Are Hybrids Good for the Environment?
By Ocean in DumbAgent.com, Featured
Along the lines of calculators, here we feature another one, this time to calculate the eco-friendliness of that new car you’re thinking of buying.
According to Wired Magazine, building a Toyota Prius consumes 113 million British Thermal Units (BTU), while a gallon of gas contains about 113,000 BTU. The 2008 Prius can go 48 miles per gallon (on highways).
A 1998 Toyota Tercel, on the other hand, does 35 mpg and, since it is used, the carbon cost of construction has already been paid.
This would mean that it would take about 129,230 miles of driving before the 2008 Prius surpasses the 1998 Tercel in eco-friendliness.
Incidentally this calculation can be made for any used car you wish to buy. You can find our worksheet that does exactly that right here.
(7 votes, average: 8.43 out of 10)
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Except… the carbon cost of the hybrid has “already been paid”, too. They don’t fabricate it on demand when you walk into the showroom.
To actually make the comparison valid, you’d need to amortise the carbon cost of constructing both vehicles over their expected lifetimes.
Jordan | Jun 6, 2010 | Reply
Actually it’s far more complicated that. By buying a 1998 Tercel, you keep someone else from buying that Tercel.
So to calculate the effect, you need to think how your choice reduces demand for hybrids, and increases demand for used Tercels, and then calculate the net effect on quantity (where the new demand meets supply).
In the case of used cars, the quantity supply only changes because people may then drive the used cars longer before retiring them. Otherwise, you’d have zero effect.
But since you are now potentially causing all used cars buyers to drive their car slightly more, you may be causing people to drive less efficient cars than they would otherwise.
Economists call these general equilibrium problems and thus not so simple at all.
Anyway, your point is quite valid, that it is not at all clear that buying a hybrid makes sense. But the calcuations for it are quite tricky.
Ben Ho | Jun 6, 2010 | Reply
oops, forgot to click on notify.
Ben Ho | Jun 6, 2010 | Reply
Yes that is true on an individual basis. On the other hand, if demand were to fall in general, or even in certain areas, production of the Hybrid would decline, while production of 1998 Toyota Tercels (and other used cars) has already occurred, no matter what the fluctuation in demand is.
Having said that, you’re right that amortizing the full cost would give a better long term value (Hybrids will start being sold as old used cars soon). There are also other ways to improve upon Wired.com’s (and therefore our excel sheet’s) theory.
So if someone were willing to create a more comprehensive calculator would be happy to feature on our site and/or link to it, and even name it after you.
Ocean | Jun 6, 2010 | Reply
Sorry Ben, just noticed your comment.
I would think an an unsold used car is still driven by its original owner. Once it is run to the ground it usually isn’t sellable, so I’m not sure if used cars are driven more when they’re resold or not.
Of course, not selling it could potentially keep the original owner of the Tercel from buying a new car, and what effect would this have? And an alternative could be that they end up in junk yards and, if so, how many are efficiently recycled, and what is the subsequent effect on the environment?
So again, you’re right in that it can get more complicated. It would definitely be a useful calculator though if the relevant information is available.
Ocean | Jun 6, 2010 | Reply
Yeah, the more I think about it, I think a full calculation would probably show that there really is little benefit in buying a used car. Because to a first order approximation, the supply of used cars is pretty much fixed.
The problem is that if I buy an additional used Tercel, someone else has to buy one less used Tercel, and if that causes that other person to buy a Prius, you’ve had zero effect. If that causes that other person to buy a new car that’s worse than a Prius, say a Hummer, you’ve now made things considerably worse.
You might say that other person could also buy a used car, but then that next person now needs to buy a different car, so at some point someone will buy a new car.
The only way you could increase the supply of used cars is if people now drive used cars more. But in general, it’s not like people are throwing away perfectly good used cars, they sell them on to somebody else who uses them (often in Mexico or Latin America).
An easier question is to compare say a new hybrid civic vs a new regular civic, (many have done this before) because here, you can easily make the argument that making the choice to buy a new regular civic would lead to one more new civic being produced, and one less hybrid being produced.
The EIA website has most of the data you’d need, to do the calculation, if anyone wants to try, but having been paid to do similar calculations once upon a time, it would be quite an endeavor.
These complications are also why most economists thought cash for clunkers was a massively inefficient program to improve fuel economy.
Ben Ho | Jun 6, 2010 | Reply
I’m not sure if someone selling a used car is necessarily in the market for a new hybrid, or a new hummer for that matter. I’m sure there is data on what type of car a seller of any specific used car is more likely to buy, but it’s a lot of work to collect (and update) that for each car, and then each assumption dilutes the precision of the calculation, and at some point it’s not worth the effort.
