The Greenest Vehicle

Great Debates
21

B can surely b calculated. You need to collect the scrap metal, grind it up, clean it, process it, melt it down, mix and refine it, and now you have usable steel which can then be manufactured again.

To calculate the savings all you need to do is compare the difference saved by recycling steel versus getting it from iron ore. According to this cite that’s an energy difference of 47%.

http://www.co.grays-harbor.wa.us/info/pub_svcs/Recycle/WhenYouRecycle.htm

You still have all the costs of turning that steel into a car, just as you would if you made it from steel from ore.

If we say 1 ton of steel per car that’s 4700 killowatt hours saved by recycling.

According ILEA it takes about 73 giga joules of energy to manufacture a car. According to my handy-dandy killowatt to Giga joules calculator that 4700 killowatt hours translates to .0047 giga joules.

Wow! What a fantastic savings!

I see. Listen. Why don’t you save us both a lot of trouble and go play in another thread or go play in the pit instead of being a threadshitter, ok?

22

Debate the debate or go off to the pit, please.

23

Want - something you would like to have
Need - Something that is necessary
Saying I need a Truck, means to me that I need a truck or I will cease to exist.

Now if you qualify it by saying I need a truck for my job that’s a different story, basically it breaks down to:
I need a truck for my job, and I want to keep my job.

Or I need my truck to maintain my standard of living, and I want to maintain my standard of living.

But when one says I need something and it’s left at that, I assume that something is along the lines of medication, or even oxygen.

24

Kanicbird:

Well than, there is really no such thing as a “need” as far as you or I are concerned.

We don’t need food water and shelter, because it is not necessary we exist. We just want to.

So, your definition breaks down and there is no difference between needs and wants.

25

No, taken to your absurd extreme nothing at all is a need and everything is a want.

Saying you need a truck diminishes humanity (or at least yourself), and can be so easially disproven by having a situation where you don’t have one.

26

The Goddess is merciful, and doesn’t care that you can’t read.

27

That’s not my absurd extreme. That’s the definition you provided. You said that a need was something that was necessary.

My survival is not necessary in any sense. So therefore I do not need food, water, or shelter, or anything.

As you’ve defined it, a need is always in service to a want. I want to survive. I need food water and shelter to do so. Or, I want to impress my friends, I need a new Lincoln Navigator with a Blaupunkt.

Presumably, you, like me find the former example worthy and the latter unworthy. This is a subjective judgement though.

You made the big deal about some people not understanding the difference between needs and wants, and you are right.

You are one of those people.

I didn’t say I needed a truck. I said I had use for a truck.

The error you are making is pretty common. You think “needs” are arbitrarily assignable and easily defined, or exist by themselves. They do not.

A need only exists in terms of a given. That given is to a larger goal that is granted as worthy.

In the case of food and water and shelter, those are only needs if you grant the goal of survival.

If you grant the goal that I should be in California in six hours than I can argue that I need to get on an airplane effectively.

If you grant the goal that I should live on a farm with 1/3 mile driveway 2 miles off the plowed milking route and that I should service the farm and be able to go to work, that I can argue that I need the use of a truck with a plow at my disposal.

As you arguing needs without defining goals it is clear that you don’t know the difference between needs and wants.

28

Perhaps you could restate what you meant simply and with clarity so that even one such as I might comprehend.

29

(deleted, might have qualified as a direct personal insult…)

30

a) Wasn’t an issue I raised. I was responding to dropzone’s post.

b) As you can tell, he and I had very divergent opinions on what you intended the debate to be. (Maybe you had something to do with that confusion.)

c) In that post, I tried to make it clear why I thought my interpretation was on solid ground, but that I was willing to concede the point if you made it clear that he was right.

d) If that troubles you, you’re going to find trouble everywhere you turn.

31

The answer to (b) was the 73 gigajoules. The rest, I assume, was in response to somebody else’s post.

I pointed out that you were asking a question that required at least a tentative answer as a starting point for your argument.

I’m sorry you have a problem with that. But it’s the sort of thing we do in GD, as you know quite well. It’s not like you’re a stranger to this place.

32

Next question: how much energy in a gallon of gasoline? 130 megajoules. That means the energy involved in building a car is roughly the equivalent of that from 560 gallons of gasoline.

There’s your basis for figuring out where your break-even point is. If you’re comparing a 16 mpg truck with a 50 mpg hybrid, then the answer, by my calculations, is that the hybrid saves you that much gas over the truck in about 13,200 miles. Smaller differences in fuel economy need more miles to justify the upfront energy cost of buying the new car.

IOW, Scylla, you’re wrong.

