MIT Study: Halving Fuel Consumption of New Vehicles in the US by 2035 Technically Possible, But Will Require Aggressive Changes and Higher Costs
19 November 2007
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| Trade-off between acceleration time and fuel consumption in average new vehicles in 2035.%ERFC is the degree of emphasis on reducing fuel consumption. Current vehicle characteristics plotted for reference. Click to enlarge. |
A study by researchers at MIT’s Laboratory for Energy and Environment has concluded that while it is technically feasible to halve fuel consumption (or double fuel economy) of new US cars and light-duty trucks by 2035, it would require changes counter to recent trends in acceleration performance; a large fraction of new light-duty vehicles propelled by alternative powertrains; and vehicle weight reductions of 20% to 35%, along with reductions in aerodynamic drag, rolling resistance and size from today.
In addition, halving the fuel consumption of the 2035 model year will increase the production cost of future vehicles with roughly the same size, weight, and performance as today by approximately 20% more than the baseline cost of today, according to the report.
...while it is technically possible to halve the fuel consumption of new vehicles in 2035, the nature and magnitude of the changes required to meet this goal run counter to the trend towards larger, heavier, more powerful vehicles over the last 25 years. Instead, these scenarios depict a transportation future where automakers might face costs up to 20% higher to produce potentially smaller vehicles with performance similar to today’s.
Automakers may be hesitant to make such large-scale changes in the product mix unless consumers are willing to forego their continuing pursuit of ever higher performance, larger vehicle size and other amenities. Such a future will challenge the auto industry to make the capital investments necessary to realize alternative technologies at a substantial scale, and requires the government to address the market failures that promote size, weight, and acceleration at the expense of higher vehicle fuel consumption and its associated impacts related to energy security and global warming.
These are striking changes from the status quo. Halving fuel consumption in 2035 vehicles will require a fundamental shift in the mindset and motivation of a broad base of consumer, industry, and governmental stakeholders. It will require a new set of policies that pushes industry to utilize new technologies, while at the same time creating market demand to pull efficiency gains toward reducing fuel consumption and aligning the interests of diverse stakeholder groups to realize this worthy and ambitious goal.
The report, Factor of Two: Halving the Fuel Consumption of New US Automobiles by 2035, examines three technology options available that could deliver average fuel economy of 42 mpg by 2035 and that can be implemented on a large scale: (1) channeling future vehicle technical efficiency improvements to reducing fuel consumption rather than improving vehicle performance, (2) increasing the market share of diesel, turbocharged gasoline and hybrid electric gasoline propulsion systems, and (3) reducing vehicle weight and size.
The report focuses on technology options that are essentially available today, and thus does not take plug-in hybrid electric, battery electric or hydrogen fuel cell vehicles in consideration, even though “they are potentially important technologies for realizing vehicle fuel consumption reductions.” Nor does the report include fuel alternatives, although some alternative fuels can offer reductions in petroleum use and greenhouse gas emissions.
Reducing fuel consumption. Over the past two decades, advances in vehicle efficiency have generally been channeled into improving performance over fuel efficiency. (Earlier post.) The first option for reducing fuel consumption is to apply conventional technologies with an emphasis of reducing fuel consumption over improving the vehicle’s horsepower and acceleration, while assuming that vehicle size remains constant.
Conventional technologies considered by the authors in the study include gasoline direct injection, variable valve lift and timing, and cylinder deactivation, which can individually realize efficiency improvements by 3-10%. Further efficiency improvements can come from dual clutch and continuously variable transmissions.
Alternative powertrains. For the report, the authors consider alternative powertrains to be turbocharged gasoline engines, high speed turbocharged diesel engines, and hybrid-electric systems. Based on these historical rates or penetration of new automotive technology into markets (diesel into Europe, hybrids into the US, front or 4-wheel drive and automatic transmissions into the US), the authors assumed that the maximum compounded annual growth rate of alternative powertrains in the US market is 10% per year.
This rate of penetration would correspond to a maximum 85% share of turbocharged gasoline engines, diesels and hybrids in the new vehicle fleet in 2035. For the analysis, the researchers initially kept the share of turbocharged gasoline and diesel vehicles fixed at five-sevenths of the hybrid market share, assuming that hybrids would remain the more popular choice. Thus, in the extreme scenario of 85% alternative powertrains in 2035, hybrids account for 35% of the new vehicle market, while turbocharged gasoline and diesel vehicles each account for 25% of the market.
