Electric vehicles are seen as an option to reduce greenhouse emissions, directly related with the electricity generation mix and with the time of charging due to the variations of the generation sources during the day. At the same time, with their widespread adoption the increase in the demand for electricity to charge these vehicles could pose significant challenges to the electrical grid in terms of additional load due to unmanaged charge strategies. In order to mitigate these problems, the charging of the electrical vehicles must be managed. This paper presents the development of a system architecture to dynamically control the charging of electric vehicles to maintain the proper operation of the local distribution grid and minimize the environmental impact. The hardware consists of two modules, a meter and controllable plugs both with communication capabilities, while the software consists in a forecast and scheduler module. The forecast module calculates the load based on the power consumption behavior and uses the renewable generation forecast to assign the best time slot to charge the vehicle. The system aims to minimize the load peaks and flatten the load profile, while minimizing the environmental impacts. Based on the user preferences, system characteristics, consumption and renewable generation forecast, the system will assign the most suitable time slot to charge the electric vehicle. For the case of multiple electric vehicles, the system will schedule their charge based on a calculated priority level, in order to maintain a reliable operation of the local electrical grid.

Regarding expected contribution of Plug-in Electric Vehicles (PEV) to improve the energy efficiency, to reduce CO ₂ emissions and to support the integration of renewable energy sources, this paper presents the legal framework for development of electric mobility in Portugal. Followed by a brief description of methods and modes of PEV charging and by an introduction to the harmonic theory, measurement results are presented for Normal Power and High Power DC charging methods. The results include the characterization of voltage and current harmonic distortion during charging operations of the ISR's Nissan Leaf, by a normal socket outlet in office-building, and the EDP's Mitsubishi i-MiEV, by a High Power DC charging point in a Galp's gas station.