Sun radiation

The Sun energy is coming continuously to the Earth with daily and seasonal changes in Sun radiation on the Earth surface. On it's way to the Earth surface approximately 30% of Sun radiation is directly reflected to space, depending also on atmospheric conditions and taking into account the Earth’s rotation, we can roughly assume, in average, 200 W/m2 [2] on Sun radiation annually resulting in more than one billion TWh of available Sun Energy annually, which is enormous (figure 2).

Figure 2 World’s energy consumption compared to all fossil reserves and its annual solar energy potential [2]

For most commercial application of Sun energy usage it is sufficient to use analytic data from available measurements data bases. The most comprehensive and recent database is coming from the Joint Research Centre (IET) of EU called Photovoltaic Geographical Information System (PVGIS) with 1 - 2 km resolution, public and available in [3].  More precise and scientific approach option is to perform detailed measurements with solar radiation measuring equipment such (thermic or semiconductor) of global (total), direct and diffuse(scattered) radiation on horizontal surface on location for at least one year measuring energy density H in [Wh/m2].

Figure 3: Solar radiation in (cross-border region of) Croatia and Hungary [3]


[2] Stefan C.W. Krauter ‘’Solar Electric Power Generation – Photovoltaic Energy Systems’’ Springer, Berlin 2006.

[3] European Commission, DG Joint Research Centre, Institue for Energy and Transport: PVGIS PhotoVoltaic Geographical Information System,, 2013

Top of the page
Image gallery