Combining Production Data Timeseries and Infrared Thermography to Assess the Impact of Thermal Signatures on Photovoltaic Yield Over Time

Photovoltaic (PV) modules with thermal signatures can be detected by infrared thermography (IRT) and the resulting power loss from these modules can be estimated through analysis of corresponding energy yield time series data. In the present work, we combine these methods to analyze the effect of PV module degradation modes on the overall energy generation in a 75 MWp PV power plant. We find that 0.2% of the PV modules are affected by thermal signatures after 5 years of operation and that the thermal signatures lead to a 0.06% reduction in power plant yield. We calculate a payback time of the IRT scan and subsequent replacement of modules affected by thermal signatures of more than 10 years for the investigated power plant. However, the power loss associated with thermal signatures seems to develop nonlinearly over time. This underlines the importance of continuous, long-term monitoring: it enables monitoring of performance in relation to warranty limits and supports prioritization of replacement actions required for cost-effective operations and maintenance strategies. This information is also required to understand PV module degradation modes, their time dependence and their dependence on module technology and climates.