Ethanol use and its production costs.

[Skidmore]

One argument I keep hearing against ethanol is that it takes fossil fuel to produce it. Why can't farm equipment be run on ethanol? I don't get this argument. If a freaking car can be modified to burn it, so can farm equipment. And I imagine any other machine burning fossil fuel in the production chain can be as well.

[Ready4Change]

1. I agree.

Most fully thought out schedules for switching to bio-fuels include switching the farm equipment first.

[melm00se]

17. i have a question

assuming that the bulk of the cars on the road today are not "flexfuel" capable how will the public make the transition? can a non-flexfuel vehicle be retrofitted to be flexfuel? (I ask as I am coming close to the need to buy a car)

[Ready4Change]

33. As I understand it, depends on the fuel.

Many current diesel vehicles can switch to some forms of biodiesel with no problems. Many gasoline vehicles can handle varying degrees of ethanol blends.

From my understanding, most gasoline cars have difficulty with pure ethanol. They don't just need changes to their control systems, like changing fuel/air ratios and ignition timings. They also need to change many of their hoses and seals, as pure ethanol can damage those over time.

I've heard there's some problems with some biofuels turning to a gell in colder temperatures as well, which requires some effort to handle.

So, conversions can be done, but it may not be as simple as just changing a chip in the engines computer.

[melm00se]

37. I got the answer from another board I frequent

(but I don't really like it)

http://www.e85fuel.com/e85101/faqs/conversion.php

[uncle ray]

44. i don't buy it either.

most regions have been using 10% ethanol for many years now, most any vehicle made in the last two decades should have no problem with deterioration of rubber fuel lines etc. because those components were re formulated to accept ethanol. on any vehicle older than that, it's fairly simple to switch over, the only problem should be decades old rubber components that are well past their life expectancy anyway, and the replacement parts that have been on the shelves for decades.

i'd like to see their data that claims that converted vehicles pollute more, if true, it's probably due to fly by night companies doing the conversion.

their whole arguement sounds like they are trying to keep money flowing to the detroit autmakers and not to any aftermarket companies that care to cash in on the trend. if gas contines to rise in price, and ethanol stays close to where it's at, it'g going to start to be profitable to convert older vehicles.

some of the best vehicles to convert are the OLD tractors and equipment that farmers use, there are an awful lot of 40-60 year old farm equipment being used everyday on farms that are dead simple to convert, kits could be marketed directly to farmers, not much more than a new carb, fuel pump some hose, and at worst, a fuel tank coating, though i've only heard claims that it could cause problems corroding the tanks, i've never heard any anecdotal evidence supporting this. i suspect farmers would be more than eager to convert to a fuel that THEY produce.

[melm00se]

55. the argument

makes sense (at least for carbuerated vehicles. if the fuel/air ratio needs to be significantly changed the jets (both pilot and mains) need to be changed (at least they do on a motorcycle), if not the ability to burn fuel can be greatly affected.

But with modern computer controlled fuel injection, i would think that this wouldn't be such an issue: remap the timing and the injection specs and off you go.

But then again I am not an automotive engineer...

I can find precious little on retrofitting which makes me lean towards the above is correct. I would assume that if it is feasible a homegrown solution should appear.

[TheFarseer]

43. All the buses in Lincoln Nebraska run on biodiesel

100% soy biodiesel, they claim. So I know it can be done pretty easily if backwards Nebraska is doing it.

[Neil Lisst]

2. I saw an ethanol plant in South America that produces its own fuel

on CNN, I think it was. What the hell do those critics think refineries run on, air?

[htuttle]

3. It really comes down to how you grow the biofuel feed stock

You can grow it like we grow food crops today, and lose a lot of energy, or you can grow it without petroleum supplements, and get less produce in the end.

The University here in Madison does a lot of outreach programs with WI farmers, teaching them various ways they can generate fuel on their own farms (for their own use). This includes not only ethanol, but methane, wind and various co-generation systems.

So yes, it's possible. I doubt that corn is the best biofuel feed stock, though. It's highly dependent on petro-fertilizers to increase crop yields.

[sendero]

9. Exactly..

.... what the naysayers are carefully not mentioning is USING CURRENT PROCESSES AND PROCEDURES, i.e. tons of petroleum-based fertilizers and pesticides, there might be a minimal net energy gain.

