Scheduling the Charge of Temporally Flexible Electric Vehicles: a Market-based Approach

TL;DR

This paper introduces a market-based charge scheduling method for electric vehicles that incentivizes drivers to delay disconnection, leveraging their flexibility to improve grid services and reduce station congestion.

Contribution

It presents a novel optimization framework and a truthful incentive mechanism for scheduling EV charging considering drivers' strategic behavior.

Findings

Enhanced vehicle-to-grid service capacity

Reduced congestion at charging stations

Effective incentive compatibility mechanism

Abstract

The increasing electrification of human activities and the rapid integration of variable renewable energy sources strain the power grid. A solution to address the need for more grid storage is to use the battery of electric vehicles as a back-up capacity. However, drivers tend to disconnect their electric vehicle when its battery is needed the most. We propose a charge scheduler that incentivizes drivers to delay their disconnection to improve vehicle-to-grid services. We also leverage drivers' temporal flexibility to alleviate congestion in oversubscribed charging stations. We formulate the computation of an optimal flexible schedule as a mixed-integer quadratic problem. We tractably approximate its solution using the Alternating Direction Method of Multipliers. Considering the possibility that strategic drivers misreport their charging preferences to the station coordinator, we then propose a Vickrey-Clarke-Groves mechanism that incentivizes truthful reporting. We conclude with a simulated case study using real-world data to quantitatively assess the added value of drivers' temporal flexibility for enhancing vehicle-to-grid services and reducing station congestion.