Energy performance index (EPI)

The energy performance index is the ratio between a system’s actual yield and simulated yield. Ideally, the value should be as close to 100% as possible. The simulated yield is calculated based on a daily irradiation value at the module level, module temperature, and the technical properties of the components, such as inverter characteristics or module efficiency.

Simulation is configured under System configuration (wrench icon) > Calculations > Simulation. See Simulation and solar power chart.

Energy performance index chart