LDV fuel consumption and GHG emissions: Where there's a will there's a way

Last week, the U.S. National Research Council released a comprehensive study of the technology potential for cutting oil consumption and GHG emissions by 80% across the U.S. light-duty vehicle fleet in 2050. (Full disclosure: I chaired the vehicle subcommittee, one of three subcommittees that worked on the report.) It received quite a bit of press coverage: see here and here and here, among others. ICCT’s official gloss on it is here.

But a picture is worth a thousand words, and some of the charts in the NRC report convey its conclusions more economically than the tightest news story could. So here are two of the most important.*

The first shows historical and projected trends in LDV fuel economy. What jumps out is how fuel-efficient internal-combustion engine vehicles are expected to become: just under 100 mpg in a fairly conservative (“mid-range”) scenario, just over 100 mpg in a somewhat more optimistic one. For cars alone—that is, excluding light trucks—which the chart doesn’t show, those numbers are even more eye-popping: about 112 mpg in the moderate case, 145 mpg optimistically. True, the ICE vehicle of the future won’t be your father’s Oldsmobile, or even your own Camry. But this isn’t Star Wars, either. This degree of efficiency gain is possible primarily with natural extensions of the technologies are already widely available in the market, such as lightweight materials, downsized highly-boosted engines, automated manual transmissions, and hybrid-electric systems—if we choose to force the issue through regulations that push the envelope of efficiency standards.

The second shows projected trends in the additional incremental cost to build these various types of more efficient vehicles. Here the first thing that jumps out is that, with the exception of plug-in hybrids (which are going to remain relatively expensive), the costs of the different technology platforms—battery and hybrid electrics, fuel cells, ICEs—converge around 2040. And the second thing is that shortly after that point, battery electrics and fuel cells will become cheaper to build than ICEs. Again this is a midrange scenario; the optimistic case puts that point of convergence about ten years earlier—around 2030, or less than twenty years from today. There are a number of reasons for this. Battery and fuel cell costs, which are falling in any case, are directly related to the loads on the vehicle, so that expected reductions in weight, aerodynamic drag, and tire rolling resistance result in much larger cost reductions for these vehicles than for conventional vehicles.

These are hopeful trends, but they should not make us complacent. There are three important caveats. First, that low-cost battery vehicle will have about a hundred-mile real-world driving range and will take about half an hour to recharge, likely limiting market share to about 20%. Second, while fuel-cell vehicles will likely be acceptable to mainstream customers in the long run, sustaining the trend in fuel-cell vehicle technology will depend on building, in advance, an entirely new delivery infrastructure and on finding a way to produce hydrogen at a price competitive with gasoline. Third, realizing the climate benefits of these advanced vehicle technologies will depend on low-carbon power to create electricity and hydrogen (which are both energy carriers). That is to say: new infrastructure investments are critical to the success of the investments already being made in alternative vehicle technologies.

There is a lot of good news in the committee’s report. Even if future barriers to alternative vehicle technologies are not overcome, there are a lot more improvements available with conventional technology than commonly believed. And if the barriers can be overcome, battery and fuel cell vehicles offer the promise of higher efficiency at lower cost. The real question is: does the U.S. have the will to enact regulations to cause these technology improvements to actually happen and to make the necessary investments for the transition to alternative vehicle technologies?

* Charts reprinted with permission from Transitions to Alternative Vehicles and Fuels, 2013, by the National Research Council of the National Academies. Courtesy National Academies Press, Washington DC.