HomeMy WebLinkAboutPillar Mountain Site 2 Wind Resource Report - Mar 2007 - REF Grant 2195365Kodiak, Alaska Site 2 Wind Resource Report
Report written by: Douglas Vaught, P.E., V3 Energy LLC, Eagle River, AK
Date of report: March 16, 2007
Photo by Doug Vaught, V3 Energy LLC
Summary Information
Pillar Mountain has superb potential for wind power development with a Class 7 rating, very low
wind shear, seasonally directional winds, and low turbulence. A significant construction
advantage of this site is that the underlying ground is mostly solid rock.
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Meteorological Tower Data Synopsis
Wind power class (measured to date) Class 7 – Superb
Average wind speed (30 meters) 8.25 m/s (measured)
Average wind speed (60 meters) 8.36 m/s (predicted)
Maximum wind speed (2 sec average) 52.0 m/s, 3/8/06 (30 m level)
Mean wind power density (50 meters) 943 W/m2 (predicted)
Mean wind power density (30 meters) 917 W/m2
Roughness Class 0.00 (description: smooth)
Power law exponent 0.023 (extremely low wind shear)
Turbulence Intensity (30 meters) 0.120
Data start date November 4, 2005
Most recent data date February 27, 2007
Community Profile
Current Population:6,088 (2005 State Demographer est.)
Pronunciation/Other Names:(KOH-dee-ack); includes Shoonaq'
Incorporation Type:Home Rule City
Borough Located In:Kodiak Island Borough
School District:Kodiak Island Borough School District
Regional Native Corporation:Koniag, Incorporated
Location:
Kodiak is located near the north eastern tip of Kodiak Island in the Gulf of Alaska. Kodiak Island, "the
emerald isle," is the largest island in Alaska, and is second only to Hawaii in the U.S. Kodiak National
Wildlife Refuge encompasses nearly 1.9 million acres on Kodiak and Afognak Islands. It is 252 air miles
south of Anchorage, a 45-minute flight, and is a 4-hour flight from Seattle. It lies at approximately
57.788890° North Latitude and -152.401900° West Longitude. (Sec. 32, T027S, R019W, Seward
Meridian.) Kodiak is located in the Kodiak Recording District. The area encompasses 3.5 sq. miles of
land and 1.4 sq. miles of water.
History:
The Island has been inhabited for the past 8,000 years. The first non-Native contacts were in 1763, by the
Russian Stephen Glotov, and in 1792 by Alexander Baranov, a Russian fur trapper. Sea otter pelts were
the primary incentive for Russian exploration, and a settlement was established at Chiniak Bay, the site of
present-day Kodiak. At that time, there were over 6,500 Sugpiaqs (Koniags) in the area and the Island
was called "Kikhtak." It later was known as "Kadiak," the Inuit word for island. Kodiak became the first
capital of Russian Alaska, and Russian colonization had a devastating effect on the local Native
population. By the time Alaska became a U.S. Territory in 1867, the Koniag region Eskimos had almost
disappeared as a viable culture. Alutiiq (Russian-Aleut) is the present-day Native language. Sea otter fur
harvesting was the major commercial enterprise, and eventually led to the near extinction of the species.
However, in 1882 a fish cannery opened at the Karluk spit. This sparked the development of commercial
fishing in the area. The "Town of Kodiak" was incorporated in 1940. During the Aleutian Campaign of
World War II, the Navy and the Army built bases on the Island. Fort Abercrombie was constructed in
1939, and later became the first secret radar installation in Alaska. Development continued, and the
1960s brought growth in commercial fisheries and fish processing. The 1964 earthquake and subsequent
tidal wave virtually leveled downtown Kodiak. The fishing fleet, processing plant, canneries, and 158
homes were destroyed - $30 million in damage. The infrastructure was rebuilt, and by 1968, Kodiak had
become the largest fishing port in the U.S., in terms of dollar value. The Magnusson Act in 1976 extended
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the U.S. jurisdiction of marine resources to 200 miles offshore, which reduced competition from the
foreign fleet, and over time, allowed Kodiak to develop a groundfish processing industry.
Culture:
The local culture surrounds commercial and subsistence fishing activities. The Coast Guard comprises a
significant portion of the community, and there is a large seasonal population. Kodiak is primarily non-
Native, and the majority of the Native population are Alutiiq. Filipinos are a large subculture in Kodiak due
to their work in the canneries. A Russian Orthodox Church seminary is based in Kodiak, one of two
existing seminaries in the U.S. The Shoonaq' Tribe of Kodiak was federally recognized in January 2001.
