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 Message Boards » » Why is gas approaching $3 a gallon again? Page 1 2 [3], Prev  
State409c
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Yea, I found it, I'm trying to decipher the language in that statement to see if it makes sense, it seems like it doesn't.

First they go from 7 barrels of oil to 8 barrels of ethanol to 7 gallons of gas to 8 gallons of ethanol, and that is just blantantly wrong.

5/8/2006 3:14:23 PM

spöokyjon

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[Edited on May 8, 2006 at 3:14 PM. Reason : ]

5/8/2006 3:14:25 PM

LoneSnark
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^^ Yes, I didn't notice that when I read it first, but the units are kinda interchangeable (replace "barrels" with "gallons" in the first sentence for sense).

That said, the statement is still taking a technical switch. You cannot turn a barrel of oil into a barrel of gasoline, but by expanding the inputs you can get close, particularly easy thanks to gasoline being about 30% less dense than crude oil.

5/8/2006 3:27:49 PM

Queti
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read over it quickly and i think points to take from it (i am not bothering with the numbers themselves) are:

1. heating values for ethanol are approx. 11.5 - 12.7 MBtu/lb versus typical gasoline numbers of around 19 - 20 MBtu/lb. in other words, ethanol doesn't supply the same amount of energy gasoline does.

2. it was also referring to the amount of oil that it takes to plant, farm and recover the corn and then process it into ethanol. diesel for the machines, then quite a bit of energy in the form of diesel and fuel oil for the furnaces, polymers and what not for storage and containers, fertilizers (made with oil byproducts and oil products to heat/run equipment). i have no clue on the gal per gal relationship with all that.

the fuzzy math you are having a tough time with is:

first they say 7 bbls of oil for 8 bbls of EtOH
then they say 7 gal of gas to 8 gal of EtOH.

it should be 7 gal of oil or 3.5 gal of gas to 8 gal of EtOH

so anyway, it takes oil to make EtOH and then you don't get the same bang per pound. so, it isn't such the awesome solution as some claim it to be.

[Edited on May 8, 2006 at 3:40 PM. Reason : er]

5/8/2006 3:36:55 PM

BelowMe
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problem with ethanol now is that apparently it takes approximately 1.25 gallons of gas to make 1 gallon of ethanol (after transport/tractor/refining)

that will hopefully come into equilbrium soon. additionally, remember that mobil/exxon only makes 30% of their profit from the US, they're in 200 countries... they arent as dependant on the US market as you would like to think

5/8/2006 3:44:29 PM

State409c
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Well, thats what I am trying to come to as a conclusion but am having trouble wading through the math.

Bottom line to me it seems that 7 gallons of oil when sent through the entire process of either gas or EtOH will produce 3.5 gallons of gas, or 8 gallons of EtOH, correct?

In which case, the EtOH would have to be churn out mpg numbers in the 43% range of gas for it to be break even from an oil useage standpoint. Meaning, that 18mpg figure for the Titan has to drop all the way down to 7.74mpgs on EtOH. And this is all before factoring in the cost of EtOH at the pump for the consumer. Somewhere, something isn't adding up I don't think.

I also take issue with

Quote :
"he Energy Department estimates"

Estimates? WT Fuck? Is it that hard to go out and actually perform this test? Did they also find the worst case scenario maybe? I found this, it's done at 35 mph, does it get drastically worse for the EtOH camp at higher speeds?

http://www.wqad.com/Global/story.asp?S=3972760

5/8/2006 3:47:18 PM

LoneSnark
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^ Well, it would be very easy to measure but the government has slapped exemptions and subsidies all over the Ethanol production system that we really have no idea what the true cost of 1 barrel of Ethanol really is.

If without any interference Ethanol had an open market price equal to or less than gasoline than one could be certain that it didn't consume more energy to make than it contains.

5/8/2006 4:28:46 PM

Queti
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hmmm looks like, based on their numbers:

15 gal gas--> 30 gal oil

15 gal of E85 (85% EtOH by vol) --> [2.25 gal of gas (or 4.5 gal oil)] + [12.75 *7 / 8 = 11.15 gal of oil] = 15.65 gal oil in the E85 plus used to make

however, you have the complications of:
- roughly 40% drop in heating value (based on pure EtOH), thus energy available. i don't have data on how that equates to fuel economy
- seasonal changes plus droughts and natural disasters that could interrupt supply
- and the fact that oil will still be required to produce diesel, jet, fuel oil, plastics raw materials, etc.
- materials compatibility
- incompatibility with non-ffv engines

etc.

honestly, i don't know how that will all shake out. meh, we shall see i suppose.

5/8/2006 4:33:18 PM

jbtilley
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If we really want to lower demand why aren't we lowering the speed limit to 55mph?

5/19/2006 7:31:46 AM

LoneSnark
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^ Because we are leaving it up to consumers. If you feel gas prices are hurting you financially then you should drive 55.

However, I seriously doubt any of us would be willing to drive 21% slower just to save a few bucks. Gasoline is still cheap, my time still is not.

That said, states today can be touchy, some would probably fight any such law, others might just ignore it.

5/19/2006 8:35:12 AM

jbtilley
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^I do drive 55, and if the speed limit were lower I might not risk death for doing so. And those few extra miles that I get per gallon save me a few bucks but they are not going to reduce the amount of national demand. If every driver got a few more miles to the gallon it just might. I'd save even more if the drop in demand lowered the price to something reasonable.

They lowered it for that very reason (supposedly) some 2 decades ago.

5/19/2006 9:28:53 AM

LoneSnark
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that you seem to be the only one driving 55, it seems to me that people don't seem to feel saving a few bucks is worth it, and neither do I.

5/19/2006 12:20:51 PM

Prawn Star
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Lowering the speed limit might actually cause an increase in gas consumption, due to higher traffic.

5/19/2006 8:23:45 PM

LoneSnark
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^ I had overlooked that, good point.

a reduced speed limit reduces the max throughput of a highway... Of course, as I understand it, that is the theoretical max throughput. The real max throughput it actually achieved at around 35 mph because at higher speeds people tend to maintain ever larger distances from the car in front of them, thus dramatically cutting down the max throughput at 70mph. This isn't a problem, of course, because people automatically slow down as more cars get on the highway, allowing vehicle density to rise at a faster rate than speed is decreasing...

Anyway, while it may be possible, I don't think a reduced speed limit is going to have negative effects upon average fuel economy.

5/19/2006 10:13:30 PM

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