Potato Hill Annual Wind Data Analysis Summary Report Prepared for: State Energy Office NC Department of Administration 1340 Mail Service Center Raleigh, NC 27699-1340 Contract # 04-SPP-BL3 Prepared by: NC Solar Center North Carolina State University Campus Box 7401 Raleigh, NC 27695 August 31, 2005
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Tater Hill Final Wind Data Reportwind.appstate.edu/sites/default/files/Final_report... · WindPRO Analysis Appendix 1 contains the WindPRO analysis of the collected data from the
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Potato Hill Annual Wind Data Analysis
Summary Report
Prepared for: State Energy Office
NC Department of Administration 1340 Mail Service Center Raleigh, NC 27699-1340
Contract # 04-SPP-BL3
Prepared by: NC Solar Center
North Carolina State University Campus Box 7401 Raleigh, NC 27695
August 31, 2005
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Potato Hill Annual Wind Data Summary Report Wind Data Collection Wind speed and direction were monitored at Potato Hill (Tater Hill) near Boone, NC for just over one year from June 4, 2004 to June 21, 2005. A ridge line formed by Tater Hill and Rich Mountain runs NNE for about 2 miles across publicly and privately held land which is mostly undeveloped. This ridge line is appropriate for 20 to 25 megawatts of large scale wind development. The winds were monitored on top of Tater Hill by instrumenting a 55 meter (180 feet) tall University of North Carolina Television tower. The tower is located on a large 195 acre parcel of land privately owned by Curtis Alan Replogle. The tower was instrumented with four anemometers, two wind vanes, a temperature sensor and a data logging computer. The data logging computer measured each of the sensors every two seconds and averaged these measurements every ten minutes, storing the average value on a data card. The data logging computer is shown attached to the right side of the tower in Figure 2. The most desirable data was collected at the 50 m height. Two anemometers and two vanes were installed at 50 m. One of the vanes and one of the anemometers at 50 m was heated to ensure data would be collected even when the tower iced over in the winter as is pictured in Figure 1. The remainder of the wind sensors were unheated and were installed at the 40 m and 30 m levels. The four wind sensor mounting booms can be seen on the left side of the tower in Figure 1. The heated wind vane and anemometer mounted at the 50 m level required electrical power for heating. The tower site had 120/240 VAC utility power available. A meter and voltage transformer, shown on the left side of the tower in Figure 2, were mounted on the tower to supply electricity to the heated sensors. The sensors are heated all year long but draw the most power during the winter. The energy used during the year by the two heated sensors was measured to be 675 kWh. Only one failure occurred with the data collection during the year. The anemometer at the 40 m level was destroyed during the tenth month due to falling ice.
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Figure 1: UNC Television Tower with Wind Sensors Installed
Figure 2: Data Collection Equipment Mounted at Base of UNC Television Tower
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Measured Versus Predicted Data The collected wind data was analyzed with WindPRO wind planning and projecting software. The measured annual average wind parameters correspond well with those estimated by the May 2004 North Carolina Wind Resource Map produced by AWS Truewind for the NC State Energy Office. The AWS Truewind wind speed map of Potato Hill can be seen in Figure 3. The annual average wind speed at 50 m was measured to be 9.1 m/s. The annual average wind speed for this location predicted by the AWS Truewind map is 9.59 m/s. The wind frequency distribution Weibull parameters for the year of measured data are A = 10.1 m/s and k = 1.84. The AWS wind map parameters for this location are A = 10.9 m/s and k = 2.14. The wind rose for the year of collected data shows that the wind blew out of the WNW sector more frequently (20% of the time) than from any other of the sixteen direction sectors. The AWS Truewind map wind rose chart shown in figure 4 also predicts winds blowing from the WNW most