Life in a Grass House

Editor's Note: This is a guest post by Kyle.

Scouring the web with an eye toward understanding a bit more about the use of biomass-based ethanol as a replacement for gasoline, it has become apparent to me that there are a substantial number of "urban legends" emerging regarding the use of switchgrass as a feedstock for ethanol. More properly, these misconceptions are "rural legends," because at least from this former farm kid's perspective they arise from the fact that most people have very little connection to the land, and as such, are simply blowing a lot of wishful smoke about the details of a biomass-based fuel system. Hopefully the analysis below will shed a bit of light on the subject.

Ethanol, or ethyl alcohol, is produced biologically from the fermentation of various sugars from carbohydrates found in agricultural crops, and more ambitiously, from cellulosic residues from crops or wood. The process generally involves grinding the feedstock, freeing the sugar by either dissolving it (corn, sugar cane) or applying some sort of enzyme to convert the cellulose in the feedstock to sugar (see Iogen's website, for example), and then feeding that sugar to microbes (yeast) that use it for food, producing ethanol and carbon dioxide in the process. The resulting liquid must then be purified to increase the alcohol concentration. This process, of course, is not new - fermentation probably has been around since shortly after humans invented agriculture, and the use of a still to concentrate alcohol is familiar to anyone who has ever watched the Dukes of Hazard.

Currently, in the US ethanol is made from corn, which any number of studies have shown is quite marginal with regard to energy return. Paraphrasing Bob Hirsch in his most recent talk, making ethanol from corn is a process by which a certain amount of energy in the forms of natural gas and diesel fuel are used to create an equivalent amount of energy in the form of ethanol, with the primary output being money from government subsidies. However, there is substantial excitement about the potential of using biomass composed primarily of cellulose rather than starch as a feedstock for ethanol - hence the mention of switchgrass by the President in the 2006 State of the Union Address.

Switchgrass is a perennial grass native to the great plains, suitable for marginal lands because it grows well with relatively moderate inputs and can effectively protect soil against erosion. So far so good - one of the major attractions to switchgrass is that it is more environmentally friendly than corn. It contains roughly 15 million btu/dry ton, equivalent on a perfect basis to 200 gallons of ethanol per ton. However, in the distillation process some of that energy is lost, leaving the best estimates of roughly 70 gallons of ethanol per ton after distillation using a state of the art bio-reactor. Estimates for yield range as high as 15 dry tons/acre per year of switchgrass, equivalent to roughly 1000 gallons of ethanol per acre. Corn, by comparison, offers about 140 bushels per acre, with an efficiency of 2.5 gallons ethanol/bushel, or 350 gallons per acre. This is why so many folks are beating their drums over switchgrass - in theory, it can be grown on marginal lands with ethanol yields 3 times that of corn with "minimal inputs." From this description, one gets the sense of legends in the making. Let's take a critical look at some of them.

Legend 1: Switchgrass does not require fertilizer or irrigation (America's strategic imperative: a "Manhattan Project" for energy by Lt. Col. John Amidon).

Fact: Switchgrass is a perennial grass, just like the grass in people's lawns. If you bag all your lawn clippings from your lawn, very quickly you will notice that your lawn will start to become yellow, and your "yield" (the number of times you have to mow) will decrease. This is because of the lack of fertilizer. Each time you remove biomass from an environment, you remove nutrients, and future yields will suffer. Switchgrass is exactly the same - if you harvest switchgrass for biomass, fertilizer must be applied in levels very similar to those applied if corn is the primary crop. The Auburn study showing up to 15 tons/acre of switchgrass applied 100 lbs of nitrogen per acre, and that amount is also recommended by the Iowa State University Extension Office if switchgrass is used for biomass. In addition, phosphorous and potassium (potash) must be applied in amounts consistent to the amount of biomass removed, which actually exceed that necessary for corn.

Regarding irrigation, it is true that you don't need to irrigate switchgrass, just like you never "need" to water your lawn. However, just like your lawn, switchgrass won't yield nearly as well if it doesn't have adequate moisture. In Biomass Yield Stability of Switchgrass Cultivars by Fuentes and Taliaferro, it is shown that the best-yielding switchgrass variety in Oklahoma in a location with 30 inches of precipiation/year provides about 6 tons/acre, while a location also in Oklahoma with 40 inches of precipitation/year yields 8 tons/acre. (Note that both of these were fertilized). Switchgrass yields vary strongly with precipitation - planting the dry plains, New Mexico, or Arizona with switchgrass will not yield much biomass.

Legend 2: It is estimated that 15 percent of the North American continent consists of land that is unsuitable for food farming but workable for switchgrass cultivation. If all that land was planted with switchgrass, we could replace every single gallon of gas consumed in the United States with ethanol. (Sam Jaffe, "Independence Way," The Washington Monthly (July/August 2004)).

Fact: There certainly is a significant amount of land that is non-productive for agriculture but could be planted with switchgrass. For example, in Iowa roughly 7% of the land is in what is called the Conservation Reserve Program (CRP), where the Federal government pays farmers a small amount per acre to keep that land out of production. However, there is a reason why that land is in the CRP program - it's not productive for agriculture! This could be for any number of reasons - poor soil conditions, steeply sloping fields, etc. It is not because the farmer doesn't want to plant the land - land rents for good farmland are substantially higher than the amount offered by the CRP program. Switchgrass would certainly grow on CRP land, but yields would not approach the 6-8 tons/acre on good agricultural land.

Legend 3: Switchgrass yields a certain amount now, but in the future, with selective breeding, etc., it will yield much more.

Fact: Switchgrass is a perennial, and needs to be seeded only once every decade. Is it reasonable to think that Monsanto is going to spend much research effort on seeds that they will only sell to farmers once a decade? Certainly one can select varieties of switchgrass that are more prolific (as has been done already in the Fuentes study above), but it is difficult to see that there will be much yield improvement beyond that, certainly not on timescales of a decade or so. For a wide variety of annually varying weather conditions, soil quality, etc., it is hard to argue that switchgrass yields will exceed the 6-8 ton/acre range. We've been growing alfalfa for many years for biomass with a very high incentive to increase yields per acre, without much success. Switchgrass probably won't be much different.

Legend 4: Switchgrass is substantially cheaper as a feedstock than corn for producing ethanol.

Fact: This is the big one. How do we analyze this? Let's start with the obscure document Estimated Costs of Crop Production in Iowa - 2006. This is a useful document, as it provides insight into not only how switchgrass compares to corn in what can be argued is the best farm state in the US, but provides some insight into how things change over time due to rising fuel costs.

Costs associated with switchgrass are found on page 9 of that document, under "Annual production costs for established alfalfa or alfalfa-grass hay." Switchgrass must be cut, allowed to dry, raked, and then bailed for transport. For large, round bales of switchgrass (the cheapest method), estimated costs are $74/ton for 4 tons/acre yield, and $66/ton for 6 tons/acre yield. Presumably, that can be extended to $58/ton for 8 tons/acre yield, and so on. Note that these costs will generally be higher for smaller fields, another black mark against the use of CRP land for growing switchgrass.

On top of those costs, there will be transportation, which currently is about $0.25/ton per mile. How far will the switchgrass have to be transported? That's a bit more involved. A reasonable sized bioreactor facility would be 10,000 bbl/d, as 200 such facilities in the US would produce about 15% of the daily gasoline usage. Such a facility would use roughly 2 million tons of biomass feedstock per year, which is the output of 250,000 acres at 8 tons/acre. That is an area of roughly 400 square miles, or about 20 miles on a side. Given that rural roads don't run straight, that 20 miles is a fair figure for the average load to travel, leaving travel costs of $5/ton. So, we are talking something in the $60-70/ton range delivered to the bio-reactor. However, that is assuming 100% of the land around the bioreactor is switchgrass. If we instead only plant marginal land, the transportation distance would go up by a factor of 3 (due to the sparseness of the switchgrass fields) to $15/ton, leaving the total cost $70-80/ton. At 70 gallons of ethanol per ton of biomass, this suggests a minimum cost of $1/gallon ethanol simply to get the switchgrass to the facility. Yields less than 8 tons/acre will lead to proportionally higher costs.

How does that compare to corn? That's a bit more dicey, as corn is heavily subsidized. Wholesale corn currently costs about $1.90/bushel, while the Iowa 2006 Crop Production Cost is $3.40 per bushel (if the difference between those numbers seems incredible, remember that you, the US taxpayer, are picking up the tab). Corn is much more dense than switchgrass biomass in terms of energy per unit mass, so transportation costs are much less, certainly under $0.10/bushel. At retail, this suggests a cost of $0.80 per gallon to get the corn to the ethanol facility based upon wholesale, and $1.40/gallon based upon the Iowa Crop Production cost of $3.40/bushel.

Given that the switchgrass costs more to make into ethanol once at the bioreactor due to need for enzymes ($5-10/barrel or $0.20-$0.40/gallon plus extra energy used), there doesn't appear to be any advantage to switchgrass over corn for ethanol. One can always argue that switchgrass/byproducts could be burned for co-generation, making the distilling process less fossil fuel intensive, but a corn ethanol facility could also burn corn/byproducts for the same purpose.

As a final note, there is sensitivity to energy prices in this analysis. However, it appears to go the wrong way for switchgrass. In 2000, the Iowa Crop Cost document states that at 6 tons/acre the cost of switchgrass was $52/ton, rising to $66/ton in 2006, an increase of 27% as the price of diesel doubled. Corn, on the other hand, cost $2.89/bushel in 2000 to produce and $3.40/bushel in 2006, an increase of 17%. This suggests that corn may become more competitive with switchgrass as time moves forward and energy costs rise, exactly the opposite interpretation most people would have anticipated. I attribute this to increased corn yields with time, which makes corn production progressively more efficient.

