Is buying a used car greener than buying a new hybrid?
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Reduce, Reuse, Recycle. One aspect of energy use that's often overlooked when comparing cars is the total lifecycle consumption. Buying a new hybrid vehicle compared to a similar sized vehicle with a conventional powertrain can certainly help you reduce. However, it takes a lot of energy to to build a car. Creating a Prius consumes 113 million BTUs of energy. Similarly, energy is required to dispose of a used car. However, those are one-time uses of energy. Fuel consumption is an ongoing variable cost. The production and disposable energy must be spread over the life of the car. The longer a car is in service, the fewer number of production and disposal BTUs per mile.
This is where Reuse comes into play. Factoring in all this energy use it may actually be better to buy a higher mileage used car than a brand new hybrid. By keeping an existing car in service that has slightly lower efficiency than a brand new one the net energy use could still be lower. However, the equation is not even as simple as all that. A ten year old car that gets 30-40mpg may actually pollute a lot more than a new car. Emissions standards have tightened over the years. And, as a car wears, the emissions typically get worse. If you choose to go for a used car, make sure it has been well maintained and that the emissions control equipment is in proper working order.
[Source: Wired Blog]
Reader Comments (Page 1 of 1)
meme 4:35PM (5/21/2008)
Study after peer-reviewed study shows that CO2 emissions from production are only a small fraction of a car's lifetime emissions. Sure, if you're only upping the mileage by a few mpg, it's probably not worth it, but if it's ten or more, it almost certainly is.
To analyze the article's opening salvo: the Prius uses 113,000,000 BTU in production. Great. A car purchased today is expected to be good for 200,000 miles or so (the current average is about 150,000). Gasoline has 133,500 BTU per gallon. Let's do the math.
Prius = 113,000,000BTU + 133,500BTU * 200,000mi / 46mpg = 706M BTU
Used car = 133,500BTU * 200,000mi / 30mpg = 809M BTU
So it comes out worse....but wait! That used car will already have miles on it, *and* won't last as many miles. You'll probably get half the miles out of it or less. So, the Prius should really have its production energy cut in half for the comparison, since it's only going through half of its lifespan. Which leads us to 637M BTU. To match that, the used car would have to get 42 mpg -- hardly a common situation.
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Karkus 3:30PM (5/21/2008)
No. Buying used is NOT better. In fact, it's worse!
Here's why:
1) Cars die at some point and have to be replaced.
2) SOMEONE HAS to buy new cars.
3) The NEW car buyers determine what is going to be on the used car market in the future.
4) The used car buyers are at the mercy of what the new car buyers bought a few years ago.
So if all us treehuggers only bought used cars, we'd all be stuck with used SUVs (which the average Joe bought a few years ago). Bad.
If all the treehuggers buy efficient NEW cars, then in a few years the used car market will have lots of efficient cars for everyone to buy. GOOD.
Another way to look at it. The the Yuppie treehuggers have to buy efficient cars now, so that there will be used efficient cars for the less well off treehuggers to buy in the future.
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armmat 3:51PM (5/21/2008)
It depends...if you actually recycle your car and NOT sell it, it's better to buy new...cleaner cars, more efficient.
Unfortunately...most new cars are heavier, have more power, etc...
If for example, Honda had maintained a 105 HP engine of teh 90's in their Civic's and maintained the weight of those cars, we'd have a current Civic that does probably 50 MPG.
My 2000 Civic DX 5 speed consistently got 35-38 MPG...I was shocked. It weighed around 2600lbs and had a 110 HP engine I think. It was plenty fast, did what it was meant to do...
These changes have been intentional. All on the industry know it's not the right thing to do. It's not the moral and proper thing to do but they do it anyway. What runs through the mind of a stupid GM SUV engineer who knows the world is going to sh&t yet he helps design a 5400lb 12 MPG POS? What was all that schooling helpful for?
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UH2L 4:48PM (5/21/2008)
Karkus,
If we all kept our cars longer, it would help the environment because less vehicles would be produced. Given that we are reaching diminishing returns on emissions improvements, if we bought new cars every 4 years instead of 8 years I doubt that the emissions improvements every four years would outweigh the emissions from manufacturing and junking twice as many cars. I don't have proof of this, but logically speaking, it makes sense. The other good thing to do is to take care of the vehicles you have so that they last longer and look better so that you don't want to buy another vehicle so soon.
Armmat,
GM engineers aren't the only ones that work on products that aren't very efficient. Toyota, Honda, VW, Ferrari engineers do it to. And what they work on isn't necessarily their choice. People today are just happy to have jobs.
Also, I knew that a lot of engineers tend to be conservative and many of them don't buy the global warming argument. It was frustrating for me as a liberal engineer who is an environmentalist.
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Karkus 4:36PM (5/21/2008)
Armmat makes good points about the increase in size, power etc. over the years. It's up to the new car buyers to keep buying cars of the same size/weight over the years. The average Joe will just go along with power size increases over the years, and so if average Joe buys all the new cars, they get bigger.
If the enviros had bought the NEW cars and made sure NOT to increase the size/weight (i.e. former Civic buyers would buy a Fit today), then we'd all still have small cars (both on the new and used car market).
But that didn't happen, and in some ways it's our own fault that we have bigger vehicles now, since we (US buyers collectivley) went along with what the auto makers' size increases.
