Early next year, the face of California's mass transit system will take on a greener tint when the first zero-emissions bus starts daily service in the Los Angeles suburb of Burbank. Created by Proterra LLC of Golden, Colorado, the HFC 35 is a purpose-built high-tech people mover made from lightweight composites and fitted with a unique electric battery and hydrogen fuel-cell power-team.
Designed to accommodate a number of different kinds of low-emission powertrain components, the HFC 35 can carry up to 37 passengers and travel up to 250 miles before it needs a reacharge/refuel stop while delivering effective economy that's double a conventional diesel-engine bus. Funded by monies from the Federal Transit Authority, the HFC 35 is fitted with a UQM Technologies-sourced PowerPhase 150 electric propulsion system rated at 201 peak horsepower and 479 lb.-ft. of torque. On-board computers regulate the power inputs between its Proterra-supplied TerraVolt energy storage system and a high-efficiency hydrogen fuel cell developed by the Hydrogenics Corporation that recharges the TerraVolt pack on the fly as well a by a super-efficient regenerative braking system.
The HFC 35 also boasts several other notable operating efficiencies. It's the first vehicle of its size to use smaller (under 67 horsepower) and more easily manufacturable automotive fuel cells, which are considerably less expensive to produce and to maintain over the vehicle's normal service life. It's also the first vehicle to use Proterra's trick fast-charge plug-in circuitry, technology which permits a full battery top-off from a normal wall outlet in just six minutes.