In general, public transportation operations have three basic options to consider for a ZEB fleet: Battery buses, which are charged overnight or while in transit; fuel cell buses, which use hydrogen as the fuel, creating a chemical reaction that generates electricity; or electric trolley buses, which use overhead wires to power the vehicle, similar to what is currently found in San Francisco and Seattle.
“More than likely, Metro will be adopting battery buses,” Henke said. “Regardless of what option Metro chooses, modifying the facilities will be a major part of the project, and they will need to work with electric utilities to connect the charging stations to the grid.”
While the price of electricity for vehicles is improving, it can still be two- to three-times as expensive as the comparable rate for gasoline vehicles, particularly in California, making the transition a difficult one for many transportation agencies to make.
“That is one of the biggest challenges we face nationwide, as electric utilities, while amenable, aren’t really set up to provide transit agencies with favorable rates,” Henke said. “We are assisting our clients in proving information as they begin negotiating with utilities to show them how much power they will need and how it might benefit both transit and utilities if rates would make ZEB operations more affordable. Fortunately, we have seen the capital cost of ZEBs versus conventional diesel narrowing over the past several years, and we anticipate it will continue to drop 10-15 percent a year over the next several years.”
As the master plan creates a time table for transition to a fully electric fleet, planners are also evaluating current bus routes throughout Los Angeles to determine if they need to be modified to accommodate these vehicles.
“The facilities need to be capable of handling the anticipated fleet, with provisions like the equipment needed to cool state-of-the-art charging units,” he said.
“It will also take an enormous amount of infrastructure planning to bury the power lines to the recharging stations and design switchgear, substations and other systems for the charging units,” Henke said. “We will assess the facilities, the routes, and how these buses will behave en route using our proprietary modeling tools.”