What's the moral in all of this? If corn ethanol is marginal on an energy returned on energy invested (EROEI) basis, it is very difficult to argue that biomass grown to make ethanol will be any better. To be blunt, if there are concentrated stocks of waste biomass in place, such as at lumber mills, then biomass ethanol probably makes sense. Otherwise, it appears to be more or less equivalent to corn based ethanol - in other words, a wash.

In summary: There is no such thing as a free lunch!  Powerdown is by far the best alternative>>> 'No Thanks--I like Empty Tanks' mindset to ssstttrreetcch the remaining detritus of ancient sunshine.

Bob Shaw in Phx,AZ  Are Humans Smarter than Yeast?

Oh no, I was dreading this day. I was hoping switchgrass wouldn't make the OilDrum headlines - at least not for a while. Who is Kyle, anyway? Isn't he one of the kids on South Park? Now I've actually got to read this.

I just switched the laptop's Firefox browser home to TOD. I'll have to work on the rest of the palace computers tomorrow. Rafael controls that stuff, so I'll have to get him to sign off on that. At least he says he's going to get an account on TOD soon, so hey, that's good news.

Congratulations, Kyle, you just got somebody else to pay attention to switchgrass.

I have been analyzing ethanol from grass and lignocellulose for 35 years, from the standpoint of conversion technology (I am a chemical and biochemical engineer).  The claims are not backed up by reality.  Major problems remain to be resolved.  The likelihood of getting around the multiple problems, of differing nature and much greater severity than with sugar fermentations, seems vanishingly small.  There is no commercially practical ethanol with eroei over 1 from cellulose today, even being shown on a test tube scale, nor any credible near term prospect of a commercially practical process.  (sugarcane sugar, as in Brazil is a separate case, and it works).  Anyone wishing to  talk this over can email me: and send me your phone number.

I make no claims to having any expertise in this subject [I gladly defer to the experts], but it seems obvious to a layman that if any plant could photosynthesize energy easily at a high ERoEI ratio: we would have a planetary covering of rich, loamy topsoil hundreds of feet thick.  Instead, we have rapidly depleting topsoil and the mindless rush to agro-fuels will only make this situation worse.

Somehow the image of thousands of slaves swinging scythes for switchgrass so that only the warlord can power his HUMMERs with machine gun .50 cals springs to mind.

Bob Shaw in Phx,AZ  Are Humans Smarter than Yeast?

The image that came to my mind was thousands of slaves swinging scythes for switchgrass to power the 4.5 liter V6 GMC you drive, Bob.
Actually there was such a system.  

The American Prairies were net builders of soil.  This was a complicated ecosystem of plants and animals that produced more biomass than was consumed on a yearly basis.  This is why midwest land has so much topsoil even today.  Some researchers think Native Americans used prescribed burns to maintain this situation.  Jury still out on that one as prairie fires can start naturally.

Removing the grazing herds and tilling the soil resulted in a less efficient system, but more specific crop foods for humans in the short term.

Correct, but let's make sure nobody thinks that we've found a silver bullet. That prairie-ruminant system took a very long time to build up all that soil. Moreover, it's a delicately balanced system. If you graze slightly too little or too much (more likely) you end up with a net loss of soil. As soon as you till the soil, erosion and organic "burn-off" ramp up, and those soil reserves begin to disappear.

I do believe that one can build soil in a sustainable way (ie. not by importing feed, minerals, or chemicals). Infact, that's my goal on my (future) farm, but I don't believe for a minute that its going to be easy...or all that profitable. Lets hope I'm wrong.

The prescribed burns seems bunk to me. Organic matter is key to building soil. You don't build up soil organic matter by burning up the soul source of  organic matter. There might be something there, but I don't see it.

The burns kept trees from taking over.    

I do believe that one can build soil in a sustainable way (ie. not by importing feed, minerals, or chemicals). Infact, that's my goal on my (future) farm, but I don't believe for a minute that its going to be easy...or all that profitable. Lets hope I'm wrong.

It can be done.   The works of Albert Howard, and the Rodale institute can give you pointers.    Don't forget the rock dust.  (you can make the rock dust yourself BTW)

It'll take years, and mostlikely someone will buy your land in the future and 'suck' all the soil value back outta it, but hey, you'll be dead.

"The burns kept trees from taking over."

No they didn't. I've addressed this misconception in a comment below.

You've outlined much of the reading that has lead me to sustainable farming. Anybody else who would like to start, or transition, to sustainable farming would be well-advised to check out some of this material. ATTRA ( is also a good source of information.

People might like to read up on slash-and-burn farming. People in the Amazon Basin have been practicing this method for thousands of years. It's a quick way to clear a field and returns nutrients from the plant matter faster than if left to rot naturally.

The problem? Nutrients in tropical soils are scarce. The input from burning doesn't last long and the farmer must clear another section of forest (every three years or so if I remember my class notes correctly). Since the forest takes longer to recover than three years, each farmer needs a significant amount of fallow land. The method still works well as long as population density is very low and the farmer is willing to sustain back-breaking amounts of labour.

I think it's accepted that Native Americans burned the plains, which prevented tree encroachment and recycled nutrients into the soil. If you go into a prescribed burn area a year or two following a burn, the growth is incredibly lush. But the burn was not every year, and much organic matter produced by plants is grown within the soil, not on top, as roots, tubers, rhizomes, etc., and obviously remains there after a burn. Legumes fix nitrogen in nodules on the roots, and after tops are removed, the n-fixing roots/nodules remain.

I greatly appreciate the post. I have an MS in Plant Science and have been baffled by the claims made by switchgrass adherents.  

"I think it's accepted that Native Americans burned the plains, which prevented tree encroachment and recycled nutrients into the soil."

My understanding is that this is not the case. A dozen years ago, I made a similar statement in an ecology class and the professor thought that the issue was important enough to ignore his planned material and spent half-an-hour raking me over the coals. The natives did burns, but their population was too small to have much of an impact. Lightning was by far the bigger contributer, but even so, burns aren't a long-term advantage. You would have seen a similar impact after grazing by sheep or goats as you did after the prescribed burn. In the long-term grazing is the better option.

Infact, ruminants and climate are what made the natural prairies. Lack of water favours grasses over trees. It's only in artificial prairies claimed from forest (ie. my farm) where one has to make an effort to keep the trees from taking the land back. But this effort is better made with livestock or a "brush-hog" than with fire. Rather than recycling nutrients into the soil, burning gassifies most of the nitrogen and potassium that would otherwise be incorporated into the soil. Enlightened farmers don't burn anything that they don't have to.

Here's the first link that "burning organic matter fertility" yielded on Google:

The right type of burn may be able to build up your soil:
That was an interesting article.

Basically, rather than burning, they are advocating charring crop residues which leaves much (well, half) of the carbon. My gut tells me (warning: WAG ahead) that it would probably be more effective, and safer (less risk of starting an uncontrolled fire), to just leave the residue in place or let livestock clean it up. Letting a ruminant get much of it's diet from crop residue seems most attractive to me, but letting residue remain as a moisture conserving mulch makes a lot of sense too.

It would be interesting to see the approach in the article compared to the alternatives. Rather than just holding up an orange and saying, "Lood at this nice orange," we could compare it to the other oranges and apples.

Prairies burn in a "non-efficient" way - they leave a lot of unburned biomass in the form of charcoal.  And charcoal holds onto soil nutrients like crazy - that's why it is so often used as a filter.  Thus although burning the prairies does fritter away some organic matter, it makes the remaining soil build up other essential nutrients.
So it looks like the claimed EROEI of 7+ is bogus. Reading this I feel like a kid who just seen Santa Claus remove his fake whiskers. Surely all is not lost with biofuels since some arguments remain valid, except perhaps the big one of significant petroleum replacement.  However I do note the bulk transport problem is being addressed by the method of localised pyrolysis plants
The liquid goo can be used locally or FT refined at a central location into traditional fuels, perhaps not so much ethanol.

Did I read an earlier item that said oil per head would decline 25% in a decade? Quick fixes are running out.

Nice work Kyle.

gimme an 'H'
gimme an  'E'
gimme a  'M'
gimme a  'P'

Oh My God!!!! They killed Weed! You bastards!
Hemp is at a small advantage when it come to inputs. This is largely because it isn't widely grown, so it doesn't experience much pressure from pests, and it is an unimproved plant. Since agribusiness hasn't made much of an effort to "improve" hemp (which goes hand-in-hand with making it dependant on farm-inputs which agribusiness happens to sell), it still has a great deal of genetic diversity, and therefore, adaptability.

But I wouldn't get too excited. When we're talking hemp, we're not talking about an order of magnitude of improvement. The underlying problem, that Kyle brings up, is that you can't get around the soil balance sheet. If you take something away from the soil (ie. grow and harvest a crop) and you don't put it back, you're going to pay the price in following seasons. And the effects are cumulative...

One way around this problem is large-scale composting of human bodily waste. It's a huge improvement over conventional waste treatment, but it's no panacea either. For example, that's a heck of a lot of material to move back to the fields.

There are problems with animal wastes as fertilizer as well.  I know of a situation where the city of San Antonio Texas was offering dried solids from their waste treatment plants.  It was low in N, high in P,K but also high in heavy metals.

This was being applied to range land as fertilizer for perennial grass pasture.  The owners had to be careful not to apply too much or too often or they ended up with heavy metals in the forage and then into the cattle.

As many people at this site say.  There are no easy answers to our energy and farming issues.  I love this site because so many knowledgeable people raise and debate issues scientifically.  There is an incredible amount of brain power being brought to bear here on solving some world (literally) shattering problems.  

And while I'm on my high horse don't underestimate the intelligence of the farming community.  They have been trying alternative crops and practices for ages and are every bit as sharp, intellectually, as many posters at this site.  They farm the way they do, often, because of the business climate they must operate in, not because it is always what they want to do.  

The excess P and K in animal wastes are a real problem. You're right that recycling animal waste is not a silver bullet. Capturing urine helps boost nitrogen, but it's not enough to offset P and K. Heavy metals should not be at worrying levels in any animal (including human) bodily waste. Sequestering human bodily waste from all the other sorts of the waste San Antonia creates would make for a much more benign and farm friendly product. But the point was really that better nutrient cycling is needed for any type (food or energy) of sustainable farming to take place.

