Session: 09-07-01: Energy Sustainability for Buildings and Cities

Paper Number: 166232

Bidirectional Charging EV Integration With EnergyPlus and Schedule Optimization to Assess Benefits of Residential EV Energy Storage 

Declining grid stability, combined with continued energy demand growth, has increased consumer interest in distributed energy resources, such as residential energy storage elements. These storage elements can benefit consumers and utility companies by providing energy resilience and shifting peak load, respectively. In spite of benefits, adoption of conventional residential energy storage elements, such as stationary batteries, remains low in the U.S. The low adoption is driven by a gap in consumer awareness about the benefits of energy storage and poor availability of economic incentives. Attaining higher adoption rates would require a large coordinated effort by home battery suppliers, utility companies, educators, and policymakers to overcome the current barriers. On the other hand, electric vehicles have demonstrated strong market penetration, probably attributed to better perceived financial incentives and individualized marketing strategies. Based on the recent study by Plug In America, most electric vehicle owners charge their vehicle at home, and would consider shifting their charging schedule for economic benefit. When compared to stationary batteries, electric vehicles’ battery capacity is normally larger. Considering pervasiveness and large capacity, there is a greater potential for bidirectional electric vehicles to serve as residential energy storage elements. However, the randomness of driving schedules, variety of vehicle types, and the variability of charging habits between user demographics make it difficult to study the effectiveness of bidirectional electric vehicle energy storage solely based on average data. The present work investigates if bidirectional electric vehicles as residential energy storage elements can realistically provide load shifting and economic benefits. In order to quantify their ability, this work delivers the following: 1) a method to integrate bidirectional charging into EnergyPlus residential building models; 2) an optimization of charging and discharging schedules to maximize economic benefits; 3) an analysis of the impact of different tariff structures on the economic viability. For the aforementioned deliverables, various profiles of electric vehicles usage is considered and categorized by: vehicle specification, charging speed, usage and availability during the day, location, weather, and income level. Each category combination is matched with a residential energy usage profile that corresponds to the same user demographic. As a preliminary study, simulations are being conducted for a timespan of one year with the following specifications: 60 kWh electric vehicle capacity, level 2 charger, San Jose, California, typical meteorological weather conditions, middle-income, and evening availability of the electric vehicle. The outcomes of this research will inform homeowners, electric vehicles drivers, car manufacturers, and policymakers of the potential for bidirectional electric vehicles to serve as residential energy storage elements.

Presenting Author: Tomy Tran San Jose State University

Presenting Author Biography: Tomy (he/him) is a master's student in the Mechanical Engineering program at San Jose State University. His research interest is in energy sustainability in the built environment. Currently he is a Research Assistant at Dr. Hohyun Lee's lab at San Jose State University researching bidirectional electric vehicles.

Authors:

Tomy Tran San Jose State University
Yulin Zeng Santa Clara University
Yuhong Liu Santa Clara University
Hohyun Lee San Jose State University