Power System Engineering

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Power System Engineering

• ECE 0909.408.01
• ECE 0909.504.02 - Lecture 13
• 1 May 2006
• Dr. Peter Mark Jansson PP PE

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Admin. Items

• Final Training Tour
• Leaves 1.00 PM THIS Thursday
• 4 May 2006
• Atlantic City Utility Authority
• 7.5 MW Wind System and 500kW PV System
• Atlantic City, NJ
• Final Quiz 3 MONDAY 4.45PM

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Aims for Today

• Course Evaluations
• The Power System of the Future
• Able to handle a myriad of distributed resources
• Power in the Wind
• PV potential
• Your ideas
• My ideas

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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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Impact of Tower Height
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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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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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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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Wind PV Production (96-03)
Wind production PV production
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Wind Grows 20 in 04, 25 in 05
59,322
2005
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U.S. Leads installs (05) - 2,431 MW
Bowling Green, Ohio
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Before Renewables Efficiency First!

• Make buildings homes that are more
• Energy Efficient
• Cost-effective to Operate
• Environmentally Friendly

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NJ Wind Resources
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Wind Turbines
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Wind Turbines

• A wind turbine obtains its power input by
  converting the force of the wind into a torque
  acting on the rotor blades.
• The amount of energy which the wind transfers to
  the rotor depends on the density of the air, the
  rotor area, and the wind speed.

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Wind Turbines

• A wind turbine will deflect the wind before it
  even reaches the rotor plane which means that all
  of the energy in the wind cannot be captured
  using a wind turbine.

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Wind Turbine Energy

• The annual energy delivered by a wind turbine can
  be estimated by using the equation

The cost of electricity will vary with wind
speed. The higher the average wind speed, the
greater the amount of energy, and the lower the
cost of electricity
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Wind Power Classifications
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Delaware Bay / Coastal Wind Speeds

• Areas along shore or in mountains may be ideal
  for wind power
• Wind speeds as low as
• 4.5 -5.5 m/s
• for res farms/comm
• gt6.0 m/s can be used
• for power farms
• At 6.5 m/s, electricity can be below
• 0.07/kWh

True Wind Solutions
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2006 NJCEP Rebates

• Wind and Sustainable Biomass Systems
• Systems lt 10 kW 5.00/watt
• Maximum incentive (60 of system costs)
• Systems gt 10kW
• First 10 kW 3.00/watt
• gt 10 to 100 kW 2.00/watt
• gt 100 to 500 kW 1.50/watt
• gt 500 kW, up to 1000 kW 0.15/watt
• Maximum incentive (30 of system costs)

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Sample 10 kW Turbine in NJ

• 5.1 m/s at ground, 24 m (80ft) 5.7 m/s aloft
• Power generated 18,000 kWh/year
• Turbine 24,750
• Tower 6,800
• Install/Misc 5,500
• NJCEP Rebate (60) 22,230
• Net Cost 14,820
• 15 year electric cost 5.5/kWh
• Simple Payback 7.5 years

- Class II wind regime
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Eachus Dairy Farm
Neptune Organic Farm
ACUA 7.5-MW New Jersey Wind Farm
Bayshore Discovery Project
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New Jersey Wind Farm 7.5MW
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Most important wind info

• Know your resource
• At least 1 year of data more preferable

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PV in NJ

• Nations First Solar State

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Wind PV Production (96-03)
Wind production PV production
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Solar Resources Total Diffuse
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Semi-Conductor Physics

• PV technology uses semi-conductor materials to
  convert photon energy to electron energy
• Many PV devices employ
• Silicon (multi-crystalline, amorphous or single)
• Other electrically active semiconductor materials
• Cadmium telluride, gallium asenide, CIS, etc.

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Historic PV modules price/cost decline

• 1958 1,000 / Watt
• 1970s 100 / Watt
• 1980s 10 / Watt
• 1990s 3-6 / Watt
• 2000-2004
• 1.8-2.5/ Watt (cost)
• 3.50-4.75/ Watt (price)

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PV cost projection

• 1.50 ? 1.00 / Watt
• 2005 ? 2008
• SOURCE US DOE / Industry Partners
• Today you could have a grid interactive PV System
  installed by a contractor (Home Depot) for
  between 6.75 and 8.45 per watt. Equipment Only
  in range of 4.10-5.50/watt.

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PV system types

• Grid Interactive and BIPV
• Stand Alone
• Irrigation Pumping / Livestock Watering Troughs
• Cathodic Protection
• Battery Back-Up Stand Alone
• Refrigeration
• Communications
• Rural Electrification
• Lighting

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How Large a System do You Need?

• Method
• First Determine Electric Use (try to reduce 1st)
• Determine Solar Resource (SP, model, calcs)
• Select PV Modules or
• Select DC-AC Inverter
• Assure Module Strings Voc and Isc meet inverter
  specifications (for max and mins)
• Estimate Your Production (1200 kWh/ kW-DC)

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Grid-interactive roof mounted
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NJ Solar (PV) Incentives

• NJ Clean Energy Program
• 5.10/watt rebate for grid connected systems up
  to 10kW (Smaller rebates above 10kW)
• Net Metering to 2MW
• Solar Renewable Energy Certificates
• NJ RPS requires 2 MW 2004 ? 90 MW 2008
• lt 8 MW currently installed in the state
• Currently trading between 80-265/MWh

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NJCEP Rebates

• Solar Electric Systems 2006 (PV Rebates)  
•  
• System Size
• 0 to 10,000 watts 5.10/watt
• 10,001 to 40,000w 3.90/watt
• 40,001 to 100,000w 3.45/watt
• 100,001 to 700,000 3.20/watt

- Reduce by ITC if eligible and to 85 of value
for self-install
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Economic Value a NJ Home

• PV Systems would have 25-30 year payback
• With NJCEP Rebates reduces to 10 year
• With SREC payments it could be less than 7 year
• 5 years of SRECs at 15 /kWh 3600 for 4kW
  system
• PV Systems can produce between 1100 and 1350 kWh
  per installed kW annually across New Jersey
• Cost After Rebate 9,000 for a 4 kW system
• 20 year electricity cost 9.4/kWh w/o SREC
• 5.6/kWh w/5yrs of SREC at 15 /kWh

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Recent Trades of SRECs (/MWhr)

• Month Max Min Cum Av
• June 05 250 80 179
• July 05 260 110 189
• August 05 265 100 201

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Solar PV - Practical Information

• Approx South Facing Roof or field
• Roof angles from 20-50 degrees
• Less than 200 from loads
• Every 70 square feet of area can yield up to 1000
  kWh per year in New Jersey

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Your Slides

• What will the electric power system look like in
  2050?
• Why do you think so?

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This Thursday (4 May - 1PM)

• Please dont forget to attend
• ACUA Wind PV Visit 2-4PM
• 100 PM departure this Thursday
• 4 May