UC Davis Institute of Transportation Studies

Truck manufacturers and vehicle component manufacturer are exploring using fuel cell auxiliary units (APUs) in lieu of main engine idling. While fuel cell powertrains continue to face significant technical and economic barriers, the truck auxiliary power application may offer a viable near-term market for small (1-5kW) fuel cells. The University of California, Davis Institute of Transportation Studies (ITS-Davis) has conducted a study to quantify the potential benefits of utilizing APUs in lieu of truck idling. ITS-Davis researchers estimated the potential reductions of (1) air pollutants and greenhouse gases and (2) heavy truck fuel and lubricant consumption through elimination of truck idling. For new tractors, idling is estimated to contribute 0.2 to 0.7 metric tons of nitrogen oxide emissions and 8-24 tons of carbon dioxide per vehicle per year. Thus, depending upon the emissions from fuel cell system production, fuel cell APUs in lieu of idling could substantially reduce pollution emissions and greenhouse gas emissions.