Why do people fall for "experts"?

Great Debates
21

The first part is technically true but kind of irrelevant. The fossil fuels are already there. It may have taken energy to get them there but, thanks to the generosity of the sun over many millions of years, it is not energy that we supplied.

The point about finding, extracting, etc. is true…But I assume this is only a fraction, perhaps not even that large a fraction, of the energy they produce. If this were not the case then it would indeed be sort of useless to use them.

So, for the reasons that people have pointed out, TVAA, the question of whether it takes more fossil fuels for us to produce ethanol than are saved through its use is a very relevant one. (Note that it is not obvious from basic physical principles that it necessarily will since the sun is also being used in the production of ethanol…i.e., fossil fuels are not the only form of energy going into the production of the ethanol.) I don’t know what the answer is but if the economist’s claim is correct, and this is what he meant (i.e., that he was doing all the accounting correctly) then it is indeed pretty damning.

Note, the production of hydrogen also takes more energy than it produces. However, one can still incur advantages if one is able to use hydrogen to effectively store energy because it might be a lot easier to produce energy to produce the hydrogen cleanly (through solar or wind or at least through fossil fuels with good air pollution abatement technology) than it is to produce the energy in an internal combustion engine. [By “produce energy”, we of course mean converting it, e.g., from chemical potential energy to mechanical energy since you don’t technically produce energy but merely convert it from one form to another. Here, we get into the problem of linguistics where people use the term “energy” in different senses.]

22

Yes, because as we all know, it is the weight of the tank that plays the biggest role in deciding how much energy it takes to run a car…
Assuming a 50l tank you’d need a 100l tank with ethanol to replace a gasoline one. That would add about 50kg of weight. Which is something like 5% the weight of a small car.

So a 5% increase in energy usage… no. Since the energy isn’t 100% effectively transfered into forward momentum, the energy increase needed would actually be less.

It is also important where and how the energy used to produce erhanol and gas is. If you have clean electricity powering the factory, energy usage isn’t a big enviromental issue.

I don’t know if ethanol is a real alternative to replacing gasoline. We have a few cars that run on it here, but quite a lot of busses. However, we get most of our electricity from clean sources (hydro). In US you get most of your electricity from fossil fuels… which makes it kind of stupid. You’ll be burning gas to produce ethanol. :smack:

23

I worked with a lot of “consultants” in my day. I eventually came up with a few consultant axioms, one of them being:

Anything said with enough confidence will be accepted as the truth.

:slight_smile:

24

** It’s quite a large fraction, just possibly not as large as ethanol.

** No kidding.

25

TVAA:
----- It’s quite a large fraction, just possibly not as large as ethanol.

You couldn’t have been pulling that “fact” out of your ass, could you?

Let’s do some calculations. scr4 provided some terrific links. An oft quoted blurb is that “about 70 percent more energy is required to produce ethanol than the energy that actually is in ethanol.” That’s from Cornell’s David Pimentel. The US Dept of Agriculture is more optimistic. They find that a gallon of ethanol requires 77228 BTU to produce, resulting in a 21105BTU gain, when ancillary outputs such as gluten are factored in.

77228/(77228+21105)= 79 percent.

So, according to an optimistic study, about 80% of the energy output of ethanol production is used to produce that unit of energy.

What’s the comparison to gasoline?

Well, we surely don’t need experts, we already have TVAA whose assured us that it’s “quite a large fraction”. But let’s do some digging anyway.

Now, I’m not a big fan of “Net Energy Analysis”, since it focuses only on energy costs, and ignores all other ones. But let’s continue anyway. Those with broadband and patience can take a look at this site, skipping down to page 274 to find the amount of “energy” to produce “energy” within the whole economy. That input/output table gives a ratio of … 8.81%. Sort of far away from 80%, ya?

But that’s not gasoline, it’s all energy in the economy. For petroleum extraction we can go here. Skip down to the bottom of the page and click on the link for N-14. There we find a chart plotting the ratio of energy outputs to inputs over time for petroleum. Today, the figure seems to be somewhere between 10 and 20. Take the reciprocal and we get 5-10%.

Huh. I am no expert at this, but it seems to me that 5, 9 and 10 percent are all quite a bit less than 79%.

