Wind Resource Evaluation: Ashland Ridge
OREGON ANEMOMETER LOAN PROGRAM
Wind Resource Evaluation: Ashland Ridge
Prepared By:
Energy Resources Research laboratory Oregon State University
February 1, 2007
NOTICE This publication was prepared as an account of work sponsored by the Energy Trust of Oregon, Inc. Neither the Energy Trust of Oregon, Inc. nor any of their contractors, subcontractors, or their employees make any warranty, express or implied, or assume any legal liability or responsibility for the accuracy, completeness, usefulness, or reliability of the research data, and conclusions reported herein, or of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. For these reasons and for the reason that the views, opinions, and conclusions contained in this material are those of the contractor.
Wind Resource Evaluation: Ashland Ridge
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OREGON ANEMOMETER LOAN PROGRAM
Wind Resource Evaluation:
Ashland Ridge
Prepared by: Philip L. Barbour Stel N. Walker, Ph.D. Energy Resources Research Laboratory Department of Mechanical Engineering Oregon State University Corvallis, OR 97331
Sponsor: Energy Trust of Oregon, Inc. 733 SW Oak Street, Suite 200 Portland Oregon,97205
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1.0
INTRODUCTION
The Oregon anemometer loan program was established in the fall of 2002 in order to assist landowners in the state evaluate the wind energy potential of their property. The program is funded by a grant from the Energy Trust of Oregon and is administered by the Energy Resources Research Laboratory at Oregon State University. The program involves several steps, beginning with a preliminary evaluation of the site. If estimates of the site show promise then a monitoring system is installed for a fixed duration (typically one year). The site is monitored regularly and the data processed and checked at regular intervals. Upon completion of the first year, the collected wind data is summarized and a report is prepared evaluating the wind data and the wind resource of the location. This report represents the final portion of the project and is designed to give the landowner the information necessary to make an informed choice about the role wind energy might play in their property. The report is separated in to sections with section 2.0 devoted to a description of the site, its location and the type of terrain found there. Section 3.0 includes a summary of the wind data collected during the study period including data quality checks and a characterization of the measured winds. In section 4.0 the wind data is analyzed to determine the amount of power production that might be expected from the site and to examine characteristics that might influence these estimates. This is followed in section 5.0 in which wind data from a nearby site is summarized and used to place the current study period in climatological context. A discussion and summary is then presented in section 6.0
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2.0
SITE DESCRIPTION Site Name: Latitude: Longitude: Elevation: County: Sensor Height: Types of Sensors: Types of Data: Installation Date: Removal Date:
Ashland Ridge 42-16-49 122-43-20 3440 ft. Jackson 67 ft. NRG Maximum #40 wind speed NRG 200 series2 wind vane 10 min. average wind speed (mph) 10 min. std. dev. wind speed (mph) 10 min. wind direction (16 categories) May 24, 2005 @ PST June 19, 2006 @ PST
Site Location: Ashland is located in southwestern Oregon along the I-5 corridor. The city sites at the base of a broad valley boardered by the foothills of the Cascades on the east and the Siskiyou Mountains to the west. The valley extends from Medford southeastowards Ashland. The Ashland Ridge site is located north of the city along a small ridge that extends out from the eastern side of the valley. Access to the site is found by turning east off of of I-5 on exit 19 and proceeding for several miles to a gated community. The property is located several miles up the hill after passing through the gate. The tower location is marked on the map included in Appendix A. The area consists of slopes with grass lands and groves of old oak trees. Pictures of the site are included in Appendix B. Project Description: The owner of this site is interested in evaluating the site for the installation of a wind turbine to help power an artist studio.
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3.0
WIND CHARACTERISTICS
In the following sections, several characteristics of the winds at the site at the Ashland Ridge site are examined and discussed. The goals are to evaluate the characteristics that can help explain the physical processes at work at the site and to highlight the properties that are important to assessing the wind energy potential. These evaluations are done using hourly averaged means that have been constructed using the 10 minute means recorded at the site. This is done so that existing analysis programs can be used and is not expected to have any appreciable influence on the interpretation of data. Data Recovery: The amount of data recovered during an observation period is important to characterize and should be examined to determine the confidence of other characteristics. During the initial annual period at this site, there were no problems detected that might influence the collected wind data. A table of site visits and the actions taken has been included in Appendix A. Data were plotted and scanned manually to identify any problems with the site. For the most part, data collection from the site was complete except for one monthly period. The data plug for this period was lost leaving a gap of roughly a month between June 22, 2005 and July 18, 2005. In addition, data for a short period in November were removed from the records because the effects of icing were detected. This was only done for periods with a clear presence of icing and it is possible that other periods with a more limited influence occurred. Icing is identified as prolonged periods with a wind speed of 0.0 mph and a constant direction.
Data Recovery
Recovery Rate (%)
100 80 60 40 20 0 Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Ann.
Figure 3.1: Data recovery by month for the Ashland Ridge site
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Month
Jun
Jul
Rec. (%)
71.4
44.2
Aug 100
Sep 100
Oct 100
Nov
Dec
95.8
Jan
100
100
Feb 100
Mar 100
Apr 100
May
Ann
100
92.9
Monthly Means: Monthly means are often constructed and used to determine the overall strength of the winds during different periods of the year. Monthly means show that the Ashland Ridge site has a weak but distinctive seasonal pattern with stronger winds possible during winter months. December had the strongest winds with a monthly mean of 13.7 mph followed by March (12.5 mph) and January (10.6 mph). All of the remainder months had monthly mean winds below 10.0 mph with the lowest winds occurring during the late summer or early fall. These summer winds are lower than those observed at another site located at a lower elevation in the area (the North Ashland site). This suggests that the hills to the north of this site may be partially blocking the flow during the summer. Monthly Means 16 14 12
(mph)
10 8 6 4 2 0 Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Ann
Figure 3.2: Monthly Mean Wind Speed Values for the Ashland Ridge site. Month Mean (mph)
Jun 8.7
Jul 7.0
Aug
Sep
6.9
5.5
Oct 5.4
Nov 9.1
Dec 13.7
Jan 10.6
Feb 8.8
Mar
Apr
May
12.5
8.2
7.6
Ann 8.7
Diurnal Means: The diurnal pattern of winds is an important characteristic for many wind sites and helps illuminate the mechanisms responsible for the winds. In general, a diurnal pattern is associated with a site at which strong thermal influences play a role. These are normally accentuated during the summer months when the daily heating cycle is at its greatest. Diurnal variations can also provide an indication of dependable and predictable winds at a site.
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As is common for most sites in Oregon, the winds at the Ashland Ridge site show a clear diurnal pattern during the summer months and is strong enough to show up in the mean for the annual diurnal average (Fig. 3.3). In general, the diurnal values for summer show that the winds are very light through the night and morning hours and begin to pick up during the late morning. At this site, the winds stay at their peak from around noon until late afternoon before tapering off slowly. On average, the winds during these days are in a usable range for about 25% to 30% of the time. The winds during these periods are predominantly from the north and are a response to large-scale heating patterns. Unfortunately, the winds during these peak periods are not exceptional by wind energy standards and on average remain below 14.0 mph. However, individual days may have higher or lower wind conditions. As expected, during the winter months there is little indication of a diurnal pattern. This is a common pattern and is a consequence of the low winter sun angle and the absence of surface heating.
Diurnal Mean Winds 14 12 10 AVE Jan Jul
8 6 4 2 0 0
300
600
900
1200
1500
1800
2100
Hour of Day
Figure 3.3: Diurnal mean wind speed values for the Ashland Ridge site.
Frequency Distribution: How the wind speed at a site is distributed over various wind speed categories is an important indication of the wind resource potential of a site. An ideal site would have winds that blow at a high rate for long periods. This is not normally the case, however, and wind records from a site show a skewed distribution with a higher frequency of winds at lower speeds. For the Ashland Ridge site (Figure 3.4) we see that the distribution is fairly typical except that it exhibits a fairly high frequency of winds in the lowest wind speed categories (below 3.0 mph). In this case there is a single peak between 3.0 to 4.0 mph and a long gradual decrease out to higher wind categories. This peak would likely be smoother with additional data. The importance of this figure is that it illustrates the amount of time that the winds are within various energy resource ranges. For example, the winds at the Wind Resource Evaluation: Ashland Ridge
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Ashland Ridge site are below 12.0 mph about 72 % of the time. This suggests that it would be possible to produce appreciable amounts of energy at the site only about 28 % of the time. In addition, the winds are above 20.0 mph only about 8 % of the time (the range at which most wind turbines produce their peak amount of power). This suggests that a typical wind turbine would produce optimal output only about 8.0 % of the time. This is relatively low for a good wind site and suggests that there is a low frequency of winds at the upper end of the range. This is significant because it is at higher wind speeds where most of the potential power is produced.
Relative Frequency 8 7 6 5 4 3 2 1 0 0
5
10
15
20
25
30
35
40
45
Wind Speed Category Figure 3.4: Wind speed frequency distribution for the Ashland Ridge site.
Wind Rose: How the wind varies with direction is also important to understanding the physical processes that contribute to the local winds at a site and eventually in designing a wind facility. A wind rose is often used to display this information and show the frequency with which the wind occurs in different direction categories. A similar plot can be used to show the strength of the wind from each of the direction categories. For this site (Figure 3.5) it is apparent that the winds come from all directions but that a higher frequency comes from two general directions; the Southeast and the Northwest (grouping together categories). Viewing the second figure we see that the mean wind speeds for the southerly directions are much higher than for the northerly directions. This is often the case at sites in the Northwest where southerly winds associated with strong storm systems during the winter months produce much of the observed wind. The higher wind speed averages for the southerly directions suggest that this is the direction from which a majority of the energy producing winds will come from. The mean winds for the Northwesterly categories are generally below 10.0 mph.
