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Fuel economy improvements show diminishing returns in fuel savings
Energy Information Administration ^ | JULY 11, 2014 | Nicholas Chase

Posted on 07/11/2014 5:23:49 AM PDT by thackney

Fuel costs, which depend on vehicle fuel economy, miles driven, and fuel price, are an important factor in vehicle purchasing decisions. However, fuel economy improvement exhibits diminishing returns in fuel savings. For example, switching from a 10-mile-per-gallon (mpg) vehicle to a 15-mpg vehicle saves more fuel and results in greater fuel cost savings than switching from a 25-mpg vehicle to a 75-mpg vehicle. The fuel and cost savings of improving fuel economy from 12 mpg to 15 mpg are the same as increasing from 30 mpg to 60 mpg.

Much of the reduction in fuel consumption and fuel cost comes from incremental fuel economy improvement at the relatively low fuel economy levels. For a consumer who drives 12,000 miles per year and pays $3.50 per gallon for gasoline, increasing fuel economy from 10 mpg to 11 mpg saves $382 in annual fuel cost and from 30 mpg from 31 mpg saves $45; raising fuel economy from 40 to 41 mpg saves just $26 and from 60 to 61 saves $11.

Vehicles that use fuels other than gasoline, such as diesel or electricity, will have different fuel savings and fuel cost. Diesel vehicles often have higher fuel economy than standard gasoline vehicles, but they also must use diesel fuel, which is more expensive than gasoline. Plug-in electric vehicles, which achieve high fuel efficiency and take advantage of relatively inexpensive electricity (compared to gasoline), can accrue significant fuel cost savings, albeit at higher incremental vehicle cost.

As light-duty vehicle fuel economy continues to increase because of more stringent future greenhouse gas emission and Corporate Average Fuel Economy (CAFE) standards through model year 2025, standard gasoline vehicles are expected to achieve compliance fuel economy levels of around 50 mpg for passenger cars and around 40 mpg for light-duty trucks. Diminishing returns to improved fuel economy make standard gasoline vehicles a highly fuel-efficient competitor relative to other vehicle fuel types such as diesels, hybrids, and plug-in vehicles, especially given the relatively higher vehicle prices projected for these other vehicle types.


TOPICS: News/Current Events
KEYWORDS: energy; gasoline; mpg
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1 posted on 07/11/2014 5:23:50 AM PDT by thackney
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To: thackney

Fun with statistics.


2 posted on 07/11/2014 5:31:36 AM PDT by Yo-Yo (Is the /sarc tag really necessary?)
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To: thackney
Of course this won't stop an enormous bureaucracy like the EPA from demanding higher and higher standards until driving is no longer economically practical.

The bureaucracy must constantly raise the bar or lose it's reason for existing - and its budget. It exists for its own sake, not because there's any real need for it anymore.

3 posted on 07/11/2014 5:32:33 AM PDT by skeeter
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To: Yo-Yo

Shows how little value there is in the new government CAFE standards.

Once you reach 30~35 mpg, it is hard to gain the cost back of more improvements.


4 posted on 07/11/2014 5:36:57 AM PDT by thackney (life is fragile, handle with prayer)
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To: thackney
The next leap forward in fuel economy will require even lighter structural parts and switching to engines that use homogeneous charge compression ignition (HCCI) technology. Fortunately, HCCI technology is now finally maturing, and if we legalize the growing of industrial hemp in the USA again, that could make it possible to cut the weight of an automobile 15-20% or more using structural parts made from hemp fiber, a major way to really improve fuel economy without sacrificing safety.
5 posted on 07/11/2014 5:45:03 AM PDT by RayChuang88 (FairTax: America's economic cure)
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To: thackney

Someone discovered ratios. Next week trig and the law of cosines... JK. Useful to keep in mind, are those last few MPG worth it based on cost or loss of features or loss of capability. ...


6 posted on 07/11/2014 5:46:00 AM PDT by ThunderSleeps (Stop obarma now! Stop the hussein - insane agenda!)
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To: thackney
I do local delivery. Everywhere I go, I see most people are not really interested in saving gas.

They zoom off when the light turns green, exceed (by a lot) the speed limit, and don't touch their brakes to stop at a red light or stop sign until the last second instead of starting to slow down early.

