Wind 101

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Wind 101

• Jerry L. Hudgins
• Electrical Engineering Department
• University of Nebraska-Lincoln

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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.

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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.
  

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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

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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

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Section 0Background and Context
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1. The electric power system is composed of 4
   layers Generation, Transmission, Distribution,
   and the Load.
2. The Supply Side is the generation and
   transmission systems. The Demand Side is the
   distribution and load.

Transmission
Distribution
Generation
Load
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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
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Sustainable Resources
Non-sustainable Resources
Sun Wind Water
Fossil fuels Nuclear?
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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.

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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.

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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

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Section IIntroduction (definitions, units, and
symbols)
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Definition No. 1

• Wind Mills pump water or grind grain.
• Wind Turbines produce electrical energy from the
  kinetic energy of the wind.

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• Definition of Energy
• The capacity for doing work
• Ref Websters 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

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Definitions

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

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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.

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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

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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

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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)

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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)

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Remember!

• Energy is Power X Time
• Power is Energy per unit Time

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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/

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Energy Power Amounts

• 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

Source Sorensen, Renewable Energy 2000
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Power

• 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

Source Sorensen, Renewable Energy 2000
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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)

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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
  103 4,120

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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.

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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

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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!

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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

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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
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Exponent Review - Continued

• Examples
• x3 ? x2 x32 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)2 x 33 161.29 x 27 4354.83 ?
  (12.7 x 3)23
• To add or subtract exponents the bases must be
  the same!

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Exercise 1

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

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Exercise 1

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

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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.

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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
• Dont have enough information

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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
• Dont have enough information
• 119 kW
• 119 J

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Exercise 1

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

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Exercise 1

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

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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

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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

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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

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Energy Transformations
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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
  Thermodynamics High-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

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

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Energy Transformations
SOURCES
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 stars nuclear
fusion explosion)
Uranium nuclear fission
Geo-thermal radioactive decay
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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 Direc
t Solar (PV)
Direct Kinetic Energy
Electric Motor
Mechanical Work
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U.S. Energy Flow (Quads)
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U.S. Energy Flow Highlights
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Electrical Energy Generation in USA
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US Daily Freshwater Withdrawals during 2000
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Exercise 2

• 1). Approximately what percentage of the
  electrical power in the USA is generated from
  combusting coal?
• 70
• 50
• 20
• 30

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Exercise 2

• 2). The energy sector that uses the most
  petroleum as an input energy source is
• Transportation
• Industrial
• Electric Power
• Residential/Commercial

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Exercise 2

• 3). The sector that uses the most energy inputs
  is
• Transportation
• Industrial
• Electric Power Generation
• Residential/Commercial

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Exercise 2

• 4). The original source of the energy that
  appears as wind is
• Photosynthesis
• Geo-thermal
• Coal
• Solar

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Exercise 2

• 5). The two applications that use the most
  freshwater are
• Industrial/Mining and Public Supply
• Public Supply and Thermoelectric Power Production
• Industrial/Mining and Irrigation/Livestock/Aquacul
  ture
• Irrigation/Livestock/Aquaculture and
  Thermoelectric Power Production