By Nicolas Pocard, Director Marketing, Ballard Power Systems
Across the world, electric buses are providing a smooth and quiet passenger experience with zero emissions at the tailpipe. As governments and cities take the lead in placing increasingly strict regulations and restrictions on internal combustion engines, transit agencies and operators are looking at electric buses as the best option to transition their fleets to zero emissions, without affecting service levels..
There are several different electric bus technologies. The principal difference is in how the electricity is delivered to the motor: through overhead wires, through 100% battery power, or through a hybrid battery-fuel cell power train—called a fuel cell bus, a “hydrogen” bus, or the ‘Other Electric Bus’.
To recharge the batteries of an electric bus, the alternatives are:
- roadside (opportunity) fast charging stations
- in depot using overnight chargers
- onboard hydrogen fuel cell “charger” as power generator
Today, the most popular electric bus option is the 100% battery bus with the batteries being recharged using either roadside fast chargers or depot overnight chargers. However, challenges have arisen as these systems are implemented at larger scales. The challenges occur with range, route flexibility, and in electric infrastructure complexity.
The fuel cell electric bus (the Other Electric Bus) address these challenges while retaining the electric bus advantages of a comfortable, smooth, near-silent, zero-emissions ride.
The fuel cell electric bus is a 100% electric bus with a hybrid battery-fuel cell power train. The fuel cell system acts as an onboard battery charger, using hydrogen as a high-density energy source. The fuel cell provides electricity to the electric drive, and maintains the bus battery at an optimum charging level. 20 of such buses were deployed for the 2010 Winter Olympics in Whistler. Today New Flyer offers 40ft and 60ft buses powered by Ballard fuel cell as a standard option of their electric bus platform to Canadian cities.
Hydrogen as a fuel source: Hydrogen stores twice the energy of a standard bus battery at a fraction of the weight. As a means of storing and transporting low-carbon fuel, hydrogen is an effective alternative to the electric grid. When produced from renewable energy, hydrogen is a true zero-emission fuel that also enables grid-balancing and large-scale, long-term energy storage.
Fuel cell electric buses provide operator with zero emission transit without compromise:
- Up to 300 miles before refueling
- Consistent power delivery during duty cycle
- Depot gas refueling (like CNG) eliminates the need for a roadside charging infrastructure
- Refueling is fast: less than 10 minutes of refueling delivers 18 hours of continuous service.
- Compact central fueling infrastructure at depot
- Operation and refueling is 1-to-1 comparable to diesel and CNG buses
Building an electric charging infrastructure often incurs additional, unpredictable costs for upgrading power grids and facilities.
Hydrogen technology delivers scalable infrastructure with minimum changes to the electrical grid infrastructure and multiple and competitive supply options for long supply agreement.
The trend is irreversible. Around the world, transit systems are “going electric”. Electric buses are the proven option for true zero emissions at tailpipe. The choice that faces cities and transit authorities is how to recharge their electric buses. Should they install a roadside-opportunity charging infrastructure, a system of overnight depot chargers, or should they install a centralized hydrogen refueling facility?
Ultimately, cities will make their choices based on their unique operational requirements, geography and climate, as well as the availability and price of electricity and hydrogen, and local constraints. Many cities will choose a combination of 100% battery buses and hydrogen fuel cell buses.