This study is a case study on the different European associations’ advocacy efforts towards the Commission during the agenda-setting stage of the recently adopted Energy Efficiency Directive. In order to understand what facilitates interest groups access to the Commission, a model of demand and supply for information is presented. This model takes the theory of access goods as the point of departure, complimented with recent studies on interest groups supply of information to European institutions. Here, information supply is understood in terms of an interest group capacity to gather information through monitoring policy developments and producing relevant policy information. The study finds out that the Commission was largely in need of technical information and that groups from the building sector were the major providers of such information. Also, since many of the interest groups lobby strategies was recognized by a high degree of coalition building, the study seeks to explain under what conditions coalition building between European federations can occur at the EU level. This refers to a specific case of coalition building, namely the Coalition for Energy Savings. This coalition will be attempted explained through the use of process tracing by drawing on earlier literature and empirical evidence of collaboration between interest groups. The study thus takes an exploratory and theory development approach. To that end, interviews were conducted with representatives from leading European federations, including coalition staff. Finally, findings indicate that both interest groups previous collaborative behavior as well as the nature of the policy issue explains why interest groups decide to establish a coalition.