Light soaking (CIS/CIGS)

What this step does

The gain of CIS and CIGS modules, whose output rises during the first hundreds of hours of sunlight, taken as a flat fraction of the array energy. It acts on the array energy right after the light-induced degradation row; the light soaking gain input sets the fraction.

The math

$$E_{after} = E_{before} + E_{ls},\qquad E_{ls} = g_{ls}\,E_{before} \tag{1}$$

where

Symbol	Meaning	Unit
$E_{before}$	the running total of the loss diagram before this row	kWh/kWp
$E_{after}$	the running total after this row	kWh/kWp
$E_{ls}$	the row, a gain	kWh/kWp
$g_{ls}$	the light soaking gain input, a fraction	—

Reading the number

A gain, positive. A common range for CIGS modules is 3 to 5 %, the same on utility and rooftop systems. The model applies it only to CIS and CIGS modules and ignores the input for every other technology. The inverter clipping takes part of it back.

API

loss.light_soaking

Symbols follow the symbol registry.