Future Smart Grids involve new kinds of stakeholders, such as Aggregators and empowered Users to enable new kinds of energy-based business cases. Those services are based on vast amounts of Distributed Energy Resources (DER) and Renewable Energy Sources (RES). Furthermore classical SCADA systems have to be complemented by new ICT systems providing necessary distributed information management. A goal of Smart Grids is to increase Energy Efficiency by, e.g., empowering end users. However, Smart Meters to that end also open up possibilities for tempering and access to critical infrastructures by adversaries. The paper addresses some challenges related to sustainavle future energy systems