fb-pixel-img
, , ,

The wheels on the bus charge the grid

As school buses make the EV switch, utility companies are eyeing added benefits for energy storage

This story is part of Works for Progress, one5c’s series showcasing individuals, initiatives, and inventions contributing to a net-zero future. 

Virginia’s Middle Peninsula region is an idyllic place, with 135 miles of shoreline along the Chesapeake Bay and the Rappahannock River. At its eastern end in Middlesex County, the rumbling of buses to and from three school buildings would normally upset the peace, but for the past two Septembers drop-offs have been quieter. 

That’s because the county is one of several in the state taking part in one of the largest electric school bus programs in the nation. Orchestrated by local utility Dominion Energy, the initiative, which has deployed 50 buses since 2021, offers relief from loud and emissions-spurting diesel engines. 

At around 480,000 vehicles, school buses represent the biggest public transportation fleet in the country. And, though today’s diesel buses may be cleaner than those manufactured as recently as two decades ago, the tailpipes add up. According to the United States Public Interest Research Group, shifting the 4 billion miles kid-haulers log each year to electric would result in a reduction of 8 million metric tons of emissions—equivalent to more than 1.7 million cars. “The amount of diesel emissions allowed from school buses is shockingly high and we’re expected to put our kids in these dirty buses,” says Ed Kim, president and chief analyst of AutoPacific, an automotive research and consulting firm. 

In addition to protecting tykes and drivers from noxious fumes, Virginia’s fleet is also a harbinger of an even bigger shift for those big yellow school buses. Dominion’s efforts are one of more than a dozen testing electric buses as a source of backup power. The technology, known broadly as vehicle-to-grid (V2G), allows the bus batteries to act as portable power banks in a variety of situations, from supplying energy to a concession stand at a track meet to keeping the lights on at an emergency shelter. They could even help smooth the transition to renewable energy—in the Old Dominion and beyond. 

How it works

The concept of V2G is fairly simple: power in, power out, in a two-way flow. Buses connect to a device called a bidirectional converter that can direct stored energy to the grid via direct-current (that’s DC) fast charging stations. Behind the scenes, V2G software manages the power flow and automatically routes it to where it’s needed most, or signals the battery to hang on to it if demand is low. 

Think of this bus like a giant PowerWall on wheels. Credit: Thomas Built Buses

Virginia’s people movers, from Thomas Built Buses, each hold 226 kilowatt-hours of electricity, enough to drive 138 miles—or power the average American home for several days. If every diesel bus in the U.S. were replaced with a V2G-capable electric model, that could provide a total of 61.5 gigawatt hours of energy storage capacity, or enough to last a full week for more than 200,000 homes. 

In the pantheon of public fleets, school buses are particularly well poised to take on this task over other community-owned vehicles like transit buses or garbage trucks. They generally run fixed routes twice per day, which means they have predictable idle times when they can discharge energy as needed. Plus, buses are generally parked for the summer when spikes in air conditioning tend to test the grid. 

The road ahead

Perhaps the biggest challenge facing EV bus adoption is the upfront cost. Electric buses can run $300,000 to $400,000, often as much as double the outlay for a diesel equivalent, and districts also have to plan for charging infrastructure.

There are ways to manage the pricetag. The EPA’s Clean School Bus Program provides $5 billion for electric and low-emissions models as part of the Inflation Reduction Act, and many states have also allocated funds for bus electrification. In April, the World Research Institute reported that 895 districts and fleet operators across all 50 states have secured 5,612 electric buses, 2,400 of which come via EPA grants. 

The promise of V2G, however, has also allowed districts to tap a different funding model. Because Dominion Energy views the buses as part of the grid, it stepped in to defray the costs. “We knew schools were interested in being more sustainable, but price was a big hurdle,” says Dominion director of electrification Kate Staples. Thomas Built sold its vehicles to the school district for roughly the same price as a diesel bus (around $100,000, according to Staples), and then Dominion made up the difference by supplying charging stations and other necessary infrastructure. Similarly, San Diego Gas & Electric took care of $1 million in electrical upgrades at the bus depot for the Cajon Valley school district.

