Condition type

STC

Real condition

1

Solar incident

angle

Always zero, irradiation beam always normal to the PV panel, (can be achieved in real operation)

Variable, and depends on time, date, and site latitude. In case of roof top system, roof orientation and inclination governs system capacity.

2

Solar irradiation

Always equal to 1000 W/m²

(cannot be achieved in real operation)

Variable and depends on the time, date, and site latitude. Limited sun shine hours bound system capacity.

3

Ambient temperature

Always 25˚C, (cannot be achieved in real operation)

Variable and depends on the time, date, weather condition and site latitude. Higher ambient temperature degrades PV panel efficiency and reduces system output.

4

Air mass

Coefficient (AM)

Always equal to 1.5 (cannot be achieved in real operation)

Variable and depends on the time, date, and site latitude. Higher AM with higher latitudes.

5

System losses (eg., wiring, inverter)

Always Zero (cannot be achieved in real operation)

Variable and depends on the design and location of PV panels, inverter, and grid meter.