The purpose of this work is to evaluate four empirical models developed in literature such as Ghouard, Perrin Brichambaut, Bird and Hulstrom and Dependent model of the Link trouble factor. The validation of these different theoretical models was carried out using solar global radiation data collected on the Cheikh Zayed Nouakchott power plant. These measurements were carried out at a time step of 5 minutes during the period of one year. (April 1, 2015 to March 31, 2016). The results show that the Ghouard model presents notable performances compared to the other models, with a determination coefficient of 96.2%. This validation also shows that the solar radiation measured and that estimated by the different models have the same pace and have good performance with a coefficient of determination greater than 93%. The available solar potential estimation was carried out using the actual measurements collected on the Cheikh Zayed plant. The results obtained showed that the available solar potential is 5 kWh / m² / d.