WHAT YOU CAN DO
Pay attention to proposals going up for votes in your local school district. In many cases, even when the funding comes from a state or federal grant, the district needs community sign-off before it can shell out any cash. 

Districts may also stand to earn back their initial outlays over time, because the per-mile operating costs of EVs are lower than their gas-guzzling counterparts. A field trip, for example, would run $42.70 in diesel fuel and only $15.50 in electricity, Middlesex County Public Schools director of operations and transportation Dustin Harris told School Transportation News. “The money put back into the school’s budget from a simple field trip isn’t super noticeable but when you start to add up every trip, it gets tangible,” he said.

Even when the batteries’ range numbers drop to the point that they’re no longer viable for trucking students around, they’re still valuable to Dominion as grid backups. At the end of the school district’s 15-year contract, Dominion gets to reclaim the batteries. “We own the components, including the battery,” Staples says. “We can use that battery for storage for V2G after the buses are finished with them.” The utility currently operates battery-storage pilots that can provide 16 megawatts of power, but is working to double that capacity. 

A storage stockpile is a vital component of a reliable renewable grid. The ability to funnel energy back into the pipes instead of burning additional fossil fuels at times of high demand—or hold on to surplus wind and solar power—can help Virginia keep pace with its goal to be carbon-free by 2045. At the same time, an electric bus is only as green as the grid that powers it: Today, the state gets the majority of its electricity from fossil fuels, and only 9% from renewables. “As the grid gets cleaner, the buses get cleaner too,” Staples says. 


The Digest: What we’re getting into this week

Two-second energy saver: Turn off the ice-maker

There’s an energy goblin hiding in your freezer. Automatic ice-makers account for anywhere from 12% to 20% of a fridge’s energy consumption. Granted, it takes energy to freeze water the old-fashioned way, too, but the heating elements that de-mold the cubes use up a full three-quarters of the power needed to make those beverage-chillers. Nixing the ice robot has other benefits, too: Faulty dispensing machinery is among fridge owners’ biggest complaints

Mark your calendars: March to end fossil fuels

This past Friday, the United Nations’s first report card on progress towards the Paris Agreement’s goals deemed the world “not on track” to meet its targets, noting that continued (and growing) investment in fossil fuels is largely to blame. This Sunday, Sept. 17, the March to End Fossil Fuels is set to take over the streets of New York City and demand change. The demonstration’s goals, endorsed by more than 500 climate-active organizations, are simple: President Biden must stop approving fossil fuel projects, end drilling on public lands, declare a climate emergency, and ensure a just transition to renewable energy. If you’re able to make it to NYC, here are all the deets you need to join the march. If that’s not possible for you, consider volunteering remotely or donating to help get more folks there IRL.  

Good read: 50 people driving change

Sorry-not-sorry to sound like a broken record, but the climate emergency is an all-hands-on-deck situation. That’s why we’re always excited to see who made Grist 50, a roster of climate advocates, creators, and innovators charting our way out of this mess. This year’s list has a collective body of work that attacks the crisis from all angles—from a CEO on a quest to get people pumped about eating more ’shrooms to a teacher helping students draft and pass climate policy. We’re not playing favorites, though: The entire list is a billion percent (not a real number) worth your time. 

Earth-friendly eats: Cookies for breakfast

Before you reach for the Jimmy Dean freezer sammie for a quickie way to fuel your morning, may we take a moment and point out that the right mix of plants can be just as—if not more—energy and protein dense as those sausage patties? More like dessert, too. This week over at Cool Beans, we’re baking up two make-ahead sweet breakfast treats that pack all the fuel you need to make it to lunch without getting hangry. 

Mic-drop climate fact

When a food-delivery app sets its utensil delivery option to “no cutlery” by default, the percentage of fork-deniers goes up by 648%, according to findings published in the journal Science. That simple nudge could eliminate 3.26 million metric tons of plastic waste a year in China, where the study took place—that’s equivalent to more than three aircraft carriers’ worth of trash.