or DG) can provide local back-up power, off-set normal reliance on the commercial power grid, and can provide income through individual or group power sales. Wind turbines are one form of a small generating system.

  11. Small and Large Wind • Small wind owners are usually interested in having back-up power, power in remote areas where the grid may not be available, or to off-set their personal electrical energy purchases from the utility company. • Another strong motivator for individuals is to reduce their demand for electricity produced from non-sustainable resources such as fossil fuels. • Large wind owners are interested in sales $$ of electrical energy.

  12. Why Wind, Not Solar? ANSWER: Cost • Typical average cost for installation of a system in 2011: • Large wind (greater then 100 kW) is about $2.25 per Watt • Small wind (under 50 kW) is about $5.00 per Watt • Solar (PV, PhotoVoltaic) is about $7.00 to $10.00 per Watt

  13. Section IIntroduction (definitions, units, and symbols)

  14. Definition No. 1 • Wind Mills pump water or grind grain. • Wind Turbines produce electrical energy from the kinetic energy of the wind.

  15. Definition of Energy: • The capacity for doing work • Ref: Webster’s New World Dictionary of the American Language • That which does work or is capable of doing work • Ref: The IEEE (Institute of Electrical and Electronics Engineers) Standard Dictionary of Electrical and Electronics Terms

  16. Definitions: • Power is the rate (in time) of energy use or production. Power = Energy/Time

  17. Units of Power and Energy • Similar to time as measured in seconds, power and energy are quantified with units so that we know what a particular number means. • Power is often measured in the International System (SI) of units in Watts • Energy is measured as Joules, also in SI units.

  18. Energy, Heat, & Work • 1st Law of Thermodynamics: Energy= Heat+ Work • Work = Force × Distance, Joules = Newtons • meters • Energy (heat) = 1 calorie is needed to raise 1 gram of water 1 degree Celsius • “Mechanical Equivalent of Heat”: 4.18 Joules = 1 calorie

  19. Power & Power Density • Power = work per unit time, Watts = Joules/second • Power Density = work per unit time and per area, Watts/meters2 = Joules/second/meters2

  20. Unit Symbols • Units are written with a symbol to simplify • Joules are represented as J (energy) • Watts as W (power) • Newtons as N (force) • meters as m (length) • seconds as s (time) • kilograms as kg (mass) • meters per second as m/s (velocity) • kilograms per cubic meter as kg/m3 (density or mass density) • meters squared as m2 (area)

  21. Units • Energy has the ability to do work • Scientific – Joule (J) 1 J = 1 Ws • Electrical – kiloWatt hour (kWh), Lincoln Electric Systems charges ~ 8 ¢/kWh for residential customers • Power is rate of delivering energy • Scientific & everyday, Watt (W), (Joule/second)

  22. Remember! • Energy is Power X Time • Power is Energy per unit Time

  23. Units and Definitions ENERGY • 1 cal (heat or energy) = 4.184 J = 1.162 x 10-6 kWh • 1 calorie of food = 1000 cal (energy) = 1 kcal • 2500 food cal = 2500 kcal = 2.9 kWh (approximate daily consumption by each person) • 1 btu (british thermal units) = 1.05435 kJ • 1 Quad = 1015 btu = 1010 therms = 1.05435 x 1015 kJ ≈ 1 EJ (Exa-Joule) POWER (Energy per unit of Time) • 1 kW = 1.34102 hp (horsepower) = 1 kJ/s • Definitions and lists of units can be found on the website: http://physics.nist.gov/cuu/Units/

  24. Geothermal Global Annual Heat Global Annual Heat Power Solar radiation Global Annual Interception Global Annual Interception Human Requirements Minimum Dietary per Day Minimum Dietary each Day 9.5 x 1020 J 3.0 x 1013 W 5.4 x 1024 J 1.7 x 1017 W 6-8 x 106 J 69-93 W Energy & Power Amounts Source: Sorensen, Renewable Energy 2000

  25. Human, resting Human, working Fire, open air Horse (1x HP) African Power Use in 1990 US Power Use in 1990 Noonday Sun intensity 60-80 W 300 W 10,000 W 750 W 400 W per capita 10,000 W per capita 1000 W/m2 Power Source: Sorensen, Renewable Energy 2000

  26. Typical Amounts of Power • Human being on bike 200 W • Small Automobile 80,000 W • Jet aircraft engine 30,000,000 W • Nebraska Utilities 4,563,000,000 W • Solar Panel 50 W (about 5 ft2 of area)

  27. Review of Scientific Notation • 100 = 1 • 101 = 10 • 102 = 10 x 10 = 100 • 10-2 = 1/102 = 1/100 = 0.01 • 43 = 4 x 4 x 4 = 64 • 4.12 x 103 = 4.12 x 1000 = 4,120 • (sometimes the “10” is dropped and an “e” is used to represent the exponent that goes on the “10”: 4.12 x 103 = 4.12e3) • Also, in programming languages, the “carat” symbol (^) is sometimes used to represent exponentiation: 4.12 x 103 = 4.12e3 = 4.12 x 10^3 = 4,120

  28. Just to Confuse You • There is also a special number (similar irrational number like, pi: p) known as “e” • e = 2.718281828…… • ex is called the Exponential Function, where x is a variable (x is also the exponent of the number “e”). Therefore, “e” appears in many mathematical descriptions, and deciding exactly which “e” is meant, must be determined from the context of the expression.

