Improving Battery Lifetime of Gridable Vehicles and System Reliability in the Smart Grid

Abstract

The intermittent nature of renewable energy sources (RESs) and unpredictable load demands are two major challenges in providing uninterrupted power supply from a smart grid. One way to address these challenges is to use storage devices that can store surplus energy from RESs and discharge the energy back to the grid when needed. Researchers have recently introduced the idea to use electric vehicles with vehicle-to-grid capability, which are called “gridable vehicles” (GVs), as storage devices in the smart grid. Using GVs as loads is well accepted, but as sources, they disrupt system reliability if insufficient GVs are available for discharging when needed. An availability planning model is thus required to address this issue. GV owners' concern over battery lifetime reductions is another issue that impedes the required participation rates for GVs in vehicle-to-grid discharge programs. In this paper, we present an intelligent smart grid system model, which mitigates real-time unavailability of GV sources via an availability planning model. We also propose a GV selection model that prevents GV batteries from premature expiry due to their vehicle-to-grid operations. Simulation results confirm that our proposed models maintain better overall reliability and increase average battery lifetime by up to 3.5 years compared with existing vehicle-to-grid models.