The farm that I've been following closely (the Nordells, in Small Farm Journal), has been using animal waste as fertilizer. In order to deal with the uneven nutrient additions they also integrate legumes into the crop rotation. The approach looks to be working.

You're thinking on the farming community parallels my own. I sincerely hope that I didn't come off as insulting farmers. The same hope doesn't necessarily apply to agri-business.

I got in a discussion about switchgrass and corn for pellet stoves and started to wonder about legumes.  I'm only an occasional gardener ... but I did a web search and came up with "field peas" as something price competitive with corn.

The amusing thing is, surfing now, I see that field pea prices are being elevated by corn/ethanol production:

A snippet there is:

"Field peas looked to be a promising alternative. The energy and protein content of field peas lies between corn and soybeans."

The soil degradation / nutrient removal issue has always been one that worries me when it comes to biofuels.

Care will need to be taken to "close the loop" by sending cellulose splitting process sludge and yeast-derived fertiliser back to where the fuel crops are grown.

Stuart.  Many thanks for all of your very  good works!  Just a question-  In this sort of analysis, why does the community all assume that the biomass has to be turned into ethanol?  How about just using it as is, or pellitized, to run things.  I of course am prejudiced in favor of stirlings, since that is where I have spent my time, but they aren't the only way to turn solid fuels into electricity, motion, plowed fields, heated  and cooled buildings and so on.

Of course it hasn't been done yet, but we talk on and on about many things that haven't been done yet, like cellulose to ethanol. Hasn't been done yet is not necessarily can't or shouldn't be done.

 It is very easy for me to see my tractor running around on pellets of switchgrass- without the assistance of any hallucinogens for either of us.

I of course am prejudiced in favor of stirlings, since that is where I have spent my time,

Great!   Now, show us some shipping mass produced stirling engines.

Solo and SMC are close to a manufactored heliostat.   Kamen likes showing off his, but can't seem to ship.  Omcharon claimed to  have a $89 1hp nitrogen charged design....yet nothing shipping.   Tamin is used in a CHP, and whispergen has went from $30,000 USD to $12000 to $5,000 for their stirling system.

Yet with all this 'hope' - no shpping mass produced stirling, unless you know something I do not.

You pays your money and you takes your choice.  If we had started stirling and steam cars in the 80's like we should have it would be moot.  But the whole point of ethanol, biodiesel, etc. is to make liquid fuels so that nobody has to change their car or truck investment.  If you go solid, you save a lot of processing money, but someone has to come up with the trillions of dollars to convert the existing transport.
This is a guest post by Kyle - no credit to me (except for being smart enough to accept it :-)
Stuart, you have earned more credit than you get, so a little misdirected credit fired off in your direction seems still appropriate. And thanks to Kyle too!

As for where the stirlings are, well, that's a hard one. Always I get the same answer--NOT ECONOMIC.  (Right- as long as you don't count the costs of everything else!).  And some other doozies, like for example  "  It pumps water burning straw and weeds? so what, water pumping is woman's work; what do I care?".  And "Generates electricity with wood or solar?  Hey, if it isn't used in the USA, it must not be first class. Don't try to pass second rate technology  off on me!".

Until recently, a general rule seemed to hold- people who want stirlings have no money, and people who have money don't want stirlings.  But now with the intense interest from NASA and the military, things might perk up in more mundane applications inside the world we ordinary mortals live in.  Like maybe tractors. Yes!  After all, that would not even take a small fraction of one Pop ($40E9, the amount US spends on soda pop/year)

Oops! Forgot to say you can buy a very nice little food cooler that does a super job of cooling/freezing food with very very little electricity.  It uses a stirling free piston gadget that is identical to the one NASA  loves except it is a cooler and is relatively speaking dirt cheap. I think Coleman sells them.  Commercial! Shipped!  Freezes Beer! Enjoy!
The soil degradation / nutrient removal issue has always been one that worries me when it comes to biofuels.

This is why seed-based biofuels is a better plan, until bio-reactors can be shrunk down in size and cost to accept input from the land where the crop is being generated, thus the crop manager has his/her own enlightned best interest to place the waste material back on the land.

Crops that have deep roots (alfpha can go down 7+ feet, and trees can run deep) will help pull elements from the subsoil and transport it to the topsoil.   The closing of the loop (management of the wastes of the animals who use the plants) still needs to be done.

Switchgrass is a perennial grass. When harvested for energy, the carbohydrates in the stem are harvested and turned into ethanol, methanol, F-T liguids or whatever. The grass is still alive and regrows the next spring. Once established, the planting, weeding and feeding parts of field corn cultivation are not needed for switchgrass. This is at the heart of the positive energy balance for switchgrass.
Thanks a lot Kyle. Another myth we can trash away.
Alright. F-This, OK. I will go along with the Kyle thing for only so long. Admit to me the story behind Kyle now and I won't expose anything. Otherwise you will have to kill me. That is not gonna be real easy. We will talk about cost benefit analysis tomorrow. (Make sure you feed fatboy) -cuz he shure cunt shovel. You belgians are so frunny. Fucking Spa - 'Spa' Hahahaha. Isn;t dat a bus station.
Beyond liking motorsports what else are you trying to say?
why is biomass a better alternative in Brasil? or is that a waste as  well?

does the sugar crop in Brasil require large fossil fuel inputs and suffer from the same problems as corn and switchgrass?


Would sugar beets work in the US?  We can certainly grow them here.
would sugar beets work


You still need energy input to:

  1. Process the beets to extract the sugar.   Chopping them up fine seems to work.
  2. Energy to sterelize the water/beet/sugar mixture.   A radioactive source (using waste radioactive material) would work, but so does heating the mixture to 'knock out' or at least repress the yeasts competion
  3. Heat energy to seperate the alcohol from the fermented beets.

After step 1, you may be able to feed pigs the 'beet sqeezings', but squeezing sugar drippin's outta beets will require work.   Imagine such a system, now try scaling it up.   Can you see how hard that is gonna be?

To make grass work with the least energy input - grow a fungus that converts complex carbs into sugar.  Such a process exists - Sake.   Or make some other burn'n fluid - say Butyonal.

If you go back to the history of WHY we do what we've done, farm animals represent an energy store and element concentrator that humans didn't need to work as hard at to accomplish.  
They take low grade feedstock (grass) convert them into a storable foodsource (their bodies) and process/concentrate valuable things like nitrogen, potasium, phopherous in their fecal/urine which humans can place in their veggie gardens to increase yeild.

Conversion of food into ethyl alcohol is a way to STORE the solar energy in a stable and eaiser form,  No mice will eat it, no fungus will rot it, and the oils in the seed can't cxause it to 'go bad' anymore.   Not to mention, humans seem to be willing to exchange goods/services for ethyl alcohol so they can achieve an altered state of mind/being.

We grow sugar cane in South Louisiana, and once did in Hawaii and South Central Florida.  Lower energy inputs and higehr yield than sugar beets.
1. Brazilians are supergeniuses, and U.S. citizens are chimps, and that is why ethanol works Brazil.
2. Because there is more sun in Brazil, that changes everything. Didn't you know that there is less sun in temperate climates than in Brazil? Shouldn't that end the discussion?
3. Brazilians are so stupid they are destroying their whole country in five years by growing such huge amounts of cane; that is the obvious the explanation.
4. The laws of physics and chemistry are different in Brazil and other places; obviously that would account for the success in ethanol in Brazil.
5. Switchgrass was advocated by Bush and is therefore stupid. Only people who like Bush advocate switchgrass, and therefore they are stupid or corrupt or both.
6. Because switchgrass is not the total answer to all of our energy needs, it is obviously useless and a totally bad idea.
7. I am shocked, SHOCKED to find that switchgrass yields can be improved with fertilizer and water.

And from these seven indisputable facts, what can we conclude?

From this seven indisputable facts we can conclude that Don Sailorman has utilised ethyl alcohol were it is supposed to be utilised for, as he failed to mention that ethanol works in Brasil because they make it from sugarcane which has a very high sugar cut. Hence the name sugarcane and hence the better EROEI.
If it isn't happy talk about a nuke plant or how women should be hav'n kids or how he's studied human behaviour, he's not a  happy Sailorman.   He's just being cranky.
Even if we could grow sugarcane, I don't think we could scale it up to the level needed.

Brazil has some advantages.  Such as cheap labor - which is only an advantage if you're not one of the laborers.

They also built much of their infrastructure when oil was cheap.  The government provided billions of dollars to build the ethanol plants, etc.  The cost would be a lot higher if the producers had to pay for it themselves.  

As far as higher plant productivity goes I wonder how bamboo would do. Not nearly as easy to process as sugarcane but copicing it could be very productive. Maybe not for N.America but places like the Philippines could do well (or do they just go straight to the sugarcane?)
>ethanol works in Brasil because they make it from sugarcane which has a very high sugar cut

And because Brazil has a large amount of undeveloped land suitable for slash and burn farming. Eventually all of the undeveloped land will be consumed, leaving no more land to crop sugar cane without fertilizer inputs. When that happens the ERORI goes negative. Smart! Whats Plan B?