33

You recently asked me to stop hijacking a thread of yours when I was off-topic and I aplogized stopped.

If you want to debate personalities motivations or junior mod about forum you think this should be in take it to the pit, and have the class to extend me the same courtesy.

Failing that have the intelligence to realize what will happen the next time the shoe is on the other foot and act accordingly.
End of subject.

34

I think it’s time to recycle your handy-dandy kilowatt to Gigajoules calculator. 4700 kWh is equal to just under 17 gigaJoules.

35

Your cite doesn’t say that. Where are you getting the number?

According to this cite “A gallon of gas contains about 60 kilowatt-hours of chemical energy, but this energy has to go through two conversion processes before we can use it in a light bulb. First the chemical energy must be turned into mechanical power by the engine of the car. Car engines don’t do this very efficiently – only about 25% of the chemical energy can be turned into mechanical power, and the rest is wasted as heat. After the engine gets done with our gallon of gas we have 15 kilowatt-hours left.”

So, an engine burning gasoline can produce 15 kilowatt hours from a gallon of gas. 15 kilowatt hours is .000015 gigajoules.

No. 4,866,666.66 gallons of gasoline.

Holy shit!

I just double checked that off the online conversion calculator. That’s right.

Nope. 143,137 miles is breakeven based on a 34 mpg differential.

That’s not the whole of it, either.

This would only be true if all the assumptions so far made were correct. They are not. One assumption being made is that the new car is made from recycled steel. According to this cite that number is more like 25%. They call that the minimum and say it can be higher so let’s say it’s 50%. 50% is going to push the breakeven point even higher.

Check my math.

36

Check here:

37

You are using the wrong conversion. You want to be using this one:

38

Sorry Scylla but I think you lose. Cool project though (and watch for my caveats and assumptions).

Harms: Scylla plunders the planet
Say a Prius gets 40 MPG (I’ve seen ranges of 35-45). Scylla got 50,000 miles out of his car (and I’m ignoring resale usage for now). At 16MPG Scylla used 3125 gallons, while the Prius would have used 1250 gallons:

3125 - 1250 = 1875 gallons plundered by Scylla.

Benefits: Scylla saves the world
Finding the energy and emission cost of building a Prius is a challenge. I settled on this site which states that, “Between 5% and 10% of the car’s consumption of energy and emissions of greenhouse gases happen when the car is manufactured.”

Ok. Say the average car gets 20MPG and is good for 125,000 miles. That means that it uses 6250 gallons after manufacture. Divide 6250 by .95 and .90 to get a range of lifetime estimates, then subtract out 6250 to get the manufacturing burden.

6950 - 6250 = 700 gallons granted to us by Scylla
6600 - 6250 = 350 gallons saved by Scylla.

So benefits are in the 350-700 gallon range while costs are about 1875 gallons, assuming (ha!) that the Prius can plow driveways and ignoring resale usage (or resale costs, since the next order didn’t buy a more fuel efficient vehicle*).

Still, we can halve 1875 and 938>700, never mind 350.

Of course, the real comparison would be buying a new truck vs. putting one together Scylla-style. What’s the most fuel efficient truck that could conceivably meet his needs?

  • Though actually, the next owner might have chosen a less fuel efficient monster truck. Who knows?
39

Fun fact!

Actually, MPG figures are somewhat misleading - what we care about is their reciprocal which is gallons per mile.

Here’s an example. Choosing a 16MPG truck over a 8MPG Hummer saves more energy than choosing hyperefficient Hybrid (50MPG) vs the 16MPG heap.

Assume 125,000 miles used:


	       MPG    Gallons	 Difference
Hummer	        8     15625	
Truck	        16     7812.5	7812.5
Fuel Efficient	50	2500	5312.5

Choosing the truck yields about 7800 gallons saved over the Hummer.
Choosing the hybrid yields about 5300 gallons over the truck.

So it’s not that we need more Priuses. Rather we need fewer monster trucks. Though actually both would be even better.

40

I guess my results aren’t completely robust. This site states: “Considering that the use phase of the vehicle contributes more than 80% of its life cycle energy consumption…”

If I assumed that manufacturing contributed 20% of the life cycle energy costs, then Scylla would have saved… 1562 gallons of gas in my example. Which is still less than 1875, but is closing in on it.

80% looks like a highball estimate though. I’m inclined to emphasize the Union of Concerned Scientists number, pending a more direct estimate of Prius manufacturing energy costs.

The site also stated that the most energy intensive part of the automotive manufacturing process is… the automotive paint process.

That’s right, the paint job results in high greenhouse gas emissions.