Thanks to their high shadow tolerance, PowerModules are very efficient even when shadows are cast over the modules or their surfaces are partly covered.
The reason for this can be found in the different cellular structure. The square silicon cells in the module are connected in substrings. On the other hand, the long, very narrow thin-film cells are connected in series.
The entire c-Si module stops working as soon as a small area, a single cell, for example, is covered or shadowed. In contrast, the CIS module continues working, only the covered or shaded area stops producing energy. The results are higher yields even in the shade.
This has the advantage that some shadowing is acceptable in designing the system, in order to achieve the highest yields. If defined shadows are to be expected, (for example: horizontal shadows in the morning or evening cast by a shed roof, or in a field system), then energy production can be optimized: in this case, the CIS modules must be installed with the cell perpendicular to the cast of the shadow. If shadowing of a module or a module row of x% occurs, there is still energy production of 100-X%.
The cell structure of the modules and the associated shadow tolerance has the added advantage that the distance between module rows can be reduced in free-field installations and on industrial flat rooftops, so more generating power, expressed in Watt-peak, can fit in a given area.
