School buses are ideal for V2G in many ways. “There is no uncertainty regarding bus use,” said Patricia Hidalgo-Gonzalez, director of the Renewable Energy and Advanced Mathematics Laboratory at the University of California, San Diego, who studies power grids but was not involved in the project. ” he says. She said, “Once transportation needs are clear, it becomes much easier for the grid to know when its assets are available.”
Zumu’s buses start running at 6 or 6:30 a.m. to take children to school and end by 9 or 9:30 a.m. While children are in class, Zum’s buses are connected to fast chargers during times when the most solar energy flows into the grid. The bus then disconnects the electricity and takes the children home in the afternoon. “It typically has a larger battery, four to six times the size of a Tesla battery, and only a fraction of the range,” said Vivek Garg, co-founder and COO of Zum. I am. “That means you have a lot of battery left at the end of the day.”
After dropping off the children, the bus reboards just as demand on the power grid is surging. But rather than adding more demand by charging, buses send excess power back to the grid. When demand subsides, the buses begin charging around 10pm, replenishing their non-solar power so they can pick up their children in the morning. Zum’s system determines when to charge or discharge depending on the time of day, so drivers can simply turn on the bus and walk away.
During weekends, holidays, or summer months, buses spend even more time unused. This means that the entire battery that would otherwise not be used is used. Given the resources required to manufacture batteries and the need for more grid storage, it makes sense to use available batteries as much as possible. “You don’t just put a battery somewhere and use it only for energy,” he says. “We use that battery for transportation, and we use the same battery to stabilize the power grid during peak hours in the evening.”
If your kids haven’t ridden an electric bus yet, get ready to see more of these electric buses. From 2022 to 2026, the E.P.A. clean school bus program is providing $5 billion to replace gasoline-powered school buses with zero-emission and low-emission school buses. States such as California, additional funds To make the switch.
One hurdle is the high initial cost for districts. Electric buses cost several times more than traditional gas-guzzling buses. However, if the bus could support his V2G, it could use excess battery power at the end of the day as energy back into the grid during peak hours, offsetting the cost difference. “We leveraged his V2G revenue to bring this transportation cost on par with diesel buses,” he says Garg.
For the Oakland Schools project, Zum has been working with local power company Pacific Gas and Electric to experiment with how this would work in practice. PG&E is testing an adaptable system. Depending on the time of day and grid supply and demand, V2G participants pay dynamic tariffs for their energy usage and are paid based on the same dynamic tariff for the energy they send back to the network. system. “Having a fleet of 74 buses and following other fleets with more Zum-equipped buses is perfect for this, because we really want something that scales and has an impact. ,” said Rudy Halbright, vehicle product manager. Grid integration pilot and analysis at PG&E.