Which is more green? Driving a beater or a new car?

Factual Questions
1

In a recent post, a poster stated that getting a new car with new emission controls would be better than driving an old vehicle that gets low gas milage?

Is this really true? Would the fuel and emissions savings of a new car over an old car balance out the pollution and fuel required to produce the new car?

As an example, use my current car: 1988 Jeep Cherokee that gets around 15 mpg. For the sake of argument, let’s assume the new car would not have been made unless I bought it. And that I wouldn’t sell my old car but junk it so it would no longer be driven.

I can’t even think of how to go about researching this…

2

Dang, over an hour and no replies? I thought this was a pretty interesting question. My brother and I had this debate just last week and my argument was that since I couldn’t afford to not sell my old car, it would be driven, and therefore I would have contributed to two cars on the road.

I do realize that’s a really week argument and hoped to get some facts from some knowledgable dopers…

3

Well, here’s some information we need:

  1. How many miles do you drive per year? City/hwy?
  2. What kind of replacement vehicle would you drive? Makes a difference if it’s a Toyota Prius or a Cadillac Escalade.
  3. How many years do you intend to drive the replacement vehicle before replacing it?
  4. How much energy goes into building your new replacement vehicle? This item will probably be the hardest to get.

Give me the above 4, I’ll work out your answer.

4

I think this is more of a debate question than a fact question, unless someone can find some evidence.

I do know that it has been proven that government recycling programs have a net adverse effect on the environment since they consume more resources to collect and recycle items than it would be to merely consume and destroy them. I’m speaking specifically of curbside recycling programs in addition to regular trash pickup.

As for your car, I think many people buy a new car because they want one. Often its a good economic decision because the cost to maintain an old car can be significant. You are right to question whether there is an exertanality - does the cost of a new car include the environmental cost of its resources? Another way to look at this is that the market price of used cars is low because of our preference for a shiny new car. This externality subsidizes the price of used cars as well. So even if your used car will be used by someone else, they are getting it at a subsidized price because of your preference for the new car.

You suggest that to defend your purchase of a new car, you would have to show that the environmental efficiency of the new car exceeds the environmental costs of the raw materials of a second car. I would suggets you have left something out of the equation - the fact that you are subsidizing a second car remaining on the road.

5

Do you think the difference will be that close? Let’s use averages because I’d like an argument that applies to more than just me.

  1. What’s average? 15,000 miles? I only drive 6,000 miles a year but I know that’s low.
  2. How about a midsize sedan that gets average fuel effeciency? What is it in the US right now? Around 25 mpg?
  3. How long do Americans generally keep their cars? Let’s say 5 years.
  4. OK, this is the basis for the whole question. If I had any idea about this, I could work out the answer on the back of an envelope.

I guess what I’m hoping someone might be able to ballpark is how much energy is required to produce a new car. From mining the raw ore, refining it, making the steel, producing the interior and trim, assembling the car. Plus the pollution involved.

Maybe for simplicity, someone might know how much energy it takes to mine and refine the iron ore and produce the steel used in an average car. What does an average car weigh? A ton? I would guess at least 75% of it’s weight would steel. If I knew this, I could add a wild guess figure of maybe, I dunno, 50%, for assembly and see where I’m at.

My gut instinct is that everything it takes to make a new car would far exceed any savings from the increased efficiency but I don’t have any facts. I’d like to be able to say, OK, I would need to drive the new car for X number of years to recoup the energy expenditure it took to manufacture it.

6

Lemon, unless you own a car which is going into the shop monthly for major repairs, you are almost never better off buying a new car. This is assuming you are driving a currently paid off auto of course. Not even factoring in the increased insurance or taxes, it would be a huge stretch in most cases to say that the purchase of a new car makes more economic sense than maintaining an old car. If anyone ever uses the words investment and car purchase in the same sentence, run away very fast for you are about to be ripped-off.

The market price of a used car is lower because it has less economic value than a new car. A car with 50,000 miles on it is not going to sell for close to the same price as a new car of the same model with zero miles on it. It has nothing to do with subsidizing or externalities, it’s simply economics. If a car is expected to have a life of 100,000 miles and I am purchasing it with 50,000, then I am only willing to pay half of what I would pay if it had zero miles. This does not even take into account its looks, features or safety.

7

LemonThrower

Yeah, I’m kinda leaving that out since this is already a complicated question and I wanted to simplify it. I do realize that most new car purchases are not driven solely by pure economics but also by emotional factors. Many people buy a new car claiming they’ll save money on maintenence when in reality the cost of the car payments far exceed any repairs they may need. So there is much that can be debated.

But, I was really hoping I could get some numbers. Maybe I should have started a thread titled “How much energy is required to produce a new car.”

8

It’s a social problem of economic (monetary) cost vs. environmental cost. I’m sure this has been discussed on the SDMB before - have you searched?

Remember the green triangle - Reduce, Reuse, Recycle. Buying/producing less cars, which have better engines/fuel efficiency, and maintaining them well, would be preferable to buying new cars frequently.

9

One argument:

Since you as an individual can not affect the number of cars a manufacturer will make (they think they know how many they can sell and produce an appropriate number of cars based on a prediction). Your purchase of a new car will only affect NEXT year’s production because you will be a “last-year’s consumer statistic.” And since it is agreed that the ecological cost of manufacturing one car, let alone ONE car off an assembly line, will be difficult to calculate at best, why not work with the information you have?

** For the sake of argument, let’s assume the new car would not have been made unless I bought it.**
OK. The car HAS already been made, based on the predictions of the manufacturer’s marketing department. A car that has already been built will result in ZERO impact on the ecology from your perspective. You could arguably be held accountable for a car produced next year, however. You could thwart this by buying a dead person’s used car–that’s what I do:).

