This paper reports on the work of the CIGRÉ C6.22 Working Group, Microgrid Evolution Roadmap, which has recently finalized its first Technical Brochure. The Working Group was asked to identify the main elements required to justify, develop, and implement viable microgrids, which the Group defined as follows: Microgrids are electricity distribution systems containing loads and distributed energy resources, (such as distributed generators, storage devices, or controllable loads) that can be operated in a controlled, coordinated way either while connected to the main power network or while islanded. The main types of microgrids are described, and a benefits estimation approach developed and demonstrated. Also, an extensive review is made of microgrid functionality and technology, and a data base of microgrid pilot projects has been built.

The increase in the amount of generators based on renewable energy sources (RES) in the power system is leading to many changes in its operation. Since the RES depends on weather conditions, coordinating the operation of the entire power system has become a more complex issue. New challenges need to be faced in order to supply the electric energy to the customers at the appropriate quality level. In this paper the concept and architecture of a complex virtual power plant (VPP) will be introduced and discussed. The focus will be paid to the optimization of the structure of the VPP as well as to its optimal operation. The result of the optimization have been presented and discussed in the paper taking into account different operation scenarios.

Due to the high volatility of the oil price, cars producers have been motivated to find new solutions for reducing or eliminating the use of fossil fuel. In the last few years, hybrid vehicles (combustion engine combined with an electric motor) and full electric vehicles (EVs) have been designed and commercialized with relatively good success. Both technologies use batteries to drive an electric motor. Nowadays there are two main options for charging the batteries: · Through the direct connection of the vehicles to the grid, so called V2G · Through a battery switch station (BSS), where the empty batteries are replaced with charged batteries. Both the V2Gs and the battery switch stations can operate either as an energy source, when the batteries are fully charged or as an electrical load, when the batteries need to be charged. The use of EVs, whose batteries are recharged by using renewable energy, can mitigate the bottleneck operative situations, which generally appear in power systems with a high penetration of generators based on renewable energy sources. Nowadays, such a problem is handled using the Net Security Management System (NSM) which limits the production of the generators based on renewable sources. Although such a device works well, it has the disadvantage of wasting "green energy". The aim of this work it to analyse the behaviour of an Autonomous Power System (APS) with a high penetration of generators based on renewable energy sources where BSS are used both for charging the EVs and for energy management purposes. Moreover, the operation of an Intelligent Management Energy System (IEMS), which optimizes the power flow depending on the power demand, will be described. If there is an electrical surplus, the IEMS directs the power flow to the battery switch station, while if there is an electrical deficit the IEMS collects electricity from it. The benefits (economical and environmental) which the BSS gives to the APS will be evaluated. The optimal storage capacity of the BSS will be estimated.