A branch of the University of Alaska Anchorage, Kodiak College is located in the City of Kodiak.
Economy:
The Kodiak economy is based on fishing, seafood processing, retail services and government.
Adaptability and diversification in a variety of fisheries has enabled the Kodiak economy to develop and
stabilize. 665 area residents hold commercial fishing permits, and numerous fish processing companies
operate here year-round. The largest processors include Trident, Ocean Beauty, North Pacific, and
Western Processors. The hospital and City also rank among the top employers. The largest U.S. Coast
Guard station lies just south of the city. The Kodiak Launch Complex, a $38 million low-Earth orbit launch
facility on 27 acres, was recently completed at Cape Narrow near Chiniak. The Kodiak Launch Complex,
operated by the Alaska Aerospace Dev. Corp., is the only commercial launch range in the U.S. that is not
co-located with a federal facility. The KLC launched its first payload in November 1998. In August 2003,
Alaska Aerospace Dev. Corp. was awarded an $8 million contract to handle two or three Missile Defense
Agency launches in 2003-2004. The Kodiak-launched missiles will be targets, not interceptors. With
similar launches planned annually over the next five years, the contract could be worth up to $40 million.
The Kodiak Chamber of Commerce provides economic development services to the area
(www.kodiak.org).
Facilities:
Pillar Creek and Monashka Creek Reservoirs provide water, which is stored and distributed by pipe
throughout the area. Piped sewage is processed in a treatment plant. All homes are fully plumbed. The
piped system has been expanded to Miller Point and Spruce Cape, to replace individual wells and septic
tanks in those areas. Refuse collection services are provided by the Borough. The landfill is located 6
miles north of the City, at Monashka Bay. Kodiak Electric Association, a cooperative utility, operates and
purchases power from the Four Dam Pool-owned Terror Lake Hydroelectric Facility. It also operates a
Coast Guard-owned plant, and owns three additional diesel-powered plants at Swampy Acres, Kodiak
and Port Lions.
Transportation:
Kodiak is accessible by air and sea. The State-owned Kodiak Airport provides three asphalt runways.
These runways measure: 7,562' long by 150' wide; 5,398' long by 150' wide; and, 5,011' long by 150'
wide. Kodiak Municipal Airport offers a 2,475' long by 40' wide paved runway. Three scheduled airlines
serve Kodiak with several daily flights, and a number of air taxi services provide flights to other
communities on the Island. City-owned seaplane bases at Trident Basin and Lilly Lake serve floatplane
traffic. The Alaska Marine Highway System operates a ferry service to and from Seward and Homer.
Travel time to Homer by ferry is 12 hours. The Port of Kodiak includes two boat harbors with 600 boat
slips and three commercial piers - the ferry dock, city dock and container terminal. Boat launch ramps and
vessel haul-outs are also available. A $20 million breakwater on Near Island provides another 60 acres of
mooring space at St. Herman Harbor. The replacement of the 32-year-old float system at the St. Paul
Inner Harbor downtown was completed in 2000. Approximately 140 miles of state roads connect island
communities on the east side of the island.
Climate:
The climate of the Kodiak Islands has a strong marine influence. There is little or no freezing weather,
moderate precipitation, occasional high winds, and frequent cloud cover and fog. Severe storms are
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common from December through February. Annual rainfall is 67 inches, and snowfall averages 78 inches.
January temperatures range from 14 to 46 F; July temperatures vary from 39 to 76 F.
(Above information from State of Alaska Department of Commerce, Community, and Economic
Development website, www.dced.state.ak.us).
Site Information and Location
Site number 7357
Site Description Kodiak, Alaska, Pillar Mountain ridgeline
Latitude/longitude N 057° 47.257’; W 152° 26.394’
Site elevation 390 meters
Datalogger type NRG Symphonie
Tower type NRG 50 meter Tall Tower, replaced with NRG 30 meter
Tall Tower
Met Tower Sensor Information
A 50 meter NRG Tall Tower was installed at Site 2 on November 4, 2005 with channels 1, 2, 3,
and 4 instrumented with anemometers, channels 7 and 8 with wind vanes, and channel 12 with a
temperature sensor. On March 30, this tower collapsed due to an accumulation of rime ice and
accompanying high winds. A 30 meter replacement tower was installed on May 12 with
channels 4 (30 meter level anemometer) and 12 (temperature) as common channels between the
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two towers. New anemometer channels 5 and 6 and new wind vane channel 9 were added.
