Nowadays, the increasing interest in Cloud computing is motivated by the possibility to promote a new economy of scale in different contexts. In addition, the emerging concept of Cloud federation allows providers to optimize the utilization of their resources establishing business partnerships. In this scenario, the massive exploitation of ICT solutions is increasing the energy consumption of providers, thus many researchers are currently investigating new energy management strategies. Nevertheless, balancing Quality of Service (QoS) with both energy sustainability and cost saving concepts is not trivial at all. The growing interest in this area has been highlighted by the increasing number of contributions that are appearing in literature. Currently, most of energy management strategies are specifically focused on independent Cloud providers, others are beginning to look at Cloud federation. In this paper, we present a …