university of minnesota - eolos wind energy research...

University of Minnesota

St. Anthony Falls Laboratory

EOLOS Educational Data Set: An Overview

Author:

Noah Stone

July 29, 2015


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Executive Summary

After receiving an $8 million grant from the United States Department of Energy, University of Minnesota’s St. Anthony Falls Laboratory built a one-of-a-kind wind research station. The EOLOS wind research station, located at UMore Park approximately 20 miles south of the Twin Cities, is home to a 129.5m meteorological tower and 2.5 MW Clipper Liberty wind turbine built specifically for scientific research. By pairing a meteorological tower with the highly instrumented turbine, EOLOS researchers are able to see the whole picture of the turbine’s power generation, giving them a unique advantage in wind energy research. The goals of the EOLOS wind research station are to increase wind energy output, mitigate ice accumulation on the blades, and improve aerodynamic performance and noise control, to name a few. These goals are attainable through the use of exceptional data captured by the meteorological tower and wind turbine.

The EOLOS wind research station collects a vast amount of data. The wind turbine’s Supervisory Control and Data Acquisition System (SCADA) records over 30 variables at 1 Hz, including power generated, pitch position of blades, and wind speed. The meteorological tower has 6 different elevations containing sensors, many of which record at 20Hz to measure wind speed, wind direction, air temperature, and relative humidity.

The data produced by both the meteorological tower and wind turbine is stored on University of Minnesota servers and made available to EOLOS researchers who then use it for various purposes. One of the objectives EOLOS researchers have is to assist in educating students on wind energy. The purpose of providing a data set is to allow the students to do calculations and analysis using real data. This has the potential to give them a better grasp of the information.

The data set provided includes 4, 1 hour time periods of meteorological and wind turbine data. A high and low wind time period from both summer and winter are included, which gives a brief glimpse of how the turbine behaves in different meteorological conditions. The data set can be used in a variety of situations. A teacher may use it to provide interesting and real world data for an application problem or a student may reference it in a project on wind energy. The dataset is intended for classroom use, but is not limited to it. Any interested individual may access the data set on the EOLOS website.


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Table of Contents Executive Summary ....................................................................................................... 1 Background .................................................................................................................... 3 EOLOS Wind Research Station Specifications ............................................................ 4 Data Collection .............................................................................................................. 5 EOLOS Educational Data Set ....................................................................................... 5 Educational Data Set Quality Control .......................................................................... 5 Intended Use/Purpose ................................................................................................... 6 Future ............................................................................................................................. 7 References ...................................................................................................................... 8 Appendix A – EOLOS Wind Research Station Drawings ............................................ 9 Appendix B – SCADA and Met Tower Variables ....................................................... 12 Appendix C – Windographer Reports ......................................................................... 14


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Background

Currently, wind power accounts for 4% of the United States’ electricity consumption and is one of the fastest growing renewable energy sources in the world. Wind power has tripled since 2008 and is projected to grow another 12% in 2016, yet wind energy has barely scratched the surface of its potential. According to American Wind Energy Association (AWEA), the wind energy potential in the United States is 10 times greater than the country’s current electricity consumption. In order for the United States to continue the expansion of wind power, time and dedication to the research and development of wind energy technology will be required.

In 2008 the United States established a goal of supplying 20% of the country’s electricity through wind power by 2030. To assist in accomplishing this goal, University of Minnesota’s St. Anthony Falls Laboratory received an $8 million grant from the U.S. Department of Energy to establish the EOLOS wind research station. EOLOS is a group of university researchers and industry partners whose mission is to “advance the production of wind-generated energy for the United States through industry-driven research, field-scale demonstration of new technologies, and workforce training.” The research station consists of a 129.5m meteorological (met) tower and 2.5 MW Clipper Liberty wind turbine. The heavily instrumented turbine paired with the advanced met tower provide EOLOS researchers a more complete look at the wind turbine’s energy generation.

The EOLOS wind research station became fully functional and began collecting data in January of 2012. After over 3 years, the research station has accumulated an enormous amount of data about the wind turbine’s operation and meteorological conditions. This data has many applications in not only research but also industry and education. An example application is the EOLOS researchers using the data to analyze and gain a better understanding of what may affect the power produced by the wind turbine. The data collected is also made available to partners of EOLOS. Time periods of the data collected by the met tower and wind turbine have been made accessible on the EOLOS website to students, teachers, or anyone interested.

The goal of providing a data set is to give basic, but comprehensive meteorological and wind turbine information that can be used for educational and informative purposes. It also serves as a brief glimpse of the immense amount of data being collected and stored by the meteorological (met) tower and the wind turbine’s Supervisory Control and Data Acquisition System (SCADA).


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EOLOS Wind Research Station Specifications

The EOLOS wind research station is located at University of Minnesota Outreach, Research and Education (UMore) Park. 80 of the 5,000 acres at UMore Park have been dedicated to the wind turbine and meteorological tower that make up the EOLOS wind research station. The wind turbine’s specific location is 44 degrees 43.693 minutes latitude, -93 degrees 2.8858 minutes longitude. UMore Park is a university owned site situated approximately 20 miles southeast of the University of Minnesota Twin Cities campus. The vision for UMore Park is to create a sustainable community of 20,000 to 30,000 people.

