ICCT: US EPA Phase 2 GHG proposal falls short of SuperTruck program targets
1 September 2015
The International Council on Clean Transportation (ICCT) conducted an interesting comparison of the efficiency targets in the proposed US EPA/NHTSA Phase 2 truck efficiency standards with those of the US DOE SuperTruck program—the analysis shows that the Phase 2 targets are significantly weaker than the SuperTruck goals and that a number of SuperTruck efficiency technologies are not being brought into the EPA standards.
The main efficiency technologies for a Class 8 tractor—including the engine, aerodynamics and tires—as well as the overall truck efficiency targets under both programs are compared in the following table.
| EPA/NHTSA Phase 2 standards | SuperTruck program | |
|---|---|---|
| Engine efficiency | Engine fuel consumption and CO2 emissions would be reduced by 10% from 2010 to 2027 (4% from 2017 to 2027). The average compliant engine in 2027 would have a peak brake thermal efficiency of about 49%. | An increase in peak brake thermal efficiency by 20%. In 2014, the Cummins/Peterbilt team reached a 51.5% thermal efficiency. In 2015, the Daimler team reached a 50.2% thermal efficiency. |
| Aerodynamics | An aerodynamic drag-area (CdA) improvement of about 37% from the reference 2010 tractor-trailer. | An improvement of 40–50% from the 2010 baseline. The Daimler program achieved about 54% improvement. |
| Tires | A 25% reduction in tire rolling resistance from the 2010 reference tires. | A reduction of 35–40%. |
| Overall efficiency | A 2027 Phase 2 Class 8 sleeper cab tractor-trailer would achieve a fuel efficiency of about 8 mpg—a fuel consumption reduction of about 33%. | The Cummins-Peterbilt truck achieved 10.7 mpg. The Daimler team achieved 12.2 mpg. These results represent a reduction in tractors’ overall fuel use by about 40–50%. |
According to the above analysis, the SuperTruck program was more technologically advanced than the EPA standards. A number of efficiency technologies demonstrated under the SuperTruck program would not be used or would be used only on a limited scale under the Phase 2 regulation. For instance, the SuperTruck waste heat recovery (WHR) technology developed by Cummins, Daimler and Volvo would achieve only an estimated 15% market penetration in heavy-duty tractors under the EPA proposed standards. Examples of other SuperTruck technologies that would not be required under the proposed Phase 2 standards include solar panels, hybridization, cab insulation, thermal management, advanced aftertreatment systems, lightweighting with carbon fiber, smart coasting, kinetic energy recovery systems, LED lighting, and electric turbocharging.
In the analysis, the ICCT also compared the truck efficiency under the two programs using the EPA Phase 2 GEM modeling tool. Considering only the engine, aerodynamics and tire technologies, the proposed Phase 2 standards utilize only about half of the SuperTruck fuel efficiency improvement potential:
- EPA 2010 reference tractor trailer achieves 5.2 mpg,
- EPA compliant 2027 tractor trailer achieves 7.8 mpg,
- EPA 2027 tractor with SuperTruck engine, aerodynamics and tires achieves 10.3 mpg.
Source: The ICCT