LIDAR–based measurements of wind characteristics within the marine boundary layer over Lake Michigan

1. LIDAR–based measurements of wind characteristics within the marine boundary layer over Lake Michigan Frank J. Marsik, Aline Cotel and Kyle Chudler(University of Michigan) Guy Meadows and Neel Desai (Michigan Technological University) 2014 Great Lakes Operational Meteorology Workshop Ann Arbor, Michigan

2. Introduction Methodology Nearshore Mid-Lake Summary Outline • A bit of motivation…. • Description of AXYS Wind SentinalTMbuoy • Description of data analysis methodology • Presentation of turbulent kinetic energy results from nearshore location (2011) • Presentation of vertical wind profile data from mid-lake plateau location (2012)

3. Introduction Methodology Nearshore Mid-Lake Summary Motivation • Overall goal of the project • Acquire data to investigate economic viability of offshore wind energy production in Lake Michigan • UM/MTU Efforts • Obtain a better understanding of turbulent kinetic energy (TKE) characteristics over the lake • Investigate season variation of vertical wind profile structure

4. Introduction Methodology Nearshore Mid-Lake Summary Washtenaw County • What: Wind energy feasibility study for Washtenaw County (2008-2009) • Where: Chrysler Proving Grounds, Chelsea, MI • Why: Determine if wind energy production would be financially viable in the county • American Wind Energy Association (AWEA) indicates that utility scale wind power plants require minimum average wind speeds of 6 m/s (13 mph) to be financially viable. http://www.ewashtenaw.org

5. Introduction Methodology Nearshore Mid-Lake Summary State of Michigan • Estimated wind speeds over land • Generally less than 6 m/sec • Estimated wind speeds offshore • Generally 7-9 m/sec Source http://www.michigan.gov/images/MI_Final_SPD50m_9Sept04_115624_7.jpg

6. Introduction Methodology Nearshore Mid-Lake Summary Field Monitoring Periods and Sites MAY – DEC 2012 65 km

7. Introduction Methodology Nearshore Mid-Lake Summary Summary for 2012 and 2013 periods Key point: On average, winds at all levels exceed 6 m/sec threshold. Courtesy of Jim Edmonson, Grand Valley State University

8. Introduction Methodology Nearshore Mid-Lake Summary AXYS WindSentinelTM buoy • Vindicator Laser Wind Sensor (hereafter, LWS) • Capable of measuring wind velocity in three directions (U,V, and W) up to 175 m above the water surface • One-second wind velocity data was collected and averaged over six 40-m vertical bins • Horizontal wind data was motion compensated

9. Introduction Methodology Nearshore Mid-Lake Summary Additional measurements • Two, three-cup anemometers located three meters above surface • Air and water temperatures • Wave height and period

10. Introduction Methodology Nearshore Mid-Lake Summary Analyses performed • Thirty-second average turbulent kinetic energy (horizontal) • Hourly-averaged horizontal wind speed • For both of these analyses… • Utilized AXYS-provided “data validity” flag • Hourly average was accepted if over 50% of data was deemed valid

11. Introduction Methodology Nearshore Mid-Lake Summary Lake Muskegon Evaluation Horizontal separation distance ~ 400 m.

12. Introduction Methodology Nearshore Mid-Lake Conclusions Lake Michigan – TKE ExampleDecember 04, 2011

13. Introduction Methodology Nearshore Mid-Lake Summary Lake Michigan – TKE example TKE (m2/s2) Enhanced TKE through through entire layer sampled

14. Introduction Methodology Nearshore Mid-Lake Summary Lake Michigan – Monthly mean example Monthly Standard Deviation 4-5 m/sec

15. Introduction Methodology Nearshore Mid-Lake Summary Lake Michigan (June 10-13,2012) June 11 June 12 Surface frontal zone passed site evening of June 11th.

16. Introduction Methodology Nearshore Mid-Lake Summary Lake Michigan (June 10-13,2012)

17. Introduction Methodology Nearshore Mid-Lake Summary Lake Michigan (June 10-13,2012)

18. Introduction Methodology Nearshore Mid-Lake Summary Lake Michigan (Sept 10-13,2012) September 12 September 13 Surface frontal zone passed site evening of September 12th.

19. Introduction Methodology Nearshore Mid-Lake Summary Lake Michigan (Sept 10-13,2012)

20. Introduction Methodology Nearshore Mid-Lake Summary Lake Michigan (Sept 10-13,2012)

21. Introduction Methodology Nearshore Summary Mid-Lake Summary and Next Steps • Two years of seasonal vertical wind profiles (2012-2013) • Vindicator Laser Wind Sensor • Annual mean wind speed results • Encouraging for viability for offshore wind production • Vertical TKE profiles • Preliminary results suggest enhanced TKE through depth of lower marine boundary layer • Shows promise for providing guidance of gustiness/turbulence at hub heights • Vertical mean wind speed profiles • Effects of stability seen in both monthly and daily profiles • Next steps for me: Investigating applicability of power law relations for wind energy potential prediction elsewhere in Great Lakes

22. Introduction Methodology Nearshore Summary Mid-Lake Summary and Next Steps where uref is wind speed at reference height zref and u2is wind speed at reference height z2 • Hsu et al. (1994) • Suggests “p-value” of 0.11 for neutral stability typical of open seas. • For variable stability and conditions in the Great Lakes….???

23. Introduction Methodology Nearshore Summary Mid-Lake Acknowledgements • GVSU Funding: U.S. Department of Energy • Special thanks to ArnBoezaart, Jim Edmonson and many others at Grand Valley State University for sharing their data