But people grew lots of crops without those things before, and they can do it again. Sure, yields won't be as high, but its not clear at all that the typical corporate farm is the most efficient.

[htuttle]

13. Current farming practices are designed to produce saleable food product...

...not biofuel feedstock.

For example, favoring corn strains that grew smaller, but more numerous, ears of corn would be a great thing for biofuel feedstock. The same strain would not be appropriate if you're trying to sell sweet corn to eat, as they are today.

Nobody cares how biofuel tastes or looks, either -- both qualities which are petro-expensive goals of our current agriculture practices. Additionally, I do not care if there are worms in my feedstock. They'll just ferment along with the corn.

[sendero]

16. I hear that the worms..

... increase the octane, sorta like a bottle of Tequila :)

[Neil Lisst]

10. sugar cane is what the Brazilians have found produces the most

[htuttle]

15. True...in Brazil

The same would not be true in more temperate climates.

Different strokes for different weather and soil conditions would be the way to go.

[MsTryska]

47. I agree!

ethanol should be regionally produced and regionally provided, imo.


I think we or rather the powers that be are stuck on stupid trying to have one region produce corn-based ethanol for the entire country.

[jmowreader]

59. What about sugar beets?

The Brazilians use sugar cane because it's what they have. We have sugar beets. Would they work?

[BlueEyedSon]

4. There's a whole lotta petrochemicals in fertilizer & pesticides too

w/r/t the crop, what matters is the ERoEI, maybe it takes a gallon of ethanol for the tractors, fermenting, transport, distilling, etc to get back 1.1 gallons, maybe you get back 10... I dunno!

[Skidmore]

7. We can't fertilize crops without petrochemicals.

What about processing all that animal doodoo from the beef and pork industries? Or using chaff or stalks of other crops?

[LARED]

12. Animal doodoo could never match fertilizers produced

by petrochemical processes in effectiveness. At least not in our present way of life.

http://www.princeton.edu/%7Ehos/mike/texts/readmach/zmaczynski.htm

[htuttle]

21. They use human doodoo around here, too

Or rather, treated sewage 'sludge'. It's what's left over after the treated water leaves the sewage treatment plants.

[MadHound]

28. The trouble with petro-fertilizers is that they actually leach

The nutrients out of the soil. Any soil so fertizlized becomes more and more barren each year you fertilize, and you find yourself having to add larger quantities of petro-fertilizers to get the same yield.

Manure fertilizing doesn't have this, it actually builds up soil quality, thus maintaining a sustainable agriculture. And the yields, while smaller that petro fertilized fields, aren't that much smaller, and given time and the build up of a good soil base will actually meet or even exceed the mark set by petro fertilizers.

[LARED]

39. I'd like to see some information about

what your saying, as it seems to me that if manure could be as effective as petro fertilizers the use of petro fertilizers would never had changed farming the way it has.

I'm sll for sustainable agriculture, but I don't want to see people starving of the price of food go higher because we cannot produce enough food.

[Squeech]

41. Marketing

Companies like Monsanto have set themselves up as one-stop shops for industrial agriculture. They'll sell you the fertilizers, the pesticides, and now the genetically engineered seeds that you need if you're going to use their pesticides (e.g. the herbicide they sell as Roundup).

They position their product line as integrated, more scientific than the old heuristics of manure. But we know bullshit when we see it.

[MadHound]

50. Here's a few resources, and further explanation

<http://en.wikipedia.org/wiki/Chemical_fertilizer>
<http://www.plantea.com/manure.htm>
<http://zzyx.ucsc.edu/casfs/gardenideas/soilfert.html>

The reason that petro fertilizers became popular are many. Convience is one, after all, do you really want to deal with tons of manure? Secondly, fertilizers were largely seen as the miracle product when they were first used back in the thirties and forties. Initially they created much larger crops. But as the soil became ever more depleted of nutrients, more and more fertilizer was needed just to get average yields. That was even seen as OK back in the sixties and seventies, hell, it was still cheap and convienent, what's a few more tons of NKP? But then we started to become enviromentally concious during the seventies, and people noticed how the run off from these fields was destroying waterways, and how fields were becoming ever more barren. Thus the sustainable agriculture movement was born. Now we're having to contend with GM foods, which have been designed to only respond favorably to both fertilizers and pesticides produced by the manufacturer of said crop. IE, Monsanto has devised many GM crops that will only grow well, if at all, with the application of Round Up pesticide and Monsanto fertilizer.

