The critical role of the electrode material characteristics in increasing the probability for observation of excess of power during electrochemical loading of palladium cathodes with deuterium is investigated, and, excesses of power production obtained by using palladium material with these identified characteristics are reported. Characterizations have been performed by using SEM and AFM microscopy as well as electrochemical analysis and XPS. The emerging scenario suggested by these results is that the poor control in achieving the identified material status is reflected in the reproducibility of the excess heat phenomenon. © 2015 ISCMNS. All rights reserved. ISSN 2227-3123.