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Annual Directional Speed
Annual Directional Frequency 18
25
16
20
14 12
15
10 8
10
6 4
5
2 0
0 N
NE
E
SE
S
SW
W
NW
CALM
Direction Category
N
NE
E
SE
S
SW
W
NW
Direction Category
Figure 3.5: Frequency (%) and average wind speed (mph) for each of 16 wind direction categories
In order understand better the winds at the site during different times of year; similar plots have been constructed using data from the individual months of January and July. These can be seen in figures 3.6a-d and show the difference between the two periods. For January, the winds most often come from the southerly directions. On average these winds are quite strong, especially the SE quadrant which shows a mean of over 16.0 mph. Winds from other directions during January are much lower In July, the winds most frequently come from the range between North to East. These winds are fairly weak on average (mostly below 10.0 mph). We have already seen that these winds can peak during the day but when averaged over the day as a whole are not particularly significant. Overall these figures suggest that most of the energy producing winds will come from the SE and during the winter.
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JANUARY
JANUARY 18 16 14 12 10 8 6 4 2 0
40 35 30 25 20 15 10 5 0 N
NE
E
SE
S
SW
W
NW
N
CALM
NE
E
SE
S
SW
W
NW
W
NW
Direction Category
Direction Category
JULY
JULY 14
18 16 14 12 10 8 6 4 2 0
12 10 8 6 4 2 0 N
NE
E
SE
S
SW
W
NW
CALM
Direction Category
N
NE
E
SE
S
SW
Direction Category
Figure 3.6: Frequency (%) and average wind speed (mph) for each of 16 wind direction categories for the months of January and July for the Ashland Ridge site.
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4.0
SITE POWER CHARACTERISTICS
In order to evaluate the wind power potential at this site a number of quantities were computed using the collected wind data. As with the wind characteristics, hourly wind data was used to complete this work. The power density calculation requires air density. This is estimated assuming a standard atmosphere and the site elevation. The computed quantities include the mean and standard deviation of the hourly values, the recovery rate, the maximum one hour average, the wind power density and the frequency that the wind was observed within a wind speed range (12 mph to 60 mph). These quantities are shown in Table 4.1 and reveal a number of things about the potential for generating energy the site. First, the quantities in Table 4.1 show a tendency for an increase in the winds during the winter months. They also indicate that this may not always be the case. The low winds during February illustrate the variable nature of the winds at this site and highlight the likelihood that strong winds are not garunteed, even duing winter months. To examine the overall amount of energy contained in the wind, the power density is very useful. It represents the amount of energy that would be available to a unit area each hour. The monthly mean values are shown in figure 4.1 and highlight the consistent, low power resource at the site for most of the year and the few periods of increase. The monthly power density for March was 754 W/M**2 and for December was 619 W/M**2. However, half of the months had values below 200 W/M**2.
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Month Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May ANN
Mean (mph) 8.7 7.0 6.9 5.5 5.4 9.1 13.7 10.6 8.8 12.5 8.2 7.6 8.7
Std. (mph) 5.38 5.02 5.18 4.37 4.58 6.85 9.80 8.45 7.66 10.36 6.30 5.15 7.45
Recovery Max 1-Hr Rate (%) (mph) 71.4 25.5 44.2 17.2 100.0 18.3 100.0 18.8 100.0 24.4 95.8 37.0 95.8 41.8 100.0 38.0 100.0 38.6 100.0 51.7 100.0 31.9 100.0 28.4 99.7 51.7
Time in Range (12-60) Power Den. mph (%) W/m^2 25.9 73 19.1 43 23.5 45 9.0 25 7.9 31 27.7 121 47.8 356 36.8 196 23.2 145 40.5 356 23.5 88 17.9 57 25.5 134
Shape Factor 1.68 1.43 1.38 1.28 1.19 1.36 1.44 1.28 1.17 1.22 1.33 1.52 1.19
Scale Factor 9.7 7.7 7.6 5.9 5.7 9.9 15.1 11.5 9.3 13.3 8.9 8.4 9.3
Table 4.1: Observed and computed power quantities for the wind site at the Ashland Ridge site.
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Power Density (W/m**2)
Power Density 800 700 600 500 400 300 200 100 0 JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
Ann
Figure 4.1: Monthly power density for the Ashland Ridge site.
In addition to evaluating these basic power characteristics it is possible to estimate how specific wind turbines might interact with the winds at a particular site. Using the collected wind data and the characteristics of a particular wind turbine it is possible to estimate the amount of power it could produce. This is done by comparing the wind data with a power curve for a specific wind turbine. A power curve is simply the curve that shows the relationship between the wind speed and the amount of power a turbine can produce. An example is provided in Figure 4.2. There are several portions of the curve that are important. At low wind speeds, below the cut-in speed, no energy is produced. Any turbine has a lower threshold below which it won’t operate. This is in part because there is little energy available at these levels. In the middle is a ramp up zone where even a small increase in wind speed results in a larger increase in power. At some point, depending on the type of turbine, the amount of power hits its rated capacity as the blades are pitched to spill energy and protect the turbine. At the upper end, energy production will stop if the winds reach a cut-out speed. This is the speed at which a turbine is shut down. In Table 4.2, energy capacity factors are shown for eight different types of turbines. The capacity factor is the ratio of the amount of energy produce to the amount of energy that could be produced if a turbine ran at its rated capacity all the time. The rated capacity is effectively a theoretical maximum and capacity factors generally range from 0.0 to 0.40. It’s difficult to compare these because of the different turbine characteristics but they are given to provide a range of values that might be expected from this site. In computing these values, it is necessary to adjust the observed data which is measured at 67 feet to the hub height of the particular turbine. In this case this is done using a standard assumption that the wind follows a typical power law profile with a coefficient of 0.143.
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120
Power Output (% of Rated)
100
80
60
40
20
0 0
10
20
30
40
50
Wind Speed (mph)
Figure 4.2: Sample power curve for a theoretical turbine
The capacity factors in Table 4.2 support the conclusions of the previous sections and indicate that there appears to be only isolated periods during which any wind resource might be available at this site. During the highest wind months (December 2005 and March 2006) capacity factors for the most efficient wind turbines were on the order of 0.300. This would indicate a good resource if the conditions persisted longer. However, capacity factors for the summer months are much lower and rarely exceed 0.100. This means a turbine at this particular site could capture less than 10% of what it might under perfect ideal conditions. For some turbines the values are as low as 1.3 % (Sep. with BWC EXCEL).
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Table 4.2: Capacity factors computed for the Ashland Ridge site using observed wind data and characteristics of eight different wind turbines. Turbine
Vestas
Vestas
Vestas
Vestas
BWC
GE Wind
Vestas
47
80
66
7.5
EXCEL-S
70.5
29
Mitsubishi
Size (kW)
660
2000
1650
55
10
1500
225
250
Hub Ht. (ft.)
131
262
197
59
79
210
103
100
Jun
0.093
0.119
0.083
0.076
0.055
0.112
0.100
0.069
Jul
0.057
0.073
0.048
0.043
0.031
0.066
0.061
0.040
Aug
0.061
0.077
0.052
0.046
0.033
0.069
0.064
0.043
Sep
0.028
0.039
0.024
0.021
0.016
0.034
0.032
0.020
Oct
0.036
0.045
0.031
0.029
0.021
0.043
0.038
0.026
Nov
0.118
0.140
0.106
0.102
0.081
0.134
0.124
0.095
Dec
0.289
0.323
0.271
0.268
0.225
0.324
0.301
0.256
Jan
0.202
0.230
0.183
0.178
0.138
0.228
0.207
0.162
Feb
0.126
0.146
0.116
0.113
0.093
0.143
0.133
0.107
Mar
0.247
0.272
0.226
0.229
0.192
0.272
0.256
0.214
Apr
0.104
0.124
0.091
0.086
0.064
0.119
0.108
0.078
May
0.069
0.086
0.060
0.055
0.041
0.080
0.073
0.050
ANN
0.124
0.144
0.112
0.108
0.086
0.140
0.129
0.100
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5.0 CLIMATOLOGICAL ANALYSIS Measurements taken over a single one-year period can provide a good estimation of the winds and wind energy potential of a site. However, this is a fairly limited period and is only meaningful if we can place the period into a larger climatological context. For the Ashland Ridge site monthly mean wind speed values from the Sexton Summit site used for this purpose. While not ideal, wind records from Sexton Summit should show the general climatological significance of this particular observation period. To accomplish this, monthly mean wind speed values and climate normals were obtained from the National Climate Data Center (NCDC). Information about the site and the monthly means and departures for this annual study period can be found in Table 5.1. First, the winds overall were similar to those observed at the Ashland Ridge site for this study period. Sexton Summit had an overall mean of 9.3 mph while the Ashland Ridge site had a mean of 8.7 mph. The sites have similar elevations, exposure and wind characteristics. Table 5.1 shows that for the first seven months of this study period the winds were slightly below normal at Sexton Summit. Overall, the winds were very close to normal (3.5 %). The highest departures and therefore the highest variability appear to happen during the winter months when changes can occur from month to month. Overall it appears that conditions during this observation period at the Ashland Ridge site were below normal except for a a few months (December and probably March).