Previously used channels 1, 2, 3, 7 and 8 in use on the 50 meter tower are not in use on the 30
meter tower.
Channel Sensor type Height Multiplier Offset Orientation Channel now
active?
1 NRG #40
anemometer
50 m (A) 0.765 0.35 070° T No
2 NRG IceFree III
anemometer
50 m (B) 0.572 1.0 160° T No
3 NRG #40
anemometer
40 m 0.765 0.35 070° T No
4 NRG #40
anemometer
30 m (A) 0.765 0.35 West Yes
5 NRG #40
anemometer
30 m (B) 0.765 0.35 East Yes
6 NRG #40
anemometer
20 m 0.765 0.35 West Yes
7 NRG IceFree III
wind vane
50 m 0.351 255 ENE No
8 NRG #200P wind
vane
40 m 0.351 180 North No
9 NRG #200P wind
vane
30 m 0.351 000 South Yes
12 NRG #110S Temp
C
2 m 0.138 -86.383 N/A yes
Data Quality Control Summary
The only common channel, besides temperature, of the original 50 meter tower and the
replacement 30 meter tower is Channel 4, the 30 meter (A) channel. Because of the
complications and inherent data error risk of synthesizing a large amount of data, it was decided
to restrict the data analysis to the original Channel 4 data from November 4, 2005 through tower
collapse on March 30, 2006 and then all the operating channels of the replacement tower
beginning on May 12, 2006. Once data was filtered to remove ice events, the data was
synthesized to create complete data sets of the anemometer channels now in use, Channels 4, 5
and 6. For the wind vane channels, data was synthesized for all three wind vane channels, even
though the 50 meter and 40 meter sensors (Channels 7 and 8) are no longer in use. For ease of
review of data relevant to the hub height of a 1500 kW turbine, a 60 meter (virtual) anemometer
was synthesized and added to the data set.
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Measured Wind Speeds
The 30 meter (A) anemometer wind speed average for the reporting period is 8.25 m/s, the 30
meter (B) anemometer wind speed average is 8.22 m/s, and the 20 meter anemometer wind speed
average is 8.14 m/s. The wind speed average for the 60-meter height synthesized anemometer
level (a virtual anemometer) is 8.36 m/s. Because of the extremely low shear at this site, the 60
m average (virtual) wind speed is scarcely any greater than at 30 meters.
Wind Speed Summary
60 m virtual speed 30 m (A) speed 30 m (B) speed 20 m speed
Month Mean Max Mean Max Mean Max Mean Max
(m/s) (m/s) (m/s) (m/s) (m/s) (m/s) (m/s) (m/s)
Jan 8.74 32.4 8.67 31.8 8.58 31.8 8.50 31.4
Feb 9.16 28.2 9.08 27.4 9.02 27.4 8.97 26.9
Mar 10.47 39.9 10.25 39.1 10.25 39.1 10.13 38.6
Apr 9.73 28.9 9.53 28.3 9.53 28.3 9.41 27.9
May 5.19 18.8 5.14 18.4 5.12 18.4 5.11 18.4
Jun 7.05 23.0 6.99 22.2 6.92 22.3 6.86 21.3
Jul 6.48 24.5 6.42 23.4 6.34 23.7 6.25 22.8
Aug 5.38 24.2 5.31 23.6 5.31 23.9 5.24 23.5
Sep 7.65 26.3 7.61 25.4 7.53 25.5 7.50 24.7
Oct 9.63 28.7 9.50 28.7 9.52 28.7 9.41 28.9
Nov 10.28 27.6 10.14 27.4 10.14 27.6 10.07 27.6
Dec 10.53 33.9 10.37 34.3 10.35 33.9 10.26 35.1
Annual 8.36 39.9 8.25 39.1 8.22 39.1 8.14 38.6
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Daily wind profile
The daily wind profile indicates that the lowest wind speeds of the day occur in the morning
hours of 2 to 11 a.m. and the highest wind speeds of the day occur during the evening hours of 9
to 12 p.m. The daily variation of wind speed is quite minimal on an annual basis, but as shown,
more pronounced on a monthly basis.
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Time Series of Wind Speed Monthly Averages
As expected, the highest winds occurred during the fall through spring months with relatively
light winds during the summer months of May through August. The unusually low winds
measured in January 2006 were due to a persistent high pressure system over Alaska that month
that resulted in relatively calm winds and extremely cold temperatures Statewide. Note that
measured winds during winter 2006/2007 are notably higher than during winter 2005/2006.
