Table 4 Estimated Emissions from Truck Cab/Sleeper and Engine
Block Heating (g/h)
VOC or THC
Auxiliary power unit
Data are not comparable; accuracy in doubt.
Volatile Organic Compounds or total hydrocarbons.
Particulate matter with Sauter mean diameter of 10
m and less.
Espar (1993). From combustion of fuel in the heaters only; excludes combustion of additional
fuel to recharge battery because the amount of fuel used is negligible (584 Btu/h, or 0.036 gal
over an 8-h cycle). Accuracy in doubt
n/i = no information.
Assumes 5 hp-h required to charge the system for 8 h of cooling under full engine load, at a
fuel consumption rate of 169 g/bhph (brake horsepower per hour; calculated on the basis of
average model-year 1996 weight-class 8B truck-specific fuel consumption [EPA 1998]). NO
and PM emitted at the 1998
2003 model-year-regulated rate of 4 g/bhph NO
0.10 g/bhph PM
Pony Pack 104, winter operation. Data from Pony Pack, Inc. (undated).
Providing 4.3 kW to truck heaters. Emissions data from Wang (1999) and DOE (1993).
4.3 Cost Analysis
Cost estimates for several of the technology options were available, and these allow us to do
a simple economic analysis of the options available to reduce overnight idling. Equipment costs
range from about $1,400 installed for a small cab heater to more than $7,000 for an APU with an
inverter to allow use of 110-V appliances. Truck owners could be deterred by the high initial cost
of some of the units, especially the APUs. However, to alleviate this concern, some equipment
manufacturers offer their units for lease, with the option to buy after three years. The capital cost
for the infrastructure for truck electrification is also high and could not be alleviated by leasing
Another economic concern is the weight of the units that supply cooling.
Although carrying this extra weight would make a negligible difference in the vehicle's fuel
economy (~300 lb out of 80,000 lb is less than 0.4%), it would reduce the load that could be
carried for trucks that are weight-limited (weight out before they cube out). The extra weight
A report by the Truck Research Institute (TRI 1996) suggests a cost of $256
341 million for an increase
of 15,032 spaces in the top-10 critical corridors, or about $17,000
22,700 per space.