20 bethke hammer_timeseries_of_spectrally_resolved_solar_irradiance_data_from_satellite_measurements

Betcke, Hammer, PVPMM Workshop, 22. October 2015, Cologne 11

PVKLIMA Timeseries of Spectrally Resolved Irradiance Data

from Satellite Measurements

Jethro Betcke, Annette Hammer,

PV Performance Modelling and Monitoring Workshop

22nd October 2015, Cologne

2/25Betcke, Hammer, PVPMM Workshop, 22. October 2015, Cologne

Content

• Why focus on spectrally resolved irradiance?

• PVKLIMA project

• Spectrally resolved irradiance from satellite data

• New developments

• Summary and outlook

• References and Funding


Variations in spectrum

Measurements: TÜV Rheinland

Wavelength (nm) Wavelength (nm)

No

rma

lize

d Ir

radi

ance

Nor

ma

lized

Irra

dia

nce

4/25Betcke, Hammer, PVPMM Workshop, 22. October 2015, Cologne 4

Spectrally weighted irradiance

Normalized spectral irradiance

E(λ) Spectral irradiance

Global irradiance

SR(λ) Spectral sensitivity of PV module

n(λ)=E(λ)/G


Error in Gw when using AM 1.5 instead of measured spectrum

• → don't neglect spectral effect!

Stuttgart, south oriented tilted plane, one year of data

Spectral measurements: Bastian ZinßerIPE Stuttgart


Seasonal effect

Spectral effect is site specific (→ presentation of Markus Schweiger)


PVKLIMA - Energy Yield of Thin Film Photovoltaic Modules under the Influence of different Climate Impacts

• Worldwide meteorological reference dataset to asses efficiency of modules under realistic working conditions

• Here: Characterizing and rating the impact of the solar spectrum on the energy yield of thin film PV modules

• (other impacts: temperature, soiling...)


PVKLIMA - Energy Yield from Thin Film Photovoltaic Modules under the Influence of different Climate Impacts

• Worldwide meteorological reference dataset to asses efficiency of modules under realistic working conditions

• Here: Characterizing and rating the impact of the solar spectrum on the energy yield of thin film PV modules

• Only possible when using satellite data!


Spectrally resolved iradiance data from satellite measurements

H2O, O

3, CO

2

absorptionAerosols: Scattering and absorption

Clouds: Scattering and absorption

ground reflection

www.clipartpanda.com


Modelling the Spectrum

• Atmospheric composition:

– Global MACC Dataset of European weather service ECMWF

• combination of ground measurements, satellite measurements and Numerical Weather Models

• Time resolution: 6 hours

• Cloud information:

– Heliosat method and geostationary satellite imagery

• Saving computing time:

– SOLIS: Parametrization of radiative transfer calculations


Spectral irradiance with SOLIS




Kato bands for faster computationN

orm

aliz

ed Ir

rad

ianc

e

Wavelength (nm)


Speed up computation time with SOLIS parametrization

slowradiation transport

calculation with libRadtran

atmospheric composition solar elevation

spectrally resolved irradiance for two

solar elevations

Fit mit „Modified Lambert Bar“

Funktion

MLB-Parameter

fit „Modified Lambert Beer“

function

fast„Modified Lambert Beer“

function

Solar elevation

Global irradiance:libRadtran supporting pointMLB FunctionlibRadtran

Direct irradiance:libRadtran supporting pointMLB FunctionlibRadtran

spectrally resolved irradiance

Two calculations for a given atmospheric composition

(Solar elevations 30° and 90°)As often as wanted Example: Irradiance at 530 nm

SZA=90°-Sonnenhöhe (°)

Based on Mueller et al 2002,EUMETSAT Conf.

x

+

Ein

stra

hlun

g (m

W/m

2)


How often do we need to calculate?

• spectral clear sky irradiance solely depends on solar elevation, if atmospheric state does not significantly change.

→ two radiative transport calculations are sufficient

• For which period can we suppose invariant atmospheric conditions?

• Preliminary study: approximately 10 days.