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Table 5.1: Monthly mean and departures for winds at Sexton Summit. SEXTON SUMMIT NWS Latitude: 42.60N
Elevation: 3832'
Longitude 123.37W Month
Normal (mph)
Mean (mph)
Departure
1982-1997
2005-2006
(%)
Jun
8.7
8.1
-6.9
Jul
9.0
8.4
-6.7
Aug
8.6
8.3
-3.5
Sep
8.6
7.8
-9.3
Oct
9.1
8.2
-9.9
Nov
10.8
9.9
-8.3
Dec
11.6
13.2
13.8
Jan
11.7
13.0
11.1
Feb
10.9
9.3
-14.7
Mar
9.9
9.9
0.0
Apr
8.1
8.2
1.2
May
8.8
7.5
-14.8
ANN
9.7
9.3
-3.5
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6.0 SUMMARY AND DISCUSSION There are a number of factors that might have an influence on the interpretation of the winds observed over this annual study period at the Ashland Ridge site. First, measurements were taken from only one tower and it is possible that other locations in the area might provide better exposure to the prevailing winds. The location of the tower was dictated in part by the constraints of the property boundaries and the terrain. Although care was taken to locate a location with good exposure to all directions, some blocking of the winds from the north is possible. While this is not expected to be a significant factor, the winds do come from this direction in the summer. In any case, the site is ideally situated to capture the flows from the southerly direction. A second factor that is important to consider is that observations were collected at only one height. Flow over hills and ridgelines can be very complex and difficult to estimate. These types of flows are influenced by many factors including the density of the air, the exact shape of the mountain and the upper air wind characteristics. Observations taken at a different height above ground would most likely show some differences that might be important to a determination of economic feasibility. In summary, 1) 2)
3)
No problems were encountered during the annual data collection period. One period of icing was detected in November and removed from the records. The observed annual mean wind speed was 8.7 mph. The Ashland Ridge site showed a distinctive seasonal cycle with stronger winds during the winter months and lighter winds dring summer. During the summer the wind are generally weak and energy producing winds are limited to a few hours during the afternoons when the diurnal cycle is strong. These winds are predominantly from the north. During the winter energy producing winds are produced by storm systems and can vary in frequency from monthto-month. These winds come from the south. A comparison with a nearby site where a longer history of observations are available suggests that this study period (June 2005-May 2006) was very close but slightly below the long-term normal (1982-1997)
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Appendix A: Topographic Map of the Ashland Ridge site.
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Appendix B: Photograph of the Ashland Ridge site tower looking southhwest (a) and to the south (b).
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Appendix C: Site Visit Records and wind gust during period prior to visit. Changes Made Date: 05/24/2005 06/22/2005 07/18/2005 09/14/2005 10/14/2005 11/17/2005 12/05/2005 01/09/2006 02/21/2006 03/16/2006 04/20/2006 05/12/2006 06/19/2006
Plug Y Y Y Y Y Y Y Y Y Y Y Y
Battery
Time
Gust (mph)
Comment Site Installed
43 Plug removed on this data was lost
Y
Y
32 33 49 60 64 49 79 61 36 44
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Appendix D: Miscellaneous analysis Tables.
STATION - Ashland Ridge WIND SPEED FREQUENCY DISTRIBUTION WITH NORMALIZED AVAILABLE ENERGY DATA PERIOD OF RECORD 6/2005 - 5/2006 NORMALIZATION PERIOD - ONE YEAR AVERAGE WIND SPEED FOR PERIOD: 8.8 MPH NORMALIZED AVAILABLE ENERGY: 1178.1 KWH/M**2/YEAR TOTAL HOURS OBSERVED: 8109 NORMALIZED SPD HOURS/ AVAIL. ENERGY MPH PERIOD RELFREQ CUMHRS CUMRELFREQ KWH/M**2/YEAR 0 494 6.09 8109 100.00 0.0 1 599 7.39 7615 93.91 0.0 2 612 7.55 7016 86.52 0.3 3 539 6.65 6404 78.97 0.8 4 489 6.03 5865 72.33 1.7 5 457 5.64 5376 66.30 3.0 6 498 6.14 4919 60.66 5.7 7 470 5.80 4421 54.52 8.6 8 461 5.69 3951 48.72 12.6 9 443 5.46 3490 43.04 17.2 10 421 5.19 3047 37.58 22.5 11 375 4.62 2626 32.38 26.6 12 345 4.25 2251 27.76 31.8 13 295 3.64 1906 23.50 34.6 14 255 3.14 1611 19.87 37.4 15 196 2.42 1356 16.72 35.3 16 164 2.02 1160 14.31 35.9 17 116 1.43 996 12.28 30.4 18 77 0.95 880 10.85 24.0 19 95 1.17 803 9.90 34.8 20 60 0.74 708 8.73 25.6 21 70 0.86 648 7.99 34.6 22 60 0.74 578 7.13 34.1 23 61 0.75 518 6.39 39.6 24 63 0.78 457 5.64 46.5 25 49 0.60 394 4.86 40.9 26 45 0.55 345 4.25 42.2 27 40 0.49 300 3.70 42.0 28 35 0.43 260 3.21 41.0 29 34 0.42 225 2.77 44.3 30 29 0.36 191 2.36 41.8 31 33 0.41 162 2.00 52.5 32 26 0.32 129 1.59 45.5 33 20 0.25 103 1.27 38.4 34 15 0.18 83 1.02 31.5 35 14 0.17 68 0.84 32.0 36 11 0.14 54 0.67 27.4 37 10 0.12 43 0.53 27.0 38 8 0.10 33 0.41 23.4 39 9 0.11 25 0.31 28.5 40 2 0.02 16 0.20 6.8 41 5 0.06 14 0.17 18.4 42 3 0.04 9 0.11 11.9 43 0 0.00 6 0.07 0.0 44 0 0.00 6 0.07 0.0 45 2 0.02 6 0.07 9.7 46 0 0.00 4 0.05 0.0 47 0 0.00 4 0.05 0.0 48 0 0.00 4 0.05 0.0 49 0 0.00 4 0.05 0.0 50 1 0.01 4 0.05 6.7 51 0 0.00 3 0.04 0.0 52 3 0.04 3 0.04 22.5
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STATION – Ashland Ridge MONTHLY WIND SPEEDS (MPH) DATA PERIOD OF RECORD 5/2005 - 6/2006 JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
AVG
2005 0.0 # OBS 0
0.0 0
0.0 0
0.0 0
0.0 0
8.7 514
7.0 329
6.9 744
5.5 720
5.4 744
9.1 690
13.7 744
8.11
2006 10.6 # OBS 744
8.8 672
12.5 744
8.2 720
7.6 744
0.0 0
0.0 0
0.0 0
0.0 0
0.0 0
0.0 0
0.0 0
9.56
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AVG SPD
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
MON
200
300
400
500
600
700
800
6.6
6.5
6.5
6.5
6.5
6.6
6.8
7.4
8.2
9.1
10.8 10.4 13.7 10.6 9.6 12.3 10.2 11.3 8.8 7.2 10.5 14.3
11.7 10.4 13.7 11.7 11.4 12.1 12.4 12.2 10.2 8.7 10.1 13.8
11.7 11.3 13.8 12.7 12.1 12.6 13.1 12.8 11.0 8.5 10.4 13.2
10.5 12.2 15.6 12.3 11.8 12.1 12.8 13.2 10.3 8.2 10.0 12.7
9.9 11.1 15.3 11.4 12.3 11.1 12.6 13.3 9.2 7.1 9.1 12.9
10.4 10.5 15.3 10.4 11.3 12.0 13.1 13.2 9.1 5.6 8.7 12.6
10.6 9.8 15.1 10.9 10.5 11.2 11.3 12.5 8.1 5.5 8.3 13.2
10.9 9.1 14.3 10.1 9.4 10.7 10.3 11.5 8.6 5.7 8.4 13.8
9.8 10.8 11.5 11.9 11.8 11.2 10.9 10.6 10.2
10.5 9.2 12.7 10.0 8.4 11.1 8.4 8.8 6.9 6.4 10.3 14.7 9.7
8.6
7.9
7.5
7.0
11.3 10.8 9.8 9.7 10.4 8.6 9.1 9.3 8.2 6.4 13.4 11.8 11.8 11.4 11.1 9.0 7.3 6.7 6.6 6.4 9.2 7.8 6.4 6.0 5.1 10.2 9.7 8.1 7.4 6.3 10.7 8.2 5.5 4.5 3.4 10.1 7.9 6.4 4.9 3.8 7.2 5.5 4.2 4.1 2.9 5.5 4.2 3.6 3.2 3.1 8.3 8.1 8.0 8.1 8.8 13.4 13.1 13.4 14.7 14.0
900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400
5/2006
11.3 11.3 11.3 11.1 10.7 10.2 10.6 9.6 9.7 10.1 6.2 7.0 7.1 8.0 7.8 8.3 7.7 7.9 8.0 8.2 10.3 10.0 10.6 10.4 10.2 11.0 11.5 11.6 12.0 12.9 5.4 4.8 5.3 5.3 5.5 5.0 5.5 6.2 7.9 9.0 4.3 3.7 3.5 3.8 4.1 4.6 5.7 6.1 7.2 7.9 5.8 6.0 5.6 5.3 4.4 5.2 5.6 7.1 7.8 9.5 2.6 1.9 1.9 1.6 1.7 1.5 2.1 3.1 4.8 6.7 2.7 2.3 1.6 1.3 1.0 1.0 1.7 2.6 4.3 6.4 2.3 2.2 2.1 2.1 1.9 1.8 1.7 2.4 3.8 5.5 3.8 4.0 3.8 4.3 4.9 4.8 4.5 5.1 5.5 5.9 8.2 8.5 8.9 8.8 9.1 8.4 8.7 9.4 10.3 10.4 13.4 14.1 13.5 13.1 13.7 13.4 13.9 14.8 15.5 14.8
100
STATION - Ashland Ridge DIURNAL WIND SPEEDS (MPH) DATA PERIOD OF RECORD 6/2005 -
8.8
10.6 8.8 12.5 8.2 7.6 8.7 7.0 6.9 5.5 5.4 9.1 13.7
AVG SPD
Wind Resource Evaluation: Ashland Ridge
24
NOTE:
N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW CALM TOTAL %
DIR
4.0
0.1 0.0 0.0 0.0 0.0 0.5 2.1 0.2 0.0 0.0 0.0 0.1 0.1 0.7 0.0 0.0
16 TO 19
2.4
0.0 0.0 0.0 0.0 0.0 0.3 1.8 0.1 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0
19 TO 22
2.2
0.0 0.0 0.0 0.0 0.0 0.4 1.7 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0
22 TO 25
1.6
0.0 0.0 0.0 0.0 0.0 0.2 1.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
25 TO 28
1.2
0.0 0.0 0.0 0.0 0.0 0.1 1.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
28 TO 31
0.8
0.0 0.0 0.0 0.0 0.0 0.1 0.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
31 TO 34
0.4
0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
34 TO 37
0.3
0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
37 TO 40
0.1
0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
40 TO 43
0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
43 TO 46
0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
46 TO 49
0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
49 TO 52
0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
52 TO 55
0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
>= 55
100.0
6.4 2.1 0.9 1.1 4.2 10.1 20.5 4.6 2.7 1.4 1.6 3.7 9.3 12.0 7.3 5.9 6.1
TOTAL %
8.8
7.9 6.2 3.9 2.6 2.6 9.1 16.1 7.3 4.7 4.0 4.0 5.6 7.9 10.3 7.5 6.9
MEAN SPEED (MPH)
MEAN SPEED OF THE TOTAL IN A WIND ROSE MAY DIFFER FROM THE SPEED FREQUENCY DISTRIBUTION FOR A GIVEN PERIOD DUE TO DATA SELECTION. SPEED FREQUENCY DISTRIBUTIONS REQUIRE ONLY A WIND SPEED OBSERVATION BE PRESENT. WIND ROSES, ON THE OTHER HAND, REQUIRE BOTH SPEED AND DIRECTION BE PRESENT FOR EACH OBSERVATION.
