The ethanol deception

Averagesupernova

Ivan I'm NOT the one forgetting that we need the corn grown today, that's my whole point. It WILL BE GROWN REGARDLESS OF WHETHER WE TAKE ALCOHOL OUT. You seem to skip over the fact that the only thing taking the alcohol out does is remove the sugars from the corn. It is still quite useful after. I am not favoring ethanol over biodiesel at all. You speak of basic economics. Well here's some food for thought: Right now a corn/soybean crop rotation is fairly common. As there is more demand for corn more of these acres are switched over from soybeans to corn. We now raise corn on the same ground year after year on more acres than previously. This naturally affects the market price of soybeans and some other crops as there are less grown. The same thing will happen if the demand for ethanol goes down and the demand for biodiesel goes up. It will be more profitable to raise soybeans and other biodiesel crops so there will be less corn grown and this shortage will raise the price of corn. Take a look at the market price for both corn and soybeans over the last few years and you will find that they track each other.
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If you don't want fuel to directly compete with food then keep energy production out of agriculture and find some other source for it.

Ivan Seeking

Sure, it can be used for some applications, but what about those that need the corn intact? The fact is that we can't process all of the corn for ethanol which is already needed for other uses, but perhaps some could be.

I also want to be clear that I am not against ethanol because of biodiesel, rather, I became a biodiesel fan on its own merits, and have been very disappointed to learn about the reality of ethanol which I once saw as a promising option to petro.

Absolutely a valid point. Parts of the solution are the other crops like cotton, canola etc which helps to spread out the pain, but....
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I see it like this: Biodiesel is superior to ethanol in many ways, not the least of which are: The diversified base of feedstock; 1.5 times the energy density; a more efficient [as a percent of yield] processing chain. Now, if we didn't have algae as a real option today, biodiesel would have the same problem as ethanol in that we couldn't possibly grow enough. But we do have the algae option, and macro plants are available today to help with the short term demand for biodiesel. In turn, biodiesel is the carrot to go diesel. So we go diesel, then biodiesel from all crops, then we begin to supplement the macro crops with algae until eventually it could supply the majority of the feedstock [of course, in reality these are concurrent events]. And most important of all, unlike ANY other option that I have ever seen, bio from algae offers a permanent solution - and one that need not compete with food.

If it wasn't for algae, there would be NO good options ready today that could actually solve the problem. [less nuclear, which I don't see as a practical reality in an age of terrorism even if we could build the plants fast enough, which we can't.]

Also, just to avoid any confusion, algae has been a practical option for some time, but it has not been competitive due to price...until now.

Averagesupernova

Ivan where do you get the 1.5 times energy density of biodiesel compared to ethanol? How is that figured?

Ivan Seeking

Biodiesel has 118330 BTUs per gallon. Ethanol has 76000 BTUs per gallon. This taken with the efficiency of the engine used for each fuel is a direct measure of the work that can be done with each gallon of that fuel. [118/76 ~= 1.5.]. Of course that 1.5 times ignores the greater efficiency of diesel over combustion engines, which makes the comparion even more drastic, as is seen below.

While we are still using regular diesel - as we convert to bio - we get 139,000 BTUs per gallon in engines that are more efficient than gasoline or ethanol powered engines. It begins to help even before we convert to bio. And the diesel cars are here or coming.

Diesel engines are already high compression engines, so the comparison is valid even if we consider engines not yet available for ethanol.

The higher energy density of bio, the greater efficiency of diesel engines, and the more efficient processing for bio suggests that Bio has about a 400% energy advantage over ethanol - every four gallons of ethanol produced can move a car down the road as far as every gallon of bio produced.

Averagesupernova

Ok. That is pretty much what I expected, but not everything I want to know. How many gallons per bushel of each? And how many bushels per acre of each?

Ivan Seeking

Note that I have a bunch of late edits in the last post [struggling for clarity]

Most common stats cited for gross yields:
Corn yields 400 gallons of ethanol per acre-year.
Algae yeilds about 10,000 gallons of biodiesel per acre-year.

Net yields [after we pay the energy price to grow and process the fuel]:
Corn = 120 gallons per acre-year
Algae = 7000 gallons per acre-year

I just saw that BBC World News is running a story that asks the question: Should we grow food to feed the world's starving, or grow crops for fuel?

Aether

As I quoted earlier, according to A.E. Farrell: "Our best point estimate for average performance today is that corn ethanol reduces petroleum use by about 95% on an energetic basis...". Therefore, in order to compute "net yields" you need to be using 0.95 instead of 0.3; and then your number above for net yields would be "...Corn = 380 gallons per acre-year".

Averagesupernova

What about soybeans and other biodiesel crops? Also, what is figured in for inputs to the crop? On a corn/soybean rotation it is common to not use fertilizer at all for the soybeans. Plant food is derived from the residue of the previous years crop as well as some of the fertilizer applied for the corn crop. I guarantee you that soybeans on the same ground year after year will require some kind of fertilizer. I know next to nothing about algae but I have a very hard time believing that all it requires is air and sunlight. There must be other input to net the amount of biodiesel we are talking about.

