I believe they are crediting ethanol from corn with the amount of CO2 that is sequestered by growing the corn in the first place; i.e., the total net CO2 from growing corn + processing it + burning ethanol is less than, say, taking natural gas, converting it to methanol, and burning it. This is a legitimate practice.

The point, though, is that producing ethanol through this method is *not* significantly less greenhouse-gas-friendly even when sequestration is taken into account than simply burning gasoline and so is not really significantly more 'friendly' in that aspect than gasoline (only about 7% better)
====author's reply follows========
I suppose you may be correct about the accounting for CO2 uptake by corn. However, if we hold ethanol demand constant for the sake of a thought experiment, the total amount of carbon tied up in corn that is destined for fermentation does not increase steadily over time. X amount of carbon is taken up by the corn, and then released during fermentation. Planting season comes and this is repeated. In effect there is a contant annual flux of carbon from air and soil into corn, through ethanol, into cars and up into the sky. This standing mass of "sequestered" carbon is a credit that should be amortized over the design life of the fermentation plant if this view is correct. If life cycle terms, the "functional unit" would be VMT but that would have to be amortised by dividing by approximately 25 years, the amount of time needed to depreciate the facility or the cars, however you wish to view it. In this perspective, the credit taking does seem somewhat spurious. In a scenario where demand for ethanol accelerates steadily for decades it is far worse.

Addundum. If ethanol gets the corn uptake "sequestration" credit, it would seem a slippery slope, as gasoline producers should then by any objective analysis, be entitled to claim that trees, shrubs, grass, and corn too for that matter, also get to "take up" the CO2 resulting from the production of oil and refining of gasoline.

Huh? Shouldn't ethanol, like any other biomass fuel, be carbon-neutral? All the carbon in it comes from atmospheric CO2. I know some energy is used in processing, but still...
===author's response====
Yes it is. But on the face of it, the direct comparison of fermentation to refining shows clearly that fermentation is far more climate impacting of the two processes. Gasoline is a lettle better in the combustion phase of the fuel life cycle, and the only reason Ethanol looks even comparable is due to the deduction of its processing emissions. Why ethanol 'gets a pass' seems to me to be a subjective policy choice, seen as legitimatebecause people view photosynthesis as "natural". Of course we all know that the corn is getting nmost of it's CO2 from non-ethanol sources. Two points follow: as long as there is a heavy burden of culturally based CO2 in the atmosphere (which will be for several centuries the way things are going), we should not delude ourselves into thinking that ethanol holds any special advantage for climate change mitigation. Given how easily confused the public has shown itself to be on ozone depletion versus climate forcing gases, getting that on the table now seems worthwhile. Second, that industry seems to be moving toward making ethanol from non-grain agricultural waste and sawdust, for example, means that carbon that formerly was being sequestered for much longer than a year now will be recycle back to the atmosphere more rapidly due to the increased use of ethanol as a fuel. The one year cycle does not equate in that process. Hope this makes better sense than my first response.

This credit is correct, although 'sequestration' is perhaps the wrong word.



The natural carbon cycle is:

-plants

CO2 + sunlight -> O2 + stored energy

-animals

O2 + carbon in food -> CO2



As plants grow, the cellulose, sugars, and other components that make up their mass comes from this carbon in the air; they absorb relatively negligible mass from the soil.



This carbon is now 'stored'. If you permanently buried the biomass deep enough that the carbon would never reenter the atmosphere, it would be 'sequestered', and you would be purifying the atmosphere of carbon.



This should be contrasted with fossil fuels, where the carbon 'cycle' is:

permanently stored carbon + O2-> CO2



The fundamental idea behind biofuels is to make automobile energy use part of the natural carbon cycle. You are correct, though, that corn-based ethanol is only marginally better than just burning gasoline from a carbon perspective. Cellulose-based ethanol and other biofuels are better options and operate on the same principle.