At this point in time, with our fields seriously depleted of nutrients, using manure in place of your petro fertilizers will not have a significant impact on crop yields. In fact if we don't get off of petro fertilizers, crop yields will continue to decrease, as will the nutritional value of our food, and it will happen at an exponential rate. I live and farm in Missouri, and I know how to test soils, did it with my Dad all over the Midwest. And let me tell you, in Missouri and surrounding states, the bread basket of this country, the soil is just plain worn out. It is turning into clay and dust, with little nutritive value. There are a growing group of farmers like myself who are working hard to build the soil back up, but we can only do so much, mostly on our own property. We have really got to wean ourselves off of petro fertilizers though, and soon. Otherwise we're going to reach the point where we're dumping mega tons of petro fertilizers on our corn fields, and only getting weeds to grow, and that's if we're lucky.

[politicat]

58. Actually, mixed use farming is more productive... but....

It has a much higher labor cost. A monoculture 1000 acre corn farm in Kansas needs 1 person to take care of it.

A 1000 acre mixed use farm with animals and multiple crops needs 10 to 20 people to care for it, depending on the crops, the animals, and the season. And it's harder to market - it's really easy to sell 70,000 pounds of corn or soy or whatever to the granary four miles away, but if you've got 400 pounds of tomatoes, 300 pounds of carrots, 400 heads of lettuce, 20 beef cattle, 400 gallons of milk a week, a gross of eggs, and 1000 pumpkins, you better have a farmers' market nearby. You're not going to be able to get those small quantities in the groceries or sell to a distributor easily.

What you save in labor costs gets eaten up in chemical, seed and mechanical costs, and vice versa. Being a farmer in America is a losing proposition, no matter what you grow.

[Sinti]

23. French intensive method

It works, gives yields higher than most American farming methods, and feeds mother earth so the soil quality improves. Under current conditions the petrol-based farming won't hold anyway, the soil is suffering, and your veggies actually have less nutritional value.

French intensive method:
http://www.motherearthnews.com/library/1980_January_February/Biodynamic_French_Intensive_Gardening

From everything I've seen, the way they're making the ethanol is not an economically feasible alternative to fossil fuels. They could do better though, it's much like making booze. Your cars could readily run on booze, that was Ford's original plan, after all.

[politicat]

57. Great for vegetables. Not practical for large scale monoculture.

And the only way to produce enough oil to reduce our need for petroleum is large scale monoculture. (In my very efficient house, with my very efficient car, and my bicycle and public transportation, I use about 8000 gallons/equivalent (I also use natural gas and coal for some of my energy) of oil a year (average american uses about 11000). That means that I need 80 acres of rapeseed growing for just my use. Multiply that times 280 million people, and we need 22.5 billion acres under rapeseed cultivation. That's about 34.5 million square miles, and that's just for fuel production - that doesn't include eating, plastic manufacturing, paper manufacturing, animal feed, construction or any of the other things we use crop land for. We have the land mass, but we don't have the water or the cultivable area. We can't raise oil crops in the Rockies or Death valley or the a lot of other land area. It's just not possible.

Now, lets assume I want to plant my own garden, using an intensive method, and I'm going to grow my own rapeseed (the best oil plant that will grow in my region) and have it pressed and convert it into biodiesel myself. I may be able to increase yields so that about 60 acres can serve my needs for heat in the winter, cooking fuel in the summer, transportation costs, lubricants, and power for my little laptop and modem, but keeping 60 acres under intensive cultivation is a LOT OF WORK. I'm gonna have to hire people or get a machine to help out - can't use horses because I won't have time to care for them. So now I gotta feed me and Joe the Farm hand, and take care of his fuel needs - so we're back up to needing about 60 acres per person, so now we're up to 120 acres. (And owning that much land in the region I live in would require a very sizable investment, and then I'd have to buy the water rights. I'm looking at $2 million before I turn a spade full of earth.) I can supplement my energy needs with solar and wind power, but solar's unreliable in most of the country, and wind also depends on region.

