Test drive: results from first year of greenhouse gas emissions program

Blog Post | April 25, 2014 - 3:51 pm
By Therese Langer, Transportation Program Director

Data on manufacturers’ compliance with the first year (model year 2012) of greenhouse gas emissions standards for light duty vehicles is now available from the U.S. Environmental Protection Agency. The bottom line is that manufacturers as a whole have met the standards with a bit of room to spare.

Manufacturers’ individual performance varied widely. The reasons for that variation provide insights into this groundbreaking greenhouse gas reduction program – directly tied to federal Corporate Average Fuel Economy (CAFE) standards – that will be unfolding from now through 2025. Several manufacturers, including Ford and the large Asian automakers, met the car standard strictly on the basis of their average tailpipe emissions, without applying the multiple flexibilities built into the program. Toyota’s 2012 cars were clean enough to meet the standards for several years to come, nearly hitting the substantially tighter model year 2017 target. Manufacturers’ light truck fleets did not hold up so well against the standards, with Honda the only large manufacturer over-complying for both cars and light trucks without taking advantage of the program’s credit provisions.[/no-glossary]

What the variation in performance does not reflect is the size of manufacturers’ products. Like the Corporate Average Fuel Economy (CAFE) standards, the greenhouse gas standards vary with the size of the vehicle. Hence the required average emissions level varies: a manufacturer’s standard depends upon the size mix of the vehicles it sells.

The greenhouse gas emissions program provides several opportunities for manufacturers to achieve credits towards compliance---other than through the basic path of ensuring that average emissions of their vehicles over the required test cycles meet the standard. Among these opportunities, the heavy-hitters in 2012 were flexible fuel vehicle (FFV) and air conditioning (A/C) credits. While the A/C credits reflect actual reductions in greenhouse gas emissions due to reduced refrigerant leakage and improved A/C system efficiency, the FFV credits deliver no real emissions reductions, as they are awarded for the sale of vehicles that can run on ethanol (E85) but almost never do so. Some manufacturers fell short of compliance with the 2012 standards even after taking advantage of the A/C and FFV credits, but were able to backfill using credits stored up from an early credit program for model years 2009-2011. Others took advantage of the option to trade with other companies, an interesting development that will influence the dynamics of the program in the coming years.

The EPA has been laudably thorough in putting the compliance information out for all to see. Vehicle greenhouse gas emissions and fuel economy programs are complicated, and providing details at the manufacturer and credit type levels is a huge public service, shedding light on whether, and how, the program is delivering on the intended benefits. One further step would be to show how individual vehicle models deliver credits for their manufacturers. This would give a more complete picture of which are truly the most environmentally friendly models on the market, in particular allowing ACEEE to use this information in evaluating vehicles for our annual Green Scores (see GreenerCars.org).