PROGRAM INFORMATION

STONINGTON - 6/16/2007 through 7/20/2008

DATA DETAILS

June 16 , 2007 through July 22, 2008:

This tower is the sole 50m anemometer tower owned by the Governor's Energy Office. It is intended for community wind projects. The anemometer tower was installed in March 2007, but the early data was lost and is unavailable. The earliest data available begins on June 16, 2007. The tower was removed from the site on July 22, 2008.

Data was collected using four (4) NRG #40 Anemometers and two (2) NRG #200P Wind Vanes, as follows:

• Anemometers
  1. 50 meters facing East
  2. 49 meters facing West
  3. 40 meters facing East
  4. 30 meters facing East
• Wind Vanes
  1. 50 meters facing North
  2. 40 meters facing North

There was also a temperature sensor at a height of 4 meters and facing West.

All sensors fed into an NRG Symphonie data logger. The data logger generates wind reports for each day. Using the Symphonie Data Retriever software, each day's data is complied into one large data file. A zipped file that contains all of the NRG data files and a text version of the aggregate data for all days are given below (these are large files - the zipped NRG file is about 3.5 MB and the text file is about 8.4 MB).

It is important to note that these are the raw files without any compensation for offset.

As can be seen below, the wind vane at 40m either failed early on or was never wired correctly. A replacement wind vane was sent and it too failed. In addition, the anemometer at 50m (165 feet) failed at 18:40 on 4/15/2008 and the anemometer at 49m (161 feet) failed at 16:10 on 5/22/2008.

From this data, an analysis of the wind resource report was developed for entire data collection period using Windographer 1.13. No offest was applied to the wind vane data as none was needed. Using the advanced algorithms in Windographer, the data collected for the anemometers at 165 ft and 161 feet after they failed were deleted and synthetic data was added Since the data set contains data for two or more wind speed sensors at different heights above the ground, Windographer considered the wind shear relationship between different wind speed sensors to synthesize missing data for those wind speed sensors. A best fit using the power law profile was chosen to synthesize the data. Once the wind shear relation was chosen, a daily influence on the wind shear profile was considered so that in each time step where the wind speed is known at one height but not at a different height, Windographer estimated the unknown wind speed based on the best-fit wind shear profile for the appropriate hour of the day.

The Windographer files (with and without data quality and with gaps where the anemometers failed) and the exported text files from Windographer are given below:

• Stonington_2007_0616_to_2008_0722_without_data_quality.windog
• Stonington_2007_0616_to_2008_0722_without_data_quality.txt
• Stonington_2007_0616_to_2008_0722_with_data_quality_gaps.windog
• Stonington_2007_0616_to_2008_0722_with_data_quality_gaps.txt
• Stonington_2007_0616_to_2008_0722_with_data_quality_filled_gaps.windog
• Stonington_2007_0616_to_2008_0722_with_data_quality_filled_gaps.txt

Wind Resource Summary

Highlights of the wind resource at this site for the entire data collection period are shown below:

Windographer was used to match up the wind at this site with the performance curves of some common turbines of various sizes and various heights, allowing for losses of about 13%. The table below shows the results. For the larger turbines, the tower height was increased to account for the larger turbine blades - the wind resource was extrapolated to these higher heights. Keep in mind that the larger and the higher the turbine, the better the wind and the greater the output. But of course, as the tower heights and turbine sizes increase so does the cost.

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