And as they deplete their soil, they cut done more rainforests to get more.
The long term viability of the Brasilian soils remains to be seen.  Meanwhile the scheme "works" for Brazil because only a small fraction of their population own motor vehicles.  Perhaps that's the Bushco plan for the USA?  The image of (hungry) slaves toiling to feed the warlord's Hummer is apt.   The alternative vision is well-fed citizens equitably working to feed themselves (perhaps including some biofuel for farm machines and for public transport).  The personal automobile is dead.
The US will never have enough ethanol/biodiesel to replace 10% of our current consumption of liquid fuels. This is based on this web site.
During 2002 the US used 15 Million barrels of liquid fuel/day. Gas, Distillate, Jet fuel, Kerosene.
During 2002 Brazil used 1 million barrels of liquid fuel/day. Gas, Distillate, Jet fuel, Kerosene.
The Other category includes asphalt, coke, aviation gasoline, lubricants, naphthas, paraffin wax, petrochemical feedstocks, unfinished oils, white spirits, and blending components. Of these Brazil used .686 Mb/day and The US 2.479 Mb/day. I suspect the ethanol share of U.S. 2.479 Mb/day is less than 10%. If we give Brazil .5 Mb/d of this .686 Mb/day it equals 33% of Brazil's liquid fuels use (1 mbd+.5 mbd), but the same amount .5 Mb/d is only 3.3% of US liquid fuels use. Brazil is 90% the size of the US,  with few mountains and little current desert. There are no other countries with large populations that can come close to this, without drastically cutting their food supply or destroying their rain forests. Also fertilizer prices will be reducing future worldwide crop yields year after year.  BTW 10% of 21 mbd is 32 billion gallons of ethanol + biodiesel annually. We are currently projecting 10 billion gallons in 10 years annually.
Here's a tinyurl link to an opinion piece by George Monbiot
I realize that vegetable oils and ETOH are different substances, but the article points out shortcomings with the veg oil and biodiesel approach too.

And here's the first bits of it:
Worse Than Fossil Fuel
Filed under:

    * climate change
    * oil

Biodiesel enthusiasts have accidentally invented the most carbon-intensive fuel on earth

By George Monbiot. Published in the Guardian 6th December 2005

Over the past two years I have made an uncomfortable discovery. Like most environmentalists, I have been as blind to the constraints affecting our energy supply as my opponents have been to climate change. I now realise that I have entertained a belief in magic.
The last time I drew attention to the hazards of making diesel fuel from vegetable oils, I received as much abuse as I have ever been sent by the supporters of the Iraq war. The biodiesel missionaries, I discovered, are as vociferous in their denial as the executives of Exxon. I am now prepared to admit that my previous column was wrong. But they're not going to like it. I was wrong because I underestimated the fuel's destructive impact.

Here's a tinyurl link to an opinion piece by George Monbiot
I realize that vegetable oils and ETOH are different substances, but the article points out shortcomings with the veg oil and biodiesel approach too.

And here's the first bits of it:
Worse Than Fossil Fuel
Filed under:
    * climate change
    * oil
Biodiesel enthusiasts have accidentally invented the most carbon-intensive fuel on earth
By George Monbiot. Published in the Guardian 6th December 2005

Over the past two years I have made an uncomfortable discovery. Like most environmentalists, I have been as blind to the constraints affecting our energy supply as my opponents have been to climate change. I now realise that I have entertained a belief in magic.
The last time I drew attention to the hazards of making diesel fuel from vegetable oils, I received as much abuse as I have ever been sent by the supporters of the Iraq war. The biodiesel missionaries, I discovered, are as vociferous in their denial as the executives of Exxon. I am now prepared to admit that my previous column was wrong. But they're not going to like it. I was wrong because I underestimated the fuel's destructive impact.

As someone still actively engaged in farming, some points should be clarified, although overall this is a very well-balanced reasonable view I believe.  Bottom line, significant energy production from switch grass is a long, long ways away.

You quote a number of 140 bushel per acre yield and 2.5 gallons per bushel ethanol.  There is little doubt that barring massive climate change from global warming, we are looking at a 160 bpa and 3 gallon ethanol yield in just a couple of years time.. The most efficent plants and corn producers are probably already there.  Those numbers really help the "net energy" case for ethanol.

Switchgrass needing fertilizer -- makes logical sense, however it is probably lower than corn -- average N rates on corn is 150#/acre, where you quoted 100#/N to grow high-yield switchgrass

The transportation issue -- WHY do we assume that the mammoth oil refineries of the past are the most efficent model for the future.  I don't know what the barrels-per-day  is, but an ethanol plant of 100 million gallon may be optimal size to maximize transport efficencies of the low value feedstock (corn).  For switchgrass, the number may be even less, even 5-10 million gallon and have plants dotting the rural landscape every few miles in high production areas  may be best economic model under high transportation costs.

All in all, excellent analysis

SS: I know this is off topic, however with the low EROIE of all renewable energy sources I feel it is appropriate. You or someone may have posted on this subject but I missed it. I suspect there is another effect controlling total liquid fuel prices besides depletion and demand, and that is the continuous decline in EROIE of total liquid fuels. If EROIE in the 60's was 25 to 1, and today it is 20 to 1, in 5 years it may be 15 to 1. That is a 1.66% loss of actual useful energy during the past 5 years, however if EROIE is currently 15 to 1 and drops to 10 to 1 in 5 years that is a loss of 3.33% or about 3 Million b/d. My guess is that ethanol is much less than 2, tar sands about 3, deep offshore 5, and much current production less than 10. Each year much more energy is consumed in liquid fuel production, leaving less for all other uses. This energy consumption doesn't show up in the 85 Mb/d world production stats. So what is the current TLF-LF used for their production equal to, and what will they be in 5 and 10 years? I know this is a Grey area, but it magnifies depletion, and depletion magnifies this problem.
It is interesting that you bring this up. If one were to take Stuart's graph of oil production to date, and subtract the amount of energy which is expended simply in producing that oil, I think it would become very clear we are already on the downslope.

Stuart - you do great work, and I appreciate it. Now, what do you think about applying a scaling factor to your graph?

Thank you very much for this enlightening post. There is a lot of quantitative data to be digested but it clearly is a milestone in analysing the biomass myth.

I am glad you said fertilizers are necessary for growing grass, because I thought I was an ecoterrorist when I ordered some fertilizer for my hay grass which I harvest twice a year for my horses and the cows of my neighbour.

We now only need a real substantiated article on algae (but some on TOD have already adressed this subject in their posts), and then we can begin with planning for the future.

We now only need a real substantiated article on algae

Algae needs tanks, algae needs food, algae need land to gather photons, and algae needs to be warm.   If you are making oil, you need to de-water that oil.

If you look at any of the articles on Algae where they project profitability - they show the algae as the way to re-fix CO2 from a smokestack.    

A workable algae plan MIGHT be using sewage to feed the algae, (We'll ignore the toxins in sewage) and glass over the top of the tanks, runways to raise the temprature, while collecting the condensation as a way to 'purify' the water.  The US government paid for some  research back in the 20th century, but the biggest stumbling blocks will be allocation of resources to set aside land and to make the algae grow tanks.

(If one is looking for a sewage->liquid fuel plan, growing cattails and harvesting 1/3 of the roots every 3 years for the starchy roots and making ethyl alcohol is a known, workable plan.   Just need to solve the toxic metals and other nasty chemicals people throw in their waste stream.)

Another hidden problem with algae from sewage:

The largest sewage systems available are near or in urban areas. Algae using sunlight will require large areas of land. How much is available and what will it cost?

Trying to replace gasoline with biofuel masks the fact that all life should be organised in a totally different way instead of trynig to keep the "party" going. This post says that again. Maybe people will also be happier withy new life-styles and will have less need for antidepresive medication.

I'm sure Don Sailorman will agree with me that this is where the ethanol process should end: "The resulting liquid must then be purified to increase the alcohol concentration", so that we can have a real party still.

I'd like to quote Kunstler to provoke thoughts:
April 11, 2005
      Over in Vermont last week, I ran into a gang of biodiesel enthusiasts. Biodiesel is oil extracted from vegetable crops that can be used to run engines and do other things as a replacement for petroleum. They were earnest, forward-looking guys who would like to do some good for their country. But their expectations struck me as fairly crazy, and in a way typical of the bad thinking at all levels of our society these days.
     For instance, I asked if it had ever occurred to them that bio-diesel crops would have to compete for farmland that would be needed otherwise to grow feed crops for working animals. No, it hadn't. (And it seemed like a far-out suggestion to them.) Their expectation seemed to be that the future would run a lot like the present, that bio-diesel was just another ingenius, innovative, high-tech module that we can "drop into" our existing system in place of the previous, obsolete module of regular oil.

Legend 1 is at the heart of a bigger question that I've been pondering:

Are Biofuels "sustainable"?

It would seem to me that any scheme that involves removing plant material for processing or other use away from where it is grown would eventually deplete the soil of nutrients. I can see biofuels working on a local level, perhaps, where the unusable plant matter gets put back into the soil. But on a larger scale, I just don't see it working for very long.

is that not the same for food or do we defecate the nutrients back?

is the transport of nutrients in and out of the field impossible and maintain a positive EROREI?


We are currently replacing the nutrients removed when food is grown with petroleum-derived fertilizers.

Farmers are being hit hard by the high prices of fuel, fertlizer, and pesticides - caused by the high cost of oil.  Frankly, I'm worried about how we'll continue to feed everyone post-peak, let alone grow biofuel.

Farmers of biofuel stock and food are likely to shift to less fertilizer intensive methods as costs rise. To me that's the big rub. Less fertilizer usually means longer fallow periods and so less overall productivity per unit area. People who say that there is enough fertile land for both are, I suspect, ignoring this. (on the bright side it will likely mean less nitrogen poisoning of our waterways.)

Once water shortages in the Mid-West are factored in the useable land base doesn't look nearly so big. Toss in the amount of water needed for ethanol production and the water shortages get even worse....

It all seems like a vicious spiral. Hope I'm wrong.

Thanks for posting this - it essentially confirms what I suspected.  But here is another take:

Once upon a time we farmed with horses. If I recall correctly (no I was not around!), it took about an acre to grow food for each horse (I'll have to see if I can verify that figure).  Of course, we had a hell of a lot less non-farming people to feed then too.  However, at even 350 gallons per acre, one could run a fair amount of equipment for each acre.  Therefore, while I do not believe Biomass Ethanol or Biodiesel can supply the fuel our nation consumes for transportation, etc, it sounds like it could be sustainable for agricultural purposes only - if each farm set aside a certain amount of acreage for growing fuel for the equipment, especially if we can increase the efficiency of the farming equipment in addition.