Weight reduction. Reductions in weight can be achieved by a combination of (i) material substitution; (ii) vehicle redesign; and (iii) vehicle downsizing. Material substitution involves replacing heavier iron and steel used in vehicles with weight-saving materials like aluminum, magnesium, high-strength steel, and plastics and polymer composites. Redesign reduces the size of the engine and other components as vehicle weight decreases, or through packaging improvements which reduce exterior vehicle dimensions while maintaining the same passenger and cargo space. Downsizing can provide further weight reduction by shifting sales away from larger and heavier to smaller and lighter vehicle categories.
Resources
Lynette Cheah, Christopher Evans, Anup Bandivadekar, and John Heywood. (October 2007) “Factor of Two: Halving the Fuel Consumption of New US Automobiles by 2035” Publication No. LFEE 2007-04 RP
Could this be any less relevant? How about starting with the silly presumption that the fleet mix will remain 50/50 between cars and trucks? Then ignoring all emerging technologies, including social/financial technologies like carsharing? Then ignoring all possible technological substitutions and demand-side factors like more walkability and better transit?
Even if substitution and demand-side questions were ignored, the basic fleet mix is the problem. There's no way we need a 50/50 mix of cars and trucks, and certainly not at the size, weight, and power of today's vehicles.
Posted by: | 19 November 2007 at 05:11 PM
Don't forget the $1.85/gallon price for gasoline in the study, as reported by the WSJ.
I unloaded on this report over on TCoE (see the "MPG, assumptions, conclusions post" from 11/18).
Posted by: Lou Grinzo | 19 November 2007 at 05:33 PM
Brilliant!! Assume the status quo and, guess what, it's just too hard. I think assuming we will have enough oil in the future to keep the current mix is an increasingly radical and ridiculous assumption.
Posted by: green menace | 19 November 2007 at 06:19 PM
Let me add the third assessment that this report is pure twaddle. PHEV's are going to reduce fuel consumption from foreign sources by about 60%, because we will burn fossil fuel only on long commutes. Cars last about 10 years, so starting in 2011, it will take to about 2021 to surpass the goal of this report.
Posted by: Van | 19 November 2007 at 06:23 PM
Why not they talk about the next 5 years instead of 30 years.
Well, 5 years ago, when Gas cost around $1.20 / gallon, 25 % of the Vehicles sold were Truck based SUV's, now this year with average gas price around $2.6 / gallon, Truck based SUV's share has declined to 12 %.
The future is going to be $3 and above. SUV's will shrink faster automatically, naturally, no matter what this MIT study says.
And they presume that people will still use Gas in 2035. LOL.
Posted by: Max Reid | 19 November 2007 at 06:33 PM
>> halving the fuel consumption of the 2035 model year
>> will increase the production cost of future vehicles
>> with roughly the same size, weight, and
>> performance
Fabulous, I look forward to seeing the flood of human-sized, non-overcompensating cars that don't need more than 150 HP to get the groceries very soon then!
Why is maintaining current size, weight and performance always the overriding constraint?
Posted by: bluegreen | 19 November 2007 at 07:06 PM
I agree with previous comments. This report is a waste of paper. Consumer choice and government policy are not going to be the drivers of vehicle choice for the next thirty years. Even amongst those that reject Peak Oil, and how can you argue against oil being a finite resource,there is general agreement that oil prices will keep on increasing.Sheer cost of fuel will drive efficiency gains and eventually pull petrol powered vehicles out of the reach of all except the very rich.
All the more reasons for a masssive development push on EV's and even if we do that well the days of our "happy motoring wonderland" are coming to a close.
Posted by: critta | 19 November 2007 at 07:33 PM
I'm getting 52 mpg in a mostly steel vehicle weighing in at a portly 3000 lbs. It features circa-1999 diesel technology. What a joke to say if we really stretch our engineering to the limit that we might reach something less than my avg. fuel economy in 28 years. This from MIT?!
Posted by: Marshall | 19 November 2007 at 09:06 PM
I should have kept the 1985 Chevy Celebrity.
