A Game-Theoretic Analysis of Pricing Competition between Aggregators in V2G Systems

While the Plug-in Electric Vehicles (PEVs) are gaining popularity, Vehicle-to-Grid (V2G) technology is becoming a reality. In V2G, a PEV provides energy as well as consumes it. Since the battery of a PEV can store a small amount of electric power, a large number of PEVs must be combined to offer useful services to the grid. However, these vehicles must be managed to provide controlled services according to the need of the grid leading to the introduction of an aggregator. This work assumes a system of multiple aggregators to which a PEV can choose to subscribe. An aggregator charges its subscribers for the V2G services. To maximize their profits, the aggregators vie with each other to get the market share. This competition dictates the prices and it is crucial for each competitor to choose an optimal price. The competition among aggregators is influenced by several factors. In this work, we analyze this competition by modeling the problem as a sequential game, in particular, using the Stackelberg Leadership Model. Solving the model provides the optimal prices. We also analyze the same problem by modeling it as a simultaneous game using the Cournot Competition Model and compare the game results with that of the Stackelberg game. We conduct an extensive evaluation of the game results to demonstrate the influence of different factors on optimal behavior.