This paper outlines the decision support system that is being developing for the performance and financial analysis of the SEAM4US system, concerned with the implementation of an Intelligent Energy Management system for Underground Stations. A critical aspect for the design and implementation of advanced sustainable solutions for the energy saving in complex buildings is the assessment of the effectiveness of the approach in terms of both the amount of the energy saving and of the cost benefits. The required dynamic analysis of the building behaviours under different operational conditions makes it difficult to figure out the relevant operational scenarios. The paper describes a scenario analysis tool that simulates the operation of an underground station in different climatic conditions and with different system technology arrangements. The paper provides cost benefit analysis under different operational scenarios and proposes suitable business models for the overall technological framework.