Scanning Lidar in Complex Terrain

Validating scanning lidar at a complex site in California

Transcript

1. SCANNING LIDAR IN COMPLEX TERRAIN 03 December 2014 Cory Sieg Erik Hale
2. | | PROBLEM AWEA Resource Assessment Workshop, Orlando, FL 2  Improve energy assessments which includes increasing accuracy and reducing uncertainty.  How do we continue to economically reduce wind flow model uncertainty? 03-Dec-2014
3. | | SOLUTIONS  Install a mast at every turbine location – ideal but sadly not practical  Coupled mesoscale and CFD models – seems to be a point of emphasis by the industry over the past couple years  Measure wind speed across the entire site – still new technology with potential AWEA Resource Assessment Workshop, Orlando, FL 3 03-Dec-2014
4. | | OBJECTIVES  Logistical and pragmatic considerations of scanning lidar deployment  Scanning lidar validation in complex terrain - we see potential AWEA Resource Assessment Workshop, Orlando, FL 4 03-Dec-2014
5. | | FREAKIN LASERS!! 5 AWEA Resource Assessment Workshop, Orlando, FL 03-Dec-2014
6. | | PRACTICAL CONSIDERATIONS - DEPLOYMENT 6 1) Transport a) ~500lb device – need people and equipment 2) Power a) Needs constant, steady power b) 500W-1600W (temp dependent) c) Manual reset after power loss 3) Set-up a) Leveling, power-up, and configure ~ 1hr b) Work closely with manufacturer c) Be Precise! 0.5 – 2 degree error leads to 20 – 70 m error at 2 km 4) Security a) Cattle, rodents, etc? b) Vandalism / theft – “no go” AWEA Resource Assessment Workshop, Orlando, FL 03-Dec-2014
7. | | CONSIDERATIONS – SCAN CONFIGURATION 7 AWEA Resource Assessment Workshop, Orlando, FL 03-Dec-2014  Highly configurable  Horizontal sweep  Use for horizontal variability  Approximately 1 second per beam ̶ Example: 90-degree sweep: beam every 2 degrees – 45 seconds total ̶ Example: Thirteen 90-degree scans in a 10-minute average  Vertical sweep  Use for vertical variability ̶ Example: Sixteen 1-degree sweep takes approximately 15 seconds ̶ Example: Forty 16-degree scans in a 10-minute average
8. | | RADIAL MEASUREMENTS 8 • Wind speeds measured along a single beam on a very short time scale • Each beam returns a radial wind speed at fixed intervals (ie. every 50 m) for the length of the beam (2km-10km, depending on system) AWEA Resource Assessment Workshop, Orlando, FL Wind Lidar beam Scanning lidar ᶿ 03-Dec-2014
9. | | PRACTICAL CONSIDERATIONS - DATA  Data transfer  Remote connection required to interface with unit and download data  ~150 MB/day of data- Cell connection? Probably not ideal. ̶ Compared to ~14.3 kB/day .rwd file (10,500 times bigger) ̶ ~54 GB for 5.5 months of data  Manual download onto USB/Hard Drive works well ̶ Requires trip to site  Data management  File types (.txt and .jpg)  Custom programming to process spatial and temporal resolution ̶ Fortran, Matlab, R ̶ Bulk of the effort spent here and actively monitoring the unit AWEA Resource Assessment Workshop, Orlando, FL 9 03-Dec-2014
10. | | LIDAR VALIDATION 10 Somewhere in California with mountain pass flow in complex terrain. (Star is not the project, its the California flag) AWEA Resource Assessment Workshop, Orlando, FL 03-Dec-2014
11. | | THE MEASUREMENT CAMPAIGN 11 AWEA Resource Assessment Workshop, Orlando, FL Scan 01 (5.5 months) Scan 02 (3 months) Mast 01 (40 m) Mast 02 (80 m) 700 m 1,050 m 03-Dec-2014 This is an extremely challenging case.
12. | | TERRAIN PROFILE FROM SCAN TO MAST 12 AWEA Resource Assessment Workshop, Orlando, FL 03-Dec-2014
13. | | CORRELATIONS – RAW RADIAL DATA  Scan 01 to Mast 01  Slope = 0.87  R2 = 0.90  Bias = -15% AWEA Resource Assessment Workshop, Orlando, FL 13  Scan 02 to Mast 02  Non-linearity  Slope = 0.60  R2 = 0.73  Bias = -39% 03-Dec-2014
14. | | CORRELATIONS – DIRECTION CORRECTED  Scan 01 to Mast 01  Slope = 1.00  R2 = 0.86  Bias = 0.4% AWEA Resource Assessment Workshop, Orlando, FL 14  Scan 02 to Mast 02  Slope = 0.99  R2 = 0.69  Bias = 1.5%  Wind vane data from mast used to correct for the difference between wind direction and beam angle. 03-Dec-2014
15. | | MANUFACTURER POST PROCESSED DATA  Leosphere processed data  Provided estimated wind speed and direction at first location  Statistical analysis using a subset of beams from a horizontal scan  Cross validated against radial wind speeds  Multiple week turn around time dependent upon amount of data  Based on flat terrain methodology outlined in a DTU research project ̶ Wagner, E., Courtney, M., (July 2014) Comparison test of WLS200S-22 DTU Wind Energy LC I-046 (EN). Denmark.  Confidence factor provided AWEA Resource Assessment Workshop, Orlando, FL 15 03-Dec-2014
16. | | PROCESSED DATA CORRELATED TO MAST 01 16 AWEA Resource Assessment Workshop, Orlando, FL Processed data to Mast 01: • All processed data • Slope = 0.96 • R2 = 0.92 • Bias = -3.8% 03-Dec-2014
17. | | FILTERED BY CONFIDENCE FACTOR 17 AWEA Resource Assessment Workshop, Orlando, FL 10-minute data CF Range Slope R2 Bias Coverage Null - - - 23% 0.0 – 0.25 0.95 0.91 -5.8% 31% 0.25 – 0.50 0.99 0.94 -1.8% 41% 0.50 – 0.75 1.02 0.92 4.5% 3% High frequency data CF Slope R2 Bias Coverage 0/6 0.90 0.67 -9.1% 11% 1/6 0.95 0.87 -5.1% 24% 2/6 0.97 0.87 -3.1% 31% 3/6 0.99 0.85 1.5% 9% 4/6 1.02 0.74 6.0% 3% 03-Dec-2014
18. | | ESTIMATED DIRECTION CORRELATED TO MAST 01 18 AWEA Resource Assessment Workshop, Orlando, FL Scan direction overlayed with Mast 01 direction at 39 m: • Mast direction (blue) and scan direction (red) • Processed data provided by Leosphere • Offset = -16 degrees • R2 = 0.55 when correlated 03-Dec-2014
19. | | CONCLUSIONS  Practical considerations:  Logistics and data processing is a heavy lift  Limit number of scans in a 10-minute period  Validation:  Data recovery – device uptime and signal (25% data loss)  Corrected data from Leosphere shows potential for measuring wind speed and direction across an area  Hopeful this could be an alternative to wind flow modeling someday  This site is a very extreme case AWEA Resource Assessment Workshop, Orlando, FL 19 03-Dec-2014
20. | | HUGE THANKS 20 Erik Hale Amanda Fleming Yiping He, PhD Josh Bennett Jared Kassebaum, PhD Email for questions or comments: Cory.Sieg@edf-re.com AWEA Resource Assessment Workshop, Orlando, FL Raghu Krishna Murthy, PhD Evan Osler Welly Cobden 03-Dec-2014