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Old 03-11-2013, 07:54 PM   #5 (permalink)
t vago
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Quote:
Originally Posted by RedDevil View Post
But, gas needs to be produced too. It needs to be pumped out of the ground, shipped, refined, shipped again, redistributed, chemically tweaked to the right octane level and doped with all sorts of additives.
The science magazine NWT ( Nature, Science, Technology, aimed at university graduates and the like) estimated that it takes 3 times as much energy to produce gas than can be derived from it.
Yah... about that...

It currently takes the energy equivalent of 1 barrel of oil to extract 20 barrels of oil from the ground, and deliver it to the refinery. If we assume that a barrel of oil is worth 1.7 MW-h, it would take about 85 kW-h to do that extraction.

At this point, we're assuming that a barrel of oil is worth (1.7 MW-h - 85 kW-h), or about 1.615 MW-h. Okay, so far, so good. Now, let's take refining costs. It Let's say that it takes about 140 kW-h to turn that 42-gallon barrel of crude oil into about 45 gallons of useful things. So, taking 140 kW-h away from out 1.615 MW-h value, and we're left with 1.475 MW-h worth of available energy from that barrel of oil.

Now, gasoline accounts for roughly 47% of that barrel by volume. That means that there is about 21 gallons of gasoline produced (remember, we just spent 140 kW-h refining that barrel of oil). Also, 45 gallons of usable stuff are produced from that barrel. If we divide the remaining available energy content of what we have, by the number of gallons, we come up with about 32.8 kW-h of available energy per gallon. It's weird, I know, but it matches rather well with the fact that gasoline is commonly thought of as being about 33 kW-h of energy per gallon.

Now, let's go nuts, and say that gasoline production accounted for all 140 kW-h of the energy spent refining that barrel of oil, and that all other petroleum products from that barrel came scot-free! Okay, then, it would have taken 6.6 kW-h of energy to produce one gallon of gasoline.

Since, in the absolute (and unrealistic) worst-case scenario, it took about 6.6 kW-h to produce something that has a value of 33 kW-h. Even if we then throw away 80% of the energy value of gasoline, in the form of radiator waste heat, exhaust, mechanical losses, blah-blah-blah, that still leaves 6.7 kW-h left per gallon that actually does something.

Sounds like this "NWT" is a fiction magazine...

Quote:
Originally Posted by RedDevil View Post
So there you go. Even if producing electricity produces CO2, producing gas is way more polluting even before it gets burned in the engine.
That's no dirty little secret; it is the elephant in the room mr. Lomborg failed to notice.
Why does he miss that? He is just an unbiased observer, right? All electricity is produced from coal, right? No bias, yeah. Maybe he missed that elephant because it blinded his eyes with a nice paycheck, or vouchers for free gas for life?
Nobody pays me for writing this of course.
First, wildly unsupportable suppositions hiding as "facts," then "messenger attacking." Yah, you're really unbiased...
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