Advantages of efficiency-aware smart charging strategies for PEVs

Plug-in Electric Vehicles (PEVs) diffusion is expected to grow considerably over the next few years. Aiming to overcome severe grid overload problems caused by a large PEV penetration, utilities and vehicle manufactures are involved in the effort of developing ad hoc charging systems interacting in real-time with smart grids in order to implement smart energy dispatching strategies for PEVs. Strategies which take advantage of varying the charging rate during the charging process appear the most effective solution to guarantee both a full exploitation of the grid capacity and suitable degrees of user satisfaction. This work demonstrates that the actual effectiveness of variable-rate-based dispatching strategies significantly depends on the energy efficiency of the battery charging process, which is in turn strongly related to the charging rate used. Simulation results for a realistic situation show that smart efficiency-aware dispatching strategies, which take into account the actual dependence between the charging efficiency and the charging rate, allow significant improvements in both the user satisfaction and the utility profit compared with non-efficiency-aware strategies. The results of the analysis performed give useful guidelines for the development of smart-grid management policies and for the design of next-generation PEVs battery chargers and charging stations. (C) 2011 Elsevier Ltd. All rights reserved.