The four vehicles parked at a station in South Burlington, Vermont, are no different from the yellow school buses that millions of schoolchildren are familiar with. But beneath their steel frames, these buses are packed with technology that could be vital in the transition to clean energy.
While their primary job remains transporting children, the vehicles take on a second task while sitting idle during school hours. The local utility runs its batteries and stores excess renewable energy so it can be pumped back into the grid when needed.
The buses are a test of the idea that electric vehicles, which skeptics often see as an expensive burden that could collapse power grids, could be the opposite: a buffer that absorbs energy when there is too much and provides it when there is demand. . Electrical surges.
Any properly equipped electric vehicle can be used to store excess electricity, avoiding the need for utility companies to turn on gas-fired power plants when there is not enough sun or wind. But school buses work especially well because they have large batteries and spend much of the day parked.
“There’s no better tool than a fleet of electric school buses to smooth out those curves,” said Duncan McIntyre, CEO of Highland Fleets, a company near Boston that provides the buses and equipment. Synop, a New York company, provides the software to manage the interaction between vehicles, chargers and the network.
Utilities across the country have been testing the ability of electric vehicle batteries to help stabilize increasingly unreliable plants and power lines that have failed under the pressure of hurricanes, heat waves and other weather conditions. extremes related to climate change.
This year’s grueling summer heat strained Texas’ grid for weeks, forcing officials to plead with homeowners and businesses to use less energy so the state could avoid rolling blackouts or the type of outage of energy that left millions of people without light or heating in 2021.
Some energy experts say one solution to these problems is to pool thousands of a city or state’s rooftop solar panels, home batteries and electric vehicles into virtual power plants. Brought together with the help of software, the collective ability of such devices to generate and store energy may be more than enough to prevent a blackout when power plants fail or high winds take down a transmission line.
Grids primarily use power plants with quick-start capabilities, known as peaking units, to serve as backup power sources. But these plants typically use gas, a major source of greenhouse gas emissions, and are expensive to operate and maintain. Many have also failed to act when they were most needed.
Electric school buses, in particular, could be very useful to the network due to their limited use during school days and their wide availability during sweltering summer temperatures.
Schools in every state except Wyoming have pledged to start using electric buses, although the number on the roads is small: fewer than 3,000 as of June 30, according to the World Resources Institutea non-profit organization that works on energy, environment and related issues.
California’s total number of school buses is the largest in the country, and Montgomery County, Maryland, has more than any other school district.
“We’re on the edge of technology, which doesn’t happen often with school buses,” said Daoud Chaaya, vice president of sales for Thomas Built, a unit of truck maker Daimler that supplied South Burlington’s electric buses.
The World Resources Institute is pushing U.S. policymakers to ensure all school buses are battery-powered by 2030, a goal that would also reduce asthma and other illnesses in children by eliminating pollution from powered buses. combustion.
“There are definitely a lot of challenges,” said Sue Gander, director of the institute’s electric school bus initiative. “It’s going to take some time for everyone to get there.”
Cost remains a big hurdle: An electric school bus can cost three times as much as a $100,000 diesel bus. The bipartisan Infrastructure Act, passed in 2021, allocated $5 billion over five years to help schools purchase electric buses, with the price expected to drop in the coming years. Meanwhile, school districts can defray their costs by allowing utility companies to use buses to store energy.
In South Burlington, the school district rents electric buses from Highland, which also supplies equipment to charge them and pays the electric bills. Those bills are lower than normal because of an agreement that allows Green Mountain Power, the utility that serves most of Vermont, to draw power from bus batteries when demand increases. They are part of a network that also includes batteries that homeowners install to provide backup power during blackouts.
In total, Green Mountain Power has access to 50 megawatts of battery storage from school buses, home batteries and other sources, said Mari McClure, the utility’s CEO. This is equivalent to a small gas power plant. Unlike a plant that runs on fossil fuels, energy is available almost instantly.
The utility last month asked Vermont regulators to allow it to install batteries in the homes of its customers who don’t already have one, an effort that would dovetail with its work on school buses.
Over time, McClure said, enough electric school buses and home batteries may be connected to the grid to prevent his utility from having to buy electricity from out-of-state power plants. Commercial vans, pickup trucks and garbage trucks could join the grid as more companies and cities purchase electric vehicles.
But connecting these vehicle batteries to the grid will not only take time but also money. While installing a standard EV charger for buses can cost between $3,000 and $7,000, initial data from early electric van demonstrations indicates that the equipment needed to return power to the grid ranges from $10,000 to $58,000, according to the Electric Power Research Institute, an independent nonprofit organization. Utility companies may also need to upgrade their power lines, transformers and other equipment.
There are also difficult legal and financial issues to resolve. Many states have struggled to determine how to compensate homeowners and businesses for the power they supply to the electric grid from batteries and rooftop solar panels.
Energy experts said these issues would be addressed and the high costs of electric vehicles would decline as utilities, regulators and manufacturers gained more experience.
Vehicle batteries can meet some of the needs of customers, utilities and the wholesale electricity market, said Daniel Bowermaster, senior director of the electric transportation program at the Electric Power Research Institute. “From a technological standpoint, those things are within the realm of possibility.”
Officials in South Burlington, whose diesel bus fleet is mostly written off, said they were willing to spend more on electric buses. The new buses are much better for the environment and public health, said Tim Jarvis, the school district’s chief financial officer.
There are other benefits too.
Sean McKenzie, transportation coordinator for South Burlington schools, who drives a bus due to a labor shortage, said children no longer had to shout over the roar of a diesel engine.
“I was surprised that they were quieter,” he said.
