Universidad Politécnica de Madrid

Instituto de energía solar

Estimation of PV plant production


The estimation of the energy productivity is the starting point for a quality control of a PV plant. Once the location and the main characteristics of the PV plant are defined, a simulation exercise based on a model of the behavior of the PV plant that relates the ambient conditions (mainly solar irradiation and ambient temperature) and its electrical response (power and energy injected into the grid) is carried out.

We use our own simulation software called SISIFO, that has three main blocks:

  • Estimation of the meteorological conditions, that is, horizontal solar irradiation and ambient temperature
  • Estimation of the operating conditions: effective irradiation on the PV generator  surface and its operating temperature.
  • Estimation of the electrical response of the PV plant (PV generator + inverter + AC transformer)


  • Collection and analysis of available solar radiation and ambient temperature information.
  • Energy losses scenario definition
  • Energetic behaviour simulation
  • Estimation and yearly energy production and future degradation
  • Design evaluation

Applied standards and references

  • Databases: PVGIS, NASA, CMSAFT, SoDa, SWERA, meteorological stations, professional data providers.
  • Own software, SISIFO, and own models for considering daily irradiance profiles, spectral and angular PV generators response, and shading impact.
  • Martin N and Ruiz J, Calculation of the PV modules angular losses under field conditions by means of an analytical model; Sol Energy Mater. Solar Cells, 70, 25-38(2001)
  • O. Perpiñán et al, On the calculation of energy produced by a PV grid-connected system. Progress in Photovoltaics: Research and Application, 15, pp. 265-274, 2007.
  • O. Perpiñán et al On the complexity of radiation models for PV energy production calculation. Solar Energy, 82, pp. 125-131, 2008.
  • L. Narvarte et al, Tracking and ground cover ratio. Progress in Photovoltaics, 16, pp. 703-714, 2008
  • E. Lorenzo et all “Tracking and Back-tracking”. Progress in Photovoltaics: Research and Applications, 19 (6), pp. 747-753, 2011.
  • F. Martinez-Moreno, J. Muñoz y E. Lorenzo, Experimental model to estimate shading losses on PV arrays, Solar Energy Materials & Solar Cells, 94(12), 2298-2303, doi: 10.1016/j.solmat.2010.07.029. Diciembre 2010

Contact person: Prof. Eduardo Lorenzo 


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