The Clipper Liberty wind turbine installed has a rotor diameter of 96m, hub height of 80m and is capable of producing 2.5 MW. The turbine has a cut-in speed of 4 m/s and cut-out speed of 25 m/s, and is heavily instrumented for scientific research. The turbine’s Supervisory Control and Data Acquisition System (SCADA) plays an important role in the data collection process. It has instruments to record wind speed, wind direction, ambient temperature, and air density at hub height (80m). It records the real power generated and is also equipped with sensors to record data about the yaw position, pitch position of the blades and many other aspects of the wind turbine. A full list of the SCADA variables recorded is included in Appendix B. During construction, the turbine was fitted with instruments to measure how the foundation responds to different wind loads and tower oscillations. The blades of the wind turbine are also equipped with fiber optic strain and temperature gauges to measure strain in the blades.

The 129.5m tall met tower is located 160m due south of the wind turbine, which is within the International Electrotechnical Commission (IEC) recommended distance of 2 rotor diameters (192m). There are 6 elevations of instrumentation on the tower. The elevations were chosen based on the boundaries of the rotor swept area, hub height, mid span of the blades, and a height to compare with other available meteorological data. The elevations are labeled 1 through 6 with 1 being the top and 6 being the bottom. 4 of the elevations have sonic anemometers attached to 18’ booms. All elevations have 10’ boom arms holding cup anemometers and wind vanes. A diagram of the met tower elevations can be found in Appendix A. Attached to the tower at all 6 elevations as well, are relative humidity and air temperature sensors. A barometric pressure sensor is also located on the tower at hub height (80m).


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Data Collection

The met tower and EOLOS wind turbine acquire a large amount of data at a rapid rate. A single sensor recording at 20 Hz will record over 1.7 million data points in a day and over 630 million data points in a year. The sonic anemometers on the met tower record data at 20 Hz, while the met tower’s relative humidity, air temperature, cup anemometers, wind vanes, and barometric pressure sensors as well as SCADA record at 1 Hz. 2 Campbell Scientific CR3000 data loggers are used to capture the met tower data. The data is time stamped and clock synchronized with the wind turbine. It is held to an accuracy of 10 milliseconds using GPS based clock setting. SCADA records the wind turbine’s data. The data collected at the research station is then backed up and stored on University of Minnesota database servers. There, it is secure and made available to EOLOS researchers.

EOLOS Educational Data Set

The data set provided includes 4 time periods: a 1 hour, high and low wind period for both summer and winter seasons at 1 Hz while the turbine is generating power. These time and wind speed periods were chosen in order to represent a wide range of meteorological conditions. The SCADA variables focused on for this data set are wind speed, power generated, ambient temperature and wind direction. The 20 Hz met tower data was averaged in order to achieve 1 Hz and match with the SCADA data. A high wind speed is greater than 10 m/s and a low wind speed is less than 8 m/s. The data set is offered as a downloadable .CSV file. This makes it more accessible and allows users to import it into the program of their choice.

Educational Data Set Quality Control

The data is recorded and stored in raw form so it must go through various measures of quality control before being used. Measures taken to ensure the quality of the data include using codes outputted by the wind turbine detailing what is happening, and Windographer.

The SCADA data was checked for quality by looking at the turbine’s state and fault codes. The turbine’s state is a number that shows what mode it is in. Fault codes are numbers that correspond to various events the turbine may experience. If the


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fault code is 0, nothing is wrong and if the turbine state is 8, it is in run mode. In 3 of the 4 time periods the fault code is 0. In the other time period, 2014-01-08, the fault code is 920. This fault code corresponds to a feather check warning and does not affect how the turbine runs, thus, the data is still valid during this time period. In all 4 time periods, the turbine state is 8 and running smoothly.

The met tower data was checked for quality using Windographer. Windographer is a computer software program that allows analysis of meteorological and wind turbine data. The data is able to be checked and automatically flagged if it is outside the parameters set up by the user. This data set was run through flags set up by Chris Milliren, an Associate Engineer at St. Anthony Falls Laboratory. The flags looked for times when tower shadow occurred and times when there were errors in air temperature, wind speed, or wind direction. A Windographer report was then generated showing the number of valid (not flagged) data points for each data column. These reports can be found in Appendix C.

Intended Use/Purpose

The data set is intended for educational and informative purposes. This may include teachers, students, and anyone interested in viewing data captured by the EOLOS wind research station.

One purpose of providing a data set is to educate students by using the data collected from the EOLOS wind turbine’s Supervisory Control and Data Acquisition System (SCADA) and the meteorological tower. By providing this information, students are able to analyze and do calculations using real data. Students will be able to create a wind rose, look at wind shear, calculate a power curve, and use the data in other investigatory ways. It will hopefully spark students’ interest and provide familiarity with data being acquired by wind turbines and meteorological towers.

