This paper presents an application of Multiple Attribute Utility Theory on strategic choices concerning energy transportation. The environmental assessment of a network reinforcement strategy is emphasized. Our assessment brings about to consider multidimensional variables in MCDM. However, Multi-Attributed Utility Theory (MAUT) cannot, as a practical matter, manage such variables. We therefore work out a methodology to transform multidimensional variables into unidimensional ones. We apply it then to a pratical case. From the application, we draw some conclusions on Multi-Attributed Utility Theory and on its interest for strategic choices dealing with environmental consequences.