  29. System International (SI) Prefixes • Typically we use prefixes in place of exponents of “10” (powers of “10”) WHEN A NUMBER HAS UNITS!!! • Tera (T) is 1012 • Giga (G) is 109 • Mega (M) is 106 • kilo (k) is 103 • milli (m) is 10-3 [centi (c) is 10-2] • micro (m) is 10-6 • nano (n) is 10-9

  30. System International (SI) Prefixes • 1 kilometer is denoted 1 km = 1 x 103 m = 1000 m (meters) • 1 ns = 10-9 s = 1/1,000,000,000 s = 0.000000001 s (seconds) • The idea is to use an SI letter to represent the power of “10” so that writing the number is shorter and easier. • Remember, these prefixes go with UNITS!

  31. Handy Conversions between SI and British Units • 1 m ≈ 3.28 ft. • 1 m/s ≈ 2.236 mph • 1 btu (british thermal units) = 1.05435 kJ • 1 Quad = 1015 btu = 1010 therms = 1.05435 x 1015 kJ ≈ 1 EJ (Exa-Joule) • 1 kW = 1.34102 hp (horsepower) = 1 kJ/s • 1 kWh = 3.6 x 106 J = 3.6 MJ • p ≈ 3.14159 ≈ 3.14 (for a quick approximation) • 2p radians = 360o in a full circle

  32. Exponents - Review • If you move exponents from the numerator or denominator, change the sign. • Examples: 1000 = 103 = 1/10-3 or 5-2 = 1/52 = 1/25 = 0.04 • Add exponents when multiplying numbers or variables. • Subtract exponents when dividing numbers or variables. exponent is -3 base is 5

  33. Exponent Review - Continued • Examples: • x3●x2 = x3+2 =x5 • y4/y2 = y4-2 = y2 • (3 x104) x (2 x 10-6) = 3 x 2 x 104+(-6) = 6 x 10-2 = 0.06 • (12.7)2x 33 = 161.29 x 27 = 4354.83≠ (12.7 x 3)2+3 • To add or subtract exponents the bases must be the same!

  34. Exercise 1 • Energy • is measured in Joules (J) • has the ability to do work • is measured in kilowatt-hours (kWh) • A., B., and C.

  35. Exercise 1 2). A megawatt (MW) is • measured in Joules (J) • one thousand Watts • 1,000,000 Watts • 102 Watts

  36. Exercise 1 3). Power is • The time rate of energy used or delivered • Measured in watts • The ability to do work • A. and B. • B. and C.

  37. Exercise 1 4). The average power produced by a wind turbine during January is 1.2 kW. The energy delivered that month is • 50 J • 892.8 kWh • 288 kWh • Don’t have enough information

  38. Exercise 1 5). The energy produced by a wind turbine on Monday was 2850 kWh. The average power produced during that day was approximately • 2850 kW • Don’t have enough information • 119 kW • 119 J

  39. Exercise 1 6). 1,340,000 W is • 1,340 kW • 1.34 MW • 1.34 x 106 W • A., B., and C.

  40. Exercise 1 7). 4.77 x 103 W is • 47.7 MW • 0.00477 kW • 4,770 W • A. and C.

  41. Exercise 1 8). 12 x 104 J ÷ 3 x 10-2 s • 4 x 102 W • 4 MW • 0.04 W • None of the above

  42. Exercise 1 9). An active human is expending on average • Several hundred watts of power • Several hundred megawatts of power • Several hundred milliwatts of power • Several hundred gigawatts of power

  43. Exercise 1 10). 0.055(4.67 x 10-3 MW) = • 0.25685 kW • 2.5685 x 10-4 MW • 0.00025685 MW • All the above

  44. Energy Transformations

  45. The Good News and the Bad News • Good news: 1st Law of Thermodynamics is that Conservation of energy holds (e.g. energy is neither created or destroyed, only changed to other forms). • Bad news: so does the 2nd Law of ThermodynamicsHigh-quality energy can do useful work, but in the process of doing the work, the energy gets transformed into low-quality energy (usually low-grade heat): Entropy always increases

  46. Electrical-Mechanical Energy Transformations Mechanical Work (kinetic energy) Electrical Energy Generator Electrical Energy Mechanical Work Electric Motor

  47. Sustainability • Solar energy is our main input (terrestrial nuclear is the other input) • Falls on vegetation, photosynthesis (3%) • Falls on oceans, evaporation, rain, (hydro) • Falls on land masses, air convection, winds (wind turbines) • Apart from photosynthesis, and lakes in mountains, it all ends up as low-grade heat in a very short time frame - • Aim:- get it to do “useful” work on its way to becoming low-grade heat.

  48. SOURCES Energy Transformations STORAGE (secondary sources) Ancient Photosynthesis Coal Oil Natural Gas Solar (Sun – nuclear fusion) Current Photosynthesis Biomass- Ethanol, Methane, Bio-diesel ENERGY FLOW Wind Hydro (evaporation and rain) Direct Solar Tidal Wave Terrestrial (originally from a star’s nuclear fusion explosion) Uranium – nuclear fission Geo-thermal – radioactive decay

  49. Energy Transformations STORAGE (secondary sources) Ancient Photosynthesis Light Coal Oil Natural Gas Combustion Heat Thermal Power Plant for Electricity Production Current Photosynthesis Biomass- Ethanol, Methane, Bio-diesel Mechanical Work (kinetic energy) Fission Uranium – nuclear fission Generator Geo-thermal – radioactive decay Electricity Wind Hydro (evaporation and rain) Tidal Wave Direct Solar (PV) Direct Kinetic Energy Electric Motor Mechanical Work

  50. U.S. Energy Flow (Quads)

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