**Slawomir Gulkowski \*, Agata Zdyb and Piotr Dragan**

Institute of Renewable Energy Engineering, Faculty of Environmental Engineering, Lublin University of Technology, Nadbystrzycka 40B, 20-618 Lublin, Poland; a.zdyb@pollub.pl (A.Z.); piotr.dragan@wisznice.pl (P.D.) **\*** Correspondence: s.gulkowski@pollub.pl; Tel.: +48-81538-4654

Received: 30 October 2018; Accepted: 26 December 2018; Published: 3 January 2019

**Featured Application: This research contributes to guiding planners and investors in the sizing, locating and selection of module types for photovoltaic (PV) installations. It can be useful for the prediction of electric energy production by different PV technologies at high latitude under temperate climate conditions.**

**Abstract:** This study presents a comparative analysis of energy production over the year 2015 by the grid connected experimental photovoltaic (PV) system composed by different technology modules, which operates under temperate climate meteorological conditions of Eastern Poland. Two thin film technologies have been taken into account: cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS). Rated power of each system is approximately equal to 3.5 kWp. In addition, the performance of a polycrystalline silicon technology system has been analyzed in order to provide comprehensive comparison of the efficiency of thin film and crystalline technologies in the same environmental conditions. The total size of the pc-Si system is equal to 17 kWp. Adequate sensors have been installed at the location of the PV system to measure solar irradiance and temperature of the modules. In real external conditions all kinds of modules exhibit lower efficiency than the values provided by manufacturers. The study reveals that CIGS technology is characterized by the highest energy production and performance ratio. The observed temperature related losses are of the lowest degree in case of CIGS modules.

**Keywords:** photovoltaic systems; thin film modules; performance assessment; PV efficiency
