Wind
in WNC
Oct 27, 2007
Andrews, NC
Brent Summerville, ASU
NC Small Wind Initiative

Appalachian State University
Project to promote wind energy
in Western NC
•
•
•
•
•
•
•

Beech Mountain wind site
Anemometer Loan Program
Mapping
Wind Site Assessments
Workshops and Presentations
Ordinance work
Media Outreach
Reach us at:
wind.appstate.edu
wind@appstate.edu
828-262-7333
Wind Power
History
1400 – 1800 years ago,
in the Middle East
800 – 900 years
ago in Europe
140 years ago,
water-pumping
wind mills
70 years ago,
electric power
2MW Mod-1 Turbine: 1979 - 1983
1980s California Wind Rush
1980s Denmark Got it Right
Today: Wind Energy is
Reliable and Cost Effective
Wind has become the least
expensive and fastest growing
source of electricity in the world
-details at www.gwec.net
Mountain Ridge Protection Act of 1983
“No building, structure or unit shall protrude at its uppermost point
above the crest of the ridge by more than 35’ “
Exemptions to Ridge Law
Water, radio, telephone or television towers
or any equipment for the transmission of
electricity or communications or both.
Structures of a relatively slender nature and
minor vertical projections of a parent building,
including chimneys, flagpoles, flues, spires,
steeples, belfries, cupolas, antennas, poles,
wires, or windmills
NC Attorney General’s 2/4/2002 letter to TVA
“The Legislature in 1983 had in mind, the traditional, solitary farm windmill
which has long been in use in rural communities, not windfarm turbines
of the size, type, or certainly number proposed here…”
Our Wind
Resource
Like most things, wind is
powered by the Sun

What causes
wind?

Differences in
pressure and
temperature
• Solar Power
• Uneven heating of
•
•
the Earth’s surface
Differences in heating
and cooling rates
Earth’s rotation
Flagging: Deformed Growth from
Persistent Winds
Extreme Flagging on Grandfather
Wind Maps
Updated Hi-res Map
Location and Percentage of High Quality Wind
Resources in the US
Class 6 (4.3%)
Class 5 (6.3%)
Class 4 & above 27.5%
Average Wind Speed is the Key

Most important variable
Power ~ V3



Double speed and power increases 8
times
73% more power in a 12 mph wind than
a 10 mph wind
This is why it is so important to carefully
assess
Western NC Wind Potential
New Hi-Res North Carolina Wind Map
We are not in South Dakota
Careful site analysis is important
North Carolina Coastal Resources
24 County Western NC Wind Map
County Wind Maps
for Western NC
True Wind Map Combined
With:
 Road data
 Digital elevation models
 Public lands
 Appalachian Trail
 Town boundaries
 Utility grid
 Tax parcel maps
www.wind.appstate.edu
What Fir Tree Farm - Watauga
Hattie Hill Site - Watauga
Wind Monitoring Activities
 Actual on-site measurements
Measuring Devices and Parameters




Anemometer
•
•
•
Best indication of energy production
Indicator of turbulence
Provide information on wind shear
Wind Vane
•
•
Wind rose
Micro siting
Temp Sensor
•
•
Identify icing events
Air density
Data Loggers
TVA Monitoring Activities
50 meter met tower
Anemometer Loan Program
Measured vs Truewind Wind Speeds
(m/s)
(.23 m/s average difference)
Truewind
Anemometer
Phoenix Mt
Chambers Mt.
Cowee Bald
Wind Springs Bald
Turkey Ridge
Hilliards Knob
Howards Knob
8
7
6
5
4
3
2
1
0
Factors Affecting Wind


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
Elevation
Obstructions
Surface Roughness
Perpendicular Ridges
Time of day
Time of year
Elevation & Wind Velocity
10
9
8
7
6
5
4
3
2
1
0
6
6.59
6.6
7.2
7.3
8
8.16
9
M/S @ 50 m
M/S @ 80
3600'
class 2
4000'
class 3
4418'
class 4
4690'
class 5
Season and Time of Day

