journal homepage: www.elsevier.com/locate/segan Editorial 1. The evolution of modern power systems as our starting point Fundamental changes are currently taking place in modern energy systems and, particularly, in electrical ones. Infrastructures have to satisfy conflicting requirements: providing reliable and secure services to an increasing number of customers, taking into account a rational use of energy and the protection of the environment. This last requirement drives major changes in electrical and energy systems where increasingly renewable energy sources need to be connected to the grid. It is generally acknowledged that these sources need to be massive and distributed, in order to provide a non-negligible part of the consumed electrical energy [1]. It is also generally agreed that such integration of renewables into existing grids depends on the successful combination of specific processes (e.g. demand side/response management, real-time consumption management, real-time local energy balance, accurate forecasting of renewables at continental, country and regional scales) and new technologies (e.g. smart meters, agent-based distributed controls).Currently, there is a major effort from different research communities, in particular those of applied mathematics, control theory, computer science and, of course, power systems, to propose, discuss and validate new methodologies for the planning, operation and control of future electrical and energy systems. It is within this context that Sustainable Energy, Grids and Networks (SEGAN) has been launched.