Three areas of focus with ZEBs
Electromobility Expert, Ryan Mackem: In the last few years we’ve seen electric buses go from a far-off hypothetical solution to emission and air quality concerns, to one that shows a real promise in leaving a world behind that is better for the next generation.
With that said, dealing with electric buses in a public transit environment presents obvious challenges such as range anxiety, selecting feasible routes for deployment, and managing the charging and in-depot processes in an economic manner. As the percentage of electric buses in a fleet increases, public transit providers will need to increasingly rely on new technologies to ensure on-time performance and consistent service for the ridership.
For simplicity, let's break down the examples of new forms of technology into 3 categories:
- Electrification of the operation control system and on-board data collection
- Intelligent charge management
- Route simulation and operational planning
The electrification of the operational control system and the on-board data collection this requires is the most critical aspect of the three categories above. Even if you’ve conducted extensive route analysis and developed an operational plan that is perfect, reality is still reality and disruptions will occur. In the event of even a small service disruption, the agency personnel charged with controlling fleet operations will need to make an immediate decision about what to do next based on the current range capabilities of the vehicle. Having this State of Charge (SoC) information available in real-time in the operations control center is critical and empowers dispatchers to make decisions based on the actual capabilities of a vehicle.
Intelligent charge management can be defied as having bi-directional communication between all 4 dimensions of the charging process. In order to have an automatically managed charging process, none of these 4 dimensions can be excluded. A word of advice would be that anybody looking at electric vehicles should immediately contact their electricity provider to begin discussions about the overall feasibility of the charging plan and what the demand charges are for energy in your area.
Route simulation and operational planning is the first important step for implementing ZEBs. My advice to an agency that is just beginning to explore a conversion to a zero-emission fleet is to start at the top and begin the route simulation and operation planning stage as soon as possible - prior to releasing any formal RFP. Without this critical information to use as a baseline, agencies won’t know which routes are feasible for zero emission buses (ZEBs), how many on-route charging points will be required, or how long the bus will need to charge in order to complete its scheduled trip.
Planning for ZEBs
Bridgette Holzapfel: The initial route analysis and operational plan development is critical to ensuring the success of an electric bus deployment. Without the information mentioned above, the planning department at a public transit agency will not be able to construct accurate or feasible blocks that can be operated in an efficient manner.
One of the many things that a planning department needs to consider is route and block length. They need to ensure that there is sufficient state of charge to complete the block. Also, if the route has many stop points, the more frequently the bus has to stop and accelerate has an impact on battery consumption.
Topology of the route or Line profile is another thing to consider when selecting a suitable route. The planning dept may look to initially assign the electric bus to a route that is relatively flat rather than hilly or with a slope. Going uphill consumes more energy.
Another significant impact that a planning department needs to consider when planning zero emission buses is the changing variables of the weather and temperature. If it’s hot, the vehicle will consume energy for the air conditioner. If it’s cold, the battery will drain faster to heat the bus. This is where a planning department may need to add additional time for preconditioning of the bus.
Finally, the planning department needs to consider not only when the vehicle can be charged, but also needs to avoid charging during high peak periods when electricity is more expensive. This is usually manageable during a pilot phase or when an agency has a few electric buses. However, when more electric buses are purchased, a tool or optimizer should be used.
This tool should be able to create scenarios that looks at:
- Different types of electric buses
- Variable sizes of electric bus fleets and or mixed fleets
- Different placements of charging stations within your network
INIT’s planning tool for e-buses allows you to simulate scenarios using your specific vehicles, charging station types, passenger loads and various temperature ranges. The robust software then delivers the most economical plan for helping you implement electric vehicles into your fleet. This solution allows you to roll out e-mobility in a way that is safe, controlled, and predictable – and ensures an efficient and successful operation of your fleet.
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