Monday, September 19, 2022

The latest light truck versus EV emissions gap

CO2 reduction from EVs compared to CO2 emissions increase from higher light truck sales,
light-duty fleet average changes from 2012 through 2021.  

Although U.S. electric vehicle sales have been growing by leaps and bounds, so too have the sales of large light trucks. Last year, my analysis of the then-current EPA data revealed that CO2 emissions due to the market shift to light trucks (mainly pickups and most SUVs) was over five times greater than the emission reduction that EVs would have achieved on their own. This gap has dropped to just under a factor of four, as shown in the chart above. In short, EVs sales still have not made a dent in the overall lifetime carbon burden of the new light-duty vehicle (LDV) fleet. 

Last year's analysis examined data through model year 2019; EPA's most recent Automotive Trends report includes preliminary data through model year 2021. Combining those data with plug-in electric vehicle (PEV) sales reports from Argonne National Laboratory (ANL, sponsored by the U.S. Department of Energy) enables an updated calculation. The methodology used is the same as that described in last year's post.

The market share of EVs (counting pure plug-in battery electric vehicles and plug-in hybrid, but not gasoline-only hybrids) reached 4.2% in 2021, up from the 2% share in 2019. But 2021 also saw the light truck share of the new LDV fleet reaching a record high of 61% (using EPA's classifications, which count small, front-wheel-drive SUVs as cars while counting all other SUVs as well as pickups and minivans as light trucks). 

These data imply a factor of 3.7 for the gap; that is to say, the excess emissions from the increased light truck sales are nearly four times greater than the potential emission reductions from the increased EV sales. So although the gap has narrowed somewhat, there is still quite a way to go before EV sales become high enough to dig us out of the hole caused by adverse market shifts. The EV reductions are termed "potential" because they are not realized on a net basis due to the fleet average nature of clean car standards. 

As in most recent years, the average CO2 emission rate of each vehicle class has declined. However, as the mix of vehicles sold has shifted to higher-emitting light trucks, fleetwide progress has all but ground to a halt. EPA's estimate for 2021 is a LDV average of 348 grams per mile (g/mi), differing only trivially from the 2020 average of 349 g/mi. 

The calculation shown here tracks progress since 2012. That year is selected as the baseline because it was when the Obama Administration finalized strong fuel economy and GHG emission ("clean car") standards. That year also saw a number of significant EV introductions even though plug-in vehicle sales were still quite small. The ANL data indicated that EVs represented just 0.4% of new LDV sales in 2012. Thus, over the nine years through 2021, EV market share has increased by an order of magnitude (to the aforementioned 4.2%). 

The EPA data show the overall fleet-average new LDV CO2 emission rate fell by 7.7%, from 377 g/mi in 2012 to the 348 g/mi preliminary estimate for 2021. That's a decline of only about 1% per year, much less than the 4%-5% annual reduction hoped for with the GHG standards issued in 2012. The reasons for this large shortfall in carbon-cutting progress include the weakening of the standards by the Trump administration as well as the market shift from cars to light trucks and the general upsizing within each class, which relax the effective stringency of the standards that automakers must meet. 

As was the case for last year's version of this analysis, it excludes the effect of the largest pickups. These ever-more-massive and powerful, ¾-ton and 1-ton pickups are omitted from EPA's public reports. Including these large, luxurious personal trucks would make the emissions gap even larger. 


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