Reliability concerns and continuous availability of superconducting magnetic energy storage (SMES) devices in photovoltaic (PV) power generation systems have been greatly increased. The PV generation systems are highly affected by the continuously changing solar irradiance levels in addition to the operating ambient temperatures. A practical power losses model based on the available experimental measures of SMES devices is proposed in this paper. In addition, this paper presents power losses performance comparison for SMES devices in PV systems with considering the fluctuations in PV generations and the various types of loading. The new proposed model is simple to be integrated with the power management controllers, in addition to being modular for various SMES ratings. A hybrid PV-SMES energy system is selected as a case study with various types of loads for validating the new proposed loss model.