Satellite-based information for planning solar energy applications

It is important to have advance knowledge on the incident solar irradiance in order to plan solar power plants and scale the heating infrastructure of buildings.

MeteoSwiss performs analyses of the spatial and temporal variability of the solar irradiance. The data used for such analyses accounts for the complex Alpine terrain and it includes the diverse interactions of horizon, snow cover and cloudiness in this terrain. The satellite climatology employed by MeteoSwiss consists of a multi-year dataset of solar irradiance derived from Meteosat Second Generation data back to 2004. It can be extended by Meteosat First Generation data back to 1983. The satellite climatology was validated with long term records of station data.

The seasonal and inter-annual variability of solar irradiance at a given location is needed in order to evaluate the suitability of a photovoltaic or thermal power plant or for calculating the energy consumption of a building. Satellite data of solar irradiance can further be used to create spatially distributed usability maps of solar irradiance. Depending on the application needs an extreme value analysis or an uncertainty estimation can be conducted.

Our analyses are jointly based on spatially distributed satellite-derived solar irradiance maps and point-scale ground measurements. Ground measurements are very accurate for each respective measurement location, and satellite-derived solar irradiance maps allow analyses for regions without station coverage. The solar irradiance is not directly measured by satellite sensors. It is calculated by use of the so-called Heliosat algorithm. Through our long-term research collaboration within the EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) the Heliosat algorithm was extended by MeteoSwiss. It is now suitable to calculate solar irradiance and radiation components in complex terrain and it for instance accounts for the reflective properties of snow. The resulting climatology was validataed with ground measurements. The satellite climatology can be de-biased with ground measurements if required by the application.

See Data Basis for more information.