Vehicle-to-Grid and Electric School Buses

A breakthrough for school bus electrification in Canada!

Published August 31st 2023

Imagine a future where our school buses not only transport students efficiently, but also contribute to a smarter, more resilient electric grid. Vehicle-to-Grid (V2G) technology, also known as bi-directional charging, enables electric school buses (ESBs) to go beyond their primary function, transforming them into smart mobile batteries capable of storing and supplying power back to the grid during peak demand periods.

At a time when extreme weather events are set to cause more and more power outages, using ESBs equipped with V2G technology seems more relevant than ever.

In August 2023, the Canadian Electric School Bus Alliance (CESBA) released its technical briefing “Vehicle-to-Grid (V2G) and Electric School Buses”, prepared by Dunsky Energy + Climate. The briefing allows a better understanding of what V2G technology is, explores its benefits for ESBs, and examines ongoing pilot projects in Canada and the United States.

Continue reading for a summary of the technical briefing.

Overview of V2G Technology

V2G is an advanced form of vehicle-grid integration (VGI) that utilizes an electric vehicle’s (EV) onboard energy storage system to provide power back to the electrical grid. As V2G goes beyond the typical unidirectional charging of EVs, it enables the bi-directional flow of electricity, allowing energy from the EV battery to be sent to a facility circuit connected to the electric power system or to the home. V2G requires the use of a direct current (DC) to alternate current (AC) inverter, which converts the DC power stored in the vehicle’s battery into the AC power required by the grid.

V2G services mimic those of a battery storage system which comes with a wide range of benefits for utilities and customers. On the utility-side, V2G enables the use of EV batteries to provide reserve generation system capacity, quickly responding to changes in system-wide demand. It also facilitates the purchase and storage of low-cost electricity during off-peak hours, allowing for the sale of electricity during periods of peak demand when prices are highest.

On the customer-side, V2G-capable vehicles, being mobile batteries, can bring a power grid back online in the event of an outage. In addition, V2G participation can help reduce peak load and demand charges by leveraging energy stored in EVs equipped with bi-directional chargers.

First, the V2G service must be in demand at the moment by the utility and/or the customer. It could be a utility requiring certain grid services, such as frequency regulation, or a customer needing backup power during a power outage.

Second, the appropriate technology and regulations must be available or in place. It includes having the right equipment, such as bi-directional chargers and inverters, as well as the relevant protocols and standards. Additionally, there should be regulatory frameworks in place that allow for V2G participation and define the rights, responsibilities, and compensation mechanisms for all involved parties.

Third, the vehicle must be hooked up to the grid and available for V2G participation.

"[School buses] spend 80% of weekdays during the school year sitting idle, and for nearly 50% of the year they're not used at all. The potential to harness the energy stored in these mobile batteries is significant, provided this downtime aligns with periods when V2G resources would be beneficial to the grid."

V2G and Electric School Buses

ESBs are well-suited for V2G participation due to their significant amount of downtime. On average, school buses are only used for 4-5 hours per day and approximately 190 days per year. In other words, they spend 80% of weekdays during the school year sitting idle, and for nearly 50% of the year they’re not used at all. This provides ample opportunity to harness the energy stored in ESBs for grid benefits.

The revenue potential of V2G participation for ESB fleets varies by region and the valuation of utility-side services provided. For example, in Ontario, it is between $3,170 – $3,340 per ESB per year, while in New Brunswick and Nova Scotia it is estimated respectively at $1,210 – $1,580 and $1,110 – $1,500. V2G revenue potential is the highest in Québec, estimated between $3,770 and $4,020.

On average, annual V2G revenue potential for an ESB is $3,000.

V2G revenue can help reduce the payback period of an ESB relative to a diesel by 2-3 years; however, this revenue alone will not offset the higher cost of ESBs – additional funding is necessary to reach price parity with diesel buses.

Challenges and Pilot Projects

First, there is an issue of battery degradation. Indeed, the back and forth power flow involved in V2G can contribute to additional usage cycles, which may impact the lifespan of the vehicle’s battery. The specific impact depends on the V2G use case and the depth of battery cycling. Battery degradation needs to be carefully managed to ensure the longevity of the battery.

Second, the absence of dedicated V2G programs and rates from utilities can act as a barrier to V2G adoption. The design of specific programs and rates that incentivize V2G participation requires careful consideration of costs and benefits for utilities and ratepayers.

Thirdly, the value and potential benefits of V2G can vary across regions. Factors such as peak demand patterns, grid constraints, and the varying valuation of utility-side V2G services by different utilities contribute to regional variations in the implementation and effectiveness of V2G.

There are no V2G pilot projects involving ESBs in Canada, although there are two noteworthy V2G pilot projects involving commercial EVs.

The first one is Nova Scotia Power that conducted a V2G demonstration as part of the broader Smart Grid Nova Scotia project. The demonstration involved the use of a bi-directional DC charger designed for commercial settings, further showcasing the capabilities of V2G technology in a real-world setting. The project aimed to explore the potential of V2G across various locations and contexts, including residential scenarios.

The second pilot project is in Ontario. The Independent Electricity System Operator (IESO) funded multiple bi-directional charging demonstration projects, one of which was developed jointly by Hydro One and Peak Power. This project involves the deployment of 10 Nissan Leafs equipped with bi-directional DC chargers. The focus of the project is to showcase both backup power functionality during outages and grid-interactive V2G services. The demonstration aims to assess the technical and operational feasibility of V2G and the potential benefits it can provide to the grid.

In the United States, over 15 utilities in 14 states are currently running V2G pilot projects.

This paradigm shift opens up a world of possibilities, blending sustainable transportation with grid services, cost savings, and environmental benefits. Together, let’s harness the power of V2G and drive towards a future where ESBs are not just for student transportation, but are key players in building a cleaner and brighter tomorrow. Let’s ignite the V2G revolution for Canada’s ESBs!

For more information about school bus electrification in Canada, we encourage you to read the other report prepared by Dunsky Energy + Climate, Pathways for Canadian Electric School Bus Adoption.

Henri Chevalier

Henri Chevalier

Intern, Sustainable Mobility

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