This report is a description and cross-regional comparison of the institutional structures and modeling methodologies of the three regions participating in the IIASA Research Program on Management of Regional Energy/Environment Systems. Descriptions are presented for the state of Wisconsin (USA), the German Democratic Republic, and the Rhone-Alpes Region (France), by specialists and policy makers from the respective regions. These descriptions demonstrate quite vividly the relationships between the institutional structure of a region and its use of models and planning tools