8.5
65.1 13.1
13 TO 16 0.5 0.1 0.0 0.0 0.0 0.9 2.1 0.3 0.0 0.0 0.0 0.0 1.0 2.7 0.5 0.1
10 TO 13
1.4 0.4 0.0 0.0 0.0 1.1 2.0 0.5 0.1 0.0 0.0 0.3 1.8 3.1 1.6 0.7
4.4 1.6 0.8 1.1 4.1 6.4 6.7 3.5 2.5 1.4 1.6 3.3 6.2 5.1 5.2 5.1
0 TO 10
SPEED CATEGORIES(MPH)
STATION - Ashland Ridge WIND ROSE FOR ALL DATA 8109 OBSERVATIONS DATA PERIOD OF RECORD - 6/2005 - 5/2006
Wind Resource Evaluation: Ashland Ridge
25
6.1
0.2 0.0 0.1 0.2 0.8 1.0 1.3 1.6 0.7 0.2 0.1 0.0
NNE
0.7
0.0 0.1 0.1 0.1 0.1 0.2 0.0 0.0 0.0 0.0 0.0 0.0
NE
0.3
0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0
ENE
1.2
0.0 0.1 0.0 0.1 0.1 0.0 0.1 0.0 0.1 0.1 0.2 0.3
E
122.4
17.8 8.7 27.4 7.0 0.7 0.8 0.4 0.1 0.6 1.3 15.5 42.1
ESE
787.1
119.4 77.5 228.4 40.0 17.9 19.6 4.2 0.2 0.8 12.4 57.1 209.6
SE
25.2
2.3 1.8 7.6 1.7 3.3 3.2 0.1 0.0 0.3 1.7 0.2 3.1
SSE
2.9
0.8 0.1 0.8 0.4 0.1 0.1 0.0 0.0 0.1 0.1 0.1 0.2
S
1.1
0.2 0.0 0.2 0.1 0.0 0.1 0.0 0.0 0.0 0.1 0.2 0.1
SSW
1.5
0.3 0.0 0.3 0.3 0.1 0.0 0.0 0.0 0.0 0.2 0.1 0.1
SW
7.1
0.3 0.4 1.9 1.1 0.4 0.1 0.3 0.2 0.4 0.8 0.5 0.7
WSW
46.4
2.6 3.8 1.6 3.4 5.7 4.5 7.0 7.0 4.9 2.1 1.8 2.0
W
107.6
9.4 5.5 5.2 6.5 7.6 14.1 13.4 17.0 6.2 3.4 11.8 7.3
WNW
28.4
1.7 0.9 1.6 1.5 2.8 4.2 4.2 4.6 3.9 1.4 1.2 0.4
NW
AVAILABLE ENERGY IN AN ENERGY ROSE MAY DIFFER FROM THE SPEED FREQUENCY DISTRIBUTION FOR A GIVEN PERIOD DUE TO DATA SELECTION. SPEED FREQUENCY DISTRIBUTIONS REQUIRE ONLY A WIND SPEED OBSERVATION BE PRESENT. ENERGY ROSES, ON THE OTHER HAND, REQUIRE BOTH SPEED AND DIRECTION BE PRESENT FOR EACH OBSERVATION.
20.3
TOT
NOTE:
0.0 0.5 0.3 2.6 2.0 2.9 3.7 4.8 2.1 1.1 0.3 0.0
N
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
MON NORM.
STATION - Ashland Ridge ENERGY ROSE (TOTALS ARE NORMALIZED AVAILABLE ENERGY (KWH/M**2) DATA PERIOD OF RECORD 6/2005 - 5/2006
16.6
0.3 0.8 0.7 1.3 2.3 2.7 2.1 2.2 1.8 1.0 1.2 0.0
NNW
1175.0
155.3 100.4 276.3 66.3 44.0 53.6 37.0 37.8 22.0 25.8 90.3 266.0
TOTAL
7505
695 652 716 676 711 489 273 630 592 664 666 741
OBS.
8760
744 672 744 720 744 720 744 744 720 744 720 744
Wind Resource Evaluation: Ashland Ridge
26
2.5 3.3 1.3 3.6 7.0 4.3 6.7 4.7 3.6 1.7 0.7 0.3
5.0
5.2 7.0 3.5 10.1 13.6 11.1 13.1 12.6 11.1 8.2 1.6 0.1
11.5
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC TOTAL %
2.7 2.5
7.4 5.2
2005 2006
NNE
N
PERIOD
2.4
1.2 3.3 2.4 2.5 2.7 1.8 1.5 1.3 2.5 1.5 0.3 0.1
1.3 1.2
NE
3.3
1.5 2.5 1.3 3.3 4.3 1.2 2.7 3.0 1.9 3.6 0.7 1.1
2.0 1.5
ENE
10.9
5.2 10.7 6.2 11.9 12.9 3.5 7.6 6.2 8.9 11.3 4.0 1.9
6.3 5.2
E
21.4
10.6 24.7 20.4 17.8 13.7 4.5 6.4 3.0 4.6 8.3 24.1 22.2
11.1 10.6
ESE
41.5
22.4 57.4 68.0 36.7 23.1 10.1 6.4 2.6 3.6 12.0 28.6 45.4
16.7 22.4
SE
9.6
5.2 9.2 14.8 10.0 10.8 5.3 1.2 1.3 2.1 4.6 2.2 7.7
3.7 5.2
SSE
5.8
3.2 5.1 9.4 8.6 4.6 1.4 0.9 1.6 2.2 1.9 2.3 3.6
2.1 3.2
S
DIRECTION CATEGORIES
DISTRIBUTIONS IN PERCENT
STATION - Ashland Ridge WIND DIRECTION FREQUENCY DISTRIBUTION DATA PERIOD OF RECORD 6/2005 - 5/2006
3.0
1.5 3.9 3.0 3.3 3.0 1.2 1.5 1.3 0.6 2.0 2.2 1.2
1.4 1.5
SSW
3.6
1.7 3.0 3.0 4.4 3.2 1.6 2.1 2.0 2.5 2.8 1.2 0.9
1.9 1.7
SW
8.0
3.9 5.1 9.4 9.4 7.5 3.3 3.0 5.5 6.4 5.4 3.6 2.6
4.5 3.9
WSW
19.6
9.5 19.0 11.6 19.7 26.3 9.5 16.1 16.0 14.0 11.8 5.6 4.0
10.8 9.5
W
24.9
12.4 19.9 22.6 28.3 26.3 18.7 12.2 17.7 13.3 7.5 15.2 6.3
12.9 12.4
WNW
15.4
7.5 12.5 12.6 16.5 19.4 11.3 9.1 11.8 12.6 8.7 4.5 2.3
8.4 7.5
NW
13.1
6.5 12.6 10.5 12.8 20.0 11.5 9.4 9.3 10.0 8.6 3.2 0.3
6.9 6.5
NNW
1.0
1.2 0.7 0.0 0.8 1.6 2.3 2.1 2.3 1.0 0.5 0.3 0.0
1.1 0.3
CALM
8111
744 672 744 720 744 514 329 744 720 744 692 744
4487 11735
TOTAL OBS
Wind Resource Evaluation: Ashland Ridge
Prepared By:
Energy Resources Research laboratory Oregon State University
February 1, 2007
NOTICE This publication was prepared as an account of work sponsored by the Energy Trust of Oregon, Inc. Neither the Energy Trust of Oregon, Inc. nor any of their contractors, subcontractors, or their employees make any warranty, express or implied, or assume any legal liability or responsibility for the accuracy, completeness, usefulness, or reliability of the research data, and conclusions reported herein, or of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. For these reasons and for the reason that the views, opinions, and conclusions contained in this material are those of the contractor.