Posted by: Robert Schwartz | 19 November 2007 at 11:11 PM
$8 and $9 per gallon gasoline will half fuel consumption long before the engineers will.
Posted by: Word | 20 November 2007 at 08:34 AM
"Acknowledgements
This project was funded by Environmental Defense. The authors thank John DeCicco and
Freda Fung from Environmental Defense for their valuable feedback and comments during this research."
http://en.wikipedia.org/wiki/Environmental_Defense
Wikipedia describes Environmental Defense as a US-based nonprofit environmental advocacy group, famous for advocating the ban on DDT. More recent achievements include:
1990 - Designed Title IV of the Clean Air Act, which incorporates market-based methods to cut air pollution and acid rain. The measures reduce sulfur dioxide pollution faster than expected, and at a fraction of the cost.
2004 - The first FedEx hybrid electric trucks hit the road, the result of a four-year partnership with FedEx to transform truck technology. The new vehicles cut smog-forming pollution by 65%, reduce soot by 96%—and go 57% farther on a gallon of fuel.
2006 - Co-authored the California Global Warming Solutions Act.
What possessed Environmental Defense to waste their money on this project?
If one of my students presented the scope and assumptions of the project as a rough first draft, I would have told them they were heading for an F grade. As spotted by all the peer reviews above, the scope and assumptions of the project are fatally flawed and the project tells us little or nothing we did not already know.
Consider the summary in the abstract:
"Over the next three decades, consumers will have to accept little further improvements in acceleration performance, a large fraction of new light-duty vehicles sold must be propelled by alternative powertrains, and vehicle weight must be reduced by 20-35% from today. The additional cost of achieving this factor-of-two target would be about 20% more than a baseline scenario where fuel consumption does not change from today’s values, although these additional costs would be recouped within 4 to 5 years from the resulting fuel savings. Thus, while it is technically feasible to
halve the fuel consumption of new vehicles in 2035, aggressive changes are needed and additional costs will be incurred."
Hands up anyone who learned anything new from that.
Automobile manufacturers have already developed and brought to market the technology to significantly reduce fuel consumption. In addition, Mercedes (Sprinter van), Toyota(Prius car)and other manufacturers have PHEV prototypes which will come to mass-market as soon as safe traction batteries reach affordable prices in mass production.
BEVs as second / commuter cars will follow as soon as battery prices fall further.
So the technology exists - the real problem is how to influence new car buyers to choose more economical vehicles.
Just taxing fuel is highly regressive economic policy (regressive meaning that low income families pay a higher proportion of disposable income than high income families.) Due to rising levels of prosperity, even in Europe with astronomical road fuel taxes, sales of gas guzzling SUVs have reached 1.2m per year and the average weight of cars is increasing.
In Italy, which has both high fuel tax and car sales tax proportional to fuel consumption, fleet average consumption is significantly lower.
If sales tax on new cars ranged from 1% on ZEVs to 60% or more on the most thirsty gas guzzlers, new car buyers would be able to afford less thirsty vehicles for a given budget. Also, the price premium on HEVs and PHEVs would be reduced.
However, could any congressman, senator or presidential candidate be elected to office in the USA if they proposed taxing our gas guzzlers in the showroom?
Posted by: Polly | 20 November 2007 at 08:39 AM
These studies take so long to do, and so many of them have a stall-and-confuse agenda.
This report assumes that costs go up 20% if size and weight stay the same...but reducing weight ala Fiber Forge, Loremo, Aluminum extrusion, or just making smaller cars more fashionable as Europe has done, would go a long ways towards reducing weight and cost. When CAFE standards were first introduced the US had huge land yachts as the symbol of affluence and success. I think Green styling could become the symbol of success. Prius sell well partly because nothing else looks like it and it's a badge for eco values. There could be lots more PHEV type cars getting triple today's mileage in just 5 years.
