The modeling of energy systems, both in physical-mathematical and engineering terms, both in economic-financial and market terms, and in environmental terms, is the sector of greatest specialization of Studio Santi, founded and directed by Federico Santi, expert model maker internationally known, for 16 years Professor of “Models for the analysis of energy systems” at the energy engineering degree course of the University of Rome Sapienza. The construction and analysis of scenarios, using advanced modeling techniques, is the element that most characterizes the studies and projects of Studio Santi, which allow a deep understanding of the phenomena (also in a forecasting key) and energy, economic-financial and environmental optimization of energy system design. For Studio Santi, modeling is the basis of the “Smart Design” of energy systems, essential for the growth of energy efficiency over time.