Wind Resource Evaluation: Ashland Ridge
ii
OREGON ANEMOMETER LOAN PROGRAM
Wind Resource Evaluation:
Ashland Ridge
Prepared by: Philip L. Barbour Stel N. Walker, Ph.D. Energy Resources Research Laboratory Department of Mechanical Engineering Oregon State University Corvallis, OR 97331
Sponsor: Energy Trust of Oregon, Inc. 733 SW Oak Street, Suite 200 Portland Oregon,97205
Wind Resource Evaluation: Ashland Ridge
iii
1.0
INTRODUCTION
The Oregon anemometer loan program was established in the fall of 2002 in order to assist landowners in the state evaluate the wind energy potential of their property. The program is funded by a grant from the Energy Trust of Oregon and is administered by the Energy Resources Research Laboratory at Oregon State University. The program involves several steps, beginning with a preliminary evaluation of the site. If estimates of the site show promise then a monitoring system is installed for a fixed duration (typically one year). The site is monitored regularly and the data processed and checked at regular intervals. Upon completion of the first year, the collected wind data is summarized and a report is prepared evaluating the wind data and the wind resource of the location. This report represents the final portion of the project and is designed to give the landowner the information necessary to make an informed choice about the role wind energy might play in their property. The report is separated in to sections with section 2.0 devoted to a description of the site, its location and the type of terrain found there. Section 3.0 includes a summary of the wind data collected during the study period including data quality checks and a characterization of the measured winds. In section 4.0 the wind data is analyzed to determine the amount of power production that might be expected from the site and to examine characteristics that might influence these estimates. This is followed in section 5.0 in which wind data from a nearby site is summarized and used to place the current study period in climatological context. A discussion and summary is then presented in section 6.0
Wind Resource Evaluation: Ashland Ridge
1
2.0
SITE DESCRIPTION Site Name: Latitude: Longitude: Elevation: County: Sensor Height: Types of Sensors: Types of Data: Installation Date: Removal Date:
Ashland Ridge 42-16-49 122-43-20 3440 ft. Jackson 67 ft. NRG Maximum #40 wind speed NRG 200 series2 wind vane 10 min. average wind speed (mph) 10 min. std. dev. wind speed (mph) 10 min. wind direction (16 categories) May 24, 2005 @ PST June 19, 2006 @ PST
Site Location: Ashland is located in southwestern Oregon along the I-5 corridor. The city sites at the base of a broad valley boardered by the foothills of the Cascades on the east and the Siskiyou Mountains to the west. The valley extends from Medford southeastowards Ashland. The Ashland Ridge site is located north of the city along a small ridge that extends out from the eastern side of the valley. Access to the site is found by turning east off of of I-5 on exit 19 and proceeding for several miles to a gated community. The property is located several miles up the hill after passing through the gate. The tower location is marked on the map included in Appendix A. The area consists of slopes with grass lands and groves of old oak trees. Pictures of the site are included in Appendix B. Project Description: The owner of this site is interested in evaluating the site for the installation of a wind turbine to help power an artist studio.
Wind Resource Evaluation: Ashland Ridge
2
3.0
WIND CHARACTERISTICS
In the following sections, several characteristics of the winds at the site at the Ashland Ridge site are examined and discussed. The goals are to evaluate the characteristics that can help explain the physical processes at work at the site and to highlight the properties that are important to assessing the wind energy potential. These evaluations are done using hourly averaged means that have been constructed using the 10 minute means recorded at the site. This is done so that existing analysis programs can be used and is not expected to have any appreciable influence on the interpretation of data. Data Recovery: The amount of data recovered during an observation period is important to characterize and should be examined to determine the confidence of other characteristics. During the initial annual period at this site, there were no problems detected that might influence the collected wind data. A table of site visits and the actions taken has been included in Appendix A. Data were plotted and scanned manually to identify any problems with the site. For the most part, data collection from the site was complete except for one monthly period. The data plug for this period was lost leaving a gap of roughly a month between June 22, 2005 and July 18, 2005. In addition, data for a short period in November were removed from the records because the effects of icing were detected. This was only done for periods with a clear presence of icing and it is possible that other periods with a more limited influence occurred. Icing is identified as prolonged periods with a wind speed of 0.0 mph and a constant direction.
Data Recovery
Recovery Rate (%)
100 80 60 40 20 0 Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Ann.
Figure 3.1: Data recovery by month for the Ashland Ridge site
Wind Resource Evaluation: Ashland Ridge
3
Month
Jun
Jul
Rec. (%)
71.4
44.2
Aug 100
Sep 100
Oct 100
Nov
Dec
95.8
Jan
100
100
Feb 100
Mar 100
Apr 100
May
Ann
100
92.9
Monthly Means: Monthly means are often constructed and used to determine the overall strength of the winds during different periods of the year. Monthly means show that the Ashland Ridge site has a weak but distinctive seasonal pattern with stronger winds possible during winter months. December had the strongest winds with a monthly mean of 13.7 mph followed by March (12.5 mph) and January (10.6 mph). All of the remainder months had monthly mean winds below 10.0 mph with the lowest winds occurring during the late summer or early fall. These summer winds are lower than those observed at another site located at a lower elevation in the area (the North Ashland site). This suggests that the hills to the north of this site may be partially blocking the flow during the summer. Monthly Means 16 14 12
(mph)
10 8 6 4 2 0 Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Ann
Figure 3.2: Monthly Mean Wind Speed Values for the Ashland Ridge site. Month Mean (mph)
Jun 8.7
Jul 7.0
Aug
Sep
6.9
5.5
Oct 5.4
Nov 9.1
Dec 13.7
Jan 10.6
Feb 8.8
Mar
Apr
May
12.5
8.2
7.6
Ann 8.7
Diurnal Means: The diurnal pattern of winds is an important characteristic for many wind sites and helps illuminate the mechanisms responsible for the winds. In general, a diurnal pattern is associated with a site at which strong thermal influences play a role. These are normally accentuated during the summer months when the daily heating cycle is at its greatest. Diurnal variations can also provide an indication of dependable and predictable winds at a site.
Wind Resource Evaluation: Ashland Ridge
4
As is common for most sites in Oregon, the winds at the Ashland Ridge site show a clear diurnal pattern during the summer months and is strong enough to show up in the mean for the annual diurnal average (Fig. 3.3). In general, the diurnal values for summer show that the winds are very light through the night and morning hours and begin to pick up during the late morning. At this site, the winds stay at their peak from around noon until late afternoon before tapering off slowly. On average, the winds during these days are in a usable range for about 25% to 30% of the time. The winds during these periods are predominantly from the north and are a response to large-scale heating patterns. Unfortunately, the winds during these peak periods are not exceptional by wind energy standards and on average remain below 14.0 mph. However, individual days may have higher or lower wind conditions. As expected, during the winter months there is little indication of a diurnal pattern. This is a common pattern and is a consequence of the low winter sun angle and the absence of surface heating.
Diurnal Mean Winds 14 12 10 AVE Jan Jul
8 6 4 2 0 0
300
600
900
1200
1500
1800
2100
Hour of Day
Figure 3.3: Diurnal mean wind speed values for the Ashland Ridge site.
Frequency Distribution: How the wind speed at a site is distributed over various wind speed categories is an important indication of the wind resource potential of a site. An ideal site would have winds that blow at a high rate for long periods. This is not normally the case, however, and wind records from a site show a skewed distribution with a higher frequency of winds at lower speeds. For the Ashland Ridge site (Figure 3.4) we see that the distribution is fairly typical except that it exhibits a fairly high frequency of winds in the lowest wind speed categories (below 3.0 mph). In this case there is a single peak between 3.0 to 4.0 mph and a long gradual decrease out to higher wind categories. This peak would likely be smoother with additional data. The importance of this figure is that it illustrates the amount of time that the winds are within various energy resource ranges. For example, the winds at the Wind Resource Evaluation: Ashland Ridge
5
Ashland Ridge site are below 12.0 mph about 72 % of the time. This suggests that it would be possible to produce appreciable amounts of energy at the site only about 28 % of the time. In addition, the winds are above 20.0 mph only about 8 % of the time (the range at which most wind turbines produce their peak amount of power). This suggests that a typical wind turbine would produce optimal output only about 8.0 % of the time. This is relatively low for a good wind site and suggests that there is a low frequency of winds at the upper end of the range. This is significant because it is at higher wind speeds where most of the potential power is produced.
Relative Frequency 8 7 6 5 4 3 2 1 0 0
5
10
15
20
25
30
35
40
45
Wind Speed Category Figure 3.4: Wind speed frequency distribution for the Ashland Ridge site.
Wind Rose: How the wind varies with direction is also important to understanding the physical processes that contribute to the local winds at a site and eventually in designing a wind facility. A wind rose is often used to display this information and show the frequency with which the wind occurs in different direction categories. A similar plot can be used to show the strength of the wind from each of the direction categories. For this site (Figure 3.5) it is apparent that the winds come from all directions but that a higher frequency comes from two general directions; the Southeast and the Northwest (grouping together categories). Viewing the second figure we see that the mean wind speeds for the southerly directions are much higher than for the northerly directions. This is often the case at sites in the Northwest where southerly winds associated with strong storm systems during the winter months produce much of the observed wind. The higher wind speed averages for the southerly directions suggest that this is the direction from which a majority of the energy producing winds will come from. The mean winds for the Northwesterly categories are generally below 10.0 mph.