Or maybe we should blame it on our very low fuel taxes. In Europe where taxes are much higher, they drive much smaller cars.
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werepants 5:11PM (5/21/2008)
Well, meme, your math is ok, but assumes that the driver will go 200,000 miles. What you really need is a break-even point analysis - at which point is it more efficient to run a Prius than a Civic?
The reality is a Prius uses 2902 BTU per mile, whereas a 30 MPG Civic uses 4450 BTU per mile. The issue is that the Civic has a 100 Million BTU headstart on the Prius, since you are reusing, and not paying for the production energy again.
If you crunch the numbers, you'll find that a Civic is greener for the first 70,000 miles, after which point the Prius has made up for production costs, and you begin to recoup your energy investment. Considering that the average driver goes about 15,000 miles in a year, a Prius would start to pay off around year 5. If you trade your car before then (which many do) it is better for the environment (and your wallet!) to buy a small, efficient gasoline vehicle.
In short: Civic = Win if Time Owned < 5 years
Prius = Win if Time Owned > 5 years
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goehring 5:51PM (5/21/2008)
If you don't drive much, buy a used gas guzzler.
If you don't buy it, someone else will who will burn more gas.
If you drive a lot, buy a new fuel sipper.
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Kevin Nugent 7:54PM (5/21/2008)
I would but the third generation Pruis as my first car . i think that hybirds are great options as a first car or so , but not when you are going to trade in your car for a hybrid because in the end you may take alot longer years to get back your savings and tehir is also alot of hassle with getting a good market value for your current car
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Luke 9:34PM (5/21/2008)
"So if all us treehuggers only bought used cars, we'd all be stuck with used SUVs (which the average Joe bought a few years ago). Bad."
That ignores the point of the article, which compared a hybrid to an efficient new car. Nothing else was being compared. For example, buying a new car wasn't being compared to driving a private jet, either.
Also, if your point is that you are willing to waste money and energy to "save the world," then everyone should just go out and buy 12 new cars and save it that much faster. That still won't defeat the conclusion to the article, but you weren't paying attention anyhow.
The fact remains that a used econobox beats a new hybrid for everyone who is good at math.
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Luke 9:38PM (5/21/2008)
Correction: I meant to say "That ignores the point of the article, which compared a hybrid to an efficient used car."
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jim 10:19AM (5/22/2008)
The greenest and cheapest scenario is often for the owner to keep driving what they have and maintain it properly, even if its a gas guzzling SUV. This will be true for owners who put or can drive relatively small numbers of miles per year, say 7000-10,000.
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studemax 11:36AM (5/22/2008)
Also, don't assume all old cars pollute like crazy!
Not long ago, a Stude club member had his early 60's Lark tested and it passed the exhaust pollutant test.
Larks get decent mileage, too - usually over 20MPG.
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Jon 11:48AM (5/22/2008)
I'd say it is important to differentiate between the decisions of individuals, and the aggregate societal affect when considering this issue.
That is, for individuals there are certainly instances where a particular used car is a net environmental benefit over a new high-mileage car, especially if you focus only on the period of that individual's ownership of the vehicle.
As a net social issue, however, given that the majority of our current fleet is made up of very low-mileage vehicles, it is almost certainly a substantial net benefit to retire those inefficient vehicles as soon as possible and take the current hit on manufacturing new high-energy vehicles in order to reap very substantial long-term gains.
And note this current question is focused only on direct energy costs, strictly defined, and does not consider the emissions issue or other external costs of a fleet of heavy, low-efficiency vehicles (worse wear on roads, higher costs of maintenance, military necessities, etc., etc.). Were those costs to be included, the scale would tilt radically towards replacing the current fleet as quickly as possible.
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Karkus 4:56PM (5/22/2008)
Yep, it's the individual vs societal impacts that need to be considered.
Buying a used efficient car (if you can find one) is almost certainly the wisest financial choice, especially in the short term. Can't argue with that. (Heck, it may be cheapest to buy a really cheap SUV if you don't drive much).
A used car may also be the best if you just look at your personal, immediate environmental/CO2 impact.
BUT, while you can look at finances individually, you can't look at pollution and CO2 individually, since it affects everyone. So from the energy/CO2 standpoint, you have to look at the whole societal impact. That's where I'm saying that buying a new small efficient car may be the best thing, since YOU are determining what will be on the road for the next 10-20 years (regardless of whether you keep it till it dies or sell it after a few years). If you always buy used, you're letting the average Joe determine the makeup of the vehicle fleet (and average MPG).
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Mik_Cal 1:57AM (5/23/2008)
Interesting discussion!
I believe the difference between buying or owning an older car with lets say 30 mpg and buying a new Prius or hybrid with a similar mileage is slight but slightly in favor of the Prius-like new car, especially if you drive many miles a year. If you drive less, an older less efficient car will do.
HOWEVER, when electric or plug in hybrid cars are either available or suitable for your needs now, these are vastly preferable. Why? Because they represent a quantum leap in efficiency and also in switching away from fossil fuels.
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BG 8:54PM (5/23/2008)
I drive a 53 year old car that has a 275HP 352 cu in engine, at 60 mph it averages 22 to 24 mpg. I consider that quite effiecient as my 2007 car which has a 350 cu in engine only gets 17 mpg
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