Evaluating the state of the art of photovoltaic performance modelling in Europe

There are many models currently available which provide detailed information regarding the performance of PV modules. This paper reviews, as part of the European co-ordination action PV-Catapult, the different performance modelling approaches currently developed by European research institutions. The aim of this paper is to provide an overview of modelling approaches available and define the inputs required for each model. This will be used to investigate the accuracy of these models for different European climatic conditions in a second
stage of the project. All methods are reviewed, highlighting strengths and weaknesses of each. None of the methods consider temporal variations, such as degradation in the case of amorphous silicon. This paper investigates the impact this has on the year-to-year performance translation of such devices. Furthermore there is very little consideration of the incident spectrum, which affects wide band gap devices and multi-bandgap devices disproportionately, but this effect commonly is folded into irradiance and temperature effects. The implications of these are discussed based on current sales practice of quoting straight kWh/kWp, indicating the need for a better, technology independent comparator based on realistic energy production, rather than today’s STC laboratory efficiency. The results indicate that most models can predict energy yield within 10%.