Prediction of the energy yield of PV plants



The requirement to make accurate predictions of the energy yield of a certain PV module (or PV plant) at a given location and the way how it is mounted arises primarily from investors in the PV power plant. It is important to the prospective investor to now how much he can expect from his investment and also to assess the energy and especially economic viability of the PV plant. In the case of predictions of the energy yield of PV modules or PV plants only on the basis of the STC or NOCT values ​​(given in data sheets by the manufacturers) often leads to overly optimistic estimates of yield. The optimistic forecast assist the investment decision, but it could lead to long term disappointment, if the too optimistic energy yield predictions are not realised.


Main influences on PV plant energy yield

  • PV generator (PV modules)
    • efficiency
    • temperature effect
    • solar radiation and specter effect
    • ...
  • Location effect
    • solar radiation
    • shading (surroundings, self shading)
    • air temperature
    • wind speed
    • ...
  • PV generator positioning
    • orientation
    • inclination
    • mounting type (open-rack mounted / building integration)
    • tracking type (fixed, one or two axis tracking)
    • ...
  • Inverter, interconection and protection elements effects