Excess wind speed
Most wind turbines have a cut-out speed of 25 m/s, or more precisely, cut-out when the 10
minute average wind speed exceeds 25 m/s. Given the powerful wind resources on Pillar
Mountain, one could expect occasional high wind speed shut downs of turbines. During a 455
day period (November 4, 2005 to February 2, 2007), there were 596 ten minute periods or 99.3
hours where predicted wind speeds at 60 meters elevation (using the virtual anemometer)
exceeded 25 m/s. This represents 0.91 percent of the time. Note however that turbines will not
immediately restart once ten minute average wind speeds dip below 25 m/s and hence the lost
production time due to high winds would be higher than the calculated 0.91 percent. This should
be discussed with turbine manufacturers.
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Wind Shear Profile
The average power law exponent was calculated at 0.023, indicating extraordinarily low wind
shear at Site 2. The practical application of this information is that a low turbine tower height is
advisable as there is very little marginal gain in average wind speed with height. Other graphs
show the variability of wind shear by direction and seasonal and daily variability. This
variability is not particularly significant at this site given the very low average shear value.
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Probability Distribution Function
The probability distribution function provides a visual indication of measured wind speeds in one
meter per second “bins”. Note that most wind turbines do not begin to generate power until the
wind speed at hub height reaches 3.5 to 4 m/s, also known as the “cut-in” wind speed. The black
line in the graph is a best fit Weibull distribution. At the 30 meter level, Weibull parameters are
k = 1.53 (indicates a broad distribution of wind speeds) and c = 9.48 m/s (scale factor for the
Weibull distribution) for the measurement period of 11/4/2005 to 2/27/2007.
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Wind Roses
Kodiak Site 2 winds are strongly directional; the 30 meter wind frequency rose (green) indicates
predominately northwest winds with a lesser component of south-southeast winds. This data
observation is even stronger when one considers the power density rose (yellow). The practical
application of this information is that several turbines can potentially be spaced closely together
perpendicular to the prevailing NW and SSE winds. The frequency of calm winds, shown in the
upper right quadrant of the frequency roses, is defined as the percent of time that winds exceed a
selected threshold value, in this case 3.5 m/s.
Wind frequency rose – 30 meters
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Power density rose – 30 meters
Wind frequency rose – 50 meters (11/04/05 through 3/30/06)
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Power density rose – 50 meters (11/04/05 through 3/30/06)
Wind Power Density Rose by Month (50 meters)
Note: only actual measured data months in 2005 and 2006 are shown (November 4, 2005
through March 30, 2006). Scale of graphs is common.
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Wind Power Density Rose by Month (30 meters)
Note: only actual measured data months in 2006 without a synthesis overlap are shown (May 12
through October 31, 2006. Scale of graphs is common.
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Turbulence Intensity
The Kodiak Site 2 turbulence intensity remains extremely favorable with a mean of 0.109 at 50
meters (five months data) and a mean of 0.120 (A channel) and 0.110 (B channel) at 30 meters.
Turbulence intensity is calculated for each time step as the standard deviation of the wind speed
divided by the mean of the wind speed.
30 meter vane – 30 meter (A) Turbulence Intensity (Mean = 0.120)
50 meter vane – 50 meter (A) Turbulence Intensity (Mean = 1.109), 11/4/05 through 3/30/06
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International Energy Agency turbulence standard comparisons
As indicated, turbulence is within International Energy Agency (IEA) Category A and B
standards for all wind directions and at all measured wind speeds.