Realistically, using the various intensive methods, crop yields are about 30% higher than monoculture methods, which is highly significant. But they also require a lot more labor, and labor has to be factored into the cost. As a part time worker and full time gardener, the most I ever managed to handle was a garden that had about 270 square feet of growing space (3 30 foot long strips, 3 feet wide, each.) That supplied 85% of our vegetable needs (for 2 people) for about 5 months. What you're suggesting is just not possible.

[LARED]

8. 6 to 1 ratio according to

http://www.sciencedaily.com/releases/2005/03/050329132436.htm

Study: Ethanol Production Consumes Six Units Of Energy To Produce Just One
In 2004, approximately 3.57 billion gallons of ethanol were used as a gas additive in the United States, according to the Renewable Fuels Association (RFA). During the February State of the Union address, President George Bush urged Congress to pass an energy bill that would pump up the amount to 5 billion gallons by 2012. UC Berkeley geoengineering professor Tad W. Patzek thinks that's a very bad idea.

[BlueEyedSon]

19. holy crap... 6 gallons of ethanol (or equivalent) to produce 1 gallon???

eeek! i always thought ERoEI ratio was at least (or close to) 1:1.

[Rabbit of Caerbannog]

36. Not true

Net energy gain with cellulosic ethanol using enzymes to break down the entire plant (stalks/leaves typically wasted) and then fermented into ethanol. Using just the corn is a waste of energy AND food.

Brazil uses sugar cane which has a MUCH higher conversion rate than corn because there are no starches to first break down into sugars like in corn

[LARED]

38. I seriously doubt there is a net energy gain

The link I posted looked at the entire cycle for producing ethanol. From planting to the pump. Not a specific step in the process. If you look at a single step in any process it is easy to draw incorrect conclusions about it's ability to deliver as an energy source.

As a side note Brazil uses sugar cane because it can. Last time it checked corn is easy to grow in the states and sugar cane is limited to extreme southern climes.

[Squeech]

40. Exactly

Rabbit of Caerbannog is proposing a technology that's still at the experimental stage, and probably wouldn't qualify for the ADM subsidy even if it were ready for prime time, so I doubt they'd use it.

Moreover, once we implement that technology, there's no reason to use corn as primary feedstock. One idea I saw involved building the fermentation plants up in the forest regions of Maine, in abandoned sawmills, and using the big piles of slowly mouldering sawdust as feedstock. Other observers propose growing hemp, because it's hardy enough to grow in marginal soils that wouldn't support more widely useful crops, because it's a nitrogen fixer that improves the soil it grows on-- oh, and I'm told it has other purposes :smoke:

Heck, if the process doesn't depend on economies of scale, you could build a small plant in every suburb, collect lawn clippings from every suburban homeowner, swapping a jug of ethanol for a bushel of raked-up grass and fallen leaves. (Having problems getting your teenage kid to mow the lawn? Promise him a bottle of alcohol :evilgrin:)

[Chemical Bill]

52. The DOE disagrees with you.

They put the energy balance at 1.32 (IIRC). That said, there are better crops than corn for ethanol, but ADM has a lock on federal money and lawmakers.

Bill

[Rabbit of Caerbannog]

54. Not just ADM:

Genencor, Novozymes Biotech and other corporations who make genetically engineered "bio-industrial products" are also getting fed (mostly DOE) money hoping to cash in on ethanol $$

[Chemical Bill]

49. Tad Patzek works for big oil.

He heads the UC oil consortium, funded by big oil. He's not exactly a disinterested party. There are refutations of his assertions about biodiesel at biodiesel.org.

Here's a snip:

Leading academics also discredited the work of Pimentel and Patzek. “There is an internationallyaccepted standard method of doing such life cycle studies. Drs. Pimentel and Patzek don’t comeclose to meeting the standards,” said Bruce Dale, professor of chemical engineering at Michigan State University. “Their studies don’t meet the International Standards Organization test of transparency—they don’t clearly state where their data comes from nor do they clearly state their assumptions. They cite themselves rather than independent sources for important data all the time. And they don’t submit their work for verification in recognized, peer-reviewed life cycle journals.”

link

Bill

[LARED]

51. Thanks for the info

Interestingly both sources, yours and mine seem to have an agenda that may slant their views.

It points out the difficulties in getting good information about critical issues.

