Advanced Power Systems

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Advanced Power Systems

• ECE 0909.402-02, 0909.504-02
• Lecture 8 Wind Power Systems
• 19 March 2007
• Dr. Peter Mark Jansson PP PE
• Associate Professor Electrical and Computer
  Engineering

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Aims of Todays Lecture

• Cover other Current Topics
• Jobs Anemometer Loan, PV
• Assessments PV, Wind, etc.
• APS Final Project Options
• Overview of Chapter 6 concepts
• Mid-Term Exam

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Wind Iberdrola, USA

• Meteorological Towers Analyst
• Iberdrola USA, a renewable energy company based
  in Radnor, PA, seeks a full-time Meteorological
  Tower Analyst for the Radnor office. The position
  will report directly to the Wind Resource
  Manager.
• Responsibilities of the position include
• Meteorological Tower Management
• Manage consultants in the installation of
  meteorological towers throughout the country
• Manage the wind database and produce preliminary
  wind resource assessment reports
• Uphold company standards in all met tower work
• Identify and implement new measuring techniques
• Coordinate with Balance of Plant operators to
  ensure permanent met tower and power curve
  testing met towers are properly procured,
  installed and commissioned
• Ideal candidate will possess a four year degree
  relevant to the wind energy industry and 1- 2
  years of experience in wind energy development,
  primarily related to met tower management.
  Candidate should be energetic, articulate,
  self-motivated, flexible, able to efficiently
  prioritize their time, able to multi-task, and
  able to quickly adapt to the changing pace of
  daily responsibilities.
• Ideal candidate will have a good knowledge of the
  wind industry market, primarily as regards the
  met tower field (installers, equipment suppliers,
  etc.).
• The ideal candidate will be well-versed in
  Microsoft Office, particularly in Excel and
  Project and have experience with related industry
  software (GIS mapping, AutoCAD, WAsP, WindFarmer)
  or other wind resource modeling programs).
• Salary is commensurate with experience, and
  Iberdrola USA offers an excellent benefits
  package.
• Interested candidates should submit a resume and
  cover letter indicating interest in this position
  to Erica Irvine at eirvine_at_iberdrolausa.com.

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PV Mesa Solar, LLC

• Looking for PV Design Engineers
• Expanding
• Malvern, PA
• (see me for info)

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APS Projects

• Dr Weisss PV powered drip irrigation
• Cumberland Regional HS Wind Assessment
• Mr. Brown, Galloway Twp Wind Assessment

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Wind Turbines

• Wind energy is proportional to V3, Why?

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Simple Rule of Thumb

• Annual Energy (kWh) 1.64 D2 V3
• D rotor diameter, meters
• V annual average wind speed (m/sec)

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Wind Turbine types

• VAWT
• HAWT downwind
• HAWT upwind, requires yaw control

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Power in the Wind
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Why using average wind speed is a poor
approximation of site potential

• Lets use our new equation to consider the
  following
• What is energy in 200 hours of 7m/s wind?
• Compare with energy in 100 hours of 4m/s and 100
  hours at 10m/s
• (NOTE both average 7m/s)?

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Power in the Wind
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LM 1

• How much power is there in 500 hours of 6m/s wind
  (per m2)?

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Impact of Tower Height
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? and z

• Tables 6.3 6.4
• Page 320

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Example

• If you have anemometer data from a 10-m tower (6
  m/s ave.) across a surface of crops, hedges, and
  shrubs and want to estimate how much higher the
  wind is at 40 meters, how do you do it?

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solution
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LM 2

• What is the average wind speed at 50 meters if it
  is 7m/s at an anemometer sited 10 meters above
  the ground in a small village?

