Improved weather forecasts for

energy operations within the

German research project EWeLiNEKristina Lundgren, Renate Hagedorn, Detlev

Majewski Deutscher Wetterdienst, DWD

Uwe Schlick / pixelio.de

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

Role of TSOs

Transport of energy using fixed infrastructure Manage the security and reliability of the power = Ensure balance between production and consumption at any time Trading 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

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

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)

Technical improvementsResearch 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

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 km20 ensemble members

Forecast: 27 hoursSoon:

40 members45 hours (3 UTC)

+ ICON (13 km / 6.5 km (Europe) later

Deterministic

Ensemble

Improved NWP - technical aspects

Current Setup:Horizontal resolution: 2.8 kmVertical levels: 50Forecast: 27 hours

Future Setup:Extended domainIncreased resolution:•Horizontal resolution: 2.2 km•Vertical levels: 65

Forecast with start at 3 UTC: +45 hours

COSMO-DE

00:00 12:00 00:00 12:00

MESZClose of day-ahead market

Improved NWP - technical aspects

Since April 9, 2014 global radiation output every 15 min

new

LETKF=Local Ensemble Transform Kalman Filter

Talk by Annika Schomburg:SCI-PS179.02 Tuesday 17:00 – 17:20

Assimilation of power data

Critical weather situations and forecast shortcommings

Windo Front passages (intensity and

spatiotemporal positioning)o Bias in stable conditions (winter)o Diurnal cycle (summer)

Photovoltaicso Post frontal cloudso Convective eventso Low stratus clouds/fogo Snow cover on PV-plants

19. Autust 2012, 12:00 UTC

Courtesy Eumetsat

Improving wind speed forecasts

Andrea Steiner, DWD

Major challenge: capture and relief stable conditions

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, DWDSee Poster by von Schumann et al: SCI-POT 1138, Tuesday, 15:00-16:30See Talk by von Schumann et al.: SCI-PS220.03 Wednesday 14:20 – 14:40

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

Challenges:

o Clear sky conditions: underestimation too high aerosol optical thickness

Improvements by modifiedAOD in the model

Improving radiation forecasts

Carmen Köhler, DWD

COSMO Tanré (op.)COSMO TegenPyranometer

Improved ensemble forecasts

o Ensemble forecasts dynamically capture the forecast uncertainty

Z. Ben Bouallègue, DWD

Lindenberg, February, 23, 2012

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

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

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

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)