the vehicles
Photo courtesy of VIA Motors
Infrastructure
to reduce the cost of operating the fleet, non-monetary benefits can also influence the choice to use electrified vehicles. One factor is operator acceptance, and while drivers are comfortable with gasoline or diesel, they often prefer to drive alternatively fueled trucks, which are usually quieter, and do not have the same smell or emissions footprint. While many drivers will accept the alternatively fueled trucks, not all do so readily. PG&E has found that spending training time with operators tends to improve acceptance. One of the earliest uses of electric delivery trucks was the venerable English milk float. Because milk is best delivered in the early morning hours, a quiet electric truck is preferable over a noisy diesel one, to avoid waking people up while delivering milk. Utility companies like PG&E face a similar problem sending crews out in the middle of the night to repair line outages. Noisy diesel trucks with standard power take-off (PTO) hydraulic buckets can wake the neighbors.
Some metropolitan areas have noise restrictions - for example, PG&E can only operate trucks with standard PTO hydraulic buckets between 7 am and 7pm. The company is now using an electrically-driven hydraulic system. During bucket operations the diesel engine can be turned off, and the hydraulic bucket system is powered from a battery pack instead. Without the diesel engine idling to power the hydraulic bucket, the trucks are quieter, so the work day can be extended.
Retrofits
While there are several companies selling newly manufactured electric trucks, commercial fleet operators routinely refurbish old trucks with new drivetrains. A truck body might have four or five engines over its life, due to routine engine replacements. This presents an opportunity to introduce an electric or plug-in hybrid drivetrain as a retrofit. This form of recycling not only preserves the investment in the truck body, but converts a dirty diesel truck into a clean electrified one.
Greening a commercial fleet isn’t just about deploying electric trucks - it must be accompanied by the proper ecosystem to support the plug-ins. This means the necessary charging infrastructure at the service depot, and assurance that electricity supply is sufficient to charge the fleet. It is generally thought that the electrical grid can support millions of electric vehicles before it would be stressed by the added demand. However, utility companies do have worries about extra demand at neighborhood or circuit levels. In the case of a commercial fleet, the electrical service for a depot could be overwhelmed. For example, the drivers could all arrive for their shift at 7 am, with all of the trucks plugged in to recharge at the same time, swamping the electrical supply for the depot. FedEx found a demand spike from 6:30 am to 9:00 am for just this reason. The spikes were high enough to incur extra demand charges from the utility company. To mitigate this, FedEx assembled an “EV Smart Grid Project” in New York, in collaboration with Consolidated Edison. The project seeks to intelligently charge the individual trucks to spread out the load required and avoid demand charges. Each truck draws 6-10 kW while charging. A depot with 120 trucks could draw as much as a megawatt if all trucks were to charge simultaneously. Automatically spreading out the load allows it to be better managed, avoiding demand charges.
Grid-Connectable
PG&E is working on two projects that it calls “job site power supply” and “exportable power.” In these
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