1. Improved weather forecasts for energy operations within the German research project EWeLiNE Kristina Lundgren, Renate Hagedorn, Detlev Majewski Deutscher Wetterdienst, DWD Uwe Schlick / pixelio.de

2. The German electricity supply  Increased share of renewables  Increased share of weather dependent energy sources o Highly fluctuating energy production o Electricity is no more generated where and when it is needed  Electricity generation in 2013

3. 3 Role of TSOs èTransport of energy using fixed infrastructure èManage the security and reliability of the power = Ensure balance between production and consumption at any time èTrading on the power exchange market Growing proportion of weather-dependent power production requires new strategies for managing the power grid German High-Voltage Transmission System

4. New challenges for the TSOs  Forecast errors: Δ(day-ahead) ≈ 3.3 GW Δ(intra-day) ≈ 1.0 GW close to the amount of control energy (±4.5 GW) Cold front and convection Improved power predictions are required.. These depend crucially on quality of underlying weather forecast

5. The research project  Overarching goal: improved wind and PV power forecasts  Users requirements are directly integrated into the R&D activities ( Daniel Lee, UAS-P400.02)

6.  Technical improvements  Research topics at DWD: o Improved initial conditions by applying new data types (data assimilation) o More accurate forecasts by optimizing the model physics o More reliable predictions through optimized ensemble forecasts and new probabilistic products o Model Output Statistics  Integration of new products in decision making processes! at DWD

7. GME  x = 20 km Forecast: 7 days COSMO-EU  x = 7 km Forecast: 78 hours COSMO-DE  x = 2.8 km Forecast: 27 hours Soon: 45 hours (3 UTC) Modelling system COSMO-DE-EPS  x = 2.8 km 20 ensemble members Forecast: 27 hours Soon: 40 members 45 hours (3 UTC) + ICON (13 km / 6.5 km (Europe) later Deterministic Ensemble

8. Improved NWP - technical aspects Current Setup: Horizontal resolution: 2.8 km Vertical levels: 50 Forecast: 27 hours Future Setup: Extended domain Increased resolution: Horizontal resolution: 2.2 km Vertical levels: 65 Forecast with start at 3 UTC: +45 hours COSMO-DE 00:0012:0000:0012:00 MESZ Close of day-ahead market

9. Improved NWP - technical aspects  Since April 9, 2014 global radiation output every 15 min new

10. LETKF=Local Ensemble Transform Kalman Filter Talk by Annika Schomburg: SCI-PS179.02 Tuesday 17:00 – 17:20 Assimilation of power data

11. Critical weather situations and forecast shortcommings  Wind o Front passages (intensity and spatiotemporal positioning) o Bias in stable conditions (winter) o Diurnal cycle (summer)  Photovoltaics o Post frontal clouds o Convective events o Low stratus clouds/fog o Snow cover on PV-plants 19. Autust 2012, 12:00 UTC Courtesy Eumetsat

12. Improving wind speed forecasts Andrea Steiner, DWD  Major challenge: capture and relief stable conditions

13. Improving wind speed forecasts  Major challenge: capture and relief stable conditions  Sensitivity studies: Single Column Model & COSMO-DE  Achievements: o adjusted turbulence parameters lead to lower turbulent diffusion coefficient for momentum (stronger atm. stability) o Improvements by artificially increased vertical mixing after sunrise Andrea Steiner, DWD See Poster by von Schumann et al: SCI-POT 1138, Tuesday, 15:00-16:30 See Talk by von Schumann et al.: SCI-PS220.03 Wednesday 14:20 – 14:40

14.  Challenges: o Clear sky conditions: underestimation  too high aerosol optical thickness o Cloudy conditions: overestimation  clouds appear too transparent Improving radiation forecasts Carmen Köhler, DWD

15.  Challenges: o Clear sky conditions: underestimation  too high aerosol optical thickness  Improvements by modified AOD in the model Improving radiation forecasts Carmen Köhler, DWD COSMO Tanré (op.) COSMO Tegen Pyranometer

16. Improved ensemble forecasts o Ensemble forecasts dynamically capture the forecast uncertainty Z. Ben Bouallègue, DWD Lindenberg, February, 23, 2012

17. Improved ensemble forecasts  Ensemble forecasts dynamically capture the forecast uncertainty  For radiation: the added value of the ensemble is expected to be highest during o spring-summer periods o increases with forecast lead time Z. Ben Bouallegue, Mausam, submitted See Poster by Lundgren et al.: SCI-POT 1028, Tuesday, 15:00-16:30

18. Improved ensemble forecasts  Methods: o Verification against measurements o Revisiting and optimizing the ensemble generation (COSMO-DE-EPS) o Correcting for deficiencies through statistical post- processing COSMO-DE-EPS future approach See Poster by Lundgren et al.: SCI-POT 1028, Tuesday, 15:00-16:30

19. Summary  Due to the German Energiewende, improved weather forecasts for weather dependent energy sources are required  Adjusted turbulence parameters and artificially increased vertical mixing after sunrise lead to first improvements in wind speed forecasts at 100m  Modified AOD lead to improved radiation forecasts for clear sky conditions  The added value of ensemble forecasts is, for radiation forecasts, expected to be highest during spring-summer periods and to increase with forecast range

20. Thanks for listening! http://projekt-eweline.de/en e-mail: kristina.lundgren@dwd.de Elsewhere at WWSOC: Monday 15:00 – 16:30: Daniel Lee (AUS-POM3014) Tuesday 15:00-16:30: Kristina Lundgren (SCI-POT1028) Jonas von Schumann (SCI-POT1138) Tuesday 17:00 – 17:20: Annika Schomburg (SCI-PS179.02) Wednesday 14:20 – 14:40 : Jonas von Schumann (SCI-PS220.03)

21. Verification Package  Verification against mast measurements and pyranometer data  Available scores:  Continous ranked probability score  Spread/skill  Rank histogram  ROC curve and ROC area  Brier score and decomposition  Quantile score and decomposition  Currently under development – more scores planned, including for single forecasts  Surface variables will also be verified, using standard methods

22. Quelle: Helmert et al. (2007) Aerosole basierend auf Tanré, 1984 (operationell) Aerosolklimatologie von Tegen, 1997 Quelle:Jürgen Helmert, DWD Bewölkungsfreie Tage