Self-Adapting Coalition Formation among Electric Vehicles in Smart Grids

In the last years, the need for using multiple energy sources made the concept of smart grids emerge. A smart grid is a fully automated electricity network, which monitors and controls all its elements being able to supply energy in an efficient and reliable way. Within this context, the use of electric vehicles (EVs) and Vehicle-To-Grid (V2G) technologies have been advocated as an efficient way to reduce the intermittent supply associated with renewable energy sources. However, operating on V2G sessions in a cost effective way is not a trivial task for EVs. To address this problem, the formation of coalitions among EVs has been proposed as a mean to improve profitability on V2G sessions. Addressing these scenarios, in this paper we introduce the Self-Adapting Coalition Formation (SACF) method, which is a local and dynamic heuristic-based mechanism for coalition structure generation. In our approach, coalitions are formed observing constraints imposed by the grid to the EVs, which negotiate locally the formation of feasible coalitions among themselves. Based on experiments, we see that SACF is an efficient method, providing good solutions in a simple and low-cost way. SACF is faster than centralized methods and provides solutions with near optimal quality. In dynamic scenarios, SACF also shows very good results, being able to keep the agents gain relatively stable along time, even in quickly changing environments. Its main advantage is that the computational effort is very low, while classical centralized methods are limited to manage no more than a dozen agents in a reasonable amount of time.