Higher winds found late in the evening and early
morning
Higher winds seen during the winter
1.000%
0.900%
0.800%
0.700%
Hrly Gen as % of Annual Total

0.600%
0.500%
0.400%
0.300%
0.200%
0.100%
0.000%
0
0
0
0
0
0
0
0
0
0
0
0
Wind Micrositing
Where to put it
Step 1: What do you want to do?
Step 2: Resource Assessment





Average annual wind speed at the
proposed hub height is critical
Wind maps
Existing data
•
Extrapolate wind speed from a lower height to hub
height
Measure
•
Anemometer, wind vane, temp, logger
Flagging, interview locals
Rule 1: Minimize Turbulence
Rule 2: Minimum Tower Height
30’ above obstructions within 300 – 500’
Tower Height Depends on Terrain
Rule 3: Stay upwind of obstacles


Know the prevailing
wind direction
The turbine would
like a clear view in
that direction
Annual Frequency and Average Annual Wind Speed
in Sixteen Compass Directions
Potato Hill, Watauga County, NC
N
35
NNW
NNE
30
NW
NE
25
20
15
WNW
ENE
10
5
W
0
E
WSW
ESE
SW
SE
SSW
SSE
S
Wind Frequency
Wind Speed
Rule 4: Minimize Compromises



The wind blows from
all directions
There may not be
the “perfect” spot
The goal is to
maximize your wind
resource
Rule 5: Voltage and wire run



Think about the wire run
Higher voltage means smaller wire
Raising the system voltage gives you
more flexibility in tower placement
Visualizing the Turbulence
Use a kite or balloon with
streamers
Measuring Heights

Shadow
method
Measuring Heights

Friend and Pen
Tree Height
Micrositing Recap
Small Wind
Turbine
Technology
Small Wind Turbine Technology
Horizontal Axis
Upwind
Horizontal Axis
Downwind
Towers
Vertical Axis
Systems
HAWT - Upwind
• Configuration: 2 or 3 blades aimed into
the wind by the tail
• Blades: Fiber-reinforced plastics
• Over-Speed Protection: Furling (rotor
turns out of the wind)
• Generator: Direct-drive, permanent
magnet alternator (no brushes), 3-phase
AC, variable-speed operation
Bergey EXCEL, 10 kW
Southwest Windpower
Flagstaff, Arizona
www.windenergy.com
Whisper 200
1000 W
AIR
400 W
Whisper 100
Whisper 500
900 W
3 kW
(Now with grid-tie)
Ned Trivette
Whisper 200
Sugar Grove, NC
Beech Mountain Wind Energy
Research & Demonstration
Site
Bergey Windpower
Norman, Oklahoma
www.bergey.com
BWC XL.1
1 kW
BWC Excel
10 kW
Bergey 10kW
Canton, NC
Abundant Renewable Energy
Newberg, Oregon
www.abundantre.com
ARE110
2.5 kW
Homebuilt
www.otherpower.com
www.scoraigwind.com
Fuhrländer
Lorax Energy Systems, Rhode Island
FL 250
250 kW
www.lorax-energy.com
FL 100
100 kW
FL 30
30 kW
Over-Speed Protection
During High Winds
• Furling: The rotor turns up and to one side, or back,
or to the side
HAWT - Downwind
• Configuration: 2 or 3 blades, no tail,
blades face downwind
wind
• Blades: Fiber-reinforced plastics
• Over-Speed Protection: Zebedee Furl
(blade coning), tip brakes, stall regulation
• Generator: Direct-drive, permanent
magnet alternator (no brushes), 3-phase
AC, variable-speed operation
Proven WT600
Proven Engineering Products, Ltd.
Scotland, United Kingdom
www.provenenergy.com
WT600
600 W
WT2500
2.5 kW
WT6000
6 kW
Proven Blade Coning




Flexible Zebedee hinge
As RPM increases,
blades are thrown
outwards by centrifugal
force
Changes aerodynamic
pitch
10-15 year hinge life
70 Foot Guyed
Tower
Southwest
Windpower
Skystream
www.skystreamenergy.com
35 Foot Monopole
Tower
Southwest
Windpower
Skystream
www.skystreamenergy.com
VAWT – Drag & Lift
• Configuration: Lift or Drag
• Drag: Anemometer, Savonius
• Lift: Darrieus, H-Darrieus
Anemometer
Savonius
Mother Earth News
Darrieus
Savonius (S-rotor)