The carbon dioxide released from a fossil fuel represents carbon that would, but for combustion, have been left in a climate-inactive liquid or gaseous hydrocarbon form belowground. (INACCESSIBLE CARBON) becomes (CLIMATE-ACTIVE ATMOSPHERIC CARBON) Fermentation or burning of plants just re-releases CO2 that was already in the atmosphere perhaps one year ago.

Essentially, we can stop dropping new CO2 into the atmosphere and just use what's already there over and over again. There is no need to amortize it, as 100% of plant carbon mass is extracted from the atmosphere in the current era, whereas 100% of fossil hydrocarbon carbon mass is not.

It's not about being "natural", it's about "are we releasing CO2 to the atmosphere that was already there last year" vs. "are we digging up carbon and releasing it?"

The carbon dioxide released from a plant - whether fermented, burned directly, no matter how you get it out - represents in its entirety carbon ALREADY IN THE SYSTEM - absorbed from the atmosphere via photosynthesis over that plant's lifetime. Sure, same thing for gas, but those plants that made up the gas were previously locked in a vault underground and OUT OF THE SYSTEM.

It is not that you have a different opinion on all this. It is that you misread a footnote and thereby designed your mass balance wrong.

Your backup position above -about alternate feedstocks - would only apply if we were out fermenting carbon that would otherwise be sequestered over our lifetime. (e.g. taken OUT OF THE SYSTEM.) However, the sawdust, corstalks, etc., you mention are pretty much headed for either burning, being left in the fields to compost / rot (same net carbon output, +/-5%, but with us getting no usable energy out of it, as rotting leaves very low residual mass - most of it goes back into bacteria, etc.)

Your claim that the gasoline producers would somehow be able to claim an uptake credit shows pretty definitively that you have flat-out misunderstood the basic factual basis of the DOE study (that uptake occurred *before* and effectively *in the same era as* fermentation / combustion, vs. gas which is effectively harvesting 60 million year old plus carbon)... it's unfortunate that Treehugger then posted it as though it were some sort of revelation or coverup or even new interpretation, vs. a well-meant but inarguable mistake.
===author's response====
Good ideas all. Here's a different perspective on the post context. Not everyone is as sophisticated and practiced in mass balance as you seem to be. Provoking some discussion as seems to have happened has merits for awareness building, especially for just such an audience. My personal view includes a highly plausible scenario in which corn won't remain viable as a fuel source. World grain reserves are already slipping; should the added pressures from drought and floods cut yields, sustainability of corn for fuel is questionable. In this scenario (others also are possible of course) ethanol would increasingly be made from perennial plants, including long lived trees. That, as well as "biomass burning' could then result in unsustainable forest harvests. Lets assume for discussion that the various tree species cut average 25 years of age at harvest. Quite different results for a mass balance involving annual crops.

That would be an intereting scenario, but ultimately unlikely:

1. I think you're completely right that corn is not a legit long-term source of hydrocarbon fuel stocks. The reason being that it has that ultimate peak of the plant value chain: you can eat it. With current population pressures, and the general heirarchy of needs, if you grow something people can eat, that's what they'll do with it. (That said, your average grain crop also involves a major amount of nonedible hydrocarbon material - e.g. for corn, the stalk, silk, etc., that you may as well use for energy if you're harvesting it.)

2. Think of the amount of effort, expense, danger, shipping, and real estate purchase involved in lumbering. It all works out on your balance sheet if you can turn around and sell it as wood, but I bet you can't cut down a tree, turn it into ethanol and make money at less than probably $25 a gallon.

3. What people will do - in fact are doing - is to develop crops that accumulate as much mass from the atmosphere as quickly as possible while still remaining cheap to harvest. Mostly grasses, and early work I believe on designer algaes. It will never make more sense to cut down a tree for its carbon - and wait 80 years for it to grow back - than it will to drive a combine over an acre of switchgrass and grow another crop the same year.

