Performance Evaluation of TransPower All-Electric Class 8 On-Road Truck

Heavy duty vehicles (HDVs) are the primary contributor to NOx emissions in the South Coast air basin and represent a large producer of greenhouse gases (GHG). Reductions in both NOx and GHG are of interest to many stakeholders and various programs are funded to reduce these emissions. This study represents a demonstration and evaluation of a Class 8 all-electric HDV designed for drayage operation, with initial demonstrations taking place at the Ports of Long Beach and Los Angeles, California. The evaluation of the vehicle was performed during laboratory testing of cycles designed around drayage operation and during real world drayage operation with commercial fleet operators such as Total Transportation Services, Inc. (TTSI). This report summarizes the laboratory work, and the results of on-road demonstrations will be presented elsewhere. Performance measurements were made while running the vehicle on the University of California, Riverside (UCR) heavy-duty chassis dynamometer over port related drive cycles, certification-like drive cycles, cycles to simulate sustained during 7% grade operation, and steady state cruise modes. All cycles were performed with the vehicle loaded to an equivalent gross vehicle weight of 72,000 lb. For the lighter duty cycles (near dock port cycle) the vehicle used 2.06 ± 0.04 kWh/mile of energy and for the heavy use cycles (regional port cycle) 2.10 ± 0.01 kWh/mile of energy, where the ± values represent single standard deviations. The vehicle’s reported battery energy storage capacity of 215 kilowatt-hours (kWh) was confirmed during the chassis testing and found to be representative. The vehicle batteries are designed to be safely discharged to a 20% state of charge, providing 172 kWh of usable energy. As such, the HDV range was found to be 84 miles for the Near Dock cycle and 82 miles for the Regional cycle, assuming the vehicle was fully charged and fully drained to 20% SOC. The all-electric HDV produced zero tailpipe hydrocarbons, carbon monoxide, nitrogen oxides, carbon dioxide, and particulate matter emissions. This is a 100% reduction in all the emissions in addition to NOx emissions compared to several conventional vehicles tested previously. Additionally, the all-electric HDV showed no performance difference between short and long drayage driving behavior. This suggests that electric HDVs of this design would be great replacements for diesel trucks where significantly higher emissions are being reported due to low exhaust temperature NOx reduction performance in port applications. In general the all-electric HDV performed well on all the cycles and showed a very reliable operation from full to 20% SOC load. Steady state tests were also performed that demonstrated the ability of the all-electric HDV to maintain sustained peaks loads without loss of performance, system deratings, or safety concerns in the range of 80 miles at 72,000 lb GVW. The TransPower electric HDV was almost two times more energy efficient than an all-electric HDVs tested at UCR in 2011 over the same cycles. This suggests the current all-electric HDV is a significant improvement in the state of the art HDVs. Additionally the on-road all-electric HDV performance statistics agreed well with the laboratory results, suggesting the laboratory testing was representative and that the overall on-road and laboratory results can be used to draw comparisons to conventional vehicles and other advanced technologies. In general this demonstration suggests that the TransPower electric HDV is a great success for reducing emissions and GHG for the communities in the South Coast air basin.