"Ethanol may not be our savour from our dependence on petroleum, but it's a step in the right direction."

Think Green: Ethanol from corn is a net energy LOSS- it is a misguided political step /should not be difficult to comprehend.

Corn is used because the frementing and distilling methods are well known and investors are slow to back the use of untried feedstocks. In some places sorghoum is being tried and time will tell if big money get behind it.

An Engineer -

just to clarify: I'`m NOT advocating the use of H2 as a vehicle fuel. However, there are uses for it in the chemical industry.

Why ferment alcohols rather than go directly to BTL? Simple: fermentation is currently a lot cheaper. Fischer Tropsch will be limited to coal and natural gas feedstocks for some time yet.

Butanol may be mixed with gasoline in any proportion without having to adapt the fuel systems of existing vehicles. Its energy content is comparable to gasoline (i.e. there is no loss of range). It can also be transported in pipelines, eliminating expensive rail travel and blending overheads at the receiving end. It can be produced from any sugary feedstock. Bottom line: if the price is right, it's a better option than ethanol.

N-butanol itself does not smell bad, more like bananas actually. The problem is the butyric acid, perhaps a chemist will figure out how to neutralize the odor in a post-processing step.

Not sure what outdated study (or editorial) you are using to suggest Ethanol production is a net energy loss, but that is widely believed to be incorrect. More recent studies have proven that there is a positive energy balance for ethanol, as some of the more publicized ones were using incorrect assumptions, 20 year old data, or not counting all of the byproducts.

That is just with EXISTING technology. We will eventually use the cellulose, and there is potential to extract oil from the kernal as well. Now that there are economic incentives to maximize the yields of corn, this WILL happen in the near future. As we become more efficient at utilizing the corn, the subsidies will eventually decrease.

Yes, such technologies have taken too long to develop in hindsight, but that had more to do with the fact that oil was simply too cheap. This is the hand we were dealt (a plethora of corn), so we'll have to make the best use of it. Once the cellulose production is in place, we can then start to think about using different feedstocks (sorghum, switchgrass)

BTW....both gas and diesel have a negative energy balance as well.

I'd like to get off track a bit; hopefully Mike won't mind.

I see a lot of discussion about Butanol, but I've had trouble tracking down more information. I don't really doubt it's chemical suitability -- I'm sure it runs great, doesn't increase emissions, etc. My question is about manufacturability.

All of the references I see discussing the manufacturability are either from or are derived from Environmental Energy, Inc., a company which claims to have created a process with higher yield than the corn ethanol process. Has anyone seen something which independantly verifies this claim (on a commercial scale) or which compares the butanol process with a cellulosic process?

What's in a name -

until very recently, the only way to produce butanol from biomass was using a very old process based on acetone. Yields were so low the biofuels industry, though aware of the good fuel propoerties, focussed on ethanol instead. The EEI process promises to change that, and I have not come across anyone refuting that claim.

Unfortunately, technological feasibility does not guarantee business success. For any startup, marketing a patent to a giant corporation can be a difficult proposition. For example, agrobusiness giant ADM is pursuing a rival and possibly inferior technology based on Clostridium beijerinckii:

http://www.news-gazette.com/news/local/2004/01/30/bacteria_gives_crud_life_anew/

Another issue is that there is competition for butanol from the chemical industry, where margins are higher. This prices butanol out of contention as a motor fuel unless production volumes were to sharply increase. Thanks to congressional mollycoddling, corn farmers may profit more from inefficient ethanol production than they would from the EEI process.

Not sure what outdated study (or editorial) you are using to suggest Ethanol production is a net energy loss, but that is widely believed to be incorrect. More recent studies have proven that there is a positive energy balance for ethanol, as some of the more publicized ones were using incorrect assumptions, 20 year old data, or not counting all of the byproducts.
Is January 2006 recent enogh for you, see http://www.sciencemag.org/cgi/content/short/311/5760/506? While the study did conclude that corn ethanol had a small positive energy balance, it also stated that the benefit was too small to make corn ethanol a candidate for replacing oil. "Nonetheless, it is already clear that large-scale use of ethanol for fuel will almost certainly require cellulosic technology."

Think of it this way: A positive energy balance of 1.2 means you have to use 100 bpd of ethanol to pruduce 20 bpd of excess. It would not take a big incident (a spill or an accident) to wipe out you 20 bpd margin. Heck, an operator's mistake could wipe out a month's worth of gain.

Sure, it will improve over time, to 1.4 or perhaps 1.5. Hardly anything to write home about.

Bottom line: There are better ways to replace oil.

A couple comments -

You originally stated that ethanol was a net energy loss - that is what I was refuting.

I never said Corn Ethanol was going to replace oil under the current techniques or even with the modest improvements that you suggested.

Utilizing the cellulose from the corn stalks and extracting the oil from the distillers dry grain that is a byproduct for a biodiesel feedstock will raise that energy balance well beyond what you have quoted.

The point of promoting CORN ethanol is not to suggest that it is the final solution - NO ONE thinks that! It is to get ethanol production off and running with enough capacity that simple economics will dictate that other feedstocks with higher yields will be used and waste products are put to use.