Another purpose is to provide a valuable free resource for teachers. There are very few free wind data sets offered and even fewer for educational and informative purposes. By pairing the EOLOS wind turbine’s data with the met tower, a very unique data set is created. The data set will be beneficial in wind energy and renewable technology classes as well as general classrooms.


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Future

EOLOS researchers continue to look at the data being collected, but there still remains a large amount that has yet to be fully analyzed and understood. The data being collected by the EOLOS wind research station will be vital for future research and further understanding wind power. For more information or questions contact Jeff Marr ([email protected]), Chris Milliren ([email protected]), or Noah Stone ([email protected]).


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References American Wind Energy Association (AWEA). (2013). AWEA fact sheets: Quick guides to wind

energy. Retrieved 07/08, 2015, from

http://www.awea.org/Resources/Content.aspx?ItemNumber=873&navItemNumber=588

Clipper Windpower. (2008). Liberty 2.5 MW windturbine facts & specifications

Cusick, D. (2014). Wind power has more than tripled in 6 years - report. Retrieved 07/08, 2015, from

http://www.governorswindenergycoalition.org/?p=8121

Ellis, C. (2013). EOLOS meteorological tower and associated sensor system University of Minnesota.

Mooney, C. (2015, 09 March). Here's how much faster wind and solar are growing than fossil fuels.

The Washington Post,

Office of Energy Efficiency & Renewable Energy. 20% wind energy by 2030: Increasing wind energy's

contribution to u.s. electricity supply. Retrieved 07/08, 2015, from

http://energy.gov/eere/wind/20-wind-energy-2030-increasing-wind-energys-contribution-us-

electricity-supply

Office of Energy Efficiency & Renewable Energy. History of wind energy. Retrieved 07/08, 2015, from

http://energy.gov/eere/wind/history-wind-energy

St. Anthony Falls Laboratory. (2012). EOLOS wind energy research consortium. Retrieved 07/08,

2015, from http://www.EOLOS.umn.edu/

U.S. Energy Information Administration. (2015). Renewables and CO2 emissions. Retrieved 07/08,

2015, from http://www.eia.gov/forecasts/steo/report/renew_co2.cfm

http://www.awea.org/Resources/Content.aspx?ItemNumber=873&navItemNumber=588

http://www.governorswindenergycoalition.org/?p=8121

http://energy.gov/eere/wind/20-wind-energy-2030-increasing-wind-energys-contribution-us-electricity-supply

http://energy.gov/eere/wind/20-wind-energy-2030-increasing-wind-energys-contribution-us-electricity-supply

http://energy.gov/eere/wind/history-wind-energy

http://www.eolos.umn.edu/

http://www.eia.gov/forecasts/steo/report/renew_co2.cfm


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Appendix A – EOLOS Wind

Research Station Drawings


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Figure 1 shows the met tower’s sensor placement. The cyan color lines show the placement of CSAT booms which contain the sonic anemometers. The green lines show where the cup anemometer, wind vane, air temperature, and relative humidity sensors are located. The elevations are labeled on the left side and correspond to how recorded data is identified in the University’s database.

Figure 1: Meteorological Tower Sensor Placement


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Figure 2 shows a Google Maps image of the EOLOS wind research station. The wind turbine’s latitude and longitude coordinates are displayed next to the star and in the search box located in the top left of the image. The meteorological tower is to the left of the turbine and is marked by the oval surrounding it. The orientation of the picture can be seen in the bottom right hand corner. North is to the right and in the direction of the red arrow on the compass.

Figure 2: Google Maps Image of EOLOS Wind Research Station

W S N E


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Appendix B – SCADA and Met Tower Variables


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Table 1 shows the variables collected by the turbine’s Supervisory Control and Data Acquisition System (SCADA) and the met tower. In addition to the variables in the table, the wind turbine also collects data for the temperature, strain, acceleration, and tilt of the foundation, and the strain, acceleration, and temperature of the blades.

Table 1: Data variables collected by SCADA and the Met Tower.

EOLOS Wind Turbine’s SCADA

Wind Speed and Direction

Turbine State Real Power

Real Power Limit Reactive Power Pitch Position of Each Blade

Generator Speed Hub Speed Rotor Position Tower Acceleration Yaw Position Yaw Error Air Density Barometric Pressure Nacelle Temperature Ambient Temperature Gearbox Oil Temperature Hydraulic Oil

Temperature Bearing Temperatures Generator Temperatures Yaw Mode and State Fault Code Fault Level Nacelle Direction Met Tower Wind Speed at 10 heights (cup & vane and sonic anemometers)

Wind Direction at 10 heights (cup & vane and sonic anemometers)

Air Temperature at 6 heights

Relative Humidity at 6 heights

Barometric Pressure


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Appendix C – Windographer

Reports


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Windographer reports for the time periods in the data set are attached on the following pages. The variable recorded is in the “label” column, with the height it was recorded at followed by the number of possible data points and valid data points. The files are 1 Hz but Windographer averages them into 1 min data points. Rows 38 to 49 were not recorded at the EOLOS wind research station, but calculated by Windographer.


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