Now it becomes a matter of maintenance costs and fuel economy. You can do a lot better than 15 mpg, and an old car with a good reputation & low miles can mitigate potential maintenance expenses.

10

A 1988 Jeep is about 5 generations of emission controls ago. As a comparison if you were to try and smog it as a 2004 car it probably would not pass on the best day it ever had (the regulations have gotten lots and lots tighter over the years)
And while there is some emissions and pollution from the making of the car, that is a one time charge. The car only gets built once. It gets driven daily, so daily it spews forth-additional pollution. And don’t overlook the fact that factories have very strict emission controls.
Right now I am looking at a slide comparing 1996 pollution limits to what our cars produce now. I don’t have exact numbers as I am trying to interpret off a PowerPoint slide, so there are approximate.
1994 HC about 0.25 grams per mile, now at 0.02 grams per mile
1994 CO about 3.80 grams per mile, now at 0.50 grams per mile
1994 NOx about 0.4 grams per mile, now at 0.01 grams per mile
A 1988 car would have much higher levels than those listed.

11

Isn’t this a false argument? You’re setting up a situation where a new car incurs the whole (energy) cost of manufacture, but a used car has no cost of manufacture. Wouldn’t something like a 1-3 year old car come out way ahead of both of your choices?

12

Of course, you need to factor in the fact that because its a Jeep, it almost never runs or almost always leaves you stranded on the side of the road when you do manage to get it running. This leads to taxis, towing and other widgets that foul up all reasonable computations of cost/benefit to the environment! :smiley:

Did I mention that I own a Jeep? It guarentees that I get plenty of exercise and practice towing vehicles. I measure its fuel efficiency in “Miles per Month”. :smiley:

Jeep stands for Junk, Each & Every Part

13

SmackFu has the right answer: the question excludes key information relevant to making the comparison.

If you compare apples to apples-- that is, a 1988 Jeep Cherokee to a (hypothetical, as they are no longer made) 2003 Jeep Cherokee, it is fair to assume that the energy necessary to obtain raw materials and fabricate the vehicle are roughly the same. If anything, advancements in mining and steel-making, factory pollution controls, etc. might make the current manufacture more environmentally friendly. At any rate, if the manufactuing burdens are comparable, there can be little debate that the newer model will produce less pollution than the older model, due to legislated environmental standards and more efficient technology.

The hidden bias in your question is the assumption that the new car must be fabricated, without considering the (sunken) costs of manufacturing the old car. Or, alternatively, the present cost of junking the old car vs. the as-yet-unnecessary future cost of someday junking the new car. (Not to mention that you introduce another false dilemma in one of your responses-- although you buy a new car, you’re not responsible for having two cars-- the old and new-- on the road. It’s fair to assume that the car market is zero sum; that is, the person who buys your old car would, had you chosen not to sell, would directly or indirectly cause the purchase of the new car you elected not to buy.)

Thus, to respond to your initial question, if all things are considered equally, it would be greener to buy a new vehicle. Of course, this answer doesn’t weigh your financial condition, or any of the numerous other factors that go into making a practical decision.

As to your sharpened question of “how much energy and resources does it take to manufacture a car, and how much pollution is generated in the process,” the answer is… dunno. Here’s one link that purports to estimate the waste and pollution for the manufacture of an average car. Here’s another one with some rough estimates and percentages and whatnot. For what it’s worth here’s a quote from the latter:

Vehicle use has the largest overall environmental impact when compared to other vehicle life-cycle stages, because these quantities are emitted every year over the lifetime of a vehicle (typically 10 to 15 years).

14

Does this hold water? Whether you buy a new or used car, you’re still spewing evil elements into the world. Considering the population of the world, and the US having many states requiring emissions test every year, our cars are what are causing global warming. If only us evil Americans would revert to horse and buggy, we could solve the ozone layer “problem”. Forget the countries that are well more populated than us and lack the environmental controls we have, I can see how a difference of a few mpg’s would kill all life in the known universe.

15

Wouldn’t it be greener to walk or take public transportation?

16

The sunk costs of manufacturing the old car would not be considered because by definition, sunk costs have already occured and have no bearing on current or future decision. If you consider the matter as the OP stated, that when buying a new car, one is manufactured, you must consider the manufacturing costs of the new car but still not the old one. In that case, the new car would be much worse for the environment.

17

I can take a $500 diesel Rabbit or Chevette and convert it to run on used deep fryer grease…not only becoming independent from foreign petroleum, but also producing far less toxic exhaust.

Free Fuel…clean exhaust.

I think that would be far easier and cheaper than converting a brand new Golf TDI.

18

If we ignore the sunk energy cost of manufacturing, that implies that, while a new car would be less green, trading off to virtually any other car built since 1988 would be more green.

19

Enola Straight, is that diesel only? I have a '92 Cavalier that is idle in the driveway, and I love working on engines. Can a 4 cyl 4-stroke be converted? It’s just waiting for modification.

20

Yes, the deep fryer grease takes place of the diesel fuel.

Both the engines in the rabbitt and chevette are 4 cyl 4 strokes.

Room temperature is far too thick to be pumped through an injector, so the grease is preheated by a circuit plummed into the car’s cooling system…the grease’s viscocity index goes down the hotter it gets…also, the grease must be very finely filtered, like up to one micron.

Anyway, if you got a gas engine, maybe you can brew up some ethanol from waste carbohydrates (stale bread, potato skins, over-ripe fruit, out of season candy, etc.).