Table 5 Economic Analysis of Equipment Options, as Function of Idling
@1,000 h @3,000 h
D5W + D1L-C
Direct heat with storage cooling
Auxiliary power unit
1,700 + 2,500/spot
$1.75/gal diesel fuel.
Estimate from SHAPE (1997).
Webasto (1999). Payback calculated assuming 59% of operation heating and 41% cooling.
Increased fuel use during operation not known or included.
only. For the units that supply cooling as well, all of the idling hours can be displaced, resulting
in a faster payback. With these caveats in mind, we can conclude that options that supply
electricity as well are economically viable for trucks that are idled for 1,000
3,000 or more hours
a year, while the heater units could be used across the board. Payback times for fleets, which
would receive quantity discounts on the prices, would be somewhat shorter.
Note that the cost for electrification includes an estimated $0.08/kW to pay for the power
used, and the payback time is calculated by assuming that only one truck can use each spot per
day. However, if occupancy were increased to two -- one sleeping at night and the other during
the day -- the payback time would be reduced to 1.9 yr for 1,000 h/yr idling and to 0.6 yr for