Non-Conforming PV Modules and Tolerances

A photovoltaic module comes with a data sheet providing electrical characteristics, the specifications of the solar panel. A crucial parameter of those specifications is the nominal power output, e.g. 200 Wp, which is usually accompanied by a tolerance such as 5% leading to the specification interval ranging from 190 Wp to 210 Wp. The nominal power output gives the energy delivered by the PV module in Watt measured under standard test conditions (STC).

The lower specification limit is defined as the nominal power output minus the tolerance times nominal power output, i.e. 190 Wp in the example above. Any PV module with a real power output less than that lower limit is called non-conforming.