Three Benefits of Electric School Buses
Tom Lombardo posted on September 21, 2019 |
Electric school buses can reduce carbon emissions, save money, and bolster the power grid.

Dominion Energy, a power company headquartered in Richmond, Va., is encouraging school districts to switch from diesel to electric school buses. Although electric buses come with a higher price tag, their total cost of ownership is lower in the long run. But Dominion recognizes that school district have tight budgets, so to sweeten the pot, the utility is offering to offset the additional costs of the electric school buses. The program, which the company claims is the largest electric school bus initiative in the United States, aims to reduce carbon emissions, help schools save money, and bolster the power grid with vehicle-to-grid (V2G) energy storage.

Reducing Carbon Emissions

In almost every instance, even taking into account the battery manufacturing and mining of materials, electric vehicles produce less pollution than those powered by internal combustion engines. Of course, that sometimes depends on the source of electricity, so I asked Dominion Energy how they generate power. The representative told me that over the past decade, Dominion has nearly eliminated the use of coal, shifting much of its production to nuclear energy and natural gas, which cut the company’s CO2 output in half. Looking ahead, Dominion’s environmental goals include a 50 percent reduction in methane emissions by 2030 and an 80 percent reduction in carbon emissions by 2050.

A zero-emission school bus. (Image courtesy of Dominion Energy.)
A zero-emission school bus. (Image courtesy of Dominion Energy.)

Dominion estimates that replacing one diesel bus with an electric bus will keep 54,000 pounds of greenhouse gases out of the atmosphere——the equivalent of taking more than five cars off the road. Once fully implemented, the utility’s school bus initiative will have the same effect as removing more than 5,000 cars from the road every year.

Saving Money

Because they require less maintenance and run on cheaper “fuel,” electric vehicles have a lower total cost of ownership, even when taking into consideration their higher initial price tag. And since Dominion will cover the difference in purchase price, the schools will save even more money—up to 60 percent less in operating expenses for the bus fleet. That’s fewer dollars spent by taxpayers and more money invested in students, teachers, educational technology and supplies.

Electric fill-ups are cheaper than diesel fill-ups. (Image courtesy of Dominion Energy.)
Electric fill-ups are cheaper than diesel fill-ups. (Image courtesy of Dominion Energy.)

Dominion will cover the entire cost of the initial phase of the program—50 buses by the year 2020. Once the program is expanded to 1,050 buses by the year 2025, Dominion will ask for a slight rate hike, amounting to less than $12 annually for a typical residential customer.

Vehicle-to-Grid Energy Storage

Dominion Energy currently generates only 4 percent of its electricity through renewable energy sources such as solar and wind, but the company wants to increase that number. In order to do so, it will need to increase its energy storage capacity to account for the intermittent nature of renewable resources.

Fleet vehicles are perfect candidates for electrification since they don’t need to go long distances between recharges. At first glance, school buses don’t seem like good candidates for vehicle-to-grid applications, since they’re typically driven during the mid to late afternoon, which also coincides with peak electricity demand. Looking a little deeper, though, and we find that peak demand is much greater in the summer when people are running their air conditioners. That’s also when many school buses are sitting idle in a garage, so why not make them part of the energy storage solution?

Vehicle-to-grid technology. (Image courtesy of Dominion Energy.)
Vehicle-to-grid technology. (Image courtesy of Dominion Energy.)

With each bus having a battery bank capable of holding nearly 200 kWh of energy, a fleet of 1,050 buses can store 200 MWh—enough to power 10,000 homes for five hours with less than an 80 percent depth of discharge on the batteries. (Repeatedly drawing more than 80 percent of a battery’s charge can reduce its life, so it’s important to leave a little in the tank, so to speak.) But the V2G initiative isn’t really intended to provide emergency power during an outage. Its purpose is to deliver additional power during peak demand hours, and 200 MWh will handle that quite well.

Dominion Energy has issued a request for proposals from bus manufacturers and expects to select a winner by November 2019. The company is currently accepting applications from schools that would like to participate in the program. The application process will close in early October.

One might think of this project as an electric company trying to sell more power by promoting electric vehicles, but the truth is that it’s in their best interest to avoid having to build additional peaker plants, which may run only for an hour or two each day—usually during the summer months. Those plants almost never pay for themselves, which is why so many power companies are looking at energy storage to fill the peak demand role. Batteries also provide other services, such as frequency regulation and, as mentioned before, support for renewable energy.

If all goes as planned, this initiative could serve as a model for other power companies to develop partnerships with school districts in their service areas. It’s good to see a company improve its bottom line while benefiting the community at the same time.


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