R-Squared Energy Blog

Pure Energy

POET Sets the Standard

In a recent post (but certainly not the first time I mentioned this), I wrote:

Corn ethanol producers have to move away from fossil fuel inputs – or they need to otherwise find inputs that don’t normally track gasoline prices. This is why the sugarcane ethanol producer can compete on a level playing field with gasoline. The fertilizer inputs for sugarcane are much lower than for corn, and the distillation energy is provided by biomass. The only way the ethanol industry in the U.S. will be able to break free from the subsidies is to adopt similar practices.

The ethanol company POET, which I recently described as setting the standard for ethanol production in the U.S., has just taken a big step in that direction. This press release was just e-mailed to me:

Waste material to power cellulosic/grain ethanol plant

POET installs anaerobic digester at pilot cellulosic ethanol facility

SIOUX FALLS, S.D. (June 17, 2009) – A self-sustaining energy cycle for producing cellulosic ethanol is close to reality with the recent startup of an anaerobic digester at POET’s pilot plant in Scotland, S.D.

Corn cobs at Project LIBERTY will not only be used to produce ethanol; the liquid waste will go to an anaerobic digester to power the cellulosic plant and offset natural gas usage at the attached grain ethanol plant as well. That’s renewable energy created at the plant, powering the plant and powering the adjacent facility.

POET installed and fired up its anaerobic digester, which was designed and built by Biothane, on May 20. The digester uses liquid waste created in the process of converting corn cobs to ethanol. That waste is used to produce methane gas, which acts as roughly the equivalent of natural gas.

“This technology will cut fossil fuels out of our cellulosic ethanol production process and further improve the benefits of grain-based ethanol,” POET CEO Jeff Broin said. “Over the long term, POET would like to eliminate the use of fossil fuels at all of our plants through a variety of alternative energy sources.” The alternative energy technologies employed at other POET facilities include a solid waste fuel boiler, landfill gas and cogeneration.

The digester is in the research phase – corn cobs have never been used in this way before. The methane is currently being flared, but once the process is refined, it will be installed as part of Project LIBERTY.

Project LIBERTY is a 25 million gallon-per-year cellulosic ethanol plant, which will be built in Emmetsburg, Iowa. Research and development work is on schedule for the plant to begin production in 2011.

A photo of the anaerobic digester is available at http://www.poet.com/news/showRelease.asp?id=169.

To see a documentary about POET’s pilot cellulosic ethanol plant visit http://www.poet.com/cellulosedocumentary.htm. Media outlets are welcome to link to the documentary in online coverage. Photos are also available for publication at http://www.poet.com/news/releases.asp.

About POET

POET, the largest ethanol producer in the world, is a leader in biorefining through its efficient, vertically integrated approach to production. The 20-year-old company produces more than 1.54 billion gallons of ethanol annually from 26 production facilities nationwide. POET recently started up a pilot-scale cellulosic ethanol plant, which uses corn cobs as feedstock, and will commercialize the process in 2011. For more information, visit http://www.poet.com.

What POET is doing is similar in spirit to what E3 Biofuels attempted. E3 had some startup problems that ultimately put them out of business, but as I described it at the time, this is I believe a necessary step for the ethanol industry. While I don’t expect this approach to be as cheap as using natural gas or coal for power, in the long run using biomass to power their plant will dampen some of the oscillations caused by volatile fossil fuel prices.

One other key issue – and I have seen conflicting information on this – is how much biomass can be removed in a sustainable manner. Since POET is just using cobs, they are probably OK. Start taking out large amounts of stover, and you may run into trouble. But using cobs solves many of the logistical challenges that cellulosic ethanol in general will face. The cob is already being collected with the corn (analogous to bagasse) so a portion of that logistics battle is already included in the deal. This is also why I think lignocellulose to fuel schemes need to focus on biomass already coming into central locations, such as landfills.

The one other obvious question is just how much natural gas can be displaced by digesting the liquid waste. Since they are still in a research phase, they probably don’t even have a good answer to this yet.


