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US EPA/NHTSA issue final GHG and fuel economy standards for MY2017-2025 light-duty vehicles

29 August 2012

The US Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA) issued a final rule for greenhouse gas (GHG) emission and fuel economy standards for model year 2017-2025 light-duty vehicles, including passenger cars, light-duty trucks and medium-duty passenger vehicles. The adopted rule follows the proposal released in November 2011.

The EPA GHG standards are projected to require, on an average industry fleet-wide basis, 163 g/mile of CO2 in model year 2025, which would be equivalent to 54.5 mpg (4.3 L/100km) if this level were achieved solely through improvements in fuel efficiency. However, it is expected that a portion of the GHG emission reduction will be made through improvements in air conditioning leakage and through use of alternative refrigerants, which would not contribute to fuel economy.

NHTSA has finalized their Corporate Average Fuel Economy (CAFE) standards for MY 2017-2021 and issued “augural standards” (representing the agency’s best estimate of the future standards) for MY 2022-2025. NHTSA will set final standards for MY 2022-2025 in a future rulemaking, due to a statutory requirement that NHTSA set CAFE standards not more than 5 model years at a time.

The MY 2017-2021 final CAFE standards are projected to require, on an average industry fleet-wide basis, a range from 40.3—41.0 mpg (5.84-5.74 L/100km) in MY 2021. The MY 2022-2025 augural CAFE standards would require a range from 48.7–49.7 mpg (4.83 to 4.73 L/100km) in MY 2025.

The new standards follow the EPA/NHTSA GHG/CAFE standards for cars and light trucks for MY 2011-2016, which raised average fuel efficiency by 2016 to the equivalent of 35.5 mpg. The new rule also represent the continuation of a harmonized, national fuel economy program.

Like the previous regulations, the new GHG standards are based on CO2 emissions-footprint curves, where each vehicle has a different CO2 emissions compliance target depending on its footprint value (related to the size of the vehicle). Generally, the larger the vehicle footprint, the higher the corresponding vehicle CO2 emissions target. Hence, manufacturers are not compelled to build vehicles of any particular size or type. Rather, each manufacturer will have its own fleet-wide standard that reflects the vehicles it chooses to produce.

The new standards maintain the CH4 and N2O emission caps introduced for MY 2011-2016, as well as the flexibility for the manufacturers to use CO2 credits on a CO2-equivalent basis to comply with the CH4 / N2O requirements.

The range of technologies available for automakers to meet the new standards includes advanced gasoline engines and transmissions, vehicle weight reduction, lower tire rolling resistance, improvements in aerodynamics, diesel engines, more efficient accessories, and improvements in air conditioning systems. EPA expects that the majority of improvements will come from advancements in internal combustion engines, although some increased electrification of the fleet is also expected through the expanded production of stop/start, hybrid vehicles, plugin hybrid electric vehicles, and electric vehicles.

The program also includes targeted incentives to encourage early introduction of advanced technologies, including:

EPA and NHTSA will conduct a comprehensive mid-term evaluation of the MY 2022-2025 standards, involving a complete rulemaking process with public notice and comment followed by final agency action by both agencies. The mid-term evaluation reflects the rules’ long time frame and, for NHTSA, the agency’s statutory obligation to conduct a de novo rulemaking in order to establish final CAFE standards for MY 2022-2025. EPA and NHTSA expect to conduct this mid-term evaluation in coordination with the California Air Resources Board, given the interest in maintaining a national program to address GHG emissions and fuel economy.

The EPA has also finalized minor changes to the MY 2012-2016 regulations, with respect to air conditioner performance, nitrous oxides measurement, off-cycle technology credits, and police and emergency vehicles.

Source: US EPA