The new paradigm in which the electric power systems are developing, defined as smart systems, have a great impact on the consumers. By adopting distributed generation in an increasing proportion, they are becoming prosumers. The electricity market is therefore undergoing a structural change, in need to address the requirements of the prosumers. The market must address a vast array of topics, ranging from the reliability of electricity transmission and distribution, all the way to energy efficiency. The efficiency of the power supplied by the renewable energy sources can be maximized when paired with an energy storage system. In this framework, current paper is addressing the issues of ancillary services. In the first section, a general analysis was performed, aimed at accurately identifying the current state-of-the art of electric market. An example was designed, starting from a real electric distribution system, in order to create an arrangement of possible issues and solutions for the prosumers which are to be connected to the future electricity market schemes.