Make from buckets,
paddles, sails, and oil
drums
originated in Finland
tsr ≈ 1
Can be useful for
grinding grain, pumping
water, and many other
tasks
…but are not good for
generating electricity
(low speed, high torque)
Darrieus Lift-Type Vertical-Axis Machines



French engineer
Georges Darrieus
patented the design in
1931
Plus: generator on
ground, yawing not
required
Minus: low to ground,
low efficiency, not selfstarting, vibration, high
bearing forces
Darrieus,
curved
blades
H-Darrieus,
straight
blades
The main issue with VAWT:
Availability on the Market
Small Wind Turbine Towers
Fixed Guyed
Tower
Tilt-Up Tower
Self-Supporting
Tower
Fixed Guyed Tower
Build on
ground
Tilt-Up with
crane
(3) guy wire
anchors, climbing,
crane
Tilt-Up Guyed Tower
Build on
ground
Tilt-Up with
winch or griphoist
(4) guys wire anchors,
maintenance on
ground, economical
Self Supporting Towers
Build on
ground
Raise with
crane
No guy wires,
requires climbing
or crane
On-Grid Wind System without
Storage
Meter
AC
Inverter
Wind
turbine
Load
02770329
On-Grid Wind System with
Storage
Meter
Regulation
and
conversion
Inverter
AC
Wind
turbine
This system has storage
which provides backup
power.
Load
02770330
The Effect of Seasons on
Hybrid Power Systems
Summer
PV modules and wind turbine
(active generation)
Battery
(storage)
Loads
(utilization)
PV modules and wind turbine
(no generation)
Battery
(storage)
Loads
(utilization)
Winter
02770322
Solar and Wind Resources
are Complimentary
400
Hours of sunshine or average
wind power (Watts/m2)
Data from SE Iowa
350
Hoursofof
Hours
sunshine/month
Sunshine
300
250
200
Average wind power
150
100
Jan
Feb Mar
Apr May Jun
Jul
Aug Sep
Oct Nov Dec
0277032
4
PV/Wind Hybrid
Project Installed
on Beech
Energy
Power

Power: Rate at which energy is delivered
Power = Energy
Time




Measured in Watts (W), kilowatts (kW), or
horsepower
Power is an instantaneous quantity
Power does not accumulate
Think gallons per minute
Energy



Energy: Ability to do something
Measured in kilowatt  Hours (kWhrs)
Why?
• Since Power = Energy/Time,
then Power  Time = Energy



Energy does accumulates over time
Think gallons
Gallons = (gallons/min)  minutes
Swept Area

The single most important parameter of a
wind turbine is its rotor’s swept area
A
Power of a Wind Turbine

The power of a wind turbine is
P = ½  v3 A C P
A: swept area of rotor
CP: rotor efficiency

Example: A 2.5 m diameter turbine with a
25% efficient rotor in our 8.0 m/s wind will
have
P = ½ (1.0 kg/m3)(8.0 m/s)3 [ (2.5 m/2)2](0.25)
= 314 W
Method of Bins

There are limitations to this method…
• Wind speed is not constant!
• Rotor efficiency depends on wind speed!
• Small turbines furl in high winds

Here’s a better method: Method of Bins
• Need to know (or approximate) your wind
•
distribution
Power Curve of turbine
Wind Distribution

Wind is known to follow a distribution
pattern
Credit:
Paul
Gipe
Power Curve

The turbine’s manufacturer will provide you
with its power curve
Bergey XL.1
Method of Bins


Calculate Energy = Power  Time for each
wind speed bin
Sum ‘um up!
Method of Bins
Power Curve
Wind
Distribution
(data)
Annual Energy Output
Power Curve



Southwest Windpower Whisper 100 and
Whisper 200
Similar rated power
Difference in energy
Charts from Manufacturer
Incentives
North Carolina Incentive
Programs

