Separate resource from technical loss
Irradiance, temperature, curtailment, inverter availability, soiling and string-level issues must be separated before assigning performance responsibility.
Review EPC quality evidence
As-built records, test results and punch-list closure can reveal whether underperformance began at delivery or developed during operation.
Improve O&M response loops
Fast fault response, cleaning discipline, inspection routines and performance analytics are often the fastest path to better energy yield.
Consultant Field Note
In real plant reviews, the most useful conclusion is rarely a single KPI. It is the connection between test evidence, alarms, operator logs, grid events and the corrective action that can be executed without creating new reliability risk.