The global power generation landscape is undergoing significant change, driven by the increasing penetration of wind and photovoltaic (PV) technologies as primary renewable energy sources. The latter, thanks to its modularity, is used on a wide range of scales, from large power plants to distributed installations on the rooftops of individual users. The operation and maintenance (O&M) management of rooftop PV systems present significant challenges for efficient oversight due to the large number and variety of potential scenarios. This research focuses on the practical challenges encountered by rooftop PV systems in the industrial sector. Electrical and environmental parameters have been monitored in three rooftop photovoltaic systems located in industrial environments, aiming to conduct a performance analysis. The industrial facilities are located in the south of Spain, each equipped with rooftop PV systems for self-consumption, they have nominal array capacities ranging from 10 kW to 50 kW. The results show a wide range of performance scenarios, with performance ratios (PRs) varying between 0.4 and 0.9. The study highlights the importance of taking into account user specific requirements, the influence of grid operators and ongoing technological advances when evaluating and analysing the performance of PV systems.