Fig. 4
The photographs show two views on the experimental table with fine ash (left and with lapilli size (right side), where the upper module shows an amount of 100 g/m2, and the lower module shows 400 g/m2. Close up views on the table illustrate that the grain size may influence the power generation of the PV-module depending on whether it is entirely covered or still operating. Contrary to the fine and coarse ash coverage, conditions as shown for the lapilli size range are unlikely to be applicable to a real scenario, however the systematic measurements highlight the general grain size dependency of tephra load vs. power output