Posted by: HealthyBreeze | 20 November 2007 at 09:33 AM
I agree with Healthy Breeze that vehicle weight reduction (coupled with reductions in coefficient of drag) can go a long way toward improved fuel efficiency. But I disagree that the PHEV is a magic bullet. It is a popularly-held belief that hybrid vehicles are the most energy efficient vehicles available. A recent study by CNW Management, however, demonstrates that hybrid powertrains are actually more energy intensive than many standard internal combustion engine powertrains on a total "life cycle" basis. See, www.cnwmr.com/nss-folder/automotiveenergy/. A primary reason for this counterintuitive conclusion is that hybrid vehicles add subsystems (batteries, electric motors, etc.) to the powertrain, which require significant "life cycle" energy inputs. There are also two powertrains in an HEV or PHEV, which add significantly to vehicle weight. Vehicle weight reduction and aerodynamic design are the two surest ways to improve fuel efficiency, as Amory Lovins has consistently argued.
PHEV's do reduce petroleum use, but then we would have to build more power plants, provide fuel for the power plants (nuclear or coal would be the cheapest) and upgrade an overtaxed power grid to support the PHEV fleet. I don't know if that is realistic to expect even factoring in wind and solar.
In my view, to eliminate petroleum from the transportation sector, we first have to develop a clean, alternative fuel that is domestically produced, as well as the necessary infrastructure to deliver the fuel. Dimethyl ether (DME) is a clean, non-toxic, low emissions signature diesel fuel that can be produced from domestic sources of natural gas, biomass or coal. Second, we must improve the "at the wheels" efficiency of DME diesel combustion by simplifying the powertrain (the opposite of the PHEV engineering approach). A properly designed diesel electric powertrain could be both simple and efficient. It would have only one powertrain (not two) consisting of a diesel-fueled motor/generator, two electric traction motors, an ultracapacitor and a computerized control center. Note how much of the standard powertrain is missing. The powertrain would be 50% hardware and 50% software. The software allows the engine to shift seamlessly between economy operation (cruising) and high power demand (acceleration) for maximum overall fuel efficiency.
Because the problem is like a game of multi-dimensional chess, there is no magic bullet. Every choice has its own consequences. But in my opinion, the problem can begin to be reasonably approached by taking several steps simultaneously: reducing vehicle weight; improving vehicle aerodynamics; gradually switching a portion of the vehicle fleet to domestic DME; and developing a simplified, but very smart, computerized DME diesel electric powertrain with a low emissions signature. None of this is easy, but it's not rocket science either.
Posted by: George Marchetti | 20 November 2007 at 02:33 PM
Holy crap, not that long debunked CNW "Dust to Dust" report again.
Please read this before referencing that "study" again:
http://www.pacinst.org/topics/integrity_of_science/case_studies/hummer_versus_prius.html
Posted by: Dave | 20 November 2007 at 02:55 PM
RE CNW Management
Walking is more inefficient than driving because eating is "actually more energy intensive than many standard internal combustion engine powertrains on a total "life cycle" basis."
Posted by: DS | 20 November 2007 at 05:46 PM
Dave:
Thanks very much for the reference to the Pacific Institute critique of the CNW methodology. The Institute's criticisms are well-taken.
I agree completely with the strategic goals of HEV/PHEV advocates: reduce reliance on petroleum as a transportation fuel, reduce total emissions per mile driven, and maintain the flexibility for both local and long distance travel. What I am suggesting is that HEV/PHEV's may not be the best means to accomplish those goals.
Rather than relying on domestically produced electricity from the power grid as the alternative fuel source, domestically produced DME can be that source. One of the benefits of DME is that it can be used in efficient diesel engines without adding a second powertrain. A second powertrain adds weight (and cost and complexity) to the vehicle. Why add excess weight if it is not necessary? One of the most fuel efficient, recent production vehicles is the four-passenger Audi A2 turbodiesel at 78 mpg (diesel)/68 mpge (gasoline equivalent). The vehicle's curb weight was only 880 kg and its coefficient of drag was 0.25. Its fuel economy was superior to any HEV or PHEV. Because the engine is a turbodiesel, it can be adapted for domestic DME.
But I think we can do even better than the Audi A2 if the powertrain is a smart, diesel electric powertrain. A diesel electric powertrain can reduce inefficiencies associated with the transmission of power from the engine to the wheels and still have regenerative braking, auto stop, etc. A diesel electric vehicle with fuel economy of 80+ mpge is realistic and the vehicle would run on a domestic fuel having a very low emissions signature. In short, I am suggesting that the HEV/PHEV strategic goals can not only be achieved, but can be exceeded, with DME and a light-weight, aerodynamic, smart, diesel electric vehicle.
