Thin film CI(G)S PV modules : results from monitored installations and comparison tests

Abstract

The paper explains the main features of the thin film CIS PV modules and tries to highlight the advantages of the technology even in Mediterranean countries. In the real world conditions CIS PV installations have a better performance in terms of specific generated output (kWh/kWp) in comparison with crystalline silicon modules, improving the return on investment for the end user/investor and maximizing the self-consumption. The main factors that contribute to the higher yields of CIS PV installations in comparison with c-Si are: the high temperature stability, the good behaviour with low light and low angle irradiation, high shadow tolerance and the light soaking effect. Several installations in different parts of the world with various weather conditions have been monitored scrupulously throughout the years with the production of a significant number of case studies. The results confirm that PV installation with CIS modules generate an average of 10% more electricity per rated power (kWh/kWp) even in optimal condition (modules facing south with 20-30° tilt). This gap increases as the condition of the weather (ambient temperature, irradiation) and of the roof (tilt, azimuth) varies from the optimal one. Due to their high flexibility in the installation it is possible to maximize the yield for the given area (kWh/sqm).