frequently, showing winds blowing from the WNW sector 29% of the time. The measured annual average wind speed and frequency distribution corresponds to a U.S. DOE NREL wind power class of 7, the highest wind class, with wind power density of over 800 watts/m2 and an average annual wind speed greater than 8.8 m/s. According to NREL’s classification system, this site has a Superb wind resource. The maximum wind gust measured during the year was 47.6 m/s (106.4 mph). This wind occurred on December 1, 2004 at 7:20 am. The maximum sustained 10 minute average wind speed was 34.1 m/s (76.3 mph), also measured at 7:20 am on December 1, 2004. WindPRO Analysis Appendix 1 contains the WindPRO analysis of the collected data from the one year period from June 4, 2004 to June 21, 2005. The table on page 1 of the WindPRO analysis shows the statistics for data recovery for the 50 m heated sensors. The 50 m sensors did not freeze over during the winter. They were used for the data analysis because their readings are correct for the entire year. Other sensors froze during the winter and give false readings for much of the winter. The table shows that 100% of the data from the monitoring period was collected with no data loss. The seven tables and charts on page 2 show wind speed and direction data for the year. The radial chart shows the wind speed versus direction for all 55,008 ten minute intervals during the year. The table shows the mean wind speed by month and the annual mean of 9.1 m/s. An hourly chart shows the diurnal nature of the wind. This diurnal chart shows that on average, the winds are greatest during non daylight hours. A monthly chart shows that the average wind speed is highest in winter and lowest in the summer. The remaining three charts show the wind speed, wind direction and turbulence intensity for each ten minute interval during the year. Pages 3, 4 and 5 are more detailed views of the charts and tables from page 2. Page 6 of the WindPRO report shows the frequency and turbulence tables by wind speed bin and direction. The values in the frequency table are number of ten minute intervals for each wind speed and direction bin. Notice the sum of the occurrences is 55,008, the number of ten minute intervals in the year. Also notice the direction with the highest
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number of occurrences is WNW. The values of the turbulence table are calculated turbulence intensity. The charts on page 7 are graphical representations of the tabulated data from page 6. The charts on pages 8-10 are frequency distribution charts for each of the 16 directions in the frequency table of page 6. The charts of pages 8 – 10 also show the Weibull curve fit and characteristics for each of the 16 directions. Page 11 is a summary of the Weibull data for the year.
Figure 3: Potato Hill 50 m Wind Speed Map
Tater Hill
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Figure 4: AWS Truewind Wind Rose Chart for Potato Hill
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Appendix 1: WindPRO Data Analysis Report
WindPRO version 2.4.0.62 Apr 2004
WindPRO is developed by EMD International A/S, Niels Jernesvej 10, DK-9220 Aalborg Ø, Tlf. +45 96 35 44 44, Fax +45 96 35 44 46, e-mail: [email protected]
Project:
Tater HillDescription:
Data from file(s)C:\NomadDesktop\Export June 4, 2004-June 21,2005.csv
Printed/Page
08/31/2005 11:37 AM / 1Licensed user:
NC State University, c/o NC Solar CenterCampus Box 7401, US-RALEIGH, NC 27695-7204+1 919 515 3480
Calculated:
08/31/2005 11:37 AM/
Meteo data report, height: 50.0 mName of meteo object: Instrumented UNC TV tower
Data from: 06/04/2004 12:10 PM Data to: 06/21/2005 12:00 PM Observations: 55008 Observations per day: 144 Recovery rate: 100%
Total A: 10.1 m/s k: 1.84 Vm: 9.0 m/s N A: 4.9 m/s k: 1.09 Vm: 4.7 m/s NNE A: 6.7 m/s k: 1.44 Vm: 6.1 m/s NE A: 5.6 m/s k: 1.38 Vm: 5.1 m/sENE A: 6.1 m/s k: 1.90 Vm: 5.4 m/s E A: 10.3 m/s k: 2.31 Vm: 9.1 m/s ESE A: 9.2 m/s k: 1.87 Vm: 8.2 m/s SE A: 8.5 m/s k: 1.87 Vm: 7.5 m/sSSE A: 7.9 m/s k: 2.01 Vm: 7.0 m/s S A: 7.7 m/s k: 1.96 Vm: 6.9 m/s SSW A: 7.6 m/s k: 2.04 Vm: 6.7 m/s SW A: 7.4 m/s k: 1.91 Vm: 6.6 m/sWSW A: 7.5 m/s k: 1.67 Vm: 6.7 m/s W A: 10.6 m/s k: 1.91 Vm: 9.4 m/s WNW A: 13.0 m/s k: 2.29 Vm: 11.5 m/s NW A: 9.9 m/s k: 1.81 Vm: 8.8 m/sNNW A: 7.7 m/s k: 1.85 Vm: 6.8 m/s