A really BIG lithium battery.

My extremely conservative rule for commuting is 50Wh per mile - most people consume between 8 to 25 Wh mile; I like to have a LOT of reserve, as the personal cost to be to lose battery power is very high. Wh = Watt-hour = Amp-hour x Volts.

How far are you going to go in a shift?

What sort of hills are you going to encounter?

Is there a possibility of charging or swapping batteries during your shift?

Your power consumption is likely to be on the high end per mile because of the frequent stops, heavier weight and lots of low speed acceleration.