Across the world, electric buses are providing a smooth and quiet passenger experience with zero emissions at the tailpipe. As Europe, California and China 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’.
The “non-rechargeable” option is overhead wires (catenary wires), traditionally called trolley buses. The costs of implementing a new catenary system today is enormous, both in the physical installation of an entire bus system and in the route restrictions of buses that are tethered to wires. For these reasons, most attention is on “untethered” electric buses with batteries. Among batteries, the choices are 100% battery buses and fuel cell electric buses.
Electric bus charging options
To recharge the batteries of an electric bus, the well-established alternatives are:
- for 100% battery buses: roadside (opportunity) charging and overnight (depot) charging
- for fuel cell electric buses: onboard hydrogen fuel cell “charger”
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 in range, route flexibility, and in electric infrastructure complexity. These challenges have again been highlighted at recent conferences in Oslo and Amsterdam.
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.
How do onboard fuel cell chargers work?
The fuel cell electric bus—the Other 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.
Hydrogen as a fuel source: a flexible alternative that’s easier on the urban power grid
Hydrogen is the Other Electric Bus’s energy 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. Hydrogen will play an important role in the decarbonization of our economy.
Range and flexibility compared: the Other Electric Bus vs. the 100% battery electric bus
Range: 100% battery bus
- Shorter range than conventional buses (average: 200 km before recharging)
- Range degrades in cold weather and when buses must be heated
- Range/performance degrades on hills and when fully loaded with passengers
- Large, heavy batteries affect performance and passenger capacity
- Additional vehicles may be needed to maintain same route service level
Range: the Other Electric Bus
- Up to 450 km (300 miles) before refueling
- Consistent power delivery: consistent performance in cold weather and when heated
- Range (including climbing and cold weather performance) is 1-to-1 comparable to diesel and CNG buses
Route flexibility: 100% battery bus
- Roadside opportunity charging is difficult, costly and complex to install in public spaces. Permitting, civil engineering, space requirements and public perception are some of the many issues that arise
- Routes are limited by bus range and the location of fast chargers, which may require changes to long-established routes
Route flexibility: the Other Electric Bus
- Depot refueling eliminates the need for a roadside charging infrastructure
- Refueling is fast: less than 10 minutes of refueling delivers 18 hours of continuous service.
- No dedicated space required at night for overnight charging
- Operation and refueling is 1-to-1 comparable to diesel and CNG buses
- Building an infrastructure for 100% battery systems often incurs additional, unpredictable costs for upgrading power grids and facilities.
- Electricity is often purchased in a regulated market: the more you buy the more expensive it may become.
- Hydrogen technology delivers scalable infrastructure with minimum changes to the electrical grid /infrastructure
- Fuel cell technology is available and proven, with years and millions of km on the road
Transit electrification is happening now
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.
Choose flexibility in your bidding process
It is essential for transit agencies and bus operators to include all zero emission options for zero emission bus tenders. The best choice is not to name any specific technology, and leave it to the bidders to propose the best technology and charging infrastructure—or combination of technologies—that present the optimum solution for a particular route and/or city.
The proposed comparisons should include all costs: vehicle and the complete charging/refueling infrastructure, including any required civil engineering and grid upgrades.
The results may surprise you: today, in some regions, fuel cell electric buses, with fixed-price hydrogen contracts (all-inclusive of H2 station equipment and operations) are already competitive with 100% electric bus solutions.
At FCB OSLO18 conference, industry stakeholders presented solution to deliver zero emission fuel cell electric buses and hydrogen infrastructure to cities and bus operators in Norway. The pathway has been prepared; now is the time to implement zero-emission fuel cell buses in our cities.
For more information on the key benefits of fuel cell buses for Scandinavia’s public transit, download our white paper below.