On decentralized coordination of electricity demand of connected electric vehicles: A review and roadmap to blockchain adoption in e-mobility

With the growing global interest towards sustainable mobility, electric vehicles (EVs) are gaining increasing popularity as a zero-emissions transportation solution with a reduced carbon footprint. Nonetheless, the growing penetration of EVs translates into an increase in the overall electricity demand of the transportation sector, which imposes additional energy generation and distribution requirements. Optimal EV charging coordination strategies are essential to ensure stable grid operation while addressing the growing demand. This optimal coordination can take place on a centralized charging controller or in a decentralized execution and decision-making system. However, while centralized coordination helps achieve global optimal results, it suffers from data security, privacy, and scalability issues. In contrast, decentralized coordination encourages EVs to optimize their charging decisions towards their self-interests while acknowledging community-level advantages. Accordingly, to ensure information security and transparency during decentralized decision-making, blockchain technologies can be utilized to secure the underlying energy coordination transactions and execute the associated algorithms on tamper-proof smart contracts. This facilitates secure peer-to-peer energy trading activities between connected EVs and effectively coordinates their energy requirements. Hence, this paper reviews state-of-the-art literature on the different decentralized EV charging coordination techniques and studies the role of blockchain technologies in improving the security, transparency, and scalability of EV charging coordination systems. The presented review helps in identifying key research gaps in this domain and provides guidelines for further studies into blockchain-enabled EV charging coordination.