Wind Resource Evaluation: Ashland Ridge
6
Annual Directional Speed
Annual Directional Frequency 18
25
16
20
14 12
15
10 8
10
6 4
5
2 0
0 N
NE
E
SE
S
SW
W
NW
CALM
Direction Category
N
NE
E
SE
S
SW
W
NW
Direction Category
Figure 3.5: Frequency (%) and average wind speed (mph) for each of 16 wind direction categories
In order understand better the winds at the site during different times of year; similar plots have been constructed using data from the individual months of January and July. These can be seen in figures 3.6a-d and show the difference between the two periods. For January, the winds most often come from the southerly directions. On average these winds are quite strong, especially the SE quadrant which shows a mean of over 16.0 mph. Winds from other directions during January are much lower In July, the winds most frequently come from the range between North to East. These winds are fairly weak on average (mostly below 10.0 mph). We have already seen that these winds can peak during the day but when averaged over the day as a whole are not particularly significant. Overall these figures suggest that most of the energy producing winds will come from the SE and during the winter.
Wind Resource Evaluation: Ashland Ridge
7
JANUARY
JANUARY 18 16 14 12 10 8 6 4 2 0
40 35 30 25 20 15 10 5 0 N
NE
E
SE
S
SW
W
NW
N
CALM
NE
E
SE
S
SW
W
NW
W
NW
Direction Category
Direction Category
JULY
JULY 14
18 16 14 12 10 8 6 4 2 0
12 10 8 6 4 2 0 N
NE
E
SE
S
SW
W
NW
CALM
Direction Category
N
NE
E
SE
S
SW
Direction Category
Figure 3.6: Frequency (%) and average wind speed (mph) for each of 16 wind direction categories for the months of January and July for the Ashland Ridge site.
Wind Resource Evaluation: Ashland Ridge
8
4.0
SITE POWER CHARACTERISTICS
In order to evaluate the wind power potential at this site a number of quantities were computed using the collected wind data. As with the wind characteristics, hourly wind data was used to complete this work. The power density calculation requires air density. This is estimated assuming a standard atmosphere and the site elevation. The computed quantities include the mean and standard deviation of the hourly values, the recovery rate, the maximum one hour average, the wind power density and the frequency that the wind was observed within a wind speed range (12 mph to 60 mph). These quantities are shown in Table 4.1 and reveal a number of things about the potential for generating energy the site. First, the quantities in Table 4.1 show a tendency for an increase in the winds during the winter months. They also indicate that this may not always be the case. The low winds during February illustrate the variable nature of the winds at this site and highlight the likelihood that strong winds are not garunteed, even duing winter months. To examine the overall amount of energy contained in the wind, the power density is very useful. It represents the amount of energy that would be available to a unit area each hour. The monthly mean values are shown in figure 4.1 and highlight the consistent, low power resource at the site for most of the year and the few periods of increase. The monthly power density for March was 754 W/M**2 and for December was 619 W/M**2. However, half of the months had values below 200 W/M**2.
Wind Resource Evaluation: Ashland Ridge
9
Month Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May ANN
Mean (mph) 8.7 7.0 6.9 5.5 5.4 9.1 13.7 10.6 8.8 12.5 8.2 7.6 8.7
Std. (mph) 5.38 5.02 5.18 4.37 4.58 6.85 9.80 8.45 7.66 10.36 6.30 5.15 7.45
Recovery Max 1-Hr Rate (%) (mph) 71.4 25.5 44.2 17.2 100.0 18.3 100.0 18.8 100.0 24.4 95.8 37.0 95.8 41.8 100.0 38.0 100.0 38.6 100.0 51.7 100.0 31.9 100.0 28.4 99.7 51.7
Time in Range (12-60) Power Den. mph (%) W/m^2 25.9 73 19.1 43 23.5 45 9.0 25 7.9 31 27.7 121 47.8 356 36.8 196 23.2 145 40.5 356 23.5 88 17.9 57 25.5 134
Shape Factor 1.68 1.43 1.38 1.28 1.19 1.36 1.44 1.28 1.17 1.22 1.33 1.52 1.19
Scale Factor 9.7 7.7 7.6 5.9 5.7 9.9 15.1 11.5 9.3 13.3 8.9 8.4 9.3
Table 4.1: Observed and computed power quantities for the wind site at the Ashland Ridge site.
Wind Resource Evaluation: Ashland Ridge
10
Power Density (W/m**2)
Power Density 800 700 600 500 400 300 200 100 0 JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
Ann
Figure 4.1: Monthly power density for the Ashland Ridge site.
In addition to evaluating these basic power characteristics it is possible to estimate how specific wind turbines might interact with the winds at a particular site. Using the collected wind data and the characteristics of a particular wind turbine it is possible to estimate the amount of power it could produce. This is done by comparing the wind data with a power curve for a specific wind turbine. A power curve is simply the curve that shows the relationship between the wind speed and the amount of power a turbine can produce. An example is provided in Figure 4.2. There are several portions of the curve that are important. At low wind speeds, below the cut-in speed, no energy is produced. Any turbine has a lower threshold below which it won’t operate. This is in part because there is little energy available at these levels. In the middle is a ramp up zone where even a small increase in wind speed results in a larger increase in power. At some point, depending on the type of turbine, the amount of power hits its rated capacity as the blades are pitched to spill energy and protect the turbine. At the upper end, energy production will stop if the winds reach a cut-out speed. This is the speed at which a turbine is shut down. In Table 4.2, energy capacity factors are shown for eight different types of turbines. The capacity factor is the ratio of the amount of energy produce to the amount of energy that could be produced if a turbine ran at its rated capacity all the time. The rated capacity is effectively a theoretical maximum and capacity factors generally range from 0.0 to 0.40. It’s difficult to compare these because of the different turbine characteristics but they are given to provide a range of values that might be expected from this site. In computing these values, it is necessary to adjust the observed data which is measured at 67 feet to the hub height of the particular turbine. In this case this is done using a standard assumption that the wind follows a typical power law profile with a coefficient of 0.143.
Wind Resource Evaluation: Ashland Ridge
11
120
Power Output (% of Rated)
100
80
60
40
20
0 0
10
20
30
40
50
Wind Speed (mph)
Figure 4.2: Sample power curve for a theoretical turbine
The capacity factors in Table 4.2 support the conclusions of the previous sections and indicate that there appears to be only isolated periods during which any wind resource might be available at this site. During the highest wind months (December 2005 and March 2006) capacity factors for the most efficient wind turbines were on the order of 0.300. This would indicate a good resource if the conditions persisted longer. However, capacity factors for the summer months are much lower and rarely exceed 0.100. This means a turbine at this particular site could capture less than 10% of what it might under perfect ideal conditions. For some turbines the values are as low as 1.3 % (Sep. with BWC EXCEL).
Wind Resource Evaluation: Ashland Ridge
12
Table 4.2: Capacity factors computed for the Ashland Ridge site using observed wind data and characteristics of eight different wind turbines. Turbine
Vestas
Vestas
Vestas
Vestas
BWC
GE Wind
Vestas
47
80
66
7.5
EXCEL-S
70.5
29
Mitsubishi
Size (kW)
660
2000
1650
55
10
1500
225
250
Hub Ht. (ft.)
131
262
197
59
79
210
103
100
Jun
0.093
0.119
0.083
0.076
0.055
0.112
0.100
0.069
Jul
0.057
0.073
0.048
0.043
0.031
0.066
0.061
0.040
Aug
0.061
0.077
0.052
0.046
0.033
0.069
0.064
0.043
Sep
0.028
0.039
0.024
0.021
0.016
0.034
0.032
0.020
Oct
0.036
0.045
0.031
0.029
0.021
0.043
0.038
0.026
Nov
0.118
0.140
0.106
0.102
0.081
0.134
0.124
0.095
Dec
0.289
0.323
0.271
0.268
0.225
0.324
0.301
0.256
Jan
0.202
0.230
0.183
0.178
0.138
0.228
0.207
0.162
Feb
0.126
0.146
0.116
0.113
0.093
0.143
0.133
0.107
Mar
0.247
0.272
0.226
0.229
0.192
0.272
0.256
0.214
Apr
0.104
0.124
0.091
0.086
0.064
0.119
0.108
0.078
May
0.069
0.086
0.060
0.055
0.041
0.080
0.073
0.050
ANN
0.124
0.144
0.112
0.108
0.086
0.140
0.129
0.100
Wind Resource Evaluation: Ashland Ridge
13
5.0 CLIMATOLOGICAL ANALYSIS Measurements taken over a single one-year period can provide a good estimation of the winds and wind energy potential of a site. However, this is a fairly limited period and is only meaningful if we can place the period into a larger climatological context. For the Ashland Ridge site monthly mean wind speed values from the Sexton Summit site used for this purpose. While not ideal, wind records from Sexton Summit should show the general climatological significance of this particular observation period. To accomplish this, monthly mean wind speed values and climate normals were obtained from the National Climate Data Center (NCDC). Information about the site and the monthly means and departures for this annual study period can be found in Table 5.1. First, the winds overall were similar to those observed at the Ashland Ridge site for this study period. Sexton Summit had an overall mean of 9.3 mph while the Ashland Ridge site had a mean of 8.7 mph. The sites have similar elevations, exposure and wind characteristics. Table 5.1 shows that for the first seven months of this study period the winds were slightly below normal at Sexton Summit. Overall, the winds were very close to normal (3.5 %). The highest departures and therefore the highest variability appear to happen during the winter months when changes can occur from month to month. Overall it appears that conditions during this observation period at the Ashland Ridge site were below normal except for a a few months (December and probably March).
