Energy systems are increasingly characterized as "multi-layered flow networks" spanning over different geographical areas. These spatial networks are global for their geographical extension. The different interacting layers of energy systems span from physical/technical (the hardware of the network), cyber (measurement, communication and control), market and business (wholesale and retail, services and operations), social (customers, users, stakeholders, …), normative (administrative issues, standards, etc.), and political (local, national and regional decision making, and geopolitical implications).
On the other hand, energy systems are constrained by environmental considerations (environmental impact, climate change and limitation of usable natural resources), and the set of externalities (from local to global; from immediate to long lasting). This results in the co-evolution of the technical, cyber, market and business, social normative and political layers that must be assessed in a global perspective.
An ideal case study are Electric Power Systems (EPS) that are multi-scale/multi-layers systems, characterized by two different interconnected and interacting levels, with different scales both in terms of extension and power/energy involved. The High and Extra High voltage transmission systems (supergrids) are emerging as global energy infrastructures spanning over continents (from EU to Russia to China to northern Africa,…); while, at a smaller scale, the distribution systems (smart grids) serve a set of prosumers with local distributed production and storage of electricity with new real-time bidirectional communications with the external word (network, retailer, …). The social networks among the prosumers, that might show different behavior in terms of acceptance or adaptation, may play a crucial role in the feasibility and sustainability of these systems.
Policy decision making, at local, national and international level, and regulation provide the rules that constrain the behavior of the different stakeholders. It is generally considered that the goal is that of maximizing the system performance (technical, economic, energetic, environmental), striving towards the highest sustainability, efficiency and security of the EPS; but social values can determine, for instance, the choice of more expensive options.
The modeling and simulation of the multi-layer interacting emerging EPS is key for supporting their design and assessment, and for anticipating future impacts and options to help all stakeholders in determining their decisions. A continuous feedback from reality will help adjusting both the models and the decision making.