Computer Weather Forecasts for
Wind Energy Plants
Khanh T. Tran
AMI Environmental
206 Black Eagle Ave, Henderson, NV 89015
(702)564-9186
http://www.amiace.com
Wind Energy Forecasts
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Growing Wind Energy Development
Wind Energy is Intermittent
Reliable Forecasts needed for Load Scheduling
Forecasts of 48-Hour and Longer
Forecasts Updated Twice Daily
Facility located in Complex Terrain
AMI Forecasting System
AMI System Modules
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Mesoscale Model MM5/WRF
> Nested Grids of 36,12,4,1.33 km spacing
> ETA/AVN Forecasts for IC/BC
Diagnostic Wind Model
> 100 m spacing or less
Adaptive Statistical Module
> Bias Removal
> Recent Onsite Data
Internet-based Forecast Delivery (website, email)
System Runs on Linux Multiprocessor PC
System Testing
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Testing at FPL Southwest Mesa Plant in
southwest Texas
12-month Testing (April 2002-March 2003)
sponsored by US DOE NREL and EPRI
Forecasts by AMI, TrueWind and Risoe
48-Hour Forecasts twice daily at 00 UTC and 12
UTC (wind speed, wind direction, ambient
temperature and wind energy)
FPL Southwest Mesa Plant
MM5 Modeling Domain
Domain Topography
System Performance Evaluation
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Forecasts compared against actual observations
(wind speed and energy)
Forecasts compared against persistence and
climatological forecasts
Statistical measures (mean error ME, mean
absolute error MAE, skill score)
Sample Wind Speed Forecast
Applied Modeling Wind Speed Forecasts
Southwest Mesa Forecasts Beginning at 1800, July 18 2002
Meteorology Fcst
Persistence Fcst
Climatology Fcst
Observed Data
14
Wind Speed m/sec
12
10
8
6
4
2
0
0
6
12
18
24
30
Forecast Hour Number
36
42
48
Sample Wind Energy Forecast
Applied Modeling Wind Generation Forecasts
Southwest Mesa Forecasts Beginning at 1800, July 18 2002
Meteorology Fcst
Persistence Fcst
Climatology Fcst
Observed Data
80,000
Wind Generation kW
70,000
60,000
50,000
40,000
30,000
20,000
10,000
0
0
6
12
18
24
30
Forecast Hour Number
36
42
48
Forecast Performance Statistics
Wind Speed (m/s)
Energy (kw)
Annual average
7.61
25,450
Forecast Error
Annual ME
Annual MAE
-0.02
2.28
1,322
12,319
Normalized Error
Annual ME
Annual MAE
-0.2%
30%
-5.2%
48.4%
Skill Score
vs. Persistence
vs. Climatology
26.1%
26.8%
28.3%
28.1%
Normalized MAE for Wind Speed
Normalized Mean Absolute Errors for
Applied Modeling Wind Speed Forecasts
Southwest Mesa FPL Energy, April 1, 2002 - March 31, 2003
Meteorology
Persistence
Climatology
Normalized Mean Abs. Error
60%
12-Month Average Wind Speed = 7.61 m/sec
50%
40%
30%
20%
10%
0%
0
6
12
18
24
30
Forecast Hour Number
36
42
48
Normalized MAE for Wind Energy
Normalized Mean Absolute Errors for
Applied Modeling Wind Generation Forecasts
Southwest Mesa FPL Energy, April 1, 2002 - March 31, 2003
Meteorology
Persistence
Climatology
Normalized Mean Abs. Error
100%
12-Month Average Wind Generation = 25,450 kW
80%
60%
40%
20%
0%
0
6
12
18
24
30
Forecast Hour Number
36
42
48
Normalized Monthly MAE for WS
Normalized Monthly Mean Absolute Errors for
AMI Wind Speed Forecasts
Southwest Mesa FPL Energy, April 1, 2002 - March 31, 2003
Meteorology
Persistence
70%
60%
50%
40%
30%
20%
10%
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0%
Ap
Normalized Mean Abs. Error
Climatology
Month
Normalized Monthly MAE for WE
Normalized Monthly Mean Absolute Errors for
AMI Wind Generation Forecasts
Southwest Mesa FPL Energy, April 1, 2002 - March 31, 2003
Persistence
Climatology
120%
100%
80%
60%
40%
20%
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20
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Au
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20
02
0%
Ap
Normalized Mean Abs. Error
Meteorology
Month
Comparison of Forecast Systems
Annual Mean Absolute Errors of Wind Speed
and Energy Forecasts
Southwest Mesa FPL Energy, April 1, 2002 to March 31, 2003
60%
Normalized Mean Abs. Error
Risoe
TrueWind
AMI
50%
40%
30%
20%
10%
0%
Wind Speed
Wind Energy
Conclusions
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AMI Forecast System based on advanced
models
AMI system tested for 12-month in southwest
Texas
AMI system provides accurate wind speed and
energy forecasts
AMI system is more accurate than other systems
AMI system runs on Linux PC and can be easily
adapted to other sites.