My father, who farmed all of his life including through the transition from horse power to tractor power (the harnesses are still where they were hung the last day they were used) observed that a horse ate about a fourth of what their draft produced.
Well, that's more then I had remembered I guess, but it should only make it more viable to support raising the fuel needed for farming (only) from the agricultural process.  Of course, tractors do not produce fertilizer.
Thanks Stuart-

For me this was a very timely post, as I have begun to wonder more and more whether this 'miracle plant' was for real. I suspected it was too good to be true to expect one to be able to repeatedly harvest switchgrass without the use of large amounts of fertilizer.

From my admittedly brief exposure to fermentation and enzymatic processes, I also had some of the same concerns voiced in this thread by pomona96 regarding the difficulties in getting such tricky processes to work the way you want them to. Microorganisms can be very temperamental.

In the environmental field someone (usually an academic doing lab-scale research) is always finding a new bug that can degrade some substance that heretofore was considered non-biodegradable. But very few of these 'breaktrhoughs' ever see the light of day in the form of an actual working process.

I'd be curious to know whether the ethanol-from-switchgrass process has actually been tried on the scale of a demonstration project or is still in the lab stage.

Back to corn. In my view, the only legitimate use of ethanol from corn is the making of fine bourbon.

Good post.  My only comment from the non-agricultural side would be that "perfect conversion" and "bioreactor" are two words that chemical engineers almost never use in the same paragraph.

Excellent post.  As I have indicated in other posts,here and here inputs to farming and yield and the profitability of crops are not as simple as most people think.

I think many of us in farm states are saying the same thing:


What you can do is make some liquid fuels out of a different feedstock than petroleum or coal.  This is a significant statement in itself.  Renewable liquid fuels are a step in the right direction.  There is still great uncertainty about what feedstock is best.  What enzymes are on the horizon.  And as pointed out what size plant is optimal.  

The other major question is what happens when farmer coops (if allowed to exist) produce sufficient biodiesel and ethanol from their fields to run their farming operations?  At that point the only imported energy is fertilizer so how can that be addressed?  The economics of this closed loop farming approach are far from worked out or even calculateable at this time.

Really, what we all need to do now is get our liquid fuels demand down into the range where renewable fuels can deliver most of the future needed supply.  That is a major change in usage and I don't see it happening (based on current leadership and incentives) for years unless we have a crisis.

Finally, a last comment on fertilizers.  I never worry too much about Nitrogen.  It can get replenished via thunderstorm rains and nitrogen fixing bacteria, which convert atmospheric nitrogen to chemical compounds.  And nitrogen is often water soluble so even applied fertilizer migrates quickly through the soil profile (to the point of getting into groundwater).  My worry is always Phosphorous (P) and potassium (K) levels.  Both of these compounds migrate slowly through the soil profile.  Particularly P levels.  Once depleted they take a very long time to replace with surface applied fertilizers.  This is one problem with woody perennial plants.  They take up and require a lot of P & K.  If all that is removed via biomass.  There will be major fertility problems down the road, that can't be easily remediated.

Have you had any success with folar feeding the Phosphorous?
Really, what we all need to do now is get our liquid fuels demand down into the range where renewable fuels can deliver most of the future needed supply.  That is a major change in usage and I don't see it happening (based on current leadership and incentives) for years unless we have a crisis.

I am afraid that it will only be when the price of gasoline gets high enough that people will get serious about reducing liquid fuel demand.  There will be a sort of game of economic chicken - see who blinks first - who cuts back their usage first.

Over the past two years or so, we have had 30% increases in crude prices.  No telling what will happen this year, of course.  What we have had so far is enough to get the general populace to start to pay attention - they still haven't a clue what to do about it though.  There are lots of people giving the public platitudes about how life will go on as usual with minor changes here or there.  Just hold tight and buy another SUV...

I would imagine that the P and K and other trace nutrients and minierals could be returned to the fields (incurring another transport hit).  It would seem that if you could purify the ethanol enough, everything else could be put back, including all the extra yeast corpses.
(not sure how much you would have to fight solubility to get everything back out).


(not sure how much you would have to fight solubility to get everything back out).

No solubility as you are using distillation to 'get the alcohol' out.   The P and K would be left in the mash.

A low pressure stipping run (which can use sunshine to power), and a temprature controlled run with packing in the colum gets ya 190+ proof.

Hey I've got an idea. Instead of worrying about EROEI for corn vs. switchgrass, instead of having to choose between food and ethanol, instead of worrying about rapidly depleting the topsoil, instead of worrying about rapidly depleting aquifers to grow crops for ethanol, instead of endlessly fretting about the we will replace oil as a transport fuel post-peak, how about we figure out how to go without cars.
Re:  How to live without cars.  Following is the final portion of an article that Khebab and I coauthored:

Proposal: Replace the Payroll Tax with an Energy Tax
Some have argued that the suburbs are dead; the suburbanites just don't know it yet. It's probably more accurate to say that the suburban commutes are dead; the suburban commuters just don't know it yet.

We recommend that the United States abolish the payroll tax (Social Security + Medicare tax) and replace it with either a liquid transportation (petroleum) fuel tax or an overall (nonrenewable) energy tax.

The majority of American households pay more in the payroll tax than in the income tax. This would be a tax cut for most households and it would a massive tax increase on those who are profligate in their use of energy. No matter where one lives, the cost of goods would go up, but if you lived close to where you work, your effective tax rate would go down. Of course, those who persisted in long commutes would pay the price.

There would of course be very powerful forces opposed to this idea--the housing industry; auto industry; airlines; trucking--the list goes on. But the fates of these industries are sealed. It's not a question of if they will contract; it's just a question of when. The sooner it happens, and the sooner these industries start emphasizing energy efficiency, the better off we all will be.

A high gasoline tax does not necessarily equate to a lower standard of living. Norway, with the highest gasoline tax in the world, has the highest standard of living in the world, perhaps partly because their car ownership per 1,000 people is about half of what it is in the US.

There would be some other benefits. As we turned to walking, biking and mass transit, our health would improve. There is pretty much a linear correlation between obesity rates and total miles driven (here in the US, we are the world champs in both categories). In addition, since this is in effect a consumption tax, everyone who now avoids paying Social Security taxes would no longer be able to avoid paying them.

However, the primary reason for implementing the proposal is that it would cause an immediate and massive across the board push for greater energy efficiency and it would unleash enormous free market forces against profligate energy use.

We all just need to start riding motorcycles. Let's see, now instead of a hummer which gets 12mpg (maybe), the single person commuting gets 50mpg. Hmmmm, that's over a four fold increase. Forget replacing oil with ethanol, start replacing SUV's with motorcycles.

Also, you could sub-divide traffic lanes so a 4 lane highway would now be 8 lanes....

A brighter idea would be to have 8 people in the hummer. That would improver it's "miles-per-gallon" x person ratio from 12 mpg to 96 mpg per person. Maybe a little less (75?) because of the extra weight of all the people.

No need for each of the 8 people to go out and buy a motorbike.



Then you might as well use a train or a bus.
The problem with these are that they are not point A point B transportation systems (neither are Airplanes or ships) like normal cares and bikes are. You always have to get to the station(stop) or get away from the station to your destination...
Thanks for this, Kyle.  Several people have noted in other threads that the less you know about farming, the more enthusiastic you are about biodiesel, but this really lays it on the line.  And most of what you wrote applies to other biofuel crops as well (hemp, algae, etc.).  

Hawai`i is building an ethanol plant.  To fuel it, they will be importing molasses.  They hope to one day grow sweet sorghum for ethanol (yes, even though they do grow sugar cane in Hawai`i).  

It's all possible due to "hefty state and federal tax breaks."

If you want more evidence that Amory Lovins is living in a fantasy land, this is it.  Jim Kunstler's point, that if you arrange your life so that don't need a car, makes more sense than ever.  
Great article, and best title ever.

FWIW, I've been cautious about switchgrass ethanol, but I do like switchgrass pellets as a heating alternative.  To the extent that they displace oil and natural gas for that purpose, it's all good.

You say "we are talking something in the $60-70/ton range delivered to the bio-reactor," well, deliver them at that price to the pelletizer and I think there is some room for profit.

If I recall correctly wood pellets, and corn for pellet stoves were selling at around $5 for a 40 pound bag this past winter.

I have purchased corn this winter from $ 92.87 to $ 101.80 per ton.  I purchased it 1200 pounds at a time. I purchased it from a local grain elevator, and it is all local corn.  I live in Michigan.  I burn it instead of natural gas.

That is $ 1.86 to $ 2.04 per 40 pounds.


Man, there isn't much room there then even for pellets.  Gotta love those subsidies ... as we burn food.
I have considered this, and decided that I have to get over the whole "burn food" thing.  Every biofuel is a food equivalent, either literally or because it supplants a food crop.  Palm oil can go into snack foods or power diesels.  Corn can make tortilla chips, and a vast range of other things, or can be blended for "gasohol" (to use the old word).

So sure, if corn is a super-productive crop, that's something to be happy about.

In our area, the corn that is used in corn stoves would have been used for food for animals but not for humans.

I'm a vegetarian, so just imagine how much corn I am "saving" by not eating beef.  :-)

Here's some backstory on pellet prices for those interested:

I have to admit, reading David Blume's talk from the first Community Solution conference makes me less pessimistic. Anyone care to counter?
Plants go ahead and take CO2 from the air. They add it to water by way of sunlight and photosynthesis, and you get a carbohydrate, carbons. So carbon dioxide plus hydrogen plus water, nothing from the soil. Ends up in alcohol. This is really quite interesting. (Emphasis added.)
Might permaculture ethanol work on a local/regional scale if the dry distiller grains are returned to the soil?

this is broadly my thinking..the crux of the problem to my mind is separating the harvested sunshine energy from the nutrient transport and maintain a positive EROEI

to make it work you need to break it down in sections and see why it doesn't work then see if these issues can be addressed

Might permaculture ethanol work on a local/regional scale if the dry distiller grains are returned to the soil?

