This paper discusses the concept of “consumption competence” at the heart of Service-Dominant Logic and the co-creation process of value. In order to examine the issues related to this emerging concept, the research methodology was divided in two parts. In the first one, we introduced a longitudinal ethnography research (2005-2007) based on participant observation and in-depth interviews with employees in a French business energy supplier called “Utility X”. This choice was the best means to understand how do managers in the energy sector consider their customers: are clients represented as active actors or as passive actors within their own consumption experiences. The second part of this research based on in-depth interviews conducted in 2009, involved a group of 10 customers of “Utility X”. The objective of these interviews was to emphasize the consumer's activation of his competencies in the energy sector. This methodology was applied in order to get crossed glances on the concept of the “consumption competencies” emerging in the energy sector.