30 meter vane – 30 meter (A) speed
50 meter vane – 50 meter (A) speed
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Turbulence Tables
Turbulence Table 50 m A speed - 50 m vane (11/04/05 to 3/30/06), threshold 4 m/s
Bin
Bin
Endpoints Records
Standard
Deviation Mean
Standard
Deviation Characteristic
Midpoint Lower Upper In of Wind Speed Turbulence of Turbulence Turbulence
(m/s) (m/s) (m/s) Bin (m/s) Intensity Intensity Intensity
1 0.5 1.5 746 0.371 0.400 0.207 0.607
2 1.5 2.5 1089 0.396 0.203 0.136 0.339
3 2.5 3.5 1168 0.474 0.160 0.102 0.262
4 3.5 4.5 1290 0.522 0.132 0.079 0.211
5 4.5 5.5 1421 0.624 0.126 0.076 0.202
6 5.5 6.5 1478 0.695 0.117 0.063 0.180
7 6.5 7.5 1536 0.780 0.112 0.060 0.172
8 7.5 8.5 1456 0.865 0.109 0.059 0.167
9 8.5 9.5 1480 0.966 0.108 0.055 0.163
10 9.5 10.5 1356 1.103 0.111 0.052 0.163
11 10.5 11.5 1129 1.193 0.109 0.048 0.157
12 11.5 12.5 991 1.280 0.107 0.046 0.153
13 12.5 13.5 862 1.359 0.105 0.043 0.148
14 13.5 14.5 739 1.466 0.105 0.045 0.150
15 14.5 15.5 687 1.486 0.099 0.044 0.143
16 15.5 16.5 667 1.569 0.098 0.043 0.141
17 16.5 17.5 597 1.656 0.098 0.038 0.135
18 17.5 18.5 433 1.724 0.096 0.038 0.134
19 18.5 19.5 343 1.850 0.098 0.036 0.134
20 19.5 20.5 279 1.831 0.092 0.033 0.125
21 20.5 21.5 205 2.000 0.095 0.031 0.126
22 21.5 22.5 166 2.044 0.093 0.032 0.125
23 22.5 23.5 147 2.016 0.088 0.023 0.111
24 23.5 24.5 99 2.038 0.085 0.021 0.106
25 24.5 25.5 41 2.239 0.090 0.024 0.114
26 25.5 26.5 41 2.390 0.092 0.020 0.112
27 26.5 27.5 33 2.561 0.095 0.028 0.123
28 27.5 28.5 17 2.600 0.093 0.019 0.112
29 28.5 29.5 18 2.822 0.098 0.021 0.119
30 29.5 30.5 18 2.961 0.099 0.021 0.120
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31 30.5 31.5 31 2.974 0.096 0.019 0.115
32 31.5 32.5 41 2.932 0.092 0.024 0.116
33 32.5 33.5 21 2.805 0.085 0.021 0.106
34 33.5 34.5 12 3.192 0.094 0.022 0.116
35 34.5 35.5 12 3.325 0.095 0.014 0.109
36 35.5 36.5 8 3.325 0.092 0.010 0.102
37 36.5 37.5 5 3.240 0.087 0.012 0.100
38 37.5 38.5 2 3.350 0.088 0.004 0.093
39 38.5 39.5 1 4.000 0.104 0.000 0.104
Turbulence Table 50 m B speed - 50 m vane (11/04/05 to 3/30/06), threshold 4 m/s
Bin
Bin
Endpoints Records
Standard
Deviation Mean
Standard
Deviation Characteristic
Midpoint Lower Upper In of Wind Speed Turbulence of Turbulence Turbulence
(m/s) (m/s) (m/s) Bin (m/s) Intensity Intensity Intensity
1 0.5 1.5 917 0.100 0.081 0.113 0.194
2 1.5 2.5 1090 0.353 0.181 0.104 0.285
3 2.5 3.5 1094 0.423 0.144 0.098 0.242
4 3.5 4.5 1296 0.487 0.124 0.083 0.206
5 4.5 5.5 1397 0.604 0.121 0.072 0.193
6 5.5 6.5 1637 0.687 0.116 0.064 0.180
7 6.5 7.5 1562 0.774 0.112 0.062 0.173
8 7.5 8.5 1558 0.867 0.109 0.060 0.169
9 8.5 9.5 1517 0.927 0.104 0.060 0.164
10 9.5 10.5 1347 1.049 0.106 0.056 0.162
11 10.5 11.5 1099 1.161 0.106 0.054 0.160
12 11.5 12.5 968 1.215 0.102 0.052 0.154
13 12.5 13.5 816 1.281 0.099 0.050 0.149
14 13.5 14.5 732 1.405 0.101 0.045 0.146
15 14.5 15.5 697 1.514 0.101 0.044 0.145
16 15.5 16.5 657 1.565 0.098 0.040 0.138
17 16.5 17.5 629 1.647 0.097 0.037 0.135
