The research group “Sustainable Energy System Analysis and Modelling” (SESAM) is part of Politecnico di Milano, Department of Energy, and operates under the auspices of the UNESCO Chair for Sustainable Development. SESAM's research focuses on the development and application of models for the analysis of systems and components within the energy field with application in both developed and developing countries. Our research builds on the well-established potentiality of integrated and cross-sectoral (electricity, heat, transport...) energy system optimisation and simulation models by expanding their domain of application to multiple spatial and temporal scales. This is achieved through: - technological characterisation (of products and/or systems) based on thermo-fluid dynamics detailed modelling of components and plants, realised through the use of both commercial (Ansys) and open-source (OpenFoam) CFD codes; - characterisation of intlinkages between the energy sector and other productive sectors (e.g. manufacturing, storage and transport of fuels, land-use) based on empirical models applied to industrial ecology (LCA, hybrid Input-Output) to estimate the economic-environmental impact of alternative energy strategies and policy options. - characterisation of the multifaceted and multidimensional complexites of the energy-development nexus in the energy access field, based on conceptual and simulation models (e.g. system thinking, system dynamics, impact evaluation frameworks) to support the planning of off-grid system and electrification strategies.