The Oil Drum

I am preparing a rather involved post for this string, but I felt it only fair to contribute a source and a thought or two to your question.

The best source regarding the questions you ask can be found here:

http://i-r-squared.blogspot.com/2006/06/e3-biofuels-responsible-ethanol....

If you are new here, you may not be familiar with Robert Rapier’s work, but he has been exhaustive in his research on ethanol, and brought the mind of chemist and a petroleum genius to the subject.

On the post I am linking, Robert is discussing one of the few ethanol process that possibly could show promise, called:
E3 Biofuels' Closed-Loop Ethanol Process

The problem with ethanol, as Robert says, is “We take fossil fuels and basically recycle them into ethanol in a very inefficient manner.”

The fuels used are of course Diesel in the equipment, but of greater concern to many of us is the natural gas. The pesticides and fertilizers are not, as many seem to believe, oil based, but natural gas derived chemicals. The U.S. is already deeply concerned about supply of natural gas, and even embarking on expensive and complex projects to import LNG (Liquified Natural Gas) from of all places, OPEC nations. It makes the claim of ethanol as a “freedom fuel” that will assist U.S. energy independence all the more ironic. Natural gas is also consumed in getting the water out of the corn (distilling) and this is no small job. Corn has a very high water content.

Even if ethanol could overcome the consumption of water, land space, topsoil, and food that the industry creates, the natural gas issue alone would be a huge barriar to acceptance by many, who see natural gas as a natural treasure, one of the last great clean chemical and energy sources in the world.

The only system that has a chance is something like the E3 Biofuels system, in which the cattle, the corn, and the waste product are recycled, without long transport, all on one site. It may work, but it will be an uphill fight.

Good Luck, and follow out some of Robert’s work on his blog, it is fascinating stuff! :-)

RC
Remember, we are only one cubic mile from freedom

Another new ethanol plant is being started here in North Iowa. Click on "slide show" to get the justification. Note how crowded it is getting with ethanol plants around here. There are also at least a couple of biodiesel plants not shown.

http://www.prairiecreekethanol.com/index.htm

As a longer term resident of Iowa and someone who worked in the Seed industry for 10 years developing hybrids I will share some perspective.

One, corn is a commodity crop and all crops can be used for food, fuel, fiber etc. The balance is determined by the market place, yields and acres planted.

Two, no matter what we do ethanol and other renewable fuels will never equal our current gasoline and diesel volume. Those are created from stored geologic reserves and we can't produce that volume on a yearly basis from current crops.

Three, ethanol and biodiesel are a part of the solution to dwindling crude oil supplies. They make nice liquid fuels. But we also need to think about chemical feedstock replacement when petroleum is scarce. Corn, soybeans, flax, peanuts and other plants can help fill this need, way in the future.

Four, ultimately we must reduce our energy consumption before we use renewable. This last point is what, IMHO, is missing. The public has been told that corn ethanol can replace the gasoline supply. It can't. And now they they are discovering this, they are upset and looking for a new replacement. There isn't one. Crops are part of the solution. They are not the solution.

The energy efficiency of photosynthesis is shockingly low compared to photovoltaics. (one or two percent compared to 10-15%, not counting the inefficiencies of using just the corn kernels, and of fermentation / distillation) And so far, I haven't heard a single report of a farm running entirely on its own product. I have heard stories of vast tracts of tropical forest being bulldozed and burned to grow oil palms, however.

I think that biofuels are better suited to small, local production than to gargantuan megaprojects. They'll eventually be "silver BBs" for local needs. Whether the crop is corn, jatropha, sugarcane, or rape will depend on the local climate.

| _{The problem will solve itself.}
|  _{But not in a nice way.}

As an example of things that need attention I am wondering how much cellulose derived ethanol could be produced by treating the corn as an edible and shunting the stalks to a collection device rather than having them returned to the field.

If the goal is cellulose, it probably makes more sense to dedicate land to crops that produce far more of it than a portion of the corn stover will provide. Industrial hemp comes to mind: far greater cellulose yield, greatly reduced pesticide use, almost no herbicide use (hemp will crowd out almost everything else), lower water requirements, works well in rotation with other crops. In a future where there is an emphasis on local production, hemp's non-cellulose fiber is also useful for paper, fabric, and manufactured "lumber".

Further improvements in the energy efficiency of ethanol production are possible, eg, membrane separation of water and ethanol. That said, in an energy constrained future, I think there are better alternatives than biomass to ethanol to ICEs possible.