Also....

I know I'm beating a dead horse here, but asoline has a negative energy balance as well, so I'm not sure if this is a good argument. Even a marginal improvement is just that - an improvement.

I believe the latest updates from the DOE suggest the energy yield of gasoline to be around .8 (or almost a 20% loss in energy). Their latest numbers for corn ethanol also peg that higher than you have quoted - around 1.35 (almost a 35% gain).

Look, many of these studies are all over the board, and you can almost always find one to support just about any opinion that you have.

In my opinion, this is a step in the right direction. Why not take these baby steps, instead of sitting around and doing nothing until the grand solution presents itself?

OK, fair enough. Cellulosic ethanol may or may not be a big part of our future fuels.

My concern is that many people are looking for the next big thing. Ethanol sounds cool. But ethanol has many problematic properties including:
1. The energy required for distillation places an upper limit on ethanol production efficiency.
2. Ethanol is quite a bit more corrosive than gasoline, which could lead to engine problems. Also, ethanol cannot be pumped with gasoline for this reason. Delivering ethanol by ship, truck or barge adds a lot of cost, especially for us in the distant markets.
3. Issues of things like vapor lock, flame visibility, and cold starts have experts concerned.
4. Increased vapor pressure of gasoline-ethanol mixtures cause increase emissions and evaporative loss.
5. The miles per gallon of ethanol is less than the miles per gallons of gasoline, due to lower energy content. All those articles of E85 being cheaper than gasoline usually fail to point that out.

I think renewable synthetic oil (BTL) has significant advantages over ethanol. That said research into cellulosic ethanol is better than doing nothing.

Is ethanol really that much more corrosive than gasoline? I know methanol is highly corrosive, but I was under the understanding that it was mostly some changes to rubber gaskets and non-metal components that are needed to make an engine flex-fuel and ready for ethanol. I mean, it's a couple hundred dollars worth of upgrades in limited production - can it really be that bad?

Are you right on #4? I thought ethanol had a much LOWER vapor pressure (around 2 PSI) than gasoline (ranging from 7-15 PSI)? I thought that is what caused the potential cold starting issues, and why they settled on E85, to keep the 15% gasoline? While low vapor pressures cause issues with starting, I thought that it was better in terms of evaporative loss (the higher the pressure, the more evaporative losses).

Also, most of the studies I have ready compare the two on an energy basis, not volume, so I think the lower energy density is less relevent. Cost wise though, you do have a point.

Yeah, there are issues, but hopefully someone will come to their senses and consider butanol for all of it's benefits (higher yields, ability to transfer in pipelines, no engine modifications required).

Back to the butanol discussion, I am very interested in learning more about this, but there seems to be a lack of information.

Now, most flex-fuel vehicles are still optimized to run on gasoline. Projects such as Saab's Biopower concept proved that an engine can be tuned to run on ethanol and produce significantly more power, due to it's higher octane rating. This can help to offset the lower energy density, since a smaller ethanol powered engine can produce the same power as a larger gasoline powered one.

Now, since butanol has an even higher octane rating than ethanol, does that mean that similar, if not better gains can be made with an engine optimized to run on butanol? That would even further widen the benefit of butanol, as that is not factored in at all in the studies I have seen....

Oil to gasoline energy gain 0.8
Corn to ethanol energy gain 1.2
Sugar beet to ethanol energy gain 2.0
Sugar cane to ethanol energy gain 4.0
Cellulose to ethanol energy gain 8.0 (est.)

Would it be fair to say that corn ethanol processing leaves more cellulose behind than those others used for comparison? If so, once we start utilizing that cellulose for ethanol, wouldn't it make corn ethanol's total yield much closer? Do the others have any other major benefits, such as significantly less cultivation/fertilizers required? Faster growing? Anything?

Corn stover, or the corn stalk is now plowed under for cultivation. It has been estimated that 50% could be harvested for cellulose ethanol while still maintaining good soil quality. That other 50% is now used for animal feed.

When corn is made into ethanol, there is the distillers grain left over that is used for high protein animal feed. The animals need protein and plant stalk for their diets. So, you can see there is a tradeoff between human food needs, animals food needs and fuel requirements.

So, to answer part of your question, you would get higher energy gain by using both the corn and the stalk, than just the corn alone, but you would get the highest by using the stalk only.

When the corn oil is extracted from the distiller's dry grain to be used as a biodiesel feedstock, does that make this grain unusable as an animal feed? Is it essentially trading animal feed for biodiesel, or can you extract both?

There was a post on here about that. A company said that you could get ethanol from the corn, corn oil from the distillers grain and animal feed from what is left. You would have to look in the ethanol topics section to see.

All you are doing is taking the starch out to make sugar then ethanol, then the fats out to make biodiesel from the corn oil and what you end up with is healthy animal feed.

Thanks. I thought I read that same thing, but you never know who to believe. All in all, if you included the sugars they could extract from the stover, that's a pretty efficient use of corn. We'll see if it actually happens!