Prepping for electric school buses (and hopefully V2G)

A few New Hampshire school districts are getting ready to enter the electric transportation era, which means they have to figure out a pretty basic question: How to get the electricity.

Once that’s solved, they will get to ponder a more interesting question: How to use those big bus batteries to make some money by helping to stabilize the electric grid.

“This whole endeavor is going to take a lot of time and a lot of cooperation from many different groups,” said Nick Voisard, director of electric vehicles in North America for National Express.

The company will be operating three electric buses for Plymouth area schools, which won a $1.58 million EPA grant as part of the multi-billion-dollar Clean School Bus Program. Henniker and Rumney also received grants under the program, with Henniker getting $1.6 million for four electric buses.

National Express owns a bus depot in Rumney that serves Plymouth area schools under a contract. The actual buses won’t arrive until next year and possibly 2024, thanks to a surge in demand and constraints in global supplies, so there’s time to get ready. And there’s money: The grant allows spending up to $20,000 per bus on infrastructure such as chargers and electric system upgrades.

For the moment, there are some pretty basic questions to answer, such as how many chargers are needed?

School bus batteries are too big to be refilled (pardon the gas tank analogy) with cheap Level 1 chargers, which plug into standard household sockets. Even a Level 2 charger of the sort commonly installed in homes with EVs – they use 240-volt circuits like the ones for clothes dryers – will take all night to refill them.

But that’s OK because school buses sit around all night. There’s probably no need to spend the big bucks to install a Level 3 fast charger.

“We should be able to charge from 6 p.m. to 6 a.m. A Level 2 charger up to 19.2 kilowatts should be able to do that without any issue,” said Voisard. “If we do a route design and we find that, let’s say the routes are very long and may require a midday recharge – in those cases, you might require a faster charger for a short window in the middle of the day.”

However, there’s also the question of the local grid. You can’t start sucking down as much electricity as you want in a single location without checking with the utility – in this case, New Hampshire Electric Cooperative – to make sure they can handle it. The wires and transformers along your road or the local substation might already be maxed out, in which case time-consuming and expensive upgrades would be needed.

That’s probably not going to be a problem since not very many electric buses are going to any one place, at least not yet.

“The amount of power required for three buses isn’t the hardest thing to come by. If you were talking about 25 (the maximum allowed under the EPA program), that’s a much larger implementation,” said Voisard.

Switching school buses from gas or diesel to electric has lots of advantages: no tailpipe pollution when they stand and idle, less noise, and much lower operating cost because electric motors are simple and the fuel is cheaper. The buses themselves are much more expensive, hence the need for government support to get the industry going.

The most interesting advantage of electric buses is their ability to store and release electricity. Those big batteries sit around a majority of the time and it would be relatively easy to, say, charge them up on a sunny day when there’s tons of solar power and release the electricity into the grid after the sun sets, balancing out the peaks and valleys in supply that are hard on traditional power plants.

That kind of grid service is worth money to the utility, although regulators still have to figure out how much it’s worth. As that happens this will become a source of income for school systems as well as cities, as they make their metro buses electric.

It will be good for the rest of us, too, since using vehicle batteries as stationary storage is one of the practices needed to keep the grid healthy as we electrify everything.

Switching all our vehicles from combustion engines to electric is not going to save the planet, although it will help. We need to cut back on the use of individual vehicles and create a world where they’re needed less to really make a difference.

For buses, however, going electric is an obvious move and it can’t happen too soon.