Fuel economy? Most people only think about it when buying a vehicle. After that, pedal to the metal!

7 posted on 07/11/2014 5:50:03 AM PDT by jeffc (The U.S. media are our enemy)
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To: thackney

Without a serious breakthrough, I think we have already hit the limits of cost/benefit. Weight is the next problem, and there is simply no (cheap) way to improve this under current safety rules. And no question that this newer generation of cars will be MUCH more expensive to maintain. Just wait until these “direct injection” engines need new fuel injector components.


8 posted on 07/11/2014 5:50:42 AM PDT by The Antiyuppie ("When small men cast long shadows, then it is very late in the day.")
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To: thackney

Not sure why the particular comparison.

How about going from 15 to 40mpg a savings of nearly 1,800 dollars a year in fuel cost, but a corresponding potential reduction in crash protection and for me the inability to carry large and long equipment and tools.


9 posted on 07/11/2014 5:53:36 AM PDT by wita
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To: The Antiyuppie
I think we have already hit the limits of cost/benefit.

Agreed. The latest CAFE standard for 54.5 mpg is not a cost savings.

10 posted on 07/11/2014 5:58:06 AM PDT by thackney (life is fragile, handle with prayer)
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To: thackney
Diminishing returns require new mandates.

11 posted on 07/11/2014 5:58:29 AM PDT by outofsalt
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To: wita
Not sure why the particular comparison.

Spending thousands of dollars per vehicle to reach the latest CAFE standard is not going to be any real savings to the consumer.

12 posted on 07/11/2014 5:59:49 AM PDT by thackney (life is fragile, handle with prayer)
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To: Yo-Yo

Fun with statistics.


Yep. They are factoring in that the number of miles driven doesn’t change, so the annual savings decreases at the higher miles per gallon.

On a side note, I drive a Scion FR-S 6 speed to work every day - 125 mile round trip. My average mileage is 30.5 mpg. However, I started hypermiling about six tanks ago. I bumped my average mileage to about 40 mpg.

Driving 125 miles per day, 50 weeks per year, is roughly 31250 miles per year. Divided by 30.5 mpg that’s 1025 gallons. Divided by 40 that’s 781 gallons per year.

At 3.50 a gallon, that works out to an annual savings of $854, or $71 a month.


13 posted on 07/11/2014 6:25:55 AM PDT by cuban leaf (The US will not survive the obama presidency. The world may not either.)
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To: thackney

“Shows how little value there is in the new government CAFE standards.”

IF

the stated goals are the actual goals, and they’re not.


14 posted on 07/11/2014 6:27:33 AM PDT by MrB (The difference between a Humanist and a Satanist - the latter admits whom he's working for)
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To: ThunderSleeps

Yeah, this revelation reads like it was written by a 12 or 15 year old.


15 posted on 07/11/2014 6:32:52 AM PDT by Sequoyah101
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To: MrB

Regardless of the intent, I’m talking about the impact on the consumer. More cost for the vehicle for less savings in fuel.


16 posted on 07/11/2014 6:38:48 AM PDT by thackney (life is fragile, handle with prayer)
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To: Sequoyah101

And yet, I’ll bet the typical purchaser still won’t understand the 3 mpg improvement from 12 to 15 mpg equals the fuel savings of 30 mpg from 30 to 60 mpg.


17 posted on 07/11/2014 6:42:58 AM PDT by thackney (life is fragile, handle with prayer)
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To: thackney

The fallacy is assuming that the fuel economy of standard cars can be raised from 30 to 60 mpg.

It would seem reasonable to assume that the marginal benefit of diminishing fuel economy will be achieved by marginal vehicle ownership costs that rise at a steeper rate.

There is no calculation for the carbon emission associated with the marginal vehicle ownership rise


18 posted on 07/11/2014 6:46:48 AM PDT by bert ((K.E. N.P. N.C. GOPc.+12 ..... Obama is public enemy #1)
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To: thackney
I think this is called "the law of diminishing returns", which can also be stated as "the pain is not worth the gain"
19 posted on 07/11/2014 7:02:54 AM PDT by Ben Ficklin
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To: Ben Ficklin

Some one needs to get Obama to understand that.


20 posted on 07/11/2014 7:03:49 AM PDT by thackney (life is fragile, handle with prayer)
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