Abstract The interesting aspect with very little maintenance for this production mode makes photovoltaic solar energy an alternative for producing electrical energy through photovoltaic (PV) solar panels. However, the maximum power of the PV module depends strongly on the environmental conditions, namely temperature and solar irradiation, hence the need to introduce a MPPT controller which will enable the maximum power point (MPP) to be continuously monitored in real time. In the literature, there are hundreds of MPPT methods associated with dc-dc converters that differ from one to another by several criteria. The very important criterion is the MPPT efficiency. In fact, the maximum power delivered by such a method can only be examined if it is compared with the true expected power. In this paper, we propose a method to predict the maximum power of a PV module permanently and in real time under different environmental conditions. The purpose of this technique is to calculate the efficiency of the MPPT methods implemented in the static converters in order to evaluate their monitoring of the maximum power point. The proposed method is founded on calculation of the expected maximum power based on a linear regression model correlated with ambient temperature and solar irradiation. This technique is independent of the internal parameters of the PV module.