The eco-design of complex industrial systems becomes a major issue for the concerned companies. Life Cycle Assessment (LCA) in particular is more adapted to "classical" products such as consumer goods. Performing LCA of such systems requires some thoughts to ensure significant results, for example concerning data granularity and quality. This article proposes a Life Cycle Assessment of an Alstom Grid AC/DC conversion substation for the aluminium industry. This LCA integrates first answers to the previous limitations. Very interesting results permit to orient the eco-design strategy of the company. Moreover they lead to imagine original ways to configure the system. Thus a first and simple parametric LCA model is proposed: four different electrical sources are used to analyze the sensitivity of the design factors to the environmental impacts of the substation. Based on design of experiments, a more advanced model of such a tool would permit to identify the best configuration in terms of environmental performance, costs and reliability.