For example, we could also say that by buying a hybrid we allow the used car to be sold to Latin America, where they are more likely to use it for a longer time than it would have been used in the US, but at some point we’re making too many generalizations and the whole argument becomes quite tenuous.
Admittedly, the calculation I featured is about as simple as it can get, but also straightforward.
As to comparing a new hybrid Civic to a regular civic, I’m sure it’s more straightforward but also much less interesting, since it is the original argument for hybrids.
Ocean | Jun 7, 2010 | Reply
Oh yeah, I agree that more assumptions leads to more noise. So you are right, it may be pointless.
But to clarify, it is important to acknowledge that by switching from a new car to a used car, you essentially force somebody out there to switch from a used car to a new car.
Let’s say there are 1,000,000 used cars out there with 1,000,000 used car drivers. If you buy one of them, you deprive somebody else of their car. If you buy one of them, there are now only 999,999 used cars for 1,000,000 drivers. So you have forced one of them to buy a new car.
That is the first order effect. There is a 2nd order effect if you cause used cars to get utilized more. But the size of that effect is ambiguous and probably small.
Which means, I think yours (and Wired’s) calculation don’t make sense. Buying a used Tercel still induces some other new car to be produced, and you have to account for that.
Ben Ho | Jun 7, 2010 | Reply
Has anyone mentioned that used cars do not have an indefinite lifespan? What portion of ‘98 Tercels still in operation can sustain 130,000 more miles? Is the EPA mpg estimate (or any other value of fuel economy) a production value that we can assume is constant, or should we presume that a ‘98 Tercel which produced 35 mpg when new will produce less than 35 mpg now?
There are probably some other valid considerations, like the demographic differences between new and used car purchasers.
It’s worth noting (again) that the used car market consists of the surviving new cars from a previous period. A more efficient mechanism to increase the fuel economy of all cars may be to increase the consumption of economically friendly new cars.
Say, for instance, that fuel conscious buyers heed the advice above and only purchase used cars. New cars will be left to be purchased by the less fuel conscious consumers. Market demand for new cars will drift away from the fuel friendly and the market for used cars will likewise follow.
I think that for the fuel conscious consumer to purchase a used car instead of a new hybrid, that consumer may be inadvertently pushing the market in the direction opposite their intention.
Micah | Jun 8, 2010 | Reply
I want to clarify and condense my previous comments with a tighter statement:
Fuel friendly used cars only exist become someone previously purchased a fuel-friendly new car.
Micah | Jun 8, 2010 | Reply
Ben: Right, I see what you mean now. Although I’m not entirely convinced of it yet. If, by buying a ‘98 Tercel, you deprive someone else of buying it, they will switch to another used car, which will start the chain reaction you mentioned, but it will likely be with cheaper and cheaper cars. So if there are 999,999 used cars for 1,000,000 drivers, the alternative for the last driver might be to stick with a bus pass, or buy a bicycle or moped, since the others will likely be able to outbid him.
Micah: a ‘98 Tercel might not be fuel friendly at all, but its production has already been accounted for. You’re right that it probably won’t last 130,000 miles, but might trading it in for a ‘99 Tercel (and probably a ‘00 Tercel later) still be more beneficial than switching to a Hybrid?
Having said that, it’s an interesting point that new cars might end up being less fuel friendly as a consequence. Yet another factor for the ever-complicating equation.
Ocean | Jun 9, 2010 | Reply
The only benefit in buying a used car vs a new car (in the scenario here) is a short-term, personal benefit.
If the goal is to save my money and reduce my carbon footprint, it works… in the short term.
If the goal is for me to be a consumer with a conscious for the broader market, I should probably purchase a new fuel efficient car and suggest all my acquaintances do the same.
One person’s carbon consumption is negligible, just like one person’s vote or political influence, but when the market changes preferences you see large effects. (Obama? Change?)
Micah | Jun 9, 2010 | Reply
“the alternative for the last driver might be to stick with a bus pass, or buy a bicycle or moped, since the others will likely be able to outbid him”
That’s a very good point. That is quite true. Though probably unlikely. By putting your money into the used car market, you are effectively raising overall demand for used cars, putting more money in that system, so unlikely for someone in this market to switch to something cheaper (like a bus), more likely they will switch to something more expensive, like a new car. But a fair point.
Ben Ho | Jun 9, 2010 | Reply