[Chemical Bill]

53. Yes, soybeans are not the best source of biodiesel...

but that's what we have, because the meat industry is using soy meal for feed, and discarding the oil.

Imagine a world where decisions are made for the good of all, not for the most profit for the few.:shrug:

Bill

[Coastie for Truth]

60. I read the full Pimentel-Patzek paper

and many of the references.

Pimentel is a little bit of a Malthusian. And some (many?) of his thermodynamics are like nothing I have seen in any of my thermo books.

Pimentel's dog just don't point or fetch.

[ProfessorGAC]

14. What Are The Petro Products In Fertilizer?

Fertilizers are essentially inorganic chemicals. Phosphorous (like ammonium phosphate), nitrates (like ammonium nitrate), elemental sulfur. There are some that have urea which is a nitrogen bearing organic chemical. But, mostly these are inorganics that aren't present to any appreciable degree in petroleum. The sulfur comes from the refining process, to be sure, but that's nearly a waste product for a refiner. They only charge about $60 per ton!

And, the total amount of pesticides put on an acre is so small that an entire farm would require only about the equivalent of a quarter barrel of oil. (Assuming the average farm is about 80 acres.)

I don't think the petro input from this process is anywhere close to what you're implying.

Besides, this is at least a step in the proper direction. No?
The Professor

[htuttle]

18. Ammonium Nitrate, I believe

More specifically, I think they use a lot of methane and natural gas to create ammonium nitrate.

There are other ways to do it, but they don't do it those ways right now on an industrial scale.

[ProfessorGAC]

22. Methane Isn't A Petro Product

Completely different source. That creates some burning of fossil fuels and still liberates CO2, to be sure. But, the hydrogen from that is used to react with nitrogen to form ammonia. It's a low efficiency process, because only 25% of the methane gets used, with the balance (the carbon) going up in smoke.

So, it seems we still have some differences in definitions, 'round here.
The Professor

[htuttle]

24. For industrial purposes, they extract methane out of natural gas

They don't make industrial methane out of bacteria. Where do you think they get it?

Look up the "definition" of the Haber Process, if you think we're having definition problems.

[ProfessorGAC]

31. I Didn't Say YOU Were Having Definition Problems

I said WE were having definition problems. We seem to be defining the same things in different ways. I meant nothing by it. Don't take it so personally.

Most natural gas and methane that is isolated (it's not extracted, it's either VSD'd or adsorbed from the ethane and propane), comes from mined natural gas. It's still a fossil fuel, and the original source is more or less the same as that of petroleum, it's still not a petroleum process. Some methane comes off certain grades of crude, but they have to be extremely light crude and the hydrocracking is very energy intensive, because of how many hydrogens are needed per unit mass of carbon.

Natural gas is a fossil fuel, but the source is seldom petroleum.
The Professor

[htuttle]

35. Apologies -- I'm cranky today

I'd considered as I posted that this is where our definitions were different, but posted anyway. :shrug:

I tend to use 'fossil fuel' and 'petroleum fuel' more or less interchangably. But you're correct in that they are technically different things.

[ProfessorGAC]

32. Dupe

..

[ThomWV]

27. Natural Gas .... Its all made from Natural Gas nt

[ThomWV]

29. This is Bullshit. Just another perpetual motion machine

Look the only way you can make ethanol at anything like a reasonable price in this country is to make corn at over 100 bushels per acre. In order to do that you need to add roughly 100 pounds of nitrogen per acre. The way to do that is with amonia nitrate. Its a white grandular stuff that will melt in your hands - it looks a lot like styrefoam beads. It not only makes a great fertilizer but its an even better explosive. The stuff is made by processing natural gas. That natural gas, to a large extent, is imported from Canada. The last time I looked Canada was well past peak gas. Their rate of production was slipping at about 8% per year the last time I looked.

So to rehash:

To make ethanol you need alcohol.

To get the alcohol you need corn.

To make the corn you need fertilizer

To make the fertilzer you need natural gas

To get the natural gas we import from Canada

Canada is running out of natural gas.

Go back to the top.

[ProfessorGAC]

34. Yes, And. . .

. . .what does this have to do with my question?

Canada's natural gas supply is not petroleum derived. It's mined just like petroleum, but it's NOT petroleum.

