current status of solar pv power forecasting · current status of solar pv power forecasting elke...
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19.11.2013, MeteoRES workshop, Oldenburg, Germany 11
Current status of solar PV Power forecasting
Elke Lorenz Jan Kühnert, Annette Hammer, Detlev Heinemann
AG EnergiemeteorologieUniversität Oldenburg
19.11.2013, MeteoRES workshop, Oldenburg, Germany 2
Outline!background: forecast requirements for trading of PV power
!overview on operational PV power prediction system*
!irradiance forecasting: combination of satellite and NWP forecasts
!PV power forecasting: evaluation for control area of transmission system operator 50Hertz
!summary and outlook
* cooperation with Meteocontrol GmbH
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Contribution of PV systems to electricity supply in Germany !installed PV power (end 2012): 32 GWpeak in Germany
!up to 42% of electricity demand from PV
!strong variability of solar and wind power
22 GW
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Balancing of solar power according to renewable energy sources act !mandatory purchase of all available renewable electricity by grid operators
!marketing and balancing of PV power by transmission system operators (TSOs) based on their respective share of the all German electricity supply (horizontal burden sharing)
!additional option of direct marketing of PV power is getting more important
need for regional forecasts
control areas of transmission system
operators
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Balancing of solar power input (RES act)by transmission system operators
!day-ahead: selling of PV power at the European Power Exchange (EPEX)
!hourly contingents !12:00 for the next day
-
hourly forecasta for next day
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Balancing of solar power input (RES act)by transmission system operators
!day-ahead: selling of PV power at the European Power Exchange(EPEX)
!hourly contingents !12:00 for the next day
!intra-day: trading of electricity at the EPEX
!hours or 15-minute periods!until 45 minutes before deliveryforecast errors influence prices
-
15min resolution forecast for next hours
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Balancing of solar power input (RES act)by transmission system operators
!day-ahead: selling of PV power at the European Power Exchange(EPEX)
!hourly contingents !12:00 for the next day
!intra-day: trading of electricity at the EPEX
!hours or 15-minute periods!until 45 minutes before deliveryforecast errors influence prices
!remaining deviations are adjusted with balancing power
-
forecasts with15 min resolution for the next hours
-
online-estimation from measured values
19.11.2013, MeteoRES workshop, Oldenburg, Germany
DWD forecast
ECWMF forecast
representativePV system sites
power predictionPV simulation
up-scaling
optimized, site-specific irradiance
prediction
regional PV power prediction
Satellite data
irradiancemeasurement
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module typenominal powerTilt and orientation..
PV system description
PV powermeasurement
irradiance forecastingforecasthorizon
hours
days
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Meteosat Second Generation (high resolution visible range)
!cloud index from Meteosat images with Heliosat method
resolution in Germany!1.2km x 2.2 km !15 minutes
Irradiance prediction based on satellite data
19.11.2013, MeteoRES workshop, Oldenburg, Germany
!cloud index from Meteosat images with Heliosat method
!cloud motion vectors by identification of matching areas in consecutive images
!extrapolation of cloud motion to predict future cloud index
Irradiance prediction based on satellite data
Meteosat Second Generation (high resolution visible range)
19.11.2013, MeteoRES workshop, Oldenburg, Germany
satellite derived irradiance maps
!cloud index from Meteosat images with Heliosat method
!cloud motion vectors by identification of matching areas in consecutive images
!extrapolation of cloud motion to predict future cloud index
!irradiance from predicted cloud index images with Heliosat method
Irradiance prediction based on satellite data
200W/m2 900W/m2
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Evaluation of irradiance forecasts: data sets! period: 1.1.-30.9.2012
! measurements:irradiance measurements of 270 stations in Germany, operated byDWD and meteomedia GmbH
! forecasts:! DWD ! ECMWF! CMV! Combined forecasts
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Evaluation: combination of ECMWF, DWD and CMV forecasts
date
I in
W/m
2
CMV: Cloud Motion Vectors
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Evaluation: combination of ECMWF, DWD and CMV forecasts
date
I in
W/m
2
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Evaluation: 3 hour ahead forecastscombination of ECMWF, DWD and CMV
for 3 hours ahead satellite based forecasts in average significantlybetter than NWP forecasts, but outliers may occur
mean Germany
rmseECMWF 41W/m2
rmseCMV 34W/m2
CMV,
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Evaluation: 3 hour ahead forecastscombination of ECMWF, DWD and CMV