Aether

The EBAMM model (ERG Biofuel Analysis Meta-Model) provides a thorough analysis of all inputs, including the agricultural phase, of ethanol production. I don't know if they provide similar information on biodiesel.

http://rael.berkeley.edu/EBAMM/.

Ivan Seeking

This has nothing to do with it. We measure the yield and look at how much energy it took to produce that yield. The multiplier is ~0.3 for net yield...and based on the technology in use, that is a best case.

Aether

The multiplier is ~0.3 for net energy, but it is 0.95 for farm land. Ethanol plants use coal and natural gas as energy inputs which accounts for the difference. If these plants had to use all ethanol or petroleum as their only energy inputs then the number for farm land would be ~0.3; but they do not have to do that, nor do they choose to do that in practice.

Ivan Seeking

Some crops are much better than others, and the amount of fertilizer needed is a critical part of the energy calculation no matter what crop we use. I don't know the specifics of soybeans but it is one of the best options after algae. I'm sure that plenty of information is found with a search as soybean is a major crop used today for biodiesel.

Nitrogen and other nutrients are needed for the algae. This was all considered in the aquatic species program and later research.

One nice thing about algae is that given the proper selection of algae strains, it can survive and even thrive in highly contaminated water. This is why it can be used to clean-up industrial, ag, and municipal waste. What is considered pollution can grow algae at tremendously high rates.

Another part of what makes algae so competitive is the percent yield as a function of oil by weight. There is one strain that has been measured as having as much as 86% oil by weight. Typical yields range between 30 and 50% oil by weight [oil weight compared to weight of dry algae before processing]. And it isn't that hard to understand when you think about it. Algae is a very simply organism that only does a few things. It is also very small - often in the range of about 5 to 10 microns in size - so it is very efficient in that it occupies 100% of the light incident area, and almost all of this is going towards fuel production rather than growing stalks, leaves, etc.

Ivan Seeking

This is not what the multiplier means. It is a measure of total efficiency. What you are talking about is using other energy to make ethanol, and this is not a viable option as we don't have the power needed to make it. In effect, what you are saying is that we should convert to coal power. And either way, we still couldn't possibly grow enough corn.

In the case of an energy carrier, hydrogen is more efficient as it returns about 50% of the energy used to make it, not 30%. And we don't need corn, just water. Also, hydrogen can be burned in traditional engines.

Aether

You are trying to use this multiplier to support your claim that farm land yields only 120 gallons of ethanol per acre-year instead of 380. This is clearly wrong.No, what I am talking about at the moment is how many acre-years of farm land it takes to make 380 gallons of ethanol. Maybe so, but that doesn't have anything to do with how many acre-years of farm land it takes to make 380 gallons of ethanol.

Incidentally, if ethanol has 30% net energy, then that means that it returns 130% of the energy used to make it; not 30%.

Ivan Seeking

If we use coal power to make ethanol, yes, it would take less land. Of course we still couldn't grow enough corn. You keep ignoring this point.

Where are we going to get the power? We don't have it, so we would have to either build a tremendous number of coal plants to produce ethanol, or use ethanol energy produced on-site to make the fuel. Either way we need to get the energy from somewhere.

When we talk about net energy returns, what we mean is how much of the available energy do we get to use. This is 30%. This is how we measure the net energy gain. You can play games all day, but the energy has to come from somewhere, and ethanol can't provide the energy, so ethanol is not an energy solution, which was the point of this thread.

Oh yes, your point about hydrogen is valid. I was using two different ways to compare. With ethanol we put in 66 BTUs and get 100, so we see a 50% gain in this sense. With hydrogen we put in 66 and get back 33 [or so].

Aether

Well, this is how we make ethanol today; using coal and natural gas.Maybe so, but this is a different issue. You don't mind if we discuss (and resolve) one issue at a time do you? We currently get the energy from domestic coal and natural gas; future plans are to use cellulosic ethanol where the energy comes entirely from lignin which is a part of the plants themselves. Wrong. If you look at the EBAMM spreadsheet you will see the detailed data from six separate published studies on the subject of the net energy of ethanol production. Here is a summary; output energy includes "coproduct credits":

Patzek: 27 MJ/L energy input vs. 25 MJ/L energy output = 93% return.
Pimentel: 26 MJ/L energy input vs. 23 MJ/L energy output = 88% return.
Shapouri: 21 MJ/L energy input vs. 29 MJ/L energy output = 138% return.
Graboski: 22 MJ/L energy input vs. 25 MJ/L energy output = 114% return.
de Oliviera: 20 MJ/L energy input vs. 25 MJ/L energy output = 125% return.
Wang: 19 MJ/L energy input vs. 25.2 MJ/L energy output = 133% return.

Ivan Seeking

Currently we have 600 coal plants producing a total of about 22.9 quads of energy annually. All petroleum used has about 38.8 quads of energy with a chain efficiency of about 80%. So we need about 31 quads of energy to replace petro, or 23 quads to make enough ethanol [with a 50% gain based on input power]. So, in order to produce enough ethanol using coal power, we would need about another 600 additional coal plants.

Late edits: I was assuming that we still need to allow for efficiencies already accounted for.