That was my only question.
The Professor

[HiFructosePronSyrup]

45. Why is natural gas needed for the Haber process?

I'm sure it's used as fuel, by why not use ethanol?

[TheFarseer]

48. currently, 200 bushels per acre is fairly reasonable

We can do without herbicides pretty easily I think, just takes a bit more manual labor. Without pesticides and fertilizers, I have no idea what yields would be - less than 200 though, that's for sure.

[LARED]

5. How ethanol is made.....

http://ethanol.org/howethanol.html

[BlueEyedSon]

20. No ERoEI numbers on that page

[Squeech]

6. Depends

The current subsidy structure privileges ethanol from corn. The agribusiness way of growing corn depends not only on energy-intensive cultivation practices, but also on heavy use of petroleum-derived fertilizers. Then there's the cargo handling involved in collecting the corn and delivering it to the Archer Daniels Midland plant. I saw a paper that claimed that, *if* everybody along the chain followed best practices, that there would still be a net gain of some 20% of overall energy-- that we would expend 5 gallons of gas to brew the equivalent of 6 gallons.

Now, what are the odds of everybody involved following best practices? Especially when the rationale for doing it in the first place is mainly to get the subsidy?

In Brazil, they make ethanol from sugar cane, which they've been growing as long as there have been Europeans in Brazil, and there's a lot of bricolage (making do without expensive tools). As a result they have an ethanol industry that really does yield net gains-- partly because sugar cane is better as a feedstock, of course, but partly because they really depend on this stuff. There are three pumps at every gas station in Brazil: gasoline, diesel, and alcohol.

[charlie]

26. Brazil has a huge advantage

in their ability to grow sugar cane. The investment/yield ratio disparity between sugar cane and our favored corn is ridiculous, something like 1/8+ vs 1/1.3.

[LuCifer]

11. K&R

But BU$Hitler says we're addicted to oil! :sarcasm:

[Stevepol]

25. Check out what Brazil has done with its sugar cane alcohol fuel.

I saw on TV recently an interview with a Brazilian official who, I am certain, said that in about a year, Brazil will be totall free of dependence on foreign oil. Just think what we could have done if we had pursued the R&D that Brazil did (by getting Gore in the WH in 2000).

Here's one article about the switch-over which is almost complete:

http://www.truthabouttrade.org/article.asp?id=5227

[Commie Pinko Dirtbag]

30. Over a year, you say? Ahem...

http://news.tradingcharts.com/futures/6/8/77916586.html

And yes, I am mighty proud.

[TheFarseer]

42. I've seen where you can run it on biodiesel

I'm not sure how ethanol would work in farm machinery because I've always seen it as a gas substitute and farm machinery runs on diesel (for the most part). I don't think biodiesel is that bad to produce. I've seen home made recipes that look like they take almost no energy to make, just running it through an electric machine and possibly driving to get the raw materials.

[MsTryska]

46. I agree

actually from what i know most farm equipment is Diesel - so it should make even more sense to use Biodeisel to produce the ethanol. more bang for the buck.

[politicat]

56. The problem with ethanol/BD is that industrial corn production requires

fossil fuels - not just for the farm machinery, though that's a big bite, but for the fertilizers that we have to put on the land to make it productive enough to grow corn. Also, most farm machinery is diesel powered, not gasoline powered, so you're really looking at biodiesel, not ethanol, and soy or rapeseed rather than corn.

Corn exhausts soil if it is grown on the same patch of land more than 2 years out of 5. It sucks up the nitrogen, tilling to kill weeds ends up damaging the microbes in the soil, so there's not much of a chance for them to do their jobs, breaking down dead root matter into new soil. (Plus, tillage leads to erosion, and water pollution and a bunch of other problems.) So the best option is to rotate back and forth between soybeans (which as legumes, fix nitrogen in the soil), corn, and a third crop, like clover pasturage (though pastures should be designated pastures and never tilled at all, but that's another discussion.)

So, say a farmer has three fields. In year one, He grows corn in field A, soy in B and leaves C fallow. In year two, he leaves A alone, corn in B and soy in C. In year three, he grows corn in both B and C and soy in A. Year four is Corn in A, soy in B and C, and in year five, it's corn in C, soy in A and B. Then repeat the cycle. In theory, he could be selling part of the soy, processing the rest into biodiesel to run the farm machinery, and selling the corn, stalks and all, for ethanol. Here's where the problem comes in: To produce the levels of crop necessary to support soy-biodiesel and ethanol production, as well as the current levels of corn consumption, we have to use herbicides, pesticides and chemical fertilizers, all of which are petroleum based. And we have to increase production of soy and corn to cover the new fuel needs.