Posted by: George Marchetti | 21 November 2007 at 09:10 AM
Tell me again, how many A2's were sold and where can I buy a brand new MY2008 A2? The formula it used was great for fuel efficiency, but for some reason that wasn't enough for it have good sales (for the class of car it is).
Posted by: Patrick | 21 November 2007 at 09:37 AM
Patrick:
The four passenger Audi A2 was produced from 1999 to 2005. Its reported fuel efficiency was 3 l/100 km or 78 mpg (diesel). Wikipedia has a good article on the car. See, en.wikipedia.org/wiki/Audi_A2 - 43k. About 175,000 of these minis were sold in Europe. None in the US. Maybe Audi gave up on the car too soon (when oil prices were stable). Maybe Audi gave up because the acceleration, to be generous, was very sluggish at best. A diesel electric motor/generator with an ultracapacitor could address the acceleration issue. The ultracapcitor supplies a lot of power to the electric traction motors for 5-10 seconds for acceleration in order to supplement the diesel motor/generator power. The ultracapacitor is then recharged in part by the motor/generator and in part by regenerative braking.
Posted by: George Marchetti | 21 November 2007 at 11:12 AM
I am new to many of the issues here but one thing seems very clear to me. We have millions of cars and trucks on the road now that will remain on the road for years to come. We need a good fuel now for those cars and trucks that can be produced here. I believe the answer is bio-butanol. It promises to deliver on all the promises that ethanol made but could not keep.
Of course, bio-butanol is not a current reality though it can be produced as efficiently as ethanol from cultivated crops. What is desperately needed is the ability to produce it from something like switchgrass that doesn't require very much work to produce. Work on such a fuel is limited to just a few companies and it will really take an effective government effort to coordinate and supplement the current R&D levels.
I cannot imagine a single alternative that could start reducing both CO2 emissions and oil imports more quickly than bio-butanol if we can make the necessary advances. This fuel will buy us time to refine and implement many of the technologies alluded to above.
Posted by: Houckster | 23 November 2007 at 09:46 AM
Perhaps a big picture analysis of how and why we use fuel would help as well. If people live closer to where they work, this could help as much as technology advances. Finding a way to make housing affordable near work or brining companies to the suburbs would go a long way towards saving fuel.
Posted by: sjc | 26 November 2007 at 09:53 AM
sjc,
Nowadays many companies are opening offices in what have traditionally been known as the suburbs. You now have people commuting from urban areas, other suburbs and the "ex-urbs" to these suburban offices.
Example: Redmond and Bellevue WA. It is easier to drive into Seattle in the morning from these suburbs (20-25 minutes with the greatest congestion times) than into Bellevue/Redmond from Seattle (40-45 minutes with the greatest congestion times).
I'd like to see an expansion of federal housing programs to take into account the cost of living of areas more to allow people to live close to where they work. I personally live within walking distance of work and walk when the weather permits.
Posted by: Patrick | 27 November 2007 at 11:37 AM
With turbodiesel technology now on the verge on meeting even the tough CARB ULEV-II emission rules, I do think within the next ten years we could improve the fuel efficiency of vehicles by at least 25-35% just from having the majority of vehicles running on clean turbodiesel technology. Any further gains would require lightening the vehicle, either by legislation imposing excise taxes if a vehicle exceeds a certain size and/or going to lighter weight materials such as aluminum/magnesium alloys, high-strength steels, composite materials, advanced technology fiberglass or better structural plastic materials.
Posted by: Raymond | 03 December 2007 at 11:25 PM
Fossil or biiomass fuels have carbon and hydrogen as primary elements.Syn gas raw material for DME can be produced from coal by gasification route.Apart from coal, the other ingredients for DME are oxygen from air and Hydrogen from steam.to this extent, the dependence on petroleum can be totally eliminated.the steam produced in gasification can be used for power generation to run the gasification plant.
even though DME has two disadvantages in diesel engines which is due to the failure of sealants and engine getting heated up, this could be sorted ouut by providing alternate sealants and lubrication of engine in between laminar and boundary lubrication.
Posted by: K.GOVINDARAJAN | 01 February 2008 at 03:12 AM