When it comes to drayage operations, such as port trucking, tractors powered by either clean diesel-certified engines, like the Volvo D13, or liquefied natural gas (LNG) are the two choices. That development has been driven forward by the Clean Truck initiative launched by the Ports of Los Angeles and Long Beach. The initiative is replacing many of the 16,800 Class 8 trucks serving the ports with LNG and clean diesel-powered vehicles, as well as banning all pre-2007 trucks by 2012.
LNG fuel is described as “low carbon” and running Class 8 drayage trucks on it can reduce greenhouse gas emissions by about 20% and nitrogen oxide emissions by 75% compared to using diesel power, according to Westport Innovations. That firm works with Cummins Inc. to produce natural gas-fueled engines, including the 15-liter ISX and the Cummins Westport 8.9-liter ISL G powerplant.
LNG engines actually run on 95% natural gas and 5% diesel. In addition to running cleaner, these engines save money as natural gas costs about 25% less per gallon than diesel, according to a port drayage fleet that has begun operating these trucks under the Clean Truck program. This fleet also reports that its LNG trucks travel about the same or a greater distance on natural gas as its diesel-powered trucks on a comparable amount of diesel fuel.
The green quotient of any drayage truck can be boosted by spec'ing idling-reduction equipment, such as APUs, as well as by selecting lightweight components and low rolling-resistance tires.