18 17.5 18.5 458 1.712 0.095 0.038 0.134
19 18.5 19.5 309 1.771 0.094 0.039 0.133
20 19.5 20.5 274 1.719 0.086 0.036 0.123
21 20.5 21.5 205 1.902 0.091 0.031 0.122
22 21.5 22.5 173 1.917 0.087 0.032 0.119
23 22.5 23.5 143 2.072 0.090 0.043 0.134
24 23.5 24.5 96 2.003 0.084 0.022 0.105
25 24.5 25.5 65 2.192 0.088 0.023 0.111
26 25.5 26.5 39 2.210 0.085 0.021 0.106
27 26.5 27.5 31 2.665 0.099 0.026 0.125
28 27.5 28.5 16 2.631 0.094 0.021 0.115
29 28.5 29.5 21 3.043 0.105 0.023 0.128
30 29.5 30.5 13 2.831 0.095 0.026 0.120
31 30.5 31.5 11 3.555 0.115 0.023 0.139
32 31.5 32.5 27 3.511 0.110 0.033 0.142
33 32.5 33.5 26 3.585 0.109 0.027 0.136
34 33.5 34.5 29 4.190 0.123 0.031 0.154
35 34.5 35.5 12 4.233 0.121 0.031 0.152
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36 35.5 36.5 13 4.200 0.117 0.029 0.146
37 36.5 37.5 5 4.680 0.127 0.015 0.142
38 37.5 38.5 7 5.329 0.141 0.021 0.163
39 38.5 39.5 6 4.700 0.121 0.013 0.134
40 39.5 40.5 5 5.420 0.136 0.004 0.140
41 40.5 41.5 5 5.540 0.136 0.006 0.141
42 41.5 42.5 4 5.175 0.123 0.015 0.138
43 42.5 43.5 2 5.300 0.123 0.003 0.126
44 43.5 44.5 1 6.200 0.140 0.000 0.140
45 44.5 45.5 0 6.200 0.140 0.000 0.140
Turbulence Table 40 m speed - 40 m vane (11/04/05 to 3/30/06), threshold 4 m/s
Bin
Bin
Endpoints Records
Standard
Deviation Mean
Standard
Deviation Characteristic
Midpoint Lower Upper In of Wind Speed Turbulence of Turbulence Turbulence
(m/s) (m/s) (m/s) Bin (m/s) Intensity Intensity Intensity
1 0.5 1.5 825 0.383 0.413 0.215 0.628
2 1.5 2.5 1014 0.426 0.221 0.148 0.369
3 2.5 3.5 1179 0.485 0.163 0.107 0.270
4 3.5 4.5 1303 0.541 0.137 0.081 0.218
5 4.5 5.5 1418 0.641 0.129 0.073 0.202
6 5.5 6.5 1464 0.721 0.121 0.063 0.184
7 6.5 7.5 1493 0.802 0.115 0.061 0.176
8 7.5 8.5 1463 0.885 0.111 0.057 0.168
9 8.5 9.5 1525 0.992 0.111 0.054 0.164
10 9.5 10.5 1283 1.142 0.115 0.050 0.165
11 10.5 11.5 1164 1.234 0.113 0.047 0.160
12 11.5 12.5 1021 1.295 0.108 0.045 0.154
13 12.5 13.5 833 1.425 0.110 0.044 0.154
14 13.5 14.5 738 1.517 0.109 0.044 0.152
15 14.5 15.5 707 1.574 0.105 0.042 0.147
16 15.5 16.5 653 1.586 0.100 0.041 0.140
17 16.5 17.5 563 1.690 0.100 0.039 0.139
18 17.5 18.5 400 1.768 0.099 0.037 0.135
19 18.5 19.5 312 1.873 0.099 0.035 0.134
20 19.5 20.5 271 1.849 0.093 0.033 0.126
21 20.5 21.5 201 2.083 0.100 0.042 0.142
22 21.5 22.5 175 2.044 0.093 0.029 0.122
23 22.5 23.5 145 2.034 0.089 0.025 0.113
24 23.5 24.5 81 2.048 0.086 0.026 0.112
25 24.5 25.5 38 2.276 0.091 0.018 0.109
26 25.5 26.5 42 2.579 0.100 0.026 0.126
27 26.5 27.5 30 2.463 0.091 0.026 0.118
28 27.5 28.5 17 2.829 0.102 0.016 0.117
29 28.5 29.5 20 2.970 0.103 0.023 0.126
30 29.5 30.5 16 2.919 0.097 0.017 0.114
31 30.5 31.5 34 3.035 0.098 0.021 0.119
32 31.5 32.5 40 3.007 0.094 0.023 0.117
33 32.5 33.5 19 2.958 0.090 0.022 0.112
34 33.5 34.5 12 3.275 0.097 0.025 0.122
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Kodiak, Alaska Site 2 Wind Resource Report 3/16/2007
35 34.5 35.5 11 3.264 0.093 0.011 0.104
36 35.5 36.5 8 3.425 0.095 0.008 0.104