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Max theoretical rotor efficiency

• Max theoretical is called Betz efficiency
• For typical turbines this is 59
• Under ideal conditions todays turbines can
  achieve 80 of the max theoretical
• So many turbines range between 45-50

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Rayleigh Probability Density Function

• With wind we typically do not have a normal
  distribution.
• A Weibull or Rayleigh p.d.f. is much more common,
  we will learn the Rayleigh a form of Wiebull when
  k2. (see below)

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Rayleigh Probability Density Function

• With the assumption of a Rayleigh distribution we
  have a very powerful analytical tool.
• To calculate the number of hours in a given year
  we will experience wind above or below a certain
  level the process is quite simple

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Example

• If we have a site where the wind speed (average)
  is 7 m/s and we assume a Rayleigh distribution,
  how many hours per year will the wind speed be
  less than 4 m/s (the cut in velocity for an NEG
  micon 1000/54 wind turbine)?

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Solution

• How many hours per year will the wind speed be
  less than 4 m/s?

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Solution

• How many hours per year will the wind speed be
  less than 4 m/s?
• 0.2262 x 8760 1982 hours

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LM 3

• If we have a site where the wind speed (average)
  is 6 m/s and we assume a Rayleigh distribution,
  how many hours per year will the wind speed be
  less than 3 m/s?

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Using this and a WT Power Spec

• Combining these two we can predict effectively
  the power generated at any given site

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Rayleigh PDF and Power Curve

• 1) build a spreadsheet
• 2) calculate hours at each speed (see below).
• 3) use manufacturers data for turbine generation
  at each wind speed
• 4) estimate annual generation

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LM 4

• What are the hours per year we will have wind
  speeds at 5, 6, 7 and 8 m/s if the average wind
  speed is 7 m/s?

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Problem 6.15

• Excellent illustration

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New homework

• HW 6 due Monday - 26 Mar
• 6.1, 6.2, 6.3, 6.4, 6.5, 6.7, 6.8, 6.12, 6.15

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Wind Power Classifications
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Southern New Jersey Wind Map 50 m
Source http//www.awstruewind.com/inner/windmaps/
windmaps.htm
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Wind Farms and Parks

• What are good engineering design standards for
  efficient power extraction from a windy site?
• Goals maximize power output, minimize downstream
  turbulence and inefficiencies, optimize overall
  site utilization (cost of equipment, power
  output, maintenance)

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Wind Farm Optimization

• For farm output higher density is better
• For maintenance higher density is better
• For land costs higher density is better
• For wind turbulence lower density is better
• For turbine output lower density is better

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Wind Farm Rules of Thumb

• Recommended spacing
• Parallel to Pre-Dominant Wind Front
• 3-5 Rotor Diameter Spacing
• Next Row(s) Behind Frontline
• 5-9 Rotor Diameter Spacing
• Stagger alternate rows downwind between upwind
  turbine shadows

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Wind Farm Example

• Suppose a wind farm has a 4 rotor diameter
  spacing along its front row and 7 rotor diameter
  spacing between rows. Assume 78 array
  efficiency and turbine efficiency of 32.
• Find the annual production per acre for 400W/m2
  winds at hub height (the edge of 50m, Class 4
  winds)
• If the farmer leases the land for 100/acre-year
  (which is 10x what he makes on cattle) what is
  the lease cost per kWh?

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Wind Farm Solution

• Find the annual production per acre for 400W/m2
  winds at hub height

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Wind Farm Solution

• If the farmer leases the land for 100/acre-year
  (which is 10x revenue on cattle) what is the
  lease cost per kWh?

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LM 5

• What is the production potential (kWh/acre) of a
  Class 3 wind site (assume 350 W/m2) in the
  Delaware Bay at 50-m hub height?
• Assume 4 x 7 spacing, 80 array efficiency and
  30 turbine efficiency.
• If the State of NJ offers 200/year leases to
  offshore developers how much would these leases
  add to production costs (per kWh)?

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LM 6

• What is the production potential (kWh/acre) of a
  Class 4 and 5 wind sites (assume 450 and 550 W/m2
  respectively) in the Delaware Bay at 50-m hub
  height?
• Assume 4 x 7 spacing, 80 array efficiency and
  30 turbine efficiency.
• How do Classes 3, 4 and 5 compare with each
  other?