Vehicle-to-grid (V2G) technology enables bidirectional energy flow between the electric vehicle and power grid thereby making the electric vehicle as a virtual power plant. This seamless exchange of energy flow is possible only when the entities involved communicate wirelessly in a secured manner. In order to ensure privacy-preserving in the V2G communication, development of a novel key establishment protocol is an active area of research. This article presents a lightweight mutual authentication and key establishment protocol for secure V2G communication among the electric vehicle user, charging station, and utility service provider. The correctness of the proposed protocol is verified using the formal method BAN logic, and many of its security threats are analyzed informally. Further, the protocol is compared for its security and efficiency with the related protocols in the literature under various aspects, and the comparison results show that our protocol outshines the others. The functional correctness of the protocol is also verified in Xilinx Zynq-7000 series FPGA board so that it can be deployed in any real-time applications.