Session: 17-01: Poster Presentations

Paper Number: 168490

168490 - Integration of Bidirectional Ev Charging Into Energyplus to Assess Load Shifting and Economic Benefits of Residential Ev Energy Storage 

Abstract: 

Power outages and rising electricity costs highlight the benefits of residential energy storage systems. Electric vehicles, which are more commonly owned than stationary batteries, have the potential to be utilized as detachable residential energy storage systems if they have bidirectional charging capabilities. However, low consumer demand of bidirectional electric vehicles means they are yet to be widely offered by manufacturers. Lack of clarity about the practical and economic benefits of residential energy storage, as well as reluctance to adopt caused by personal preferences and income level, all contribute to low demand of bidirectional electric vehicles. The uncertainty of residential EV energy storage viability is, in part, due to the randomness of vehicle usage and variety in electric vehicle types. Driving habits and power needs can vary per individual demographics and situations such as: income level, day of the week, weather, and location. Representation via average data cannot cover the differences between use cases and categories. Hence, there is a need for realistic vehicle usage and building demand models when analyzing bidirectional electric vehicles as residential energy storage. To the best of our knowledge, no tools or methods exist that can comprehensively simulate a building’s realistic energy usage together with various types of bidirectional electric vehicles. In response, this research presents a method to simulate realistic charging and discharging schedules of different electric vehicles connected to residential buildings with varying energy needs. A bidirectional electric vehicle model class and battery simulator was developed to integrate with EnergyPlus. The battery simulator implements a standard battery charge and discharge model, but the bidirectional electric vehicle model adds functionality to represent the variable availability and state of charge of an electric vehicle battery from the perspective of the EnergyPlus building simulator. Generation of realistic electric vehicle trip chains and of realistic building energy demand is performed with an LLM trip chain generator and residential model program generator, respectively, presented in previous works by our group. The class generates time-series data that includes: residential building demand; electric vehicle charging and discharging load; electric vehicle state of charge; and the time-based availability of the electric vehicle. Annual costs can be estimated and compared for bidirectional electric vehicles and normal electric vehicles while considering multiple tariff strategies with the aggregate load data. The presented method and simulation data will inform homeowners, electric vehicle manufacturers, and grid stability researchers about the ability of bidirectional electric vehicles to function as residential energy storage.

Presenting Author: Tomy Tran San Jose State University

Presenting Author Biography: Mechanical engineering master's student at San Jose State University.