V2G Hits the Big Time with Dominion Electric School Bus Project

Program builds on PJM, University of Delaware pilot project


The concept that a battery could not only power a car but also discharge power into the grid was demonstrated a decade ago in a joint pilot project by PJM and the University of Delaware.

Now, the PJM region is at the forefront of another vehicle-to-grid technology first: Dominion Energy Virginia is poised to roll out the nation’s largest electric school bus deployment.

When the plan is fully implemented, the fleet of bus batteries could store up to 105 MWh of electricity – enough to power more than 10,000 homes.

A Sign of Things to Come

PJM’s Scott Baker, senior business solution analyst – Applied Innovation Department, was an instrumental member of the University of Delaware project team – first as a graduate student, then as a PJM employee and liaison for the project.

“It’s definitely a harbinger. This is going on at the same time transit authorities are integrating all-electric buses – in D.C., Chicago, Philadelphia,” he said. “It’s the start of electrifying the transportation fleet.”

In Virginia, Dominion initially expects to spend $13.5 million replacing 50 diesel buses with electric vehicles that will be on the road by the end of 2020. The cost will be included in its current base rate.

Photo: Dominion Energy Virginia

One Thousand Fifty Electric Buses by 2025

With state approval, Dominion will grow the fleet by 200 vehicles per year through 2025, at an estimated cost of $1 per month for a typical residential customer.

“Transportation is the No. 1 source of carbon emissions in the United States,” Dominion Energy Chairman, President and CEO Thomas F. Farrell II said in the Aug. 29 announcement.

“Electric school buses will provide a wide range of benefits for the customers and communities we serve, including cleaner air, cost savings for school districts and enhanced grid reliability.”

Replacing a diesel bus with an electric vehicle is equivalent to taking 5.2 cars off the road, emissions-wise, according to Dominion, which serves about 2.5 million PJM customers in Virginia.

New Grid Resource for All Customers

While not everyone will experience a ride on an electric school bus, the project will benefit all customers by creating a grid resource to provide additional energy storage to support Dominion’s integration of distributed energy resources like solar and wind.

When the buses are not in use, their batteries will be able to be plugged in and tapped to ease high energy demand or provide stability to the grid when renewable output is intermittent.

In an emergency or power outage, these portable batteries could serve as mobile power stations, the company said.

Fleets of vehicles such as school buses, mail carriers and garbage trucks, which have regimented schedules, are naturals for vehicle-to-grid subjects.

Trend Toward Electric Vehicles

Photo: Dominion Energy Virginia

Dominion’s school bus project fits into a larger trend toward electric vehicles across the country and within the PJM footprint.

Because of this, for the first time in 2020, PJM plans to explicitly account for plug-in car charging in its load forecast model.

Particularly, PJM wants to make sure it reflects how much car charging will be adding demand to the system at peak summer hours.

“We’ve been looking at it for a number of years,” said PJM’s John Reynolds, senior lead economic analyst with the Resource Adequacy Planning Department, of the plug-in electric vehicle forecast from the U.S. Energy Information Administration. “This year, it ticked up significantly, and we thought, now’s probably the time to work this into our load forecast.”

Car charging is expected to grow from 800 MW to 1,200 MW at the summer peak by the end of PJM’s 15-year planning window, he said. Already, the added annual energy consumption is noticeable.

Forecasters start with the number of electric vehicles registered in each state, add new sales, and subtract electric vehicles expected to be retired.

Then, they make assumptions about how many are charging at what hours – Thursday is a popular day to “gas up” for the weekend – and whether they’re using home plugs or larger-voltage charging stations.

Vehicle-To-Grid Finally Hits the Road

For Baker, it’s gratifying to see vehicle-to-grid technology taking off.

The University of Delaware project PJM was involved in “was instrumental in demonstrating, for the first time, a vehicle could provide grid services. We knew that the system was physically capable of doing it, but we had to write software around it and design things that didn’t exist,” he recalled.

There wasn’t even a standard plug for electric cars at the time, he said.

The project ended up generating more than $100 per car, per month.

“A decade later, you have a utility who’s putting this concept into practice with bigger batteries,” Baker said.

Extension of the Sharing Economy

Baker sees it as a natural extension of the sharing economy that spawned services such as Airbnb and Uber.

“The vehicle-to-grid analogy is you’ve bought this expensive car that just sits parked for 23-hours a day. It’s a high-value asset, but it’s just sitting. If there’s a battery in that car that can be used for other purposes and actually generates value for customers, why not use that asset? “I think it’s an inevitable concept.”