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14
Table 5.1: Monthly mean and departures for winds at Sexton Summit. SEXTON SUMMIT NWS Latitude: 42.60N
Elevation: 3832'
Longitude 123.37W Month
Normal (mph)
Mean (mph)
Departure
1982-1997
2005-2006
(%)
Jun
8.7
8.1
-6.9
Jul
9.0
8.4
-6.7
Aug
8.6
8.3
-3.5
Sep
8.6
7.8
-9.3
Oct
9.1
8.2
-9.9
Nov
10.8
9.9
-8.3
Dec
11.6
13.2
13.8
Jan
11.7
13.0
11.1
Feb
10.9
9.3
-14.7
Mar
9.9
9.9
0.0
Apr
8.1
8.2
1.2
May
8.8
7.5
-14.8
ANN
9.7
9.3
-3.5
Wind Resource Evaluation: Ashland Ridge
15
6.0 SUMMARY AND DISCUSSION There are a number of factors that might have an influence on the interpretation of the winds observed over this annual study period at the Ashland Ridge site. First, measurements were taken from only one tower and it is possible that other locations in the area might provide better exposure to the prevailing winds. The location of the tower was dictated in part by the constraints of the property boundaries and the terrain. Although care was taken to locate a location with good exposure to all directions, some blocking of the winds from the north is possible. While this is not expected to be a significant factor, the winds do come from this direction in the summer. In any case, the site is ideally situated to capture the flows from the southerly direction. A second factor that is important to consider is that observations were collected at only one height. Flow over hills and ridgelines can be very complex and difficult to estimate. These types of flows are influenced by many factors including the density of the air, the exact shape of the mountain and the upper air wind characteristics. Observations taken at a different height above ground would most likely show some differences that might be important to a determination of economic feasibility. In summary, 1) 2)
3)
No problems were encountered during the annual data collection period. One period of icing was detected in November and removed from the records. The observed annual mean wind speed was 8.7 mph. The Ashland Ridge site showed a distinctive seasonal cycle with stronger winds during the winter months and lighter winds dring summer. During the summer the wind are generally weak and energy producing winds are limited to a few hours during the afternoons when the diurnal cycle is strong. These winds are predominantly from the north. During the winter energy producing winds are produced by storm systems and can vary in frequency from monthto-month. These winds come from the south. A comparison with a nearby site where a longer history of observations are available suggests that this study period (June 2005-May 2006) was very close but slightly below the long-term normal (1982-1997)
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Appendix A: Topographic Map of the Ashland Ridge site.
Wind Resource Evaluation: Ashland Ridge
17
Appendix B: Photograph of the Ashland Ridge site tower looking southhwest (a) and to the south (b).
Wind Resource Evaluation: Ashland Ridge
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Wind Resource Evaluation: Ashland Ridge
19
Appendix C: Site Visit Records and wind gust during period prior to visit. Changes Made Date: 05/24/2005 06/22/2005 07/18/2005 09/14/2005 10/14/2005 11/17/2005 12/05/2005 01/09/2006 02/21/2006 03/16/2006 04/20/2006 05/12/2006 06/19/2006
Plug Y Y Y Y Y Y Y Y Y Y Y Y
Battery
Time
Gust (mph)
Comment Site Installed
43 Plug removed on this data was lost
Y
Y
32 33 49 60 64 49 79 61 36 44
Wind Resource Evaluation: Ashland Ridge
Site Removed
20
Appendix D: Miscellaneous analysis Tables.
STATION - Ashland Ridge WIND SPEED FREQUENCY DISTRIBUTION WITH NORMALIZED AVAILABLE ENERGY DATA PERIOD OF RECORD 6/2005 - 5/2006 NORMALIZATION PERIOD - ONE YEAR AVERAGE WIND SPEED FOR PERIOD: 8.8 MPH NORMALIZED AVAILABLE ENERGY: 1178.1 KWH/M**2/YEAR TOTAL HOURS OBSERVED: 8109 NORMALIZED SPD HOURS/ AVAIL. ENERGY MPH PERIOD RELFREQ CUMHRS CUMRELFREQ KWH/M**2/YEAR 0 494 6.09 8109 100.00 0.0 1 599 7.39 7615 93.91 0.0 2 612 7.55 7016 86.52 0.3 3 539 6.65 6404 78.97 0.8 4 489 6.03 5865 72.33 1.7 5 457 5.64 5376 66.30 3.0 6 498 6.14 4919 60.66 5.7 7 470 5.80 4421 54.52 8.6 8 461 5.69 3951 48.72 12.6 9 443 5.46 3490 43.04 17.2 10 421 5.19 3047 37.58 22.5 11 375 4.62 2626 32.38 26.6 12 345 4.25 2251 27.76 31.8 13 295 3.64 1906 23.50 34.6 14 255 3.14 1611 19.87 37.4 15 196 2.42 1356 16.72 35.3 16 164 2.02 1160 14.31 35.9 17 116 1.43 996 12.28 30.4 18 77 0.95 880 10.85 24.0 19 95 1.17 803 9.90 34.8 20 60 0.74 708 8.73 25.6 21 70 0.86 648 7.99 34.6 22 60 0.74 578 7.13 34.1 23 61 0.75 518 6.39 39.6 24 63 0.78 457 5.64 46.5 25 49 0.60 394 4.86 40.9 26 45 0.55 345 4.25 42.2 27 40 0.49 300 3.70 42.0 28 35 0.43 260 3.21 41.0 29 34 0.42 225 2.77 44.3 30 29 0.36 191 2.36 41.8 31 33 0.41 162 2.00 52.5 32 26 0.32 129 1.59 45.5 33 20 0.25 103 1.27 38.4 34 15 0.18 83 1.02 31.5 35 14 0.17 68 0.84 32.0 36 11 0.14 54 0.67 27.4 37 10 0.12 43 0.53 27.0 38 8 0.10 33 0.41 23.4 39 9 0.11 25 0.31 28.5 40 2 0.02 16 0.20 6.8 41 5 0.06 14 0.17 18.4 42 3 0.04 9 0.11 11.9 43 0 0.00 6 0.07 0.0 44 0 0.00 6 0.07 0.0 45 2 0.02 6 0.07 9.7 46 0 0.00 4 0.05 0.0 47 0 0.00 4 0.05 0.0 48 0 0.00 4 0.05 0.0 49 0 0.00 4 0.05 0.0 50 1 0.01 4 0.05 6.7 51 0 0.00 3 0.04 0.0 52 3 0.04 3 0.04 22.5
Wind Resource Evaluation: Ashland Ridge
21
STATION – Ashland Ridge MONTHLY WIND SPEEDS (MPH) DATA PERIOD OF RECORD 5/2005 - 6/2006 JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
DEC
AVG
2005 0.0 # OBS 0
0.0 0
0.0 0
0.0 0
0.0 0
8.7 514
7.0 329
6.9 744
5.5 720
5.4 744
9.1 690
13.7 744
8.11
2006 10.6 # OBS 744
8.8 672
12.5 744
8.2 720
7.6 744
0.0 0
0.0 0
0.0 0
0.0 0
0.0 0
0.0 0
0.0 0
9.56
Wind Resource Evaluation: Ashland Ridge
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Wind Resource Evaluation: Ashland Ridge
23
AVG SPD
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
MON
200
300
400
500
600
700
800
6.6
6.5
6.5
6.5
6.5
6.6
6.8
7.4
8.2
9.1
10.8 10.4 13.7 10.6 9.6 12.3 10.2 11.3 8.8 7.2 10.5 14.3
11.7 10.4 13.7 11.7 11.4 12.1 12.4 12.2 10.2 8.7 10.1 13.8
11.7 11.3 13.8 12.7 12.1 12.6 13.1 12.8 11.0 8.5 10.4 13.2
10.5 12.2 15.6 12.3 11.8 12.1 12.8 13.2 10.3 8.2 10.0 12.7
9.9 11.1 15.3 11.4 12.3 11.1 12.6 13.3 9.2 7.1 9.1 12.9
10.4 10.5 15.3 10.4 11.3 12.0 13.1 13.2 9.1 5.6 8.7 12.6
10.6 9.8 15.1 10.9 10.5 11.2 11.3 12.5 8.1 5.5 8.3 13.2
10.9 9.1 14.3 10.1 9.4 10.7 10.3 11.5 8.6 5.7 8.4 13.8
9.8 10.8 11.5 11.9 11.8 11.2 10.9 10.6 10.2
10.5 9.2 12.7 10.0 8.4 11.1 8.4 8.8 6.9 6.4 10.3 14.7 9.7
8.6
7.9
7.5
7.0
11.3 10.8 9.8 9.7 10.4 8.6 9.1 9.3 8.2 6.4 13.4 11.8 11.8 11.4 11.1 9.0 7.3 6.7 6.6 6.4 9.2 7.8 6.4 6.0 5.1 10.2 9.7 8.1 7.4 6.3 10.7 8.2 5.5 4.5 3.4 10.1 7.9 6.4 4.9 3.8 7.2 5.5 4.2 4.1 2.9 5.5 4.2 3.6 3.2 3.1 8.3 8.1 8.0 8.1 8.8 13.4 13.1 13.4 14.7 14.0
900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400
5/2006
11.3 11.3 11.3 11.1 10.7 10.2 10.6 9.6 9.7 10.1 6.2 7.0 7.1 8.0 7.8 8.3 7.7 7.9 8.0 8.2 10.3 10.0 10.6 10.4 10.2 11.0 11.5 11.6 12.0 12.9 5.4 4.8 5.3 5.3 5.5 5.0 5.5 6.2 7.9 9.0 4.3 3.7 3.5 3.8 4.1 4.6 5.7 6.1 7.2 7.9 5.8 6.0 5.6 5.3 4.4 5.2 5.6 7.1 7.8 9.5 2.6 1.9 1.9 1.6 1.7 1.5 2.1 3.1 4.8 6.7 2.7 2.3 1.6 1.3 1.0 1.0 1.7 2.6 4.3 6.4 2.3 2.2 2.1 2.1 1.9 1.8 1.7 2.4 3.8 5.5 3.8 4.0 3.8 4.3 4.9 4.8 4.5 5.1 5.5 5.9 8.2 8.5 8.9 8.8 9.1 8.4 8.7 9.4 10.3 10.4 13.4 14.1 13.5 13.1 13.7 13.4 13.9 14.8 15.5 14.8
100
STATION - Ashland Ridge DIURNAL WIND SPEEDS (MPH) DATA PERIOD OF RECORD 6/2005 -
8.8
10.6 8.8 12.5 8.2 7.6 8.7 7.0 6.9 5.5 5.4 9.1 13.7
AVG SPD
Wind Resource Evaluation: Ashland Ridge
24
NOTE:
N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW CALM TOTAL %
DIR
4.0
0.1 0.0 0.0 0.0 0.0 0.5 2.1 0.2 0.0 0.0 0.0 0.1 0.1 0.7 0.0 0.0
16 TO 19
2.4
0.0 0.0 0.0 0.0 0.0 0.3 1.8 0.1 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0
19 TO 22
2.2
0.0 0.0 0.0 0.0 0.0 0.4 1.7 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0
22 TO 25
1.6
0.0 0.0 0.0 0.0 0.0 0.2 1.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
25 TO 28
1.2
0.0 0.0 0.0 0.0 0.0 0.1 1.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
28 TO 31
0.8
0.0 0.0 0.0 0.0 0.0 0.1 0.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
31 TO 34
0.4
0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
34 TO 37
0.3
0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
37 TO 40
0.1
0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
40 TO 43
0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
43 TO 46
0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
46 TO 49
0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
49 TO 52
0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
52 TO 55
0.0
0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
>= 55
100.0
6.4 2.1 0.9 1.1 4.2 10.1 20.5 4.6 2.7 1.4 1.6 3.7 9.3 12.0 7.3 5.9 6.1
TOTAL %
8.8
7.9 6.2 3.9 2.6 2.6 9.1 16.1 7.3 4.7 4.0 4.0 5.6 7.9 10.3 7.5 6.9
MEAN SPEED (MPH)
MEAN SPEED OF THE TOTAL IN A WIND ROSE MAY DIFFER FROM THE SPEED FREQUENCY DISTRIBUTION FOR A GIVEN PERIOD DUE TO DATA SELECTION. SPEED FREQUENCY DISTRIBUTIONS REQUIRE ONLY A WIND SPEED OBSERVATION BE PRESENT. WIND ROSES, ON THE OTHER HAND, REQUIRE BOTH SPEED AND DIRECTION BE PRESENT FOR EACH OBSERVATION.
