A Reality Check On Electric Cars: Arithmetic Required
During the Obama Administration a regulation was passed requiring all automobile manufacturers to achieve an average efficiency for all their vehicles of 54 miles per gallon by the year 2025. President Trump recently canceled the ordinance recognizing such a requirement could never be reached without sacrificing the safety of the drivers which we will attempt to explain.
A simple tutorial requiring a little arithmetic follows, and the fallacy of the benefits of electric cars will slowly dissolve.
The energy in gasoline is not appreciated. An automobile that gets 40 miles per gallon uses only six tablespoons of gasoline traveling each mile. As good as that sounds, cars cannot be perfectly efficient. There must be friction resistance just to get them going and there is no avoidance of aerodynamic resistance. Sports cars tend to have smoother machined parts that does reduce friction and account for the greater cost. This is true in bicycles as well. On a bicycle your body will feel the difference between a $500 bicycle and a $2500 bicycle.
In a car there is a practical limitation to achieving higher burn temperatures in the engine in order to increase thermodynamic efficiencies for converting chemical energy to mechanical energy. Higher burn temperatures are accomplished in Diesel engines, but the higher temperatures also requires a heavier engine block. They are super efficient for trucks, trains and ships where the cargo weights are large. More weight eventually means lower miles per gallon for autos.
There is an efficiency calculation that applies to all normal personal vehicles. It is energy per unit distance per unit weight. For example, it may be stated in kilowatt-hours (kWh) per mile (mi), per ton (t) (2000 pounds). The majority of all consumer purchased gasoline-fueled cars utilize about 0.65 kWh/mi/t. Some of the heavier, more efficient cars,(less friction from high performance parts) achieve close to 0.6 kWh/mi/t, which is nearly an 8% improvement. That tonnage must include the weight of the driver and whatever he/she is transporting.
A gallon of gasoline will normally produce 34 kWh of energy. Divide the 34 kWh by the highway miles per gallon (mpg), and then divide by the “curb weight” in tons and add a tenth of a ton (200 pounds) for the driver to that curb weight. A car, for example, that achieves 38 mpg and has a curb weight of 2600 pounds achieves 0.64 kWh/mi/t. That is an excellent car. If the car weighs more (and good luxury cars weigh more than 3400 pounds), the technological advantages must be enhanced to achieve kWh/mi/t values of 0.60 to 0.65.
For the same high standards of engineering, and 54 miles per gallon that was being required by the Obama administration, the car’s curb weight must be limited to less than 2000 pounds. That’s a bitter reality. Many good engineers strongly believed the Obama effort to get cars to 54 mpg, was to put it bluntly, going to create death traps.
Enter the all-electric car. It is deceptive to employ “miles per gallon EQUIVALENTS” as being comparable to the true miles per gallon for a gasoline (or a gasoline-battery hybrid) engine. Purveyors of all electric cars, treat the electricity that flows into their batteries from the wall socket at home or from a charging station as if it were a faucet of free energy.
An accountant would be fired for such an omission. For each 10 kWh that flows from the socket, there are about 33 kWh of stored chemical energy in the coal or natural gas that must be burned back in the local power plant. The kWh that is used in the correct application of an efficiency calculation is supposed to be the ultimate source of the energy, not a deceptive free gallons equivalent coming from the socket.
So the 110 to 120 MPG equivalent values that we are so often told for electric vehicles turns out to be only 37 to 40 MPG equivalent for all the source energy. One can claim 110 MPG equivalent, only if one has his/her own solar collection system with battery storage, and charging facilities. Tesla doesn’t dare suggest that buyers should buy the car PLUS the solar unit. Without this pairing, there is only a very slight reduction in carbon dioxide emissions.
The latest push to have electric cars with longer range, has resulted in the elimination of mpg quotes in the range of 110 to 120 MPG equivalents. In fact MPG is now rarely even mentioned, only the extended ranges. So much battery weight is being added that the reduction in engine weight of an electric car is no longer a valid positive argument. The true source energy per mile per ton may become lower, but only because the total tonnage has increased. Eight hundred pounds of extra battery weight to increase range, for example, is the equivalent of carrying four extra passengers at all times. The additional battery weight is not the equivalent of useful cargo.
The gasoline-battery hybrids (without plug-in) such as the Prius are definitely more efficient. They can achieve close to 0.5 kWh/mi/t, when reaching 50 miles per gallon. The Prius is definitely not a sport car. It has low weight and near-minimum required power. It is superbly engineered to achieve the goals of high miles per gallon (low source energy per mile), and one pays considerably more for it than for any similar sized gasoline powered car.
With the longer range all-electric (battery) car, designers will never achieve a total weight that approaches 0.5 kWh of source energy per mile per ton.
William T. Lynch PhD is a retired Department Head from Bell Telephone Laboratories, with lifetime expertise in all areas of energy modeling, performance metrics, solar and nuclear energy, atmospheric modeling, and semiconductor processing and electronics.
Dr Jay Lehr contributes posts at the CFACT site. Jay Lehr is a Senior Policy Analyst with the International Climate Science Coalition, and he is the author of more than 1,000 magazine and journal articles and 36 books.
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T. C. Clark
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I just paid $1.89/gal and the station has since dropped to $1.82. The price would likely be 10 cents/gal cheaper if it was 100% gasoline instead of the alcohol blend. The price includes taxes for highway maintenance which electric cars are not paying at the current time. CO2 is not a problem. The warmists must know but are keeping a secret…what is the ideal temp of earth? What is the ideal CO2 percent of the atmosphere?