Not to mention, the mass result balance in your trees-to-gas scenario is not that different. In fact, it's just slightly better. Think about it, you're now sequestering some portion of the atmospheric carbon for, say, 25 years before reintroducing it, instead of 1 year or less. It's as if everyone put their paychecks into the bank for a year before they used them; the result would be a slight-but-real decrease in the circulating money supply.

Raising awareness is great! And discussions are great! But I look at your original post, and I don't see that intent. I see a nontrivial mistake, in a publication designed to provide environmental information. Sure, not everyone is that sophisticated on mass balances. But it doesn't make them more sophisticated to read wrong information, and an interesting subsequent discussion in the comments, far off the front page, does not remedy the misinformation given to the (presumably much larger?) number of people who read the original article and came away with the "ethanol is a scam" mentality.

What would - and what would, I think result in a net gain for readers & everyone, would be a follow-up / semi-correction including some compressed version of the discussion above.

Frankly, John, I think you've sort of admitted that the central message / thematic basis of the article was erroneous - if you want to turn that lemon into some lemonade, it's time for a mea culpa and an explanation up "above the fold"...
===authors' response===
An interesting proposal. I'll contemplate it for a few days as I still am concerned several items: one is the potential for harvesting long-lived perennial plants at an accelerated pace (Paul Bunyan style) in a setting when petroleum supplies are falling away rapidly. I see that as a plausible scenario unfortunately. Think about how much boreal forest is currently being cut at unsustainable rates to make toilet tissue. That won't go a way and adding the demand for massive amounts of ethanol feedstock could have a significant impact.

The other major concern I have is whether future political processes will align with the logical thin king you outline. Carbon sequetration rights are already being discussed in a "trading" context, a variety of climate change damage claim based lawsuits have been filed; and, other crazy schemes will no doubt be hatched from every direction if storm damage panic sets in. Perspective about IN and OUT OF SYSTEM carbon is still a bit untied for me as well. I'm doubtful that a broad consensus would remain on that difference if storm damage were to accelerate dramatically and every possible emission reduction looked vital. On this point, the best lemonade of all would be, in my opinion, to have the ethanol fermentation plants capture and sequester the C02 directly, before it disperses, parallel to the carbon dioxide sequestration technologies now being developed for coal fired generation plants. That I think is the way the general public, or at least much of it, will view things (supposition of course).

This is definitely a complex area, and your last statement really expands it from just ethanol/biofuels out to overall energy policy.
A couple of my favorite resources in this area are:
Stabilization wedges
which breaks the problem into more manageable chunks, and:
Overall energy policy
Which is a relatively politically balanced look at energy security and global warming. Pdf pages 89-97 specifically cover biofuel issues, including cropland use.
A big problem in this area is that it is overly tempting to propose a single solution that comprehensively changes the way energy is created and used (ie, a 'Silver Bullet'). The reality is likely to be a long slog of progressive improvement, involving solutions that are profitable at the time they are implemented. I think the real secret will be setting up the right conditions for success.

OK; make that:
http://tinyurl.com/7ewn6
for 'Stablization wedges' and
http://tinyurl.com/d6ldt
for overall energy policy.

WOV writes: "it doesn't make them more sophisticated to read wrong information, and an interesting subsequent discussion in the comments, far off the front page, does not remedy the misinformation given to the (presumably much larger?) number of people who read the original article and came away with the "ethanol is a scam" mentality."

I am going to have to agree with WOV here. Far more people are going to read the headline and beginning of your article than are going to spend the time to read a series of complicated back and forths in the comments. While you may still have concerns about the ethanol process, it serves NO real purpose to allow your (unintentionally) erroneus article to go uncorrected (factual articles can illicit healthy discussions too). The simple fact is, your article presents misleading information that does not capture the truth of the matter and regardless of how "sophisticated" it is, you have a responsibility to correct it, as soon as possible, not after waiting a few days for "contemplation." I know this isnt a fully fledged journalistic institution but it seems like you folks still strive to maintain some kind of journalistic integrity (for which I applaud you). Maintaining that level of journalism would entail correcting mistakes in articles promptly (newspapers and news media do it all the time).

