Second poster accepté à la conférence PVSEC de Villepinte 2013

Clear sky models assessment for an operational PV production forecasting solution

Sylvain Cros , Olivier Liandrat, Nicolas Sébastien, Cyril Voyant, Nicolas Schmutz

Second poster accepté à la conférence PVSEC de Villepinte 2013
Ce sera donc le second papier auquel j'aurai contribué qui sera proposé lors de cette conférence internationale. Un grand merci à l'équipe Reuniwatt qui est à la base de ce projet de comparaison de modèles de ciel clair. Le résumer de cette présentation est :

Photovoltaic power production relies upon solar radiation received at ground level, that remains
difficult to predict. Accurate forecast of surface solar irradiance is essential for grid operators in
order to accommodate this intermittent energy in their scheduling, dispatching and regulation of
power. Surface solar irradiance forecasting methods can be described as the prediction of the cloud
physical property over a specific area. This information is then combined with the value of the
irradiance under a clear sky for the same area at the same forecast time. Then, uncertainty of
irradiance under clear sky can affect significantly the forecast results accuracy.
Many clear sky models have been designed and are routinely used to compute surface solar
irradiance under a sky with no cloud for a diversity of applications. The required inputs for such
tools are varying from model to another. The simplest models just take into account the solar elevation, while more detailed ones may include other inputs such as concentration of atmospheric
components (aerosols, water vapor, ozone), elevation of the site, ground albedo, in order to
represent a realistic atmosphere transmittance. However, availability and quality of some inputs are
not always guaranteed at every locations.
The objective of our study is the selection and performance quantification of a clear sky model
usable with an innovative solar radiation forecasting tool. We selected the models Bird, Solis, ESRA
and McClear. These models demonstrated their accuracy and robustness and their features are
suitable for operational processes. We undertook our study over three sites located in Corsica,
French Guiana and Reunion Island. We collected available atmospheric parameters (aerosol optical
depth and water vapor) at these locations through the AERONET network and the MACC-IFS
reanalysis outputs. We compared simulated global irradiation with ground measurements at clear
sky situations. Comparisons have been made at a time step of one minute.
In our results, we present the intrinsic accuracy of each models for the three different sites. We
demonstrate explicitly that atmospheric inputs data quality are more important than the choice of
the clear sky model itself. However, for each models we quantified the loss of accuracy for clear
sky radiation according to the time sampling of atmospheric input data (monthly and daily). Finally,
we present recommendations for an efficient clear sky model setting according to the effective
availability of atmospheric input parameters at a given location.

5bv_4_69.pdf 5BV.4.69.pdf  (258.63 Ko)

Rédigé par Cyril VOYANT le Dimanche 16 Juin 2013 à 09:28 | Lu 327 fois