Anyway, I would say that many people trust experts more than people talking out of their posterior because it’s rational behavior. In that spirit, I humbly urge others to check my work.

26

Yes , but you can’t drink gasoline :slight_smile:

It used to be that people were generalists in Education , that the average person would have a general knowledge of quite a few things. Now people are over focused and the field of knowledge that they possess may make them really smart in one area , but totally clueless in others.

But back to my point about ethanol specifically , it helps to have gasoline as the major fuel source , as its only consumeable via combustion engine, having people start up their own stills , either at home , or as a small cottage type industry , could lead to revenue not making its way into government coffers , hence its a really good idea to have so called experts expound on the energy claims.

Declan

27

Simply put, there is a net energy deficit with using ethanol as fuel.
Strictly speaking, we’re better off burning fossil fuels directly.

The rise of “experts” has something to with a generalised appeal to authority - a classic logic fallacy of course. Of course, often experts really are. Unfortunately, there are any number of self-appointed experts in the socio-political realm who are largely oxygen thieves and we would all do well to at least ignore them or preferably take the opposite view on general principles.

28

Great example. Economists are technological morons.

I think our schools are designed to make people subservient to authority. Modeled after our churches. They don’t teach science worth a damn. People that are good at science mostly don’t want to be teachers.

Dal Timgar

29

Well, Tedster, if we restrict our analysis strictly to “energy out/energy in” then you might be right (I don’t know, and I don’t intend to argue that). However, that is not representative of why we use various energy sources.

Of course, if I created my own electricity it’d be more efficient since transmission lines introduce losses, but I think we’re not all on the verge of independent power production because of it.

Sources of power are not strictly chosen because of their methodological efficiency. The range of their use is also very important, which is why electricity is so great. It is pretty hard to power my refrigerator, my LCD monitor, and my coffee maker all from burning coal. The flexibility of electricity as a source of power can easily make up for the losses we experience in its transmission and creation. Furthermore, by centralizing electricity production from fossil fuels, we have localized pollution production (whose cleanup requires energy itself, of course). Switching to cleaner fuels would also (possibly) have this effect, and that might greatly outweigh the loss of efficiency.

Take solar panels, for example. I’ve heard it said (and I’ve never sought to verify it, and my point doesn’t hinge on its truth anyway) that it takes more energy to create solar panels than they can usefully collect in a person’s lifetime (or some long period of time, anyway). But that isn’t the only appeal of solar power, of course. Tossing solar panels on portable road signs (in combination with chemical batteries) yields an incredible flexibility in movement and placement. In some cases, this advantage far outweighs efficiency losses.

Ultimately, ethanol creation seeks to gather energy in ways we cannot (very efficiently). Plants are much better at gathering solar energy than we are, and it is pretty much impossible for us to mix sun and dirt and get a usable fuel; yet this is just what the plant-derived alcohols give us. If we decrease our dependence on foriegn products, and localize pollution production from fossil fuels, the benefits of this might outweigh the efficiency loss.

Again, I don’t know if this is the case, I’m just saying that direct efficiency calculations are really a small part of the story.

I don’t think anyone is suggesting we violate thermodynamic laws.

30

---- Plants are much better at gathering solar energy than we are, and it is pretty much impossible for us to mix sun and dirt and get a usable fuel; yet this is just what the plant-derived alcohols give us.

Not quite. To get 10 gallons of ethanol we’re actually mixing the energy equivalent of 8 gallons of gasoline, some depreciated (eroded) land, lots of fertilizer and a fair amount of machinery. Oh yes, there’s a tiny bit of sun in there as well.*

That’s on the cost side. On the benefit side we may get somewhat lower NOx emitted into the air, though we almost surely get higher CO2, since we have to burn the 8 gallons (equivalent) of fuel plus the final 10 gallons of ethanol.

The Point

  1. None of the analysts were considering the original energy required to produce the fossil fuels, so the “Law of Thermodynamics” shtick isn’t especially relevant.

  2. Ultimately it’s a cost benefit issue. The factoid that it takes the equivalent of 1.7 gallons of petrol to create 1 gallon of ethanol (using Cornell figures and ignoring the energy embodied in the byproducts of the production process) underlines the high cost of producing the stuff.

