The wheels on this bus do indeed go round and round. His wipers swing. And his horn beeped. However, hidden within its interior is something special – a car that does not worship, but along with an emerging technology that can help the grid to spread with renewable energy.
These new buses, developed by a company called Zum, drive cleanly and quietly because they are fully electric. Along with them, California’s Oakland Unified School District just became the first large district in the United States to switch to 100 percent electrified buses. The vehicles now transport 1,300 students to and from school, replacing diesel-powered buses that pollute the children’s lungs and the neighborhoods with particles. As in other US cities, Oakland’s underserved areas tend to be closer to freeways and industrial activity, so air quality in those areas is already terrible compared to the city’s wealthier parts.
Pollution from buses and other vehicles contributes to chronic asthma among students, leading to chronic absenteeism. Since Oakland Unified only provides bus services for its students with special needs, the problem of missing school for preventable health issues is particularly acute for them. “We’ve already seen the data — more kids riding the buses, that means more of our most vulnerable not missing school,” Oakland Unified School District Superintendent Kyla Johnson-Trammell said during a press conference Tuesday. “This means over time they learn more and performance increases.”
What’s more, a core challenge to weaning our society off fossil fuels is that utilities will need to produce more electricity, not less of it. “In some places, you’re talking about doubling the amount of energy needed,” said Kevin Schneider, an expert in power systems at Pacific Northwest National Laboratory, who is not involved in the Oakland project.
Counterintuitively, the buses’ massive batteries aren’t pushing the grid; they benefit from it. Like a growing number of consumer EV modelsare the buses equipped with vehicle-to-grid technologyor V2G. This allows them to charge their batteries by connecting to the grid, but also to send energy back to the grid if the electric utility needs extra power. “School buses play a very important role in the community as a transportation provider, but now also as an energy provider,” says Vivek Garg, co-founder and COO of Zum.
Matt Simon
And provide the buses must. Demand on the grid tends to increase in the late afternoon, when everyone returns home and turns on appliances such as air conditioners. Historically, utilities can only build more generation at a fossil fuel power plant to meet that demand. But as the grid is loaded with more renewable energy sources, intermittency becomes a challenge: You can’t ramp up power in the system if the sun isn’t shining or the wind isn’t blowing.
If every EV has V2G capability, it creates a distributed network of batteries for a utility to draw on when demand rises. The nature of the school bus makes it perfect for this as it is on a fixed schedule, making it a predictable resource for the utility. In the afternoon, Zum’s buses take children home, and then plug back into the timetable. “They have more energy in each bus than they need to do their route, so there’s always plenty left over,” said Rudi Halbright, product manager of V2G integration at Pacific Gas and Electric Company, the utility that together with Zum and Oakland work. Unite for the new system.
As the night wears on and demand subsides, the buses reload to be ready for their morning routes. Then they charge again during the day, when there is plenty of solar power on the grid. On weekends or holidays, the buses would be available all day as backup power for the network. “Obviously, they’re going to take a very large amount of cost,” said Kevin Schneider, an expert in power systems at Pacific Northwest National Laboratory, who is not involved in the Oakland project. “But things like school buses don’t run that often, so they have a lot of potential to be a resource.”
That resource isn’t free: utilities pay owners of V2G vehicles to provide power to the grid. (Because V2G is so new, utilities are still experimenting with what this rate structure looks like.) Zum says that that revenue helps lower the transportation costs of its buses to be on par with cheaper diesel-powered buses. Oakland Unified and other districts could get even more money from the EPAs Clean School Bus Programwhich is handing out $5 billion between 2022 and 2026 to make the switch.
The potential of V2G is that there are so many different types of electric vehicles (or vehicle types left to electrify). Garbage trucks run early in the day, while delivery trucks and city vehicles do more of a nine-to-five. Passenger vehicles are kind of everywhere, with some people taking them to work, while others sit in garages all day. Basically, lots of batteries – big and small – have been parked idle at different times to send power back to the grid.
All the while, more intense heat waves will require more energy-hungry air conditioning to keep people healthy. (Although ideally, everyone would get a heat pump instead.) “We’re still going to need more generation, more power lines, but energy storage is going to give us the flexibility so we can deploy it faster,” Schneider said. In the near future, you may be able to come home on a sweltering day and still be able to turn on your AC – thanks to an electric school bus sitting in many.