Furthermore, it isn't really that complex: co2 from fossil fuels takes otherwise permenantly sequestered carbon and releases it to the atmosphere (thats what is getting us in trouble in the first place, adding more co2 to a previously balanced system (the atmosphere, oceans and global biosphere), throwing that system out of wack); co2 from biofuels comes from the system and goes back into the system when its burned. As long as we arent deforesting at unsustainable levels for fuels or to make room for more cropland for biofuel feedstock, we arent adding anything to the system (incidentally, we DONT need to do either of the above see the report here for more on how we can sustainably secure upwards of a billion dry tons of biofuel feedstock annually in the US alone).

The valid critique about biofuels is that they DO have fossil fuel inputs in the form of natural gas used to make fertilizers, diesel and gas used to power farm implements, transportation, fossil fuel-produced electricity to power the refining plant, etc. If this lifecycle analysis in the report is accurate (I havent read it yet) then it includes these co2 inputs. However, we still can discount the co2 absorbed by the plant from the amount released by its burning as a biofuel as this amount of co2 was already in the system.

Anyway, please post a correction to this article. Everyone makes mistakes. Good journalists correct them.

Cheers,
Jesse Jenkins aka WattHead
watthead.blogspot.com
===author's response====
Please see "Update #1" included as an addendum to main post. Hopefully this short Update's position as well as it's content will be viewed as responsive to the concerns expressed down in the thread. If several of you feel strongly that more still needs to be done, we'll watch for further comments and try to accomodate. Note: I took what time I felt was needed to think everyone's comments through carefully, then write something short and fair to all perspectives. If a good consensus can not be achieved after one more iteration, taking the post down is an option. Learning from each other is the preferred course, but do feel free to speak up.

Thanks for responding to my comment John. Your update to the article is a start. However, I think it may be better to rewrite or delete the second portion of the original article to remove the potentially misleading portion.

The beginning of the article focuses on the idea that "A US Department of Energy published study from 1994 (partial excerpt of relevant points shown below) indicates ethanol is roughly equivalent to gasoline in CO2 emitted/VMT." On this point you are more or less correct (ethanol emissions are actual 6% lower than gasoline according to the above chart and considering the scale of fuel use, that 6% can mean a significant decrease in tons of co2 emissions from tranport fuels). It is important not to view ethanol as an emissions-free fuel. It is not.

However, you the rest of the article is focused on the issue of the sequestration number which I hope we have established, you misinterpreted. Thus, in my opinion, the rest of the article probably should either be rewritten or removed. Either that, or your update should more clearly recognize the error. Either that or you should include a comment before going into the contentious portion of the article to make sure people know that it is contentious before reading it. That way you wont have to worry about them getting any wrong impressions before reading your update at the very end of the article.

Also, you write the ""deduction" in the balance sheet of fermentation emitted carbon dioxide has generally been considered "legitimate" practice for a life cycle inventory study of alternative fuels. On the other hand, climate change presents a high risk challenge that can benefit from a look from new perspectives." This to me implies that you still view the question of whether the 'sequestration' figure for ethanol is potentially misleading (I guess 'sequestration' is a confusing word but we've already discussed what this figure means in the thread above). You use the words "generally considered" "'deduction'" and "'legitimate'" (the later two quoted as if to cast doubt as to the appropriateness of their use here) implying that you still have some doubts here.

What do you mean by "climate change presents a high risk challenge that can benefit from a look from new perspectives"? New perspectives are fine but don't you think that if that perspective turns out to be based on a misinterpreted figure, we ought to revise our perspective? Sorry to harp on this. You guys do great work and I appreciate it. I just don't want too many people going away from this article thinking ethanol is somehow worse than gasoline in terms of co2 emissions because this (at least according to the study you cite) is not the case.