combination much better than single models ccerror(ECWMF,DWD)=0.51, ccerror(ECWMF,MVF)=0.29
mean Germany
rmseECMWF 41W/m2
rmsecmv 34W/m2
rmsecombi 25W/m2
improvement*
vs ECMWF39%
improvement*
vs MVF26%
CMV,
*
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Evaluation: 3 hour ahead forecastscombination of ECMWF, DWD and CMV
combination much better than single models: in particular outliers are reduced
mean Germany,rmse Δmax
ECMWF 41W/m2 167W/m2
CMV 34W/m2 -177W/m2
combi 25W/m2 113W/m2
cmv
19.11.2013, meteoRES workshop, Oldenburg, Germany
Evaluation: rmse in dependence of forecast horizon
!CMV forecasts better than NWP based forecast up to 4 hours ahead
!CMV forecast better than persistence of cloud situation from 2 hours onwards
!large improvement with combined model
calculation time of MVF: sunel > 10°only hours with all models available included in dependence on forecast horizon
19.11.2013, meteoRES workshop, Oldenburg, Germany
Evaluation: rmse in dependence of forecast horizon
improvement with combined forecasts more pronounced for regional average forecasts
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Evaluation of day-ahead irradiance forecasts combination of ECMWF and DWD
mean Germany
rmseECMWF 43W/m2
rmseDWD 51W/m2
!ECMWF irradiance forecasts better than DWD irradiance forecasts
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Evaluation of day-ahead irradiance forecasts combination of ECMWF and DWD
mean Germany
single sites
rmseECMWF 43W/m2 107W/m2
rmseDWD 51W/m2 114W/m2
rmsecombi 40W/m2 103W/m2
improvement 8% 4%
!ECMWF irradiance forecasts better than DWD irradiance forecasts
! improvement with combined approach
19.11.2013, MeteoRES workshop, Oldenburg, Germany
DWD forecast
ECWMF forecast
representativePV system sites
power predictionPV simulation
up-scaling
optimized, site-specific irradiance
prediction
regional PV power prediction
Satellite data
irradiancemeasurement
38
module typenominal powerTilt and orientation..
PV system description
PV powermeasurement
forecasthorizon
hours
days
PV power prediction
*Cooperation with Meteocontrol GmbH
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Data sets!control area 50Hertz
!December 2011- November 2012
!hourly values
!PV measurements:
!monitoring data Meteocontrol: > 1000 PV systems, ca. 20% of installed power
!single site evaluation: 80 selected systems
!measurement of overall PV power feed-in control area not available
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Sel
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Estimation of PV power feed-in in control area
!Upscaling using Meteocontrol monitoring data
!all systems in the control area
!considering spatial distribution with 2digits PLZ resolution*
!considering distribution of PV system size*
!overall installed power Pnom (given by 50Hertz)
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*based on „EEG Data“ 16.8.2012
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Data sets!forecasts
!06:00, 1-3days ahead
!11/11-05/12: ECWMF only
!06/12-11/12: ECMWF & DWD
!11:00, intra-day
!09/12-11/12: combination of NWP and CMV
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Evaluation
only daylight values,normalization to installed power
control areacontrol area single sitessingle sites
bias* rmse* bias* rmse*
Intra-day
0.9% 4.9% 1.1% 12.0%
day-ahead
0.7% 5.7% 1.2% 12.8%
3days 0.5% 6.2% 0.9% 13.4%
19.11.2013, MeteoRES workshop, Oldenburg, Germany
Evaluation:annual course of forecast errors
!largest rmse values Feb-April 2012
19.11.2013, MeteoRES workshop, Oldenburg, Germany
!largest rmse values Feb 2012 snow
Evaluation:annual course of forecast errors
19.11.2013, MeteoRES workshop, Oldenburg, Germany
!largest rmse values Feb 2012 snow
Evaluation:annual course of forecast errors
19.11.2013, MeteoRES workshop, Oldenburg, Germany
!largest rmse values Feb-April 2012 snow and fog
Evaluation:annual course of forecast errors
50Hertz, day-ahead, April 2012
19.11.2013, MeteoRES workshop, Oldenburg, Germany
!largest rmse values Feb-April 2012 snow and fog
!from June onwards: combination of DWD and ECMWF irradiance forecasts
Evaluation:annual course of forecast errors
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EvaluationEvaluation:timeseries
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Evaluation:combination NWP and satellite based CMV forecasts
o NWP, 06:00x combi, 11:00
o NWP, 06:00x combi, 11:00
large improvement with combined model
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Summary !PV power prediction contributes to successful grid integration of more than 32 GWpeak PV power in Germany
!irradiance forecasts based on satellite data significantly better than NWP based forecasts up to 4 hours ahead
!significant improvement by combining different data sources, in particular when combining satellite and NWP based forecasts
!need for further research (in particular for fog and snow)
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Outlook
!integration of additional data sources:!different NWP systems!additional meteorological parameters!cloud detection with IR satellite images!online measured PV power data
!advanced statistical methods to integrate the different data sources