37 36.5 37.5 5 3.220 0.087 0.010 0.097
38 37.5 38.5 2 3.750 0.098 0.009 0.107
39 38.5 39.5 0 3.750 0.098 0.009 0.107
Turbulence Table 30 m A speed - 30 m vane (11/04/05 to 2/27/07), threshold 3.5 m/s
Bin Bin Endpoints Records
Standard
Deviation Mean
Standard
Deviation Characteristic
Midpoint Lower Upper In of Wind Speed Turbulence of Turbulence Turbulence
(m/s) (m/s) (m/s) Bin (m/s) Intensity Intensity Intensity
1 0.5 1.5 3182 0.482 0.521 0.331 0.852
2 1.5 2.5 4598 0.511 0.264 0.164 0.428
3 2.5 3.5 4973 0.556 0.190 0.125 0.315
4 3.5 4.5 4729 0.644 0.163 0.104 0.267
5 4.5 5.5 4751 0.708 0.143 0.079 0.222
6 5.5 6.5 4871 0.806 0.135 0.071 0.206
7 6.5 7.5 4916 0.879 0.126 0.062 0.188
8 7.5 8.5 4839 0.946 0.119 0.057 0.176
9 8.5 9.5 4628 1.052 0.117 0.053 0.171
10 9.5 10.5 3959 1.139 0.115 0.050 0.165
11 10.5 11.5 3570 1.224 0.112 0.049 0.161
12 11.5 12.5 3153 1.286 0.108 0.046 0.154
13 12.5 13.5 2711 1.395 0.108 0.045 0.153
14 13.5 14.5 2320 1.504 0.108 0.047 0.155
15 14.5 15.5 1994 1.581 0.106 0.046 0.152
16 15.5 16.5 1745 1.634 0.102 0.046 0.149
17 16.5 17.5 1599 1.677 0.099 0.045 0.144
18 17.5 18.5 1258 1.748 0.097 0.043 0.141
19 18.5 19.5 984 1.842 0.097 0.042 0.139
20 19.5 20.5 764 1.876 0.094 0.039 0.133
21 20.5 21.5 639 1.975 0.094 0.042 0.136
22 21.5 22.5 459 1.929 0.088 0.038 0.126
23 22.5 23.5 344 1.961 0.086 0.034 0.120
24 23.5 24.5 223 2.045 0.086 0.038 0.124
25 24.5 25.5 148 1.914 0.077 0.036 0.113
26 25.5 26.5 130 2.243 0.087 0.041 0.127
27 26.5 27.5 80 2.333 0.087 0.040 0.127
28 27.5 28.5 46 2.453 0.088 0.038 0.126
29 28.5 29.5 36 3.006 0.104 0.034 0.138
30 29.5 30.5 22 3.316 0.111 0.035 0.146
31 30.5 31.5 35 3.180 0.103 0.019 0.121
32 31.5 32.5 46 3.363 0.105 0.023 0.128
33 32.5 33.5 24 3.325 0.101 0.023 0.124
34 33.5 34.5 15 3.507 0.103 0.026 0.130
35 34.5 35.5 12 3.275 0.094 0.014 0.108
36 35.5 36.5 12 3.533 0.098 0.010 0.108
37 36.5 37.5 5 3.360 0.091 0.005 0.096
38 37.5 38.5 4 3.500 0.092 0.010 0.102
39 38.5 39.5 2 3.850 0.099 0.009 0.107
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Kodiak, Alaska Site 2 Wind Resource Report 3/16/2007
40 39.5 40.5 0 3.850 0.099 0.009 0.107
Turbulence Table 30 m B speed - 30 m vane (11/04/05 to 2/27/07), threshold 3.5 m/s
Bin
Bin
Endpoints Records
Standard
Deviation Mean
Standard
Deviation Characteristic
Midpoint Lower Upper In of Wind Speed Turbulence of Turbulence Turbulence
(m/s) (m/s) (m/s) Bin (m/s) Intensity Intensity Intensity
1 0.5 1.5 3335 0.549 0.592 0.436 1.029
2 1.5 2.5 4600 0.579 0.300 0.194 0.494
3 2.5 3.5 4878 0.603 0.205 0.129 0.334
4 3.5 4.5 4706 0.661 0.167 0.103 0.270
5 4.5 5.5 4794 0.719 0.145 0.081 0.226
6 5.5 6.5 4918 0.790 0.132 0.069 0.201
7 6.5 7.5 5035 0.850 0.122 0.061 0.183
8 7.5 8.5 4750 0.908 0.114 0.056 0.170
9 8.5 9.5 4608 0.965 0.108 0.053 0.161
10 9.5 10.5 3880 1.009 0.101 0.052 0.153
11 10.5 11.5 3570 1.055 0.096 0.050 0.147
12 11.5 12.5 3148 1.123 0.094 0.049 0.143
13 12.5 13.5 2787 1.182 0.091 0.048 0.139
14 13.5 14.5 2313 1.258 0.090 0.049 0.140
15 14.5 15.5 1948 1.250 0.084 0.050 0.134
