Value of Fleet Vehicle Grid in Providing Transmission System Operator Services

TL;DR

This paper presents a stochastic model for EV fleet V2G services, demonstrating significant cost savings and emission reductions in a future UK electricity grid, while accounting for vehicle usage, battery degradation, and system flexibility.

Contribution

It introduces a new aggregated EV fleet model with a frequency-constrained stochastic unit commitment, incorporating battery degradation and various flexibility scenarios.

Findings

EV fleet V2G can save up to a312,000 annually

Reduces CO2 emissions by 60 tonnes per year

Battery degradation costs can be reduced by 16%

Abstract

In this paper a new aggregated model for electric vehicle (EV) fleets is presented that considers their daily and weekly usage patterns. A frequency-constrained stochastic unit commitment model is employed to optimally schedule EV charging and discharging as well as the provision of frequency response (FR) in an electricity system, while respecting the vehicles' energy requirements and driving schedules. Through case studies we demonstrate that an EV with vehicle to grid (V2G) capability can reduce system costs in a future GB electricity grid by up to {\pounds}12,000 per year, and reduce CO2 emissions by 60 tonnes per year, mainly due to reduced curtailment of wind power. The paper also quantifies the changes in the benefits of fleet V2G resulting from variations in FR delivery time, the penetration of wind or uptake of alternative flexibility providers. Finally , a battery degradation model dependent on an EV's state of charge is proposed and implemented in the stochastic scheduling problem. It enables significant degradation cost reductions of 16% with only a 0.4% reduction of an EV's system value.