US EPA, DOT propose Phase 2 GHG and fuel efficiency standards for heavy-duty trucks

19 June 2015

The US Environmental Protection Agency (EPA) and the Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) have jointly proposed Phase 2 GHG (greenhouse gas) emission and fuel efficiency standards for medium- and heavy-duty vehicles.

The EPA estimates that medium- and heavy-duty vehicles account for about 20% of GHG emissions and oil use in the US transportation sector. In February 2014, the US president B. Obama directed the EPA/DOT to develop the Phase 2 GHG standards. The proposed standards cover model years 2021-2027, following the current Phase 1 regulations that are being phased-in over the period of 2014-2018.

The proposed vehicle and engine performance standards would cover model years 2021-2027, and apply to semi-trucks, large pickup trucks and vans, and all types and sizes of buses and work trucks. The ranges of CO₂ emission and fuel consumption reductions necessary to meet the Phase 2 standards in model year 2027, relative to the respective 2018 vehicle categories, are:

• Class 8 tractors: Up to 24% emission reduction,
• Vocational vehicles: 12-16%,
• Commercial pickups and vans: 16%.

The proposed standards do not mandate the use of specific technologies. Rather they establish standards to be achieved through a range of technology options, and allow manufacturers to choose those technologies that work best for their products and for their customers, noted the EPA. The technologies considered by the EPA/NHTSA include improved transmissions, engine combustion optimization, aerodynamic improvements and low rolling resistance tires.

The proposed Phase 2 standards maintain separate CO₂ emission standards for complete vehicles and for engines. From the environmental impact point of view, only the vehicle standards are important—ultimately, it matters little how the overall emission reduction is split among the particular components, be it engines, transmissions, powertrains, tires, or vehicle aerodynamics. Therefore, during the Phase 2 proposal development process, the EPA was inclined to eliminate the engine standards. From the business point of view, however, separate standards for vehicle components are important for the respective component suppliers—the Phase 2 engine standards have been supported by engine and component suppliers (Cummins, Eaton) and opposed by vehicle manufacturers (Volvo).

The engine standards, however, appear to have one advantage—the criteria of compliance are well defined and emissions are determined through physical testing using an engine dynamometer test bench, Vehicle emissions, on the other hand, are determined though computer models that are not necessarily a perfect approximation of real vehicle emissions.

The proposal also includes efficiency and GHG standards for trailers (which were not included in the Phase 1 standards). The EPA trailer standards (which exclude certain categories such as mobile homes) would begin to take effect in model year 2018 for certain trailers, while NHTSA’s standards would be in effect as of 2021, with credits available for voluntary participation before then. The efficiency technologies envisioned for trailers include aerodynamic devices, light weight construction and self-inflating tires.

The proposed standards are cost effective for consumers and businesses—according to the EPA—delivering favorable payback periods for truck owners; the buyer of a new long-haul truck in 2027 would recoup the investment in fuel-efficient technology in less than two years through fuel savings.

The Phase 2 proposal—published today—is very complex, making is difficult to understand its stringency and other implications without a more thorough study. Experts from the ICCT noted that the full package—including preamble, NPRM, Draft Regulatory Impact Assessment, and other supporting information—comes in at well over two thousand pages. The heavy-duty vehicle fleet is structured into 10 categories of tractors, 18 categories of medium- and heavy-duty vocational vehicles, 2 work-factor indexed categories for commercial pickups and vans, 10 categories for trailers, and 6 categories for engines.

The two-year payback period emphasized by the EPA would seem to indicate that the Phase 2 standards are not overly stringent and would not force complex powertrain and/or vehicle technologies. The Phase 1 GHG standards, with an estimated payback period of up to three years, have not brought any significant technical challenges (at least in the case of urea-SCR diesel engines). The Phase 1 standards were significant as (1) a political statement (the world’s second heavy-duty vehicle fuel economy standards, after Japan), and (2) an outlier elimination program (to ensure that production of inefficient engine models be discontinued). Industry observers have been wondering whether the Phase 2 standards would require more complex efficiency technologies, such as powertrain hybridization and/or exhaust heat recovery.

The proposed standards are fully harmonized between the NHTSA and the EPA. The agencies have worked closely with the California Air Resources Board (ARB) in developing the proposed standards, said the EPA. In a statement on the EPA/NHTSA proposal, ARB Chairman M. Nichols said that the draft Phase 2 greenhouse gas regulations are a “positive next step for controlling emissions from trucks and other heavy-duty vehicles” and that the ARB will be working to ensure the final regulations help California meet its GHG emission reduction goals for 2030 and beyond. California harmonized its heavy-duty vehicle GHG program with the federal Phase 1 GHG standards in 2013.

A public comment period on the Phase 2 proposal will be open for 60 days after it is published in the Federal Register. The NHTSA and EPA will also host two public hearings for stakeholders.

Source: US EPA