Work to replace the energy level of what is being used today?   Hell no.  

But a conversion of excessive and damanged grain/old grain stock with a return of the leftovers of mashing, leavlings and leftover wash will stem the loss of elements from the land.   The problem is most of the 'plans' point to some large agra-business plan - and no where do the plan pimpers show their work on getting biomass to the factory, or the post-process material back to the land.  

(the 5 ton of spent brewing grain in my backyard garden yields  the largest nightcrawlers I've ever seen.   When the plant tap roots hit the buried grain, they get darker green and the taste improves.)

Well, it's entirely incorrect to state that in the photosythesis process nothing is taken from the soil. All green plants contain varying amounts of nitrogen, phosphorus, potassium, and lesser amount of other inorganic elements. These are mostly taken up from the soil via the plant's root system.

As to the subject of returning the distillers grain to the soil, if I am not mistaken, some of the more favorable EROEIs claimed for ethanol-from-corn take a credit for the distillers grain being used as animal feed. I believe they do this by subtracting from the total energy inputs the energy that WOULD HAVE been expended in producing an equivalent amount of animal feed. So, if the distillers grain goes back to the soil instead of being used for animal feed, that energy credit disappears and the EROEI shinks down closer to unity.

I'm not 100% sure of this, but I think that's how distillers grain enters into some of the EROEI calculation.

The point is that nothing from the soil necessarily ends up in the alcohol, so in theory, the nutrient loop can be closed (not that I trust Cargill/ADM/etc to do so -- I'm thinking smaller than that).

So no, I don't pretend that this can replace our current system, but it gets closer to answering what I think is the most important question regarding biofuels: are horses more efficient?

are horses more efficient?

Not at all on a photon -> work process.   Modern PV is very good, so are helostats.   A Wind machine lets you take photons from over there and extract the work where you are.    

But you'll have to "pony up" for a rather expensive PV array to drive a 40 HP electric tractor.   Upside?   There is a market for your 'waste' PV generated power, if you are grid connected.

The above screens shows that 12.3% of agricultural land would be required to replace 50% of US gasoline. That is, if switchgrass has an EROEI of 4:1 and a yield of 1,150 gallons per acre (as the Globalist claims). Click on the image for more info.
You seem to be missing the point of what the post was about.  It is not about EROEI per se, but simply the cost of moving this stuff from field to bio-reactor.  For your figures above, (115 million acres) x (15 tons/acre) = 1.725 billion tons.  Multiplied by $70/ton average figure I noted, we are looking at $120 billion dollars per year, just to get that crop from field to ethanol facility.  Just to get an idea of the enormity of this figure, the ENTIRE US corn crop is about 10 billion bushels per year, which at an average cost of $2/bushel has a value of $20 billion/year.

In other words, to replace 50% of US gasoline, we will have to expand the cash crop farm economy by something like a factor of 5.  This is not going to be easy from a labor or equipment standpoint - who wants a 1 month a year job?

Also, I seriously question your 1250 gallons/acre figure.  That result is based upon one study done by Auburn, where they found 15 tons/acre in yield.  Real field results will be substantially less than that, probably by a factor of at least 2 and more likely 3.  Consider the case of alfalfa.  It is easy in the test plot with good moisture and controlled conditions to get yields of 10 tons/acre or more.  However, actual US alfalfa yields sit down there in the 3.5 tons/acre level.  The test plot is not reality - this is the lack of "farm sense" that I discuss in my opening paragraph.  Moreover, there are other inefficiencies that I didn't even discuss, as roughly 10% of the switchgrass volume will be lost in transport (try driving behind a hay wagon), and 10% will be lost in storage, further dragging down the field-to-reactor yield.  

So plugging in your numbers into the calculator, now you are talking about something on the order of 35-40% of the US agricultural land to replace that 50% of our gasoline, which moves from the convenience level to the level of requiring large-scale lifestyle changes.  Again, this is not saying that large scale switchgrass is impossible, it simply means that (1) it will be very costly, and (2) the government will have to jump in with both feet with subsidies, which I don't forsee happening on necessary scales, given other competing interests (medicare, social security, defense) that will be looking for dollars in the next few decades.    

Kyle, thanks for your comments (and for your original post). We seem to be debating the Globalist quoted figure of a 4:1 EROEI figure for switchgrass. If it does not include transportation energy to the processing center, or the energy cost of enzymes/production then it is indeed a meaningless figure. Please note that the calculator folds back the EROEI figure into the land required, ie it assumes that ethanol is used as the energy source to produce ethanol. Less land would be required if LevinK has his way and we go nuclear (or if we use any other non-biofuel source of energy)...
That's a really cool calculator. Why can't I change the ERoEI to the right value (<2)?
A limitation of the calculator is that it assumes the Globalist figures are correct :) Note that corn with an EROEI of less than 2 (ie 1.5) requires 3 times the land if corn is used as the energy input (toggle the EROEI included: dropdown from Yes to No to see this). This would be true for switchgrass too, giving 3 * 9.2% land = 27.6% @ EROEI = 1.5.

When I have time, I might modify the calculator to allow any numbers to be entered :)

Stuart, how much EROEI improvement might we see with genetically modified Corn or Soy or Rapeseed?  Might this be a useful purpose for GMO's?  Is this another urban legend?
Don't you think that all of these fuel fixes without a serious program to address fuel efficiency (with vehicles the size of ATV's or the Tango) are hopelessly irrelevant?
Thanks for all yor efforts....
Instead of the US subsidizing our hugely inefficient and unhealthy diet of meat and dairy, how about we let the free market take care of things?  Check this out:  

"It takes more land, water, and energy to produce meat than to grow vegetarian foods. It's several times more efficient to eat grains directly than to funnel them through farmed animals. According to the Audubon Society, roughly 70 percent of the grain grown and 50 percent of the water consumed in the United States are used by the meat industry. A Minority Staff of Senate Committee on Agriculture, Nutrition & Forestry report states the beef in just one Big Mac represents enough wheat to make five loaves of bread (Scientific American, 8/99)."

Just by correcting this incredible innefficiency, there would be much more plant food for both eating and creating fuel sustainably (if that's possible).  Sorry, what was I thinking!  This act might backfire because death rates from artery disease, diabetes, cancer, etc, would PLUMMET, thus increasing population... ;)    

Ok, I don't want to get into an argument but I'd like to point out a few things.

The gray-brown material in a Big Mac (or most McDonalds products for that matter) should not be considered meat.

As for the reasons for heart disease, see above, and consider that diet soda is worse for you than regular soda. Yea, America is obese, and its because the amount of energy each person consumes per day is many times the amount of energy each person exerts each day. Balance the equation, and people will be healthy again.

I believe your body evolved to run on many types of food, meat included. If you do not balance your intake accordingly (eat no meat) you will become unhealthy. In other words, we have canine teeth for a reason.

Eat a steak, it tastes SOOOOO good. I'd buy one even if it cost $40, though less frequently. (Yea, that's called elasticity of demand)

Nothing in the article you linked to suggests that humans need to eat meat in order to remain healthy. They don't. The reason we are adapted to eating a varied diet is that our ancestors couldn't count on any one thing as an exclusive food source. That doesn't mean we need to eat the whole range of things we are able to eat.
The tech lovers roll on. Let's plant thirteen percent of the US, I presume the high yielding portion as this is the only possible way to get the yields necessary without dinging the EROEI, and forget about feeding the people.

Brilliant. Cars, not food.

Lord save us from the techies. They give one with the right hand and take two with the left.

There are ethical and policy questions, but my personal breakthrough today is to separate them from which crops are more "food like" or "fuel like."

Put another way, we've heard for decades of starving countries who are forced (one way or another) to grow "cash crops" for export.  Some of those cash crops are food, some are fiber, and some might already be fuel ... but I think the ethical and policy is about who you grow for.

It is the old "cash crop" problem revisited.

And you're off again blaming "techies" (whoever they are), for pushing bio ethanol.  I've got news for you - it is not the engineers who believe that there is a technical solution to all of this, it is everyone.  Those who must implement it are far more inclined to study it, see the facts, and say "it won't work".  But those who are not technical will say "just shut up and do it - where's your can-do attitude?"  

This is a problem with SOCIETY, not a problem with engineers.  A refusal to see and understand the problems by the vast majority of the population.

So since I'm fed up with your bullshit attitude, let me ask you - what is it you do, and how are you so all knowing about what to do?  How do you propose to feed everyone?  And lastly, why is it that you think examining those things that have been proposed as solutions (as was done here) is not worthwhile - do you prefer ignorance, or are you simply so superior in intelligence that you already know all the answers?

After coming here for close to a year, the actual engineers (with some exceptions) are rather more pessimistic, especially in the engineering disciplines like chemical, civil, mechanical, etc.  As Heading Out has said on a few occasions, technology only in the lab is probably decades away from being commercial, and is usually much harder to implement than you think.  Also if you've been involved in billion dollar projects you have an idea of the time lags involved just building the things.

On the other hand, our involvement in industry makes up suspect that conservation is not going to be any picnic, either.  The easy stuff has been done, and now the response to increased fuel prices in the U.S. is to outsource.  If the U.S. absolutely has to drop its per capita fuel use by 20% in the next ten years, I suspect it's not going to be a flat 20% for everyone, but more like the bottom 3/4 of the U.S. get to use almost none while the top 1/4 get to double their use.

The problem is there is no technical solution, at least as most people would have it. That does not require any special intelligence, ad hominem attacks, or a feeling of superiority. All it takes is a simple knowledge of physics. We CANNOT support the planet's population by keeping the automobile culture going. IT IS NOT POSSIBLE. The safest, sanest way to an ecologically sound existence on this planet is to acknowledge that. In other words, quit worshipping the tech gods. And yes, all manufactured goods are tech, i.e. flint axes etc. And NO I do not propose we go back into the trees.

