Load-scheduling and Plug-in Hybrid Electric Vehicles in the Smart Grid

Peak demand is a well-known problem in the power grid. It denotes the amount of power required to supply consumers at times when demand is highest. Load peaks can have a negative impact on the stability of the power grid and maintenance costs for transmission and generation companies. Because of this, electricity prices often increase during peak demand. Currently, increasing use of plug-in hybrid electric vehicles (PHEV) further proliferates this problem because charging patterns are expected to coincide with peak demand hours, and especially the afternoon peak hours when people return home from work. To avoid the problem that increasing PHEV demand will further aggravate peak demand hours, several different multi-agent scheduling mechanisms have been investigated, including two centralized scheduling mechanisms and two decentralized scheduling mechanisms. For both of the decentralized mechanisms, the PHEV agents choose their own charging plans without relying upon a centralized scheduler, while in the centralized scheduling mechanisms, the PHEVs agents defer control to a central agent for creating their charging plans. From the results, we found that while both the centralized mechanisms and the decentralized mechanisms helped to reduce the average maximum peak, the performance of the centralized mechanisms proved to be highly dependent on how the day-ahead portfolio was calculated. Because of this, the overall best performer was decentralized mechanism, which gave the best results for reducing the average maximum peak without compromising the ability of the PHEVs to charge their batteries too much.