Optimal Capacity Sizing for Completely Green Charging Systems for Electric Vehicles

Although proliferation of electric vehicles (EVs) is associated with significant environmental benefits, these benefits would be forfeited if the associated EV charging systems would rely only on conventional power grid, whose power is mainly generated by fossil-fueled power plants. In contrast, utilizing distributed renewable energy sources (RES) will preserve and further amplify these environmental benefits. However, planning of green EV charging systems has not been adequately investigated in the technical literature. This paper studies the optimal sizing of a completely green charging system, which relies entirely on the power generated by RES, specifically by solar panels. In particular, this paper presents a methodology to determine the optimal resource size (e.g., the number of solar panels and the energy-storage capacity) that minimizes the charging system's investment costs, while meeting the charging system's performance metrics. A search-based algorithm is devised to solve the formulated nonlinear integer programming problem in order to efficiently explore the problem's solution space. A 3-D Markov chain model is used to account for the intermittency in solar power production. Finally, an example of a completely green charging system is presented to demonstrate the use of the proposed methodology.