Cuba managed to overcome the sudden onset of Peak Oil. They planted permaculture gardens all over the place, got rid of centralized farming, rode bicycles, gave up cars, lived more frugally. What they did not do is vainly try to maintain an unmaintainable lifestyle. Of course, you could say, they had to. They had no choice. If they could have found new energy sources, they would have continued to live the vida loca. That begs the question. OIL IS FINITE. COAL IS FINITE. NATURAL GAS IS FINITE. URANIUM IS FINITE. LAND IS FINITE. WATER IS FINITE. WE CANNOT CONTINUE TO GROW.

The next part of the solution is population control. We need to give free birth control to everyone. Sex education. Free abortions. Financial incentives to not have children. Unfortunately, most of our population control will come in the form of war, famine, and disease inspired by energy shortages.

This is not hard. It really isn't.

Instead of thinking, Gee, we could develop alcohol to power my SUV so I can continue my destructive lifestyle, maybe we should think, Gee, we could try to see what is the best path to powerdown. Maybe alcohol fuels can provide some transition, but it should NOT be the goal. I say, work towards deindustrializing, depopulating, decentralizing, and detoxifying.

And yes, I will continue to point out stupid ideas such as biofuel designed to continue a disfunctional, destructive, and demented lifestyle. Stop feeling inferior, get off your mental ass and do some thinking.

Funny thing is, your tirade against techies came in a post that refutes the viability of bio ethanol, a premise that quite a few of us techies agreed with.  So what was the point of jumping in and attacking techies?  It was just another irrelevant BS attack.  Did a geek beat you up in school?  

I don't support growing alcohol to maintain our transportation system, as I don't think it's sustainable.  Why?  Because I have sufficient technical skills to understand the problems with it.  

And who the hell are you to assume I'm not already working on changing my own lifestyle - it's quite possible I'm way ahead of you in that regard.  

Powerdown is another way of saying dieoff, unless it happens over a long time span.  We cannot support the present population of the earth without continuing to require large sources of energy.  "Ttransistion" will not be short - it will take a long time to change our patterns of living as a nation, and it will require a large amount of new infrastructure.  Moving to a simpler lifestyle with a lower population can only happen gradually, or it will be a disaster.  "Powerdown" is a cop-out for those too mentally lazy to deal with the serious problems we face.  For every complicated problem, there is a simple solution - that is utterly wrong.

This is no doubt an unwelcome suggestion, but maybe some attention should be given to Jared Diamond's: THE WORST MISTAKE IN THE HISTORY OF THE HUMAN RACE. It's not just about biofuels.
That is one of my favorite Jared Diamond essays.  

However, it's a bit late, wouldn't you say?  It's agriculture that has allowed us to cram 6.5 billion people on the planet, and 300 million in this country.  What are we going to do with all the "extra" people if we give up agriculture?

Which was Cheronkov's point concerning this bio-fuel issue: cars or crops...

For me, it's hard to imagine wrecking what's left of our agricultural infrastructure to make ethanol. Soil tilth is not improved with synthetic fertilizers or mono culture. I speak not as a farmer but an organic gardener with almost 25 seasons behind me. It takes about 6 years to get things right with the soil. You have to grow a lot of microbes, establish good populations of beneficial insects, attract bats, brush birds, a snake or two... It's a bit like Noah's Ark out there once you leave the rototiller in the shed.

Diamond is very entertaining. Has anyone seen an article by him on Peak Oil impacts. I had expected to see some thoughts in "Collapse" but did not.

Yeah, late for sure. The question that unfortunately has to be answered is: how can humanity live in sustainability on this planet? I assume that since Diamond's essay is a personal favorite, you likely agree with its implications regarding sustainability. Estimates of a sustainable human population usually revolve around a billion or less. I don't have a clue how to get from here to there without a terrible price being paid. As I've mentioned before, we are in the midst of a massive species die-off, and we are one of the species. If agriculture provides any hope of easing the transition from six and half to one, I surely can't see how the waste and concomitant loss of biodiversity that bio-fuels implies, can possibly offer anything ameliorative to human suffering in that transition
Yes, I agree.  We are going to be hard-pressed to feed ourselves without oil.  Demanding that agriculture support our transportation system as well is folly.  

If we are to transition to something sustainable, reducing our population must be our #1 priority.  Unfortunately, I don't see that happening.  Indeed, population growth rates may soar again, as people return to the country, where children are valuable free labor.  Even in China, rural families are exempt from the one-child law.  

Diamond was focused on the incremental improvement/loss from hunter-gatherer societies to the stage of primitive agriculture, as shown in the archaeological record.

Many folks still live in the state of primitive agriculture today.  They are the ones who often suffer famine and need help from ... nations with advanced technical agriculture.

So, while it's true that health, height, and lifespan decreased in the initial transition from hunter-gatherer to primitive agriculture, that is not to say that we would see an increase in well-being if (even a few of us) made the transition from technical society back again.

I know that I had a medical operation a 3 mo. age.  I'd be dead and dragging down your computed lifespan ...

"Estimates of a sustainable human population usually revolve around a billion or less. I don't have a clue how to get from here to there without a terrible price being paid."

That's because it cannot be done without a terrible price being paid.

It really does all come down to this though. There are too many of us. The planet is a super-organism capable of regeneration, using sunlight, but only up to a certain carrying-capacity. The laws of thermodynamics prevent any attempt, long term, to exceed that carrying capacity.

We are now way, way beyond it. Because of a variety of human failings, it is all too easy to imagine us incapable of the sort of concerted, worldwide action that might mitigate the chaotic and brutish downward spiral which will return the planet to balance.

Cherenkov -

I don't think it's been your despised 'techies' that have been touting up ethanol-from-corn as the answer to our energy problem. Rather, most of the cheerleading has come from i) mega ag business companies that stand to profit handsomely such as Archer Daniels Midland,  ii) politicians from states that grow a lot of corn, and iii) naive Greenies who automatically like anything  that sounds 'natural'.

In fact, it's been the engineers who have been the most critical of these ethanol-from-corn schemes.

I think you are absolutely correct. WIthout subsidies, biofuels would be a non-start on its face. Most people seem to think that crops magically appear out of the ground.

The primary fertilizer used in the US is dollars backed by oil.

A very large percentage of the mass of all our crops is not edible. We already pay the price of growing it in both economic and energy terms. Thermal Depolymerisation would convert this biomass to diesel fuel more efficiently than converting it to ethanol. Could it replace petromass fuels entirely? Maybe if combined with hybrid technology, wind, solar, nuke, and unused hydro potential.
Biomass fuel changes the economics of agriculture by not exporting dollars from the land betwwen the Apilatchian and Rocky mountains.
The point of this post was that the non edible parts are not waste.  They need to be returned to the soil, of the soil will be ruined.  
A very large percentage of the mass of all our crops is not edible.


Thermal Depolymerisation would convert this biomass to diesel fuel more efficiently

Really?   I can take a crop RIGHT NOW and make ethanol.  In fact, I can go to a local brewpub and see/taste the result of such technology.  

In fact, I can do this basic technology in any old container.

With a slightly more technological item called a oil press, I can get the raw material for making biodiesel.

Thermal Depolynerization needs MUCH more technology.  And there is high pressure/temprature cycling of vessels to do this process.   Do you have fatigue and replacement analysis on these vessels and what the replacement cost will be?   When you plan this 'take crops and make fuel' system, have you included transporting the waste products back to the farmland?

The pressures and temps of TDP are much lower than those used in the F-T process so durability of components should not be a problem. TDP can be an entirely self powered process unlike the distillation of grains. The solid residues of TDP can be returned to the soil. Less than 1/4 of a plant's mass needs to be left in place between growing seasons to prevent erosion and aid in maintaining fertility. Take a drive in corn country and see for your self how short the stalks are compared to harvest size. TDP produces a high cetane diesel fuel that can be used with no modification to the engines.
No surprize hidden in the grass...
the ERoPI (error rate of political information)  remains consistent.
As usual  ... our political leadership finds the worst ways to speak their 'truth' as a science fact... but it is not  science or fact or truth.  the last important truth that i can remeber/consider was the announment that Pearl Harbor was bombed. (some of the announcement was -- i was not there/alive).
Just wanted to tell you I really appreciate the post, Kyle. It cleared up some misconceptions and filled some gaps for me.
I found more info at The Ag Marketing Resource Center switchgrass page.  Their productivity data is in line with Kyle's.

I have some questions:

Is it practical to use the mash from the bioreactor, or ash from switchgrass-fueled generator, to fertilize the soil where the switchgrass is grown?

Bioreactors and stills scale down very nicely, I have heard.  Would smaller setups be more cost-effective?

Does anyone know of a commercial project involving switchgrass?  

Presumably, the Sam Jaffe quote ("If all that land was planted with switchgrass, we could replace every single gallon of gas consumed in the United States with ethanol.") completely ignores economic growth. Even if the quote was an accurate representation of the possibility, which Kyle's post demolishes, it says nothing about what the US does after all the "spare" land has been planted. There is also no mention of the vagaries of agricultural yields. Are there not expected to be bad years for switchgrass (or corn, for that matter)? Or maybe there will be miraculous consistent yields regardless of weather, climate and mono-culture prone diseases.
Nitrogen and phosporous are minerals that are not removed  when switchgrass is harvested in Winter as a fuel/ethanol crop. During the Winter, those minerals reteat to the roots of the switchgrass and are available to grow new plants the succeeding season. It is only when switchgrass is harvested as a forage crop that it must be continuously fertilized. Forage harvesting cuts the plant when it's green and carrys away the carbohydrate,the protein and the minerals in the growing plant.
Here are a few pieces I put together recently on other listserves (see below) related to using grasses for energy, mainly bioheat. A portfolio of warm season grasses can be ecologically grown for bioenergy around the world. I think cellulosic ethanol has more potential in the semi-arid tropics. We should focus on heating and cooling applications with biomass in NA, Europe and China.


