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Engine idling vs other methods


Line haul trucks waste a great deal of fuel idling their big engines overnight to power small “hotel loads” that cool, heat, and power personal electronics within truck cabs. While auxiliary power units (APUs) cut idling by two-thirds and continue to gain market share, electrified parking spaces eliminate the need for trucks to idle at all. Idling overnight can consume 7–9% of a truck’s fuel. Using a 15 L engine to provide a 3–5 kW load for hours on end is extremely inefficient. APUs displace that idling with a small diesel engine, fuel cell, or battery pack. They cost over $7,000. However, EPA’s “Smartway” and Cascade Sierra Solutions financing programs have met with great success: for a truck traveling 100,000 miles a year at 6 mpg, an APU’s fuel savings can put an additional net $234 a month into the pockets of truck drivers after loan payments and interest.


Northeast States Center for a Clean Air Future, International Council on Clean Transportation, Southwest Research Institute, and TIAX. 2009. Reducing Heavy-Duty Long Haul Combination Truck Fuel Consumption and CO2 Emissions. Boston, MA: NESCCF link

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