Heliosat method

Bild: EUMETSAT

reflectivity ρ of given image

one month of images VIS

cloud index n: measure of clouds

clear sky index k*:transmission through clouds

ground albedo ρground

n=ρ−ρgroundρcloud−ρground

0≤n≤1

k =GG clearsky

= 1−n

*

for each pixel:search forcloud freescene

Meteosat Second Generation: spatial resolution: up to 1x1 km temporal resolution: 15 minutes




Quality of method

PCA_SPEC: simple empirical method, clear sky index and solar elevation are only input


PVKLIMA results and future stepsFrequency of

calculation(preliminary study done)

Parametrization of Aerosol optical thickness(publication in preparation)

broken clouds

Developtilt conversion for spectral irradiance(in progress)

Application onMeteosat EastGOESvalidation starts now


PVKLIMA results and future stepsFrequency of

calculation(preliminary study done)

Parametrization of Aerosol optical thickness(publication in preparation)

broken clouds

Developtilt conversion for spectral irradiance(in progress)

Application toMeteosat EastGOESvalidation starts now


Tilt conversion

• Angle-resolved spectral irradiance can be determined with radiative transport calculations(computational intensive)

• -> simple model of hemisphere, similar to Perez or Klucher model and parametrization per Kato band.

• Spectral data for validation:

– Measurement of tilted spectral irradiance at the five PVKLIMA/TÜV Rheinland sites

– Simultaneous measurements of horizontal and tilted spectral irradiance at University of Oldenburg (RAMSES spectrometer, spring 2015)

Source: Perez et al., Solar Energy 39, 1987


Summary and Outlook

• Spectral impact on PV-yield can be analyzed with site specific timeseries of spectral irradiance

• for areas this information can be obtained with a combination of models, MACC and satellite data.

• The method is already available, further optimizations will be developed within PVKLIMA


References• LibRadtran:

–Mayer, B., and Kylling, A., 2005. Technical note: The libRadtran software package for radiative transfer calculations-description and examples of use. Atmospheric Chemistry and Physics 5, 1855–1877.

• SOLIS:

–Mueller, R.W., Dagestad, K.F., Ineichen, P., Schroedter-Homscheidt, M., Cros, S., Dumortier, D., Kuhlemann, R., Olseth, J.A., Piernavieja, G., Reise, C., Wald, L., Heinemann, D., 2004. Rethinking satellite-based solar irradiance modelling: The SOLIS clear-sky module. Remote Sensing of Environment 91, 160 – 174. doi:http://dx.doi.org/10.1016/j.rse.2004.02.009

• Tilt conversion of diffuse irradiance:

–Klucher, T.M., 1979. Evaluation of models to predict insolation on tilted surfaces. Solar Energy 23, 111–114.

–Perez, R., Seals, R., Ineichen, P., Stewart, R., Menicucci, D., 1987. A new simplified version of the Perez diffuse irradiance model for tilted surfaces. Solar energy 39, 221–231.

• Spectral irradiance from satellite data:

–Betcke, J., Behrendt, T., Kühnert, J., Hammer, A., Lorenz, E., Heinemann, D., 2010. Spectrally resolved solar irradiance derived from meteosat cloud information - Comparison of two methods, in: Proceedings of the 2010 EUMETSAT Meteorological Satellite Conference. Cordoba, Spain.

–Mueller, R., Behrendt, T., Hammer, A., Kemper, A., 2012. A New Algorithm for the Satellite-Based Retrieval of Solar Surface Irradiance in Spectral Bands. Remote Sensing 4, 622–647. doi:10.3390/rs4030622

Behrendt, T., Kuehnert, J., Hammer, A., Lorenz, E., Betcke, J., Heinemann, D., 2013. Solar spectral irradiance derived from satellite data: A tool to improve thin film PV performance estimations? Solar Energy 98, 100–110. doi:10.1016/j.solener.2013.05.011


Acknowledgements

• The project PVKLIMA is funded by the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMU) following an order by the German Federal Parliament (BMU FKZ 0325517B). The content of the presentation is the sole responsibility of the authors

Presentations & Public Speaking

20 bethke hammer_timeseries_of_spectrally_resolved_solar_irradiance_data_from_satellite_measurements