At CTE, we pride ourselves in working with the latest and greatest in zero-emission technology. There are many misconceptions about battery electric and fuel cell electric buses as completely different systems for clean transit when they are similar electric drive solutions. We’re going to break down the basics of battery electric and fuel cell electric bus options to dispel any doubts about both technologies.
In the infographic to the left, there is a breakdown of the similarities and differences between the two technologies. Overall, there are more commonalities in the buses than there are differences. In the first section, we talk about energy storage. In a battery electric bus, as the name suggests, power is stored in a battery pack in the rear of the bus until it is time to be converted to kinetic energy. For a fuel cell electric bus, the fuel cells will also be stored in the rear of the bus along with a battery pack similar to a conventional battery electric bus. Hydrogen is stored in tanks on the roof to be used by the fuel cells that create onboard energy to recharge the batteries.
As the battery electric bus decelerates through taxi or stopping, kinetic energy is brought back into the battery via regenerative braking. Fuel cell electric buses also have this available technology, in order to reduce unnecessary waste of energy when bringing the bus to a halt.
A technological difference between battery electric and fuel cell electric bus technology is in the fueling infrastructure. For a battery electric bus, the battery may be charged in a variety of places inside or outside of the depot. Advances in charging technology have allowed for battery electric buses to recharge en-route via overhead charging at a stop, or even wirelessly. Charge time for battery buses can vary from 10 minutes of short en-route quick charge to 8 hours of slow charge at the depot.
For fuel cell electric buses, the infrastructure for fueling is tied to a designated space, similar to traditional diesel or CNG fueling stations. Hydrogen fuel is stored at the station in specialized tanks and pumps that dispense hydrogen into the buses in a manner almost identical to the way regular diesel or CNG buses are refueled. Fuel cell buses are refueled in about 10 minutes.
The biggest difference in bus technology comes in the form of application: fuel cell electric buses typically perform better in longer routes compared to battery electric. There are many factors that can affect the range of a battery electric bus – elevation changes, average route speed, level of stop and go, weather conditions, and even the way an operator drives the vehicle. Fuel cell electric buses perform similarly to conventional diesel and gasoline vehicles that can be fueled once and travel for longer distances. The most effective application for each technology will be highly dependent upon the site and operational characteristics where it will be deployed.
Most importantly, both buses are a zero-emission technology. Neither bus emits toxins or greenhouse gases, like tropospheric ozone. Fuel cell electric buses emit only water vapor. Both are a necessary technological advancement to reduce the US’s emissions in transportation.
If you’re interested in learning more about the world of fuel cell electric bus technology, we have prepared a document explaining more. To stay up-to-date with our fuel cell and battery electric projects, as well as to stay in the know about the industry, follow us @Go_CTE on Twitter.