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
TVA Green Power Switch
NC GreenPower
NC Personal Renewable Energy Tax Credit
NC Corporate Renewable Energy Tax Credit
Green tags
Renewable Energy Equipment Manufacturers
Incentive
Energy Improvement Loan Program
USDA Farm Bill
www.dsireusa.org
Green Tags
TVA Green Power Switch Generation
Partners Program
Details
 Wind or PV
 (.5 – 50 KW)
 Residential or small
commercial
 $.15/kWh credit
 Energy used on site
is billed at standard
rate
www.tva.com/greenpowerswitch/partners/index.htm
NC GreenPower Program
www.ncgreenpower.org
To improve the quality of the environment by
encouraging the development of renewable
energy resources through consumers’ voluntary
purchase of green power.



RFP process for green power
No wind producers yet
Green Power program initially
quoted an estimate of .06/kwh
NC Net Metering
Credited to a customer's next monthly bill,
but reset to zero at the beginning of each
summer (June 1) and winter (October 1)
billing season. Any renewable-energy
credits associated with net excess is granted
to the utility when the balance is zeroed out.
20 kW for residential systems; 100 kW for
non-residential systems
Investor-owned utilities (Progress Energy,
Duke Power, Dominion North Carolina
Power)
Photovoltaics, Landfill Gas, Wind, Biomass,
Anaerobic Digestion
NC Renewable Energy Tax
Credits




35% for all
technologies
Can take tax credit
over 5 years
No more than half of
tax liability
No refund based on
tax credit
Wind Turbine Installed Cost
Example
Updated: Oct04
Southwest Windpower
Whisper H40
High Cost
Low Cost
Wind turbine & Controller
Tower (80 guyed)
Inverter
Battery and Containment
Shipping
Installation
Permits/Fees
Sales Tax, 5%
$2,045
$2,220
$1,000
$300
$200
$1,200
$200
$358
$2,045
$2,045
$690
$2,500
$2,220
$500
$800
$200
$400
$150
$2,500
$0
$500
$0
9%
0%
Total
$7,523
$10,033
$5,115
Tax Credit
$2,633
$3,511
$1,790
Final Cost
$4890
$6,522
$3,325
USDA Farm Bill
Section 9006
Farmers and Rural
Small Business Owners
Can Apply for:
•25% from $2,500 to
$500,000
•Or up to $10 million in
guaranteed loans
Contact
H. Rossie Bullock
Business Programs Specialist
440C Caton Rd.
P.O. Box 7426
Lumberton, NC 28359-7426
Phone: (910) 739-3349 ext. 4
Fax: (910) 618-9444
email: rossie.bullock@nc.usda.gov
Wind Turbine Installed Cost
Updated:
Bergey Excel-S (10 kW)
11-Oct-04
High Cost
Low Cost
Wind turbine & inverter
Tower (100 ft guyed)
Tower Wiring Kit
Shipping
Installation
Permits/Fees
Sales Tax, 5%
$24,750
$7,800
$860
$1,500
$8,000
$500
$2,146
$24,750
$25,100
$24,750
$6,200
$1,070
$2,000
$860
$1,000
$10,000
$2,000
$3,500
$0
9.3%
none
Total
$45,556
$72,272
$34,810
USDA Grant
$11,389
$18,068
$8,702
Adjusted Total
$34,167
$54,204
$26,108
Small Wind Economics in North Carolina
35% State Income Tax Credit & 25% USDA Grant
(wind speed at 10 m)
40
10.6 mph (Class 2)
Simple Payback, Years
35
16.3 mph (Class 7)
30
25
20
15
10
5
Residential Electric Rates for
North Carolina Utilities
0
5
6
7
8
9
10
11
Electric Rate, ¢/kWh
12
13
14
15
Questions?
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Thanks
Brent Summerville
Call or email me
for more info
828-262-7333
wind@appstate.edu
wind.appstate.edu
My presentations will be available at wind.appstate.edu
Click on REPORTS….CONFERENCE PRESENTATIONS