8.5
65.1 13.1
13 TO 16 0.5 0.1 0.0 0.0 0.0 0.9 2.1 0.3 0.0 0.0 0.0 0.0 1.0 2.7 0.5 0.1
10 TO 13
1.4 0.4 0.0 0.0 0.0 1.1 2.0 0.5 0.1 0.0 0.0 0.3 1.8 3.1 1.6 0.7
4.4 1.6 0.8 1.1 4.1 6.4 6.7 3.5 2.5 1.4 1.6 3.3 6.2 5.1 5.2 5.1
0 TO 10
SPEED CATEGORIES(MPH)
STATION - Ashland Ridge WIND ROSE FOR ALL DATA 8109 OBSERVATIONS DATA PERIOD OF RECORD - 6/2005 - 5/2006
Wind Resource Evaluation: Ashland Ridge
25
6.1
0.2 0.0 0.1 0.2 0.8 1.0 1.3 1.6 0.7 0.2 0.1 0.0
NNE
0.7
0.0 0.1 0.1 0.1 0.1 0.2 0.0 0.0 0.0 0.0 0.0 0.0
NE
0.3
0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0
ENE
1.2
0.0 0.1 0.0 0.1 0.1 0.0 0.1 0.0 0.1 0.1 0.2 0.3
E
122.4
17.8 8.7 27.4 7.0 0.7 0.8 0.4 0.1 0.6 1.3 15.5 42.1
ESE
787.1
119.4 77.5 228.4 40.0 17.9 19.6 4.2 0.2 0.8 12.4 57.1 209.6
SE
25.2
2.3 1.8 7.6 1.7 3.3 3.2 0.1 0.0 0.3 1.7 0.2 3.1
SSE
2.9
0.8 0.1 0.8 0.4 0.1 0.1 0.0 0.0 0.1 0.1 0.1 0.2
S
1.1
0.2 0.0 0.2 0.1 0.0 0.1 0.0 0.0 0.0 0.1 0.2 0.1
SSW
1.5
0.3 0.0 0.3 0.3 0.1 0.0 0.0 0.0 0.0 0.2 0.1 0.1
SW
7.1
0.3 0.4 1.9 1.1 0.4 0.1 0.3 0.2 0.4 0.8 0.5 0.7
WSW
46.4
2.6 3.8 1.6 3.4 5.7 4.5 7.0 7.0 4.9 2.1 1.8 2.0
W
107.6
9.4 5.5 5.2 6.5 7.6 14.1 13.4 17.0 6.2 3.4 11.8 7.3
WNW
28.4
1.7 0.9 1.6 1.5 2.8 4.2 4.2 4.6 3.9 1.4 1.2 0.4
NW
AVAILABLE ENERGY IN AN ENERGY ROSE MAY DIFFER FROM THE SPEED FREQUENCY DISTRIBUTION FOR A GIVEN PERIOD DUE TO DATA SELECTION. SPEED FREQUENCY DISTRIBUTIONS REQUIRE ONLY A WIND SPEED OBSERVATION BE PRESENT. ENERGY ROSES, ON THE OTHER HAND, REQUIRE BOTH SPEED AND DIRECTION BE PRESENT FOR EACH OBSERVATION.
20.3
TOT
NOTE:
0.0 0.5 0.3 2.6 2.0 2.9 3.7 4.8 2.1 1.1 0.3 0.0
N
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
MON NORM.
STATION - Ashland Ridge ENERGY ROSE (TOTALS ARE NORMALIZED AVAILABLE ENERGY (KWH/M**2) DATA PERIOD OF RECORD 6/2005 - 5/2006
16.6
0.3 0.8 0.7 1.3 2.3 2.7 2.1 2.2 1.8 1.0 1.2 0.0
NNW
1175.0
155.3 100.4 276.3 66.3 44.0 53.6 37.0 37.8 22.0 25.8 90.3 266.0
TOTAL
7505
695 652 716 676 711 489 273 630 592 664 666 741
OBS.
8760
744 672 744 720 744 720 744 744 720 744 720 744
Wind Resource Evaluation: Ashland Ridge
26
2.5 3.3 1.3 3.6 7.0 4.3 6.7 4.7 3.6 1.7 0.7 0.3
5.0
5.2 7.0 3.5 10.1 13.6 11.1 13.1 12.6 11.1 8.2 1.6 0.1
11.5
JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC TOTAL %
2.7 2.5
7.4 5.2
2005 2006
NNE
N
PERIOD
2.4
1.2 3.3 2.4 2.5 2.7 1.8 1.5 1.3 2.5 1.5 0.3 0.1
1.3 1.2
NE
3.3
1.5 2.5 1.3 3.3 4.3 1.2 2.7 3.0 1.9 3.6 0.7 1.1
2.0 1.5
ENE
10.9
5.2 10.7 6.2 11.9 12.9 3.5 7.6 6.2 8.9 11.3 4.0 1.9
6.3 5.2
E
21.4
10.6 24.7 20.4 17.8 13.7 4.5 6.4 3.0 4.6 8.3 24.1 22.2
11.1 10.6
ESE
41.5
22.4 57.4 68.0 36.7 23.1 10.1 6.4 2.6 3.6 12.0 28.6 45.4
16.7 22.4
SE
9.6
5.2 9.2 14.8 10.0 10.8 5.3 1.2 1.3 2.1 4.6 2.2 7.7
3.7 5.2
SSE
5.8
3.2 5.1 9.4 8.6 4.6 1.4 0.9 1.6 2.2 1.9 2.3 3.6
2.1 3.2
S
DIRECTION CATEGORIES
DISTRIBUTIONS IN PERCENT
STATION - Ashland Ridge WIND DIRECTION FREQUENCY DISTRIBUTION DATA PERIOD OF RECORD 6/2005 - 5/2006
3.0
1.5 3.9 3.0 3.3 3.0 1.2 1.5 1.3 0.6 2.0 2.2 1.2
1.4 1.5
SSW
3.6
1.7 3.0 3.0 4.4 3.2 1.6 2.1 2.0 2.5 2.8 1.2 0.9
1.9 1.7
SW
8.0
3.9 5.1 9.4 9.4 7.5 3.3 3.0 5.5 6.4 5.4 3.6 2.6
4.5 3.9
WSW
19.6
9.5 19.0 11.6 19.7 26.3 9.5 16.1 16.0 14.0 11.8 5.6 4.0
10.8 9.5
W
24.9
12.4 19.9 22.6 28.3 26.3 18.7 12.2 17.7 13.3 7.5 15.2 6.3
12.9 12.4
WNW
15.4
7.5 12.5 12.6 16.5 19.4 11.3 9.1 11.8 12.6 8.7 4.5 2.3
8.4 7.5
NW
13.1
6.5 12.6 10.5 12.8 20.0 11.5 9.4 9.3 10.0 8.6 3.2 0.3
6.9 6.5
NNW
1.0
1.2 0.7 0.0 0.8 1.6 2.3 2.1 2.3 1.0 0.5 0.3 0.0
1.1 0.3
CALM
8111
744 672 744 720 744 514 329 744 720 744 692 744
4487 11735
TOTAL OBS
