'Energy regions' are regional initiatives, which are engaged in becoming energy self-sufficient by using regionally available energy sources. They support the overall transition towards renewable-based energy and are of key interest to understand how the energy systems and institutional settings in these energy regions changed over time. In this article, a historical and integrative perspective is employed in analyzing the transition process of an Austrian energy region towards energy self-sufficiency. Specifically, (i) an Energy Flow Analysis (EFA) was performed for three points in time (1990, 2000, and 2010); (ii) the institutionalization process was analyzed in terms of the key actors, key milestones, and key factors influencing the transition process; and (iii) an integrative analysis was performed to indicate how the technical and social systems are interrelated. It was found that the most significant changes in the energy region were the efforts made in setting up a decentralized energy system. The co-action of actors from all spheres of society is crucial for aiding energy transition while this process needs to be supported by activities fostering awareness, generate acceptance, and engage the public at large. While there is a clear correspondence between improvements in energy self-sufficiency and the requisite effort at institutionalization, there is also a noticeable time delay between the development of an 'energy vision' and the subsequent impact on energy infrastructure.