We have been working on grass pellets and other agrifibres for energy since 1991. We have had to wait for the combination of high energy prices and advances in combustion technology to get the industry commercial.

Agri-fibre pellets/cubes from the crop milling residue industry are now commercially being used in Ontario and Manitoba for applications including greenhouse and farm building heating applications and crop drying. In Canada we can pellet/cube and burn oat hulls, pin oats, wheat bran, soy hulls, corn fibre, flax shives, corn cobs, sunflower hulls and combinations of these fuels. Whole plant corn has also been harvested mid winter (after leaching) and direct burned without processing by one Canadian geeenhouse producer.
Corn cobs can also be used without densification. I have been burning late fall and overwintered switchgrass in my house for the last two winters in a gasifier pellet stove. Canadian farmers will be planting small acreages (the most I have heard is 150 acres) of switchgrass and prairie sandreed this year as we anticipate that the cheap crop milling residues are soon going to be used up. With energy grasses in Eastern Canada, delayed harvesting reduces the potassium content to about .35% at the time of late fall harvesting and 0.06% if spring harvested. Summer harvested switchgrass is like wheat straw about 1.2% potassium. I don't know anyone that can burn summer harvested switchgrass or wheat straw over an extended period.

Wheat bran or middlings is a cheap binder for difficult to pellet fuels using standard pellet equipment. Switchgrass needs a little more energy to pelletize than alfalfa but less than wood fibre. The energy aspects of growing grasses and their grinding and densification was recently reviewed in our recent paper: "The potential of C4 grasses for developing a global Bioheat industry".
Critical Reviews in Plant Sciences   Publisher:  Taylor & Francis   Issue:
Volume 24, Number 5-6 / September-December 2005   Pages:  461 - 495,7,7;journal,2, 72;linkingpublicationresults,1:103858,1

Necessity is the mother of invention. There are now about a half dozen Canadian combustion technology companies selling a range of small to medium sized equipment (10 kw to 2 MW) with the ability to efficiently burn agri-fibre feedstocks with moderate levels of potassium and chlorine. Some
equipment has more fuel flexibility than others, you need to shop around.  

The grass pellet fuel cycle can produce 7 times more net energy gain from an acre of land than a corn ethanol fuel cycle (If George Bush is listening this is 7 times faster a way to find energy independence). Even direct combustion of grains is getting more popular in Canada this winter. If oil can stay around $65/barrel and natural gas at $10 mmbtu, we are going to see an enormous industry evolve which will drive up grain prices to about $200/tonne. Great for crop producers but it will put an end to the grain burning and ethanol industries. The green energy revolution from grasses is poised to replace king corn as the energy champion of farmers.  

Roger Samson
Executive Director
Resource Efficient Agricultural Production (R.E.A.P.) - Canada Box 125 Centennial Centre CCB13 Ste. Anne de Bellevue, QC, Canada H9X 3V9
"Working to create ecological energy, fibre and food production systems"


Ash isn't the most problematic issue for an appropriately designed combustion appliance it's the potassium and chlorine content of the ash that we need to reduce. Small pellet stoves have the most difficulty handling difficult fuels while bigger combustion units have less problems. I have an advanced gasifier pellet stove in my house that I have been burning switchgrass and other fuels the last two winters. There is still work to be done to improve these systems, but they can work well on many fuels. Overwintered switchgrass is a pretty friendly fuel with chemical properties for N, chlorine and potassium similar to wood. Best strategy is to work on both biomass quality of agri-fibres and stove design. An agency in China we work with has pellet stoves and boilers for the Chinese market that are burning moderately high ash fuels. They are developing 3 in 1 systems where you get heat, hot water and cooking. So the technology is also advancing in developing countries.


The Frontier Centre for Public Policy has recently posted some information on pelletized biomass energy from grass for western Canada on their web site. This includes a powerpoint presentation I recently gave and some of their editorial in western Canadian newspapers supporting the concept.

"During the Winter, those minerals reteat to the roots of the switchgrass and are available to grow new plants the succeeding season. It is only when switchgrass is harvested as a forage crop that it must be continuously fertilized."

Not quite. All perennial plants store energy in their roots during dormancy - trees do it, grasses do it, etc. - but minerals such as nitrogen and phosphorous are in every cell, in the protein and amino acids of plant flesh, and when that flesh is hauled off so are those minerals.

All plants require continuous fertilization. Period. Nitrogen is fixed by lightning and falls in rain if nothing else, but there are other sources as well. Soil fungi transport massive amounts of nutrients long distances in soil, bacteria do some nitrifying, roots mine the subsoil, birds deposit dung gifts etc.

Productivity rises as fertility rizes when that's the limiting factor. Water and photoperiod are examples of other limits that can't be overcome by fertility. The claims made for high productivity in switchgrass - as many have noted here already - depend on high fertility and added nutrients.


Debunking # 1

If fertilizer and irrigation were required to make switchgrass grow it never would have evolved as a climax community species of the north american tallgrass prairie. It is a resource efficient plant that is an excellent nutrient scavenger. With delayed harvesting potassium largely leaches back into the soil. In an end of season harvest you extract 1-3 kg K20/tonne. Some varieties of switchgrass (like warm season grasses in the tropics) fix agronomically significant levels of N. Switchgrass is highly mychorizal,  it is largely not responsive to phosphorus even though its roots are coarse.    

Debunking #2

We have a problem in North America of surplus food production capacity.  Diverting 15-20% of the farmland into energy crop production would create genuine demand enhancment for the farm sector and create an across the board rise in commodity prices. Over 80% of US farmland is used for meat-culture agriculture. There is not a food security related production problem in the US, there is an obesity problem from eating too much meat. Perennial warm season grasses were selected by the USDOE because of their adaptation to marginal farmlands. They are deep rooted, C4 grasses that have double the water use efficiency of C3 species like hybrid poplars or bromegrass.  Less leafy C4 species such as sand bluestem and prairie sandreed have better yield potential in the dryland areas than switchgrass.

Debunking #3

Alfalfa is a C3 species that doesn't generally respond to breeding improvements for yield because it is water limited in most environments. C4 grasses like switchgrass have much higher potential for yield improvement by breeding because they are much more water use efficient. The Brazilians have been doing excellent work to improve sugar cane yields for similar reasons.  

Debunking #4.

Switchgrass is a resource efficient perennial plant. It simply regrows every year unlike corn which is high input annual.  Its cost of production per tonne produced is about 40% that of grain corn. This is the fundamental advantage it has for cellulosic ethanol. With grain corn you get about 400 litres per tonne and swithgrass 320 litres per tonne. I believe the cellulosic ethanol and cane ethanol industries will prevail as the main liquid fuel systems from agriculture. The grain corn ethanol industry will crash because both corn production and the ethanol conversion process are highly dependent on fossil fuels.  Also corn can be burned directly to substitute for heating oil or natural gas why go to the trouble of building and running an ethanol plant to turn it into a liquid fuel and recovering only 55% of the energy in a liquid form to burn to run a car? Corn ethanol is as bright an idea as going into IRAQ to secure America's energy future.  

roger samson

"If fertilizer and irrigation were required to make switchgrass grow it never would have evolved as a climax community species of the north american tallgrass prairie."

This isn't a debunking since the claim is that it produces modest amounts of dry matter when not fertilized or when grown in dryland, not that it can't survive.

"We have a problem in North America of surplus food production capacity. "

What a bizarre way to characterize the wealth of natural resources and arable land in N. America coupled with the capital and technology to exploit that wealth. A problem? No sale.

"Diverting 15-20% of the farmland into energy crop production would create genuine demand enhancment for the farm sector and create an across the board rise in commodity prices. Over 80% of US farmland is used for meat-culture agriculture. There is not a food security related production problem in the US, there is an obesity problem from eating too much meat."

Obesity is from eating too much grain and grain products not from eating too much meat. It's the twinkie diet that fattens and kills. If you want to improve health then stop growing so much grain on land that would do better as pasture for livestock anyway. It takes far less energy and produces far more healthful food.

"Alfalfa is a C3 species that doesn't generally respond to breeding improvements for yield because it is water limited in most environments. C4 grasses like switchgrass have much higher potential for yield improvement by breeding because they are much more water use efficient."

Rubbish. Alfalfa has already benefited hugely from breeding improvements for both quality and yield, just as maize, a c4 grass, has been improved. Switchgrass would likely respond well to a breeding program since it has not yet been domesticated and improved, not because it is a c4 grass.

"Switchgrass is a resource efficient perennial plant. It simply regrows every year unlike corn which is high input annual."

Once switchgrass has been improved it will also be a high input cultivar though not an annual. But perhaps more importantly maize could also be bred to produce more biomass rather than more seed. Most current cultivars are intentionally bred to produce less leaves and stalks but more grain heads since that is the part that has value. But there are cultivars bred for silage use where the whole plant is used rather than just the grain head, and it produces more biomass. There are also cultivars bred for grazing that produce more biomass and can regrow after predation to a limited extent.

The debate is a bit silly in that if we ever develop cellulosic ethanol technologies and there are not better uses for biomass (there are, but bear with the hypothetical here) then a wide variety of cultivars will be bred to exploit particular environments.

On another site I demonstrated the math that says that even with a positive energy balance (but not a huge one), that it would take more than twice the land area of the US (all land area, not arable land) to replace just the gasoline usage with ethanol.  

Forget about using it as a feed stock for other sources.  
It left a rather disquieting feeling because nobody could find anything wrong with the math.  Oops!

I haven't read through all of the comments yet, so I don't know if someone posed this yet:

You keep comparing switch grass to lawns and corns in terms of requirements. Is there any reason why people can't just grow the grass in their yards instead of regular grass and have it collected by counties? If you add up the acreage of residential lawns and the existing fertilization going into them, this would be one heck of a bi-product!