Governments Drive Carbon Dioxide Reduction
Larger Vehicles Often Meet Carbon Dioxide Targets
Climate change concerns have now become the overwhelming driver for reducing emissions from vehicles. As such, concerns with vehicle emissions are now focused primarily on reducing carbon dioxide emissions and fuel consumption rather than the traditional hydrocarbon, nitrogen oxides, carbon monoxide and particulate emissions. Currently, there is intense pressure by governments around the world for the OEMs to develop vehicles that have a substantial reduction in emissions, especially greenhouse gas emissions such as carbon dioxide. In fact, emission limits for the years 2020 and beyond will require significant vehicle technology shifts in order to meet the new fuel consumption and carbon dioxide emission limits. For example, the US government, in agreement with the OEMs, has developed regulations that will require a 54.5 mpg fuel economy by 2025.
As this century moves into its second decade there continue to be significant improvements in vehicle fuel economy in many different regions. In the US, these improvements have not come at the expense of vehicle power as shown in the accompanying chart. A similar story continues to evolve in Europe where new vehicles are introduced with downsized engines that have lower fuel consumption than their predecessors whilst often improved torque and power. Boosting is one of the keys to this success.
At the same time as improvements continue in powertrains, the OEMs continue to be adept at using a limited number of base engines across many different vehicle variants. A case in point is Volkswagen and more recently Volvo.
With its LEV I, LEV II and ZEV programs, California has been a leader in the development of low emission vehicle regulations. On September 27, 2006, Governor Schwarzenegger signed Assembly Bill 32 known as AB 32. This bill put into law a requirement for greenhouse gases (GHGs) to be reduced to 1990 levels by 2020. A reduction in GHG emissions to 1990 levels from those projected for 2020 requires a reduction of about 25 percent from today’s GHG emissions. In the longer term, California has an Executive Order that requires GHG emissions to be reduced to 80 percent of 1990 levels by 2050.
In the US, fuel economy standards have been in place since 1978. These standards known as the Corporate Average Fuel Economy (CAFE) are under the responsibility of the National Highway Traffic Safety Administration (NHTSA). The Environmental Protection Agency (EPA) is responsible for establishing the test procedures and calculation methods. Fuel consumption standards in the US are now covered by both CAFE and greenhouse gas (GHG) standards. These emission standards are applied to an OEMs fleet and the emission/economy standards vary with the footprint area of the vehicle. Separate standards are used for passenger cars and light trucks. As a result an OEM no longer has to strive to have smaller vehicles to achieve CAFE targets.
Automakers are making progress to meet future CO₂ standards with both conventional and electrified powertrains. As show in the figure, over 17% of all vehicles and 13% of 2016 conventional powertrain vehicles meet 2020 CO₂ emission targets.
On August 28, 2012, the final rules were signed for carbon dioxide and CAFE standards for 2017 to 2025. It has been forecast that these footprint-based standards will by Model Year 2025 reach average industry-wide compliance levels of 163 g/mi carbon dioxide and between 48.7 and 49.7 mpg for CAFE. The 163 g/mile carbon dioxide compliance level would be equivalent to 54.5 mpg if all carbon dioxide emissions reductions are achieved solely through improvements in fuel economy.
A significant portion of compliance with 2025 EPA GHG CO₂ standards is expected to come from off-cycle credits (see exhibit below). ITB projects that a/c and other off-cycle credits are expected to account for 15-20% of 2025 standards compliance. Such technologies include start-stop (SS), sailing and coasting, active aerodynamics (AA), cabin ventilation (VENT), seating heating/cooling (SEAT), solar glass, and powertrain warm-up (PTWU).
In Europe, the average target for each OEM is based on vehicle weight. The exhibit below illustrates the required improvements each OEM will need to make in order to meet the 2021 targets. We note that:
- The required improvements for each OEM do not vary according to vehicle size. For example, PSA, Toyota, Volvo and Nissan are making good progress.
- Hyundai and Suzuki have bigger challenges to meet 2021 targets.
- High production volume OEMs such as Volkswagen, Renault, and Ford are in the middle of the OEM group.
There has been substantial discussion in different regions concerning the use of vehicle weight versus vehicle footprint. A major concern with the use of vehicle weight for calculating an OEMs’ average fleet emissions is that reducing vehicle weights results in reduced carbon dioxide targets for the OEM. This in turn could reduce the OEM’s desire to reduce a vehicle’s weight even though vehicle weight is one of the effective methods for reducing transportation based carbon dioxide emissions. Theoretically, vehicle footprint is a more effective approach although to some degree could result in an OEM increasing the average footprint of its fleet but of course there are limitations to this. Calculations have shown that there should not be a significant impact on the OEMs’ targets whether or not a weight-based or footprint-based target is used. Total difference in emissions reduction between 2009 and 2020 would be between 2 and 4 g/km.