Granted, I imagine if ethanol had an energy content that was 1000 times higher and clean burning, it might have its uses (rocket fuel???). But nobody has demonstrated any unusually large benefits of the stuff, except to Presidential candidates who want to have a prayer of winning the Iowa caucuses.

Ergo, I have serious doubts about whether ethanol passes a reasonable cost/benefit test. Then again, I should concede that I haven’t read a detailed analysis of this issue.

  1. OTOH, a breakthrough in biotechnology could conceivably make biofuels a lot more economically feasible. But we’re not there yet.
  • I’m using the optimistic Dept of Agriculture numbers here, rather than the Cornell numbers: the latter would imply using the equivalent of 13 gallons of gasoline to make 10 gallons of ethanol.
31

Running over some calculations[sup]†[/sup], taking liquid density into account, gasoline combustion will create 1.28 times as much CO[sub]2[/sub] as one gallon of ethanol, while we would have to burn 1.49 gallons of ethanol to equal one gallon of gasoline WRT energy output (assuming complete combustion); so, contrary to my rather idle and speculative thoughts, we can’t even save on CO[sub]2[/sub] emissions.

However, I was wondering about something. The US, as it is, harvests and basically destroys quite a bit of grain, isn’t that so? So we are already expending some energy there for zero gain. Getting ethanol from that surely wouldn’t hurt anything.

Of course, I didn’t even bring it up, I was mostly responding to its previous mention.

Wouldn’t rule out that between localized coal, turned to electricity, to finish the production of ethanol being thermodynamically impossible. If the goal is eliminating the reliance on foreign fossil fuels, the US has enormous amounts of coal, so I’m still not sure it is a complete pie in the sky scheme. Not that I cared to argue one way or the other—I feel that bears repeating.

However, it is pretty safe to say, I think, that those who would champion such a switch haven’t looked at the figures properly.

Actually, 13gal gas + 10gal eth = 3458 moles of CO[sub]2[/sub], while the equivalent gasoline use of 7.81gal of gas used straight (equivalent end-energy-consumption of 10gal ethanol) will yield 1296 moles of CO[sub]2[/sub]. However, to calculate this fairly we’d need to know how much gas it takes to get gas, which doesn’t simply fall from the sky. I don’t know if it compares, though, I’m just qualifying the calculation properly.

†[sub]Assumptions made about gasoline: molecular weight 111g/mol, # of carbon atoms=7, density 0.692g/ml[/sub]

32

All that you’re arguing about in this thread is that it’s incredibly fucking stupid to burn gasoline or coal in order to distill ethanol. (Not directed at any particular poster, just a general observation).

33

Actually, sheesh, I think I even made a mistake in my last calculation. More like 6.7gal of gasoline is equal to 10gal of ethanol, energy-wise. Not only that, but given the figures I missed earlier in the post, where gasoline extraction is certainly more efficient, that shows even the CO[sub]2[/sup] emissions are far and away smaller, probably by a factor of two.

Overall, I suppose desmostylus has it.

34

Actually, eris and I are more or less in sync. The ethanol program isn’t so much “pie-in-the-sky” as a $1 billion subsidy program with dubious public merits. (OTOH, I haven’t evaluated how it compares with other farm subsidies. I should also repeat that I have not looked at any detailed cost benefit analyses, but I would guess that the benefit side would have to be rather enormous to justify ethanol subsidies, given our discussion.)

— However, I was wondering about something. The US, as it is, harvests and basically destroys quite a bit of grain, isn’t that so? So we are already expending some energy there for zero gain. Getting ethanol from that surely wouldn’t hurt anything.

The Cornell guy claims that the price of corn would drop if ethanol subsidies were eliminated. I do not know whether he took into account pre-existing farm programs when he made that claim. If he did not, that would be problematic.

Put another way, it appears that corn grown for ethanol substitutes for corn grown for other purposes. If the Cornell guy is correct.

(Furthermore, I don’t know what form current farm subsidies take, quite frankly. So I don’t know whether the government still buys, stores and wastes tons of corn per year.)

Now if we could get some sort of fuel from agricultural waste products, that might get interesting…

35

Why trust an expert? Because he’s a guy from out of town, wearing a suit, & charging a nice fee.