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Andy Rowlands
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One of either Mann / Hansen / Schmidt (can’t remember which) said the ideal temperature is that which existed before the Industrial Revolution, which means the Little Ice Age. As for the ideal level of CO2, the work of Craig & Sherwood Idso suggests that would be 1200ppm.
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Andy Rowlands
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I don’t understand how making cars less than 2000lbs would make them ‘death traps’, and no explanation is given in the article. If you make a claim like that, you need to fully explain what you mean.
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Herb Rose
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Hi Andy,
In collisions kinetic energy is absorbed by crumpling steel. The less steel the more plastic or aluminum means more crumpling. What the government needs to do is mandate that all cars should be made of titanium, problem solved.
Herb.
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Andy Rowlands
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Ah now, that is an explanation. Yes making them lighter would make them weaker. Shame the article didn’t actually say that.
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Limitless Energy
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The article says “arithmetic required” not “a spoon fed reality check on electric cars”
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Aaron Christiansen
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I am not a fan of EV, primarily as the people espousing their use imply they are “saving the environment” when a large portion of the EV use is recreational. The other reason is the long-term battery creation and disposal issue, which is a deferred cost / process not many appear to be considering.
That said, to calculate the mileage of an EV by including the creation cost of the electricity seems fair, as long as you calculate and include the creation cost of fuel in your thesis. Something I do not think you have done.
Just as electricity pumped into an EV takes more energy than that pumped in, there is in fact no fuel in the environment, it’s oil. Oil that needs to not only be processed to fuel, but also transported to the users, stored, pumped, etc.
I’d like to see an apples to apples, life-time energy creation and usage cost breakdown. Otherwise this article seems ideological rather than purely logical.
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geran
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Aaron pontificates:
“Just as electricity pumped into an EV takes more energy than that pumped in, there is in fact no fuel in the environment, it’s oil. Oil that needs to not only be processed to fuel, but also transported to the users, stored, pumped, etc.”
Aaron, those sentences make no sense.
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Aaron Christiansen
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Geran let me see if I can type it slowly enough for you, given you apparently did not read the article, nor what I wrote in toto.
The article says, “For each 10 kWh that flows from the socket, there are about 33 kWh of stored chemical energy in the coal or natural gas that must be burned back in the local power plant.”
The ICE (internal combustion engine) shares the same predicament, to wit “For each litre that flows from the dispenser, there are about 40-70 litres of crude oil that must be extracted from the ground, converted into that fuel, then transported, stored and pumped into a car.”
Please let me know if you still have trouble with comprehension, it’s the one thing I will believe immediately.
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Aaron Christiansen
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It appears you can’t edit comments, ugh.
The conversion is not 1 litre to 40-70, but there’s a similar cost to converting the oil to fuel, transporting and storing it, then pumping it,.
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Tom O
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Aaron, there is also the background costs of the fuel being burned to make the electricity that flows from the wall socket. There is also the background costs of making the battery that collects the electricity that flows from the wall socket. You are nit picking. The truth will still be that the EV is not the economical nor ecologically wonderful device it is being pushed to be. It might be a fine vehicle if I lived in the city in a small country or state. It is a useless device in a large country since distances greater than 275 miles, which is about the best you can get from Tesla’s long distance version car, are commonly travelled. Yes, if we all lived in rat warrens and never ventured out of them, EVs would be sufficient.
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Aaron Christiansen
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Could not agree more, Tom O, however the assumption from reading the article is that there is no cost / losses associated with pumping fuel into a vehicle, however there are losses / costs associated with pumping electricity into an EV.
Science is about facts.
Science does not have an agenda other than the truth. ESL people like Geran might not understand such a simple claim, but I dare him or anyone else to rationally argue otherwise.
To be scientific when comparing 2 items you need to present both sides completely. To present the losses of electricity but not fuel is ideological, not scientific.
Mr B J Man
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Aaron C
You entirely miss the point.
Say you have a diesel fuelled car and a diesel fuelled power station.
In BOTH cases the crude oil is explored for, drilled for, pumped out, transported refined, transported again to the power plant.
It is then burned in a power plant to drive the diesel car or spin the power station generator.
Up to that you have comparable efficiency for both routes.
And at that point the car is already motoring.
Then ON TOP of that you have the voltage transformations up and down and power lines losses to get to the plug.
AND THEN YOU HAVE THE ELECTRIC CAR’S MOTOR’S INEFFICIENCY ON TOP!
Mr B J Man
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Oh, and I forgot all about the battery ON TOP OF ALL THAT!
Mr B J Man
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As you say:
“To be scientific when comparing 2 items you need to present both sides completely.”
Except:
“To present the losses of electricity but not ITS fuel is ideological, not scientific.”
geran
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At least I can now make a guess as to what you are struggling to state.
Thanks for trying.
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Aaron Christiansen
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Good trolling, Geran, good trolling.
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Tom O
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I particularly enjoyed this line –
This is true in bicycles as well. On a bicycle your body will feel the difference between a $500 bicycle and a $2500 bicycle.
If only I could afford the $500 bicycle! I am sure the difference between the bike I can afford, about $120, and the $500 bicycle would leave me, well. less breathless.
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T. C. Clark
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EV vehicles were manufactured over a century ago….lead acid batteries….better than a horse and buggy for an urban area. The no. 1 problem with EVs has always been recharge time. The cost would come down with mass production but currently there is not even a universal charger system….Tesla does allow those other EVs to use their system….and their system is not as available as gasoline. EVs might find a market on merits but CO2 is not a reason for EV vehicles.
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