16 15.5 16.5 1748 1.269 0.080 0.050 0.129
17 16.5 17.5 1560 1.301 0.077 0.047 0.124
18 17.5 18.5 1204 1.344 0.075 0.048 0.123
19 18.5 19.5 975 1.410 0.074 0.046 0.120
20 19.5 20.5 733 1.436 0.072 0.046 0.118
21 20.5 21.5 621 1.419 0.068 0.045 0.113
22 21.5 22.5 454 1.443 0.066 0.045 0.111
23 22.5 23.5 335 1.301 0.057 0.042 0.099
24 23.5 24.5 226 1.433 0.060 0.045 0.104
25 24.5 25.5 156 1.606 0.064 0.044 0.108
26 25.5 26.5 131 1.596 0.062 0.045 0.107
27 26.5 27.5 82 1.446 0.054 0.045 0.099
28 27.5 28.5 49 1.457 0.052 0.045 0.098
29 28.5 29.5 39 1.649 0.057 0.054 0.110
30 29.5 30.5 19 1.366 0.045 0.050 0.095
31 30.5 31.5 40 1.417 0.046 0.046 0.091
32 31.5 32.5 43 1.278 0.040 0.040 0.080
33 32.5 33.5 24 0.937 0.028 0.024 0.052
34 33.5 34.5 15 0.848 0.025 0.032 0.057
35 34.5 35.5 12 0.721 0.021 0.012 0.033
36 35.5 36.5 12 0.865 0.024 0.015 0.039
37 36.5 37.5 5 1.185 0.032 0.008 0.040
38 37.5 38.5 4 0.557 0.015 0.007 0.022
39 38.5 39.5 2 0.686 0.018 0.006 0.023
40 39.5 40.5 0 0.686 0.018 0.006 0.023
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Kodiak, Alaska Site 2 Wind Resource Report 3/16/2007
Air Temperature and Density
Over the reporting period, Kodiak Site 2 had an average temperature of 4.8° C. The minimum
recorded temperature during the measurement period was -17.0° C and the maximum
temperature was 25.6° C, indicating a cool temperate operating environment for wind turbine
operations. Consequent to Kodiak’s cool temperatures, but counterbalanced by Site 2’s elevation
of 390 meters, the average air density of 1.214 kg/m3 is approximately three percent higher than
the standard air density of 1.1798 kg/m3 (at 12.5° C and 96.7 kPa) at this elevation. Density
variance from standard is accounted for in turbine performance predictions.
Temperature Air Density
Month Mean Min Max
Std.
Dev. Mean Min Max
(°C) (°C) (°C) (°C) (kg/m³) (kg/m³) (kg/m³)
Jan -3.1 -17.0 4.0 5.494 1.249 1.216 1.316
Feb -1.0 -15.2 6.1 4.052 1.239 1.207 1.307
Mar -0.5 -9.4 7.3 2.595 1.236 1.202 1.278
Apr 4.3 -1.3 12.4 2.461 1.215 1.180 1.240
May 9.5 0.5 25.6 5.265 1.193 1.128 1.232
Jun 9.6 5.1 18.7 2.792 1.192 1.155 1.211
Jul 11.9 7.3 21.6 2.947 1.182 1.143 1.202
Aug 12.6 8.7 20.5 2.373 1.180 1.148 1.196
Sep 9.7 4.8 16.7 1.866 1.192 1.163 1.213
Oct 6.0 -2.2 13.0 2.956 1.207 1.178 1.244
Nov -2.1 -13.3 7.3 4.021 1.244 1.202 1.297
Dec 0.3 -11.1 6.2 3.835 1.233 1.206 1.286
All data 4.8 -17.0 25.6 6.764 1.214 1.128 1.316
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Kodiak, Alaska Site 2 Wind Resource Report 3/16/2007
Air Density DMap
The DMap is a visual indication of the daily and seasonal variations of air density (and hence
temperature). Air densities higher than standard will yield higher turbine power than predicted
by turbine power curves (which are calibrated for a sea level temperature of 15° C, air pressure
of 101.3 kPa, and air density of 1.225 kg/m3, while densities lower than standard will yield lower
turbine power than predicted by the power curves.
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