Cheers...

(I guess sequestration is a bad word but we've already discussed what this figure means in the thread above)

Suppose you are a passenger on a ship which is taking on water in a bad storm. Provisions have broken out of storage shelves, with ship's water and rum spilling about and mixing with the seawater. Passengers are terrified of the seas coming over the gunwales and soon are asking the ship's Officers if the Captain will and ask everyone to start bailing what they can...before water in the hold overtakes the pumps.

Not wanting to wait for a distracted Captain, some passengers begin to act on their own, tossing buckets of water over the side as fast as it rolls toward the hold. A volunteer bucket brigade forms. Leaking water and rum casks are passed up the ladder and thrown overboard to help save the ship.

The passengers on the metaphorical ship did not take the time to quarrel over which liquid should be bailed out. Whatever liquid was conveniently at hand was summarily dumped. Everyone pitched in..and over, recognizing the looming danger to themselves and the captain if they did not take action immediately.  This is exactly as things stand now for Spaceship Earth. Climate change storms loom, while the Captain is distracted or in denial. The major difference between our and the metaphorical situation is that the collective "we" , as well as the people discussing the ideas of this post in particular, are quibbling over which water to bail instead of grabbing what is conveniently at hand .

Gaseous CO2 emitted from fermentation processes is relatively clean and concentrated compared to other byproduct C02 streams. I suspecct it would be far more cost effective to sequester CO2 from the fermenters than from the hot corrosive dusty off-gas of a coal fired boiler, for example. Especially so since the designs are brand new and battery limits only just now being defined. From this point of view, a sequestration "credit" for fermenting operations dis-empowers the passengers, reinforces the Captain's attitude; and, perhaps worse, misses a convenient and cost effective opportunity to create a potentially profitable co-product .

All points of view, commenters herein, the mythical captain's, and the passengers, are equally valid in my opinion.

John, thanks for including a new update and a note before the contentious portion of the article. I appreciate it.

However, I still dont think you entirely got what I was arguing. You write in your latest update: "Even though ethanol may release a significant amount of greenhouse gas per mile traveled, this can be considered "recycled CO2" which was previously pulled from the atmosphere by corn (or other plants)." This still doesnt entirely capture the report. What should really be said about ethanol is this: 'Even though ethanol may release a significant amount of greenhouse gas per vehicle mile traveled (VMT), some of this CO2 (299.1 grams per VMT of the total 624.6 grams per VMT according to the study) can be considered "recycled CO2" which was previously pulled from the atmosphere by corn (or other plants). Thus the effective net CO2 emissions per VMT for ethanol is 325.5, roughly a 6% decrease in emissions from gasoline.

So am I saying forgive ethanol for all its emissions? No. All Im saying is forgive it for the amount that came from the atmosphere already. Give ethanol an accurate accounting (which the report tries to do). Ethanol is not necessarily a solution to global warming (although a 6% decreases isnt nothing). It may be a solution to peak oil (depending on its energy return on investment and on the effectiveness of new cellulosic-refining processes) and it may be a sustainable fuel (although not emissions free).

Finally, you mention sequestration of the off-gas from fermentation. Sure, why not? This would then get ethanol's effective CO2 per VMT even farther down. However, an accurate accounting that includes a 'sequestration' credit for the amount of CO2 absorbed by the corn does not "dis-empower the passengers." We've still got 325.5 grams CO2 per VMT left to deal with. Only now we are dealing with a fuel source that has the potential (I am skeptical of the energy return on investment of current ethanol refining methods but see lots of promise in new methods that can refine cellulosic biomass) to be grown renewably and domestically, employs US farmers and workers in its production and refining, does not require transport from overseas, and doesnt require costly (both in human and monetary terms) wars and interventions in some of the most unstable hotspots in the world.

Cheers...