This is not all in jest-think people from Rochester Minnesota have as much faith in the Mayo Clinic as outsiders do?

36

If the pdf document I found through above links shows anything, it is that the viability of ethanol as a fuel is not in question, more like the scope of its use. It couldn’t be a complete switch at this time. However, the trends pointed out seem to indicate that, given the same rate of technological progress in distillation and farming, it could very well become viable in the not so distant future. Certainly something to keep an eye on. Even if we increase CO[sub]2[/sub] ommissions, I seem to recall that ethanol does burn cleaner and would have fewer pollutants than gasoline, which could be a winning situation in the long run.

I am especially intrigued by the genetic experiments done on corn which could very well prove to create a vastly superior crop. As ever, the damage done to the land through farming would then become a very important concern.

Essentially, something to keep an eye on, but nothing to move on right this instant.

37

Ethanol is not a viable fuel. If the world were forced to immediately switch away from fossil fuels to ethanol, your next fender-bender would likely result in Thunderdome.

Biomass – the raw material in fuel production – is an extremely inefficient power source. From an economist’s standpoint, in order to replace one year’s worth of fossil fuels, we would need to consume almost one fourth of the world’s “primary production.*”

One fourth of the world’s grains and grasses (hays, oats, wheat, clover, alfalfa, heath, etc.), brush, small trees and other such greenery, one fourth of the world’s biomass would be used up in a single year.

As to the science of the question: consider all the fossil fuels used in 1997. It is estimated that it took 400 years[sup]†[/sup] of primary production – photosynthesis, growth, propagation and death – to amount to one year of fossil fuels.

Refining, strip-mining, it makes no odds: It took 400 years of sunlight to produce one year of fossil fuels.
Scientists are currently developing new enzymes to speed the production of ethanol, but as described above, we will be limited by the availability of our raw materials.

[sup]*[/sup]Organic material, produced by photosynthesis.
[sup]†[/sup]In my lifetime, we will have consumed more than 40,000 years’-worth of our world’s resources.

38

Carbon dioxide isn’t an issue. Every bit we pump into the atmosphere from burning ethanol was taken out of the atmosphere by the plants in question. Net change: zero.

Compare this to fossil fuels, which by definition are composed of carbon compounds that were pulled out of the atmosphere and buried. Burning them increases the net amount of carbon dioxide in the atmosphere.

And flowbark, if you can’t see how extracting, processing, and shipping fossil fuels requires significant amounts of energy, I doubt you should be weighing in on this topic.

39

TVAA:

— Carbon dioxide isn’t an issue. Every bit we pump into the atmosphere from burning ethanol was taken out of the atmosphere by the plants in question. Net change: zero.

Very good point, one that I ignored. ( :smack: ) Of course we are still left with the .8 - 1.3 (energy equivalent) gallons of oil/coal/natural gas that are burnt in order to produce that 1 gallon of ethanol.* The ethanol that is burnt in the internal combustion engine, however, appears to simply return CO2 to the air that was there to begin with.

— And flowbark, if you can’t see how extracting, processing, and shipping fossil fuels requires significant amounts of energy, I doubt you should be weighing in on this topic.

Yikes. I’d say that extracting, processing and shipping fossil fuels takes about 5-10% of the energy that they contain.** Furthermore, I have backed this statement up above with empirical evidence from 2 different studies. Those interested can inspect my post above. If you want to call 5-10% “significant”, that’s fine with me. I’m just saying that it’s a lot less than 80-130%. (Apparently, distilling ethanol currently requires a great deal of energy. Growing corn is also a fairly fuel-intensive process as well.)

As for whether I should be weighing in on this topic, hmmpph. Generally speaking, I would assert that empirical investigation is a superior method of answering empirical questions than baseless assertions.

  • Admittedly some share of those fossil fuels may be converted in fertilizer: more investigation here might modify that claim somewhat.

** I would lean towards the upper end of that range, BTW.

40

I don’t believe greenhouse gases disperse quite so efficiently. If they did, there’d be no smog issue. Unless we burned all of the ethanol in the farm I think CO[sub]2[/sub] emission is still a realistic concern.