An acre of soybeans produces about 40 bushels (just over a ton, at 2240 pounds). We get about 48 gallons of oil per acre. In converting to biodiesel, there's about an .8 efficiency, so an acre of soybeans produces 38 gallons of biodiesel. Current average diesel use for farm use only is 28.9 gallons per acre. So an acre of soy can produce just a little over 9 gallons of surplus diesel (above what it own needs). Average farm runs about 500 acres, that's 4500 gallons of diesel, and the sale price for bulk diesel is about 2.30 a gallon. That's just over $10,000. The cost of the seed, the fertilizer, the pesticides and the herbicides to make that original 40 bushels of soybeans per acre is about $184 per acre (In Iowa. The price varies depending on location, cost of living, cost of land, etc. But Iowa's a good rule of thumb, since they're about the middle of the cost structure.). So assuming the 500 acres of soybeans... $92,000 to raise the crop. Most farmers need to make about $12,000 over costs to cover living expenses. (http://journeytoforever.org/biodiesel_yield.html, http://msucares.com/news/print/cropreport/crop99/cr990611.htm)

With a higher yield oil crop (like rapeseed, peanuts, or jojoba), the oil yields go up, but the break-even point goes up, too. Rapeseed and peanuts can be mechanized, but jojoba isn't yet.

Monoculturing is hard on the land - that's why it has to have so much in the way of chemical assistance. But a mixed use farm - where there's manure and chickens who scratch and hooves that break up the soil and nibble down the grasses and vegetables growing alongside grain - while more productive per acre, require more labor per acre, and when labor costs for commodity crops (like soybeans, rapeseed and corn) go up, producer profits go down, and require producers to put more land under monoculture.

As far as ethanol goes: an acre of corn produces 7100 pounds of corn and that can produce about 328 gallons of ethanol. The market wholesale price for ethanol is currently about $1.60 for a gallon of ethanol, and costs between $375 to $440 an acre to produce the corn. (Biomass ethanol production - like on cornstalks - is still not as well developed as making ethanol from corn, so I'm not going to get into that one.) Assume 100 acres. $32,800 to sell the ethanol versus $37,500 to grow the corn. It's a losing proposition unless we go back to the old method of land subsidy supports. Using 97 numbers (the oldest ones I have right now), it cost us $237 an acre to grow our corn (and we grow organically). Ethanol sold for $.87 in 1997. Productivity numbers were about the same - so we would have made a very small profit - not enough to cover living expenses for our farm manager, much less support anyone else. It all depends on the year, the price of corn, what supports are in place, etc. But profits are either going to be small, nonexistent, or the farmer takes a loss.
http://www.sciencedaily.com/releases/2005/03/050329132436.htm, http://corn.agronomy.wisc.edu/WCM/1999/W060.html, farm records for M***** Farms, Greentown, Indiana.)

Read "The Omnivore's Dilemma" by Michael Pollan. Other than the fact that he got a kinda major fact wrong* his statistics on petroleum use in industrial, organic, beyond-organic and the wild food chains are pretty solid, and jibe with numbers from my family farm and with national USDA numbers.

*The fact he got wrong is that all poultry and pigs may not be fed hormones ever, at all, for any reason, in the United States, and we don't import either chickens or hogs (This is a major FDA ruling, and one of the few that is in very simple english), so there are never any artificial hormones in chickens or hogs. (Cattle are another story.) Antibiotics can only be used medicinally and not within essentially 5 days times the metabolic excretory rate (i.e. chickens metabolize antibiotics out of they system in about 3 days, so they cannot have antibiotics at all in the last 2 weeks before slaughter; pigs metabolize out in about 4 days, so they can't have antibiotics in the last 20 days before slaughter.) Again, cattle are another story. Hormone free, antibiotic free labels are marketing when they're slapped on chicken or pork -- all chickens and all pork are hormone and antibiotic free. See the USDA consumer fact sheets at: http://www.fsis.usda.gov/Fact_Sheets/