Instead of trying to outfit an existing diesel bus with electric batteries and fuel cells, the Hydrogen Hybrid Bus represents an initiative by Proterra to build a unique and efficient zero emission bus from the ground up. So what makes this bus so different?
Besides the already unique outward appearance, the body of the bus is 35 feet long and made up of a lightweight composite material. This allows for greater efficiency and makes the body about 20-40 percent lighter than similar transit buses while still allowing space for up to 37-seated passengers - similar to a conventional 40 foot bus.
The bus is equipped with an all-electric energy storage system made up of lithium-titanate batteries with fast charge abilities. Using only the fully charged batteries, the bus has a range of about 25-40 miles; however, the range can be extended using regenerative braking and a fuel cell system. Regenerative braking means that the bus is configured to recover up to 90 percent of the energy expended by the batteries when the bus slows down or stops. This energy is then reused to recharge the batteries.
The fuel cell system is made up of two small proton exchange membrane or PEM fuel cells that can run separately or in parallel. Allowing the fuel cells to shut down when not needed should enable a longer system life. Hydrogen to power the fuel cells is stored in tanks on the roof of the bus. These systems continuously recharge the batteries as the bus is running and extend the distance the bus can travel without having to return to the charging station.
For more information about the location of the bus, click here
