16 September 2009

US Environmental Protection Agency (EPA) and US Department of Transportation (DOT) have jointly proposed a rule establishing a national program to improve vehicle fuel economy and reduce greenhouse gas (GHG) emissions from light-duty vehicles. The proposal is a follow up to the announcement by US President Obama to implement a national fuel efficiency program.

The proposed program, which covers model years 2012 through 2016, includes miles per gallon requirements under NHTSA’s Corporate Average Fuel Economy Standards (CAFE) program and the first-ever national emissions standards under EPA’s greenhouse gas program. Under the proposed program, car manufacturers would be able to build a single, light-duty national fleet that satisfies all federal requirements as well as the GHG standards of California and other states.

The proposed national program would require model year 2016 vehicles to meet an estimated combined average emission level of 250 g CO2 per mile (155.4 g/km). If all GHG emission reductions were made through fuel economy improvements, the overall light-duty vehicle fleet would reach 35.5 mpg in model year 2016. If this occurs, Congress’ fuel economy goal of 35.0 mpg by 2020 will be met four years ahead of schedule. This would surpass the CAFE law passed by Congress in 2007, which required an average fuel economy of 35 mpg in 2020.

The proposal introduces a set of fleet-wide average CO2 emission standards for cars and light trucks. These standards are based on CO2 emissions-footprint curves, where each vehicle has a different CO2 emissions compliance target depending on its footprint (a parameter related to the size of the vehicle). Generally, the larger the vehicle footprint, the higher the corresponding vehicle CO2 emissions target. The projected fleet-wide CO2 emission level requirements under the proposed footprint-based approach are shown below.

Projected Fleet-Wide CO2 Emission Compliance Levels (g/mi) and Corresponding Fuel Economy (mpg)
Passenger Cars (g CO2/mi)261253246235224
Light Trucks (g CO2/mi)352341332317302
Combined Cars & Trucks (g CO2/mi)295286276263250
Combined Cars & Trucks (mpg)

The vehicles subject to the proposed rule are responsible for almost 60% of all US transportation-related GHG emissions, and account for about 40% of all US oil consumption. The program will provide important energy security benefits by conserving 1.8 billion barrels of oil, which is twice the amount of oil (crude oil and products) imported in 2008 from the Persian Gulf countries.

In developing this proposal, the EPA and NHTSA have worked closely with many stakeholders including automakers to ensure the standards are both aggressive and achievable. NHTSA and EPA expect automobile manufacturers would meet the proposed standards by improving engine efficiency, transmissions and tires, as well as increasing the use of start-stop technology and improvements in air conditioning systems. EPA and NHTSA also anticipate that these standards would promote the more widespread use of advanced fuel-saving technologies like hybrid vehicles and clean diesel engines.

NHTSA and EPA are providing a 60-day comment period that begins with publication of the proposal in the Federal Register.

Source: US EPA (press release | proposed rulemaking)