June 17, 2009 - Posted by | biomass, cellulosic ethanol, ethanol, POET


  1. Forget where they plan to get their heat for distillation from. They accutually have a cellulosic ethanol technology that is ready for full scale production? Do elaborate…

    Comment by Optimist | June 17, 2009

  2. Optimist, if you're really interested you can kick around the Rhapsody in Green. website. There's a lot of information, there, regarding their "Project Liberty" (the name of their cellulosic program.One of the advantages of corn cobs is that they add very little nutrients back into the soil. Somewhere between 2%, and 6%, depending on the study. They are also dense enough (much more so than leaves, husks, stalks, etc.) to make transportation somewhat viable.People have known "how" to do cellulosic for almost a hundred years; the trick is how to evolve the enzymes to the point where it's a "viable" technology.Reading between the lines, it seems that Poet thinks they can produce cellulosic for about $2.50/gal, today; and that they are hoping that they can do it for around $2.00/gal by 2011.Thanks for sharing this, RR. It's Not a Bullet, but it might be a BB.

    Comment by rufus | June 17, 2009

  3. "They actually have a cellulosic ethanol technology that is ready for full scale production?"No, I wouldn't go nearly that far. What they have done is reduce the fossil fuel inputs into their cellulosic process. However, I think they will find that cellulosic ethanol is an energy hog. It will consume all of those corn cobs and more.I would have done things differently. I would have used corn cob boilers to produce steam for their corn ethanol plants. That would be the most efficient usage of those cobs, directly backing out natural gas. What they are going to end up using them for is to boil off water from a 4% ethanol solution produced from the cellulosic ethanol process.RR

    Comment by Robert Rapier | June 17, 2009

  4. BTW, a significant fraction of the corn kernel is lignin. The last I read the Project Liberty plant will utilize fractionation to separate out the different elements of the kernel.This means that part of the kernel (the lignin) will be sent to the digester along with the lignin from the cobs.

    Comment by rufus | June 17, 2009

  5. POET is doing a number of things right, including moving slowly on their cellulosic project that first got approved for a $70+ million DoE grant over two years ago. Just want to correct the notion that corn cobs get collected routinely with kernals. That was the case a generation ago, but modern combines do the shucking right in the field and spit the cobs and stover back out. POET has been working hard with farm equipment manufacturers to come up with a good cob harvesting approach, and they'll do it. Would also note that cobs make very good syngas source too, and the CVEC plant in MN is piloting a project on that. I'd agree that burning them is probably much smarter than converting them to liquid fuel. Will POET's cob process work? Maybe. But I'd think it would take a couple of years of operation before one could make that kind of determination. Cob harvest, transport, storage, and processing all seem to be nontrivial pieces that have not been proven out yet, and probably won't be until 2013 or so.

    Comment by Anonymous | June 17, 2009

  6. Actually, the cob is not collected with the corn–most modern combine harvesters strip off the kernels and leave the cobs in the field. There are machines that grind up the entire ear of corn, but that probably degrades the value of the kernels for conventional ethanol production while not making cellulosic production that much better.That being said, Table 5 at this linkhttp://www.ipm.iastate.edu/ipm/icm/2007/8-6/nutrients.htmlshows that the cobs account for almost 8% of corn's biomass but contain less than 4% of the nutrients used, making them the ideal part of the corn plant for further harvesting.

    Comment by Farm Power | June 17, 2009

  7. I suppose in another 20-30 years, when corn yields are much higher (yields have been rising by 2 percent a year for decades) ethanol might stand on its own, without subsidies. Maybe. Palm oil yields will be rising much more quickly, as palm has not been selectively bred for as long.Still, with the blending of ethanol into gasoline we lose mpgs. Maybe an all-ethanol car makes sense, as they can use higher compression ratios. Realy, I think CNG and PHEVs are the way to go.

    Comment by Benny "Boom, No Doom" Cole | June 17, 2009

  8. Watch the POET videos carefully. You will note that the farmers say they are storing up the corn cobs to be used later. This implies to me an energy/mass balance and eventually a logistical problem. More energy is required for distilling the ethanol than the corn cobs alone produce. So farmers have to gather and store more than one year's worth of cobs to distill a single year's worth of feed corn harvest. That doesn't sound very sustainable to me. Better, yes.

    Comment by KingofKaty | June 17, 2009

  9. I don't think so, King. This is a new thing, and only a few farmers are taking part in the early experimentation. They are being paid to be "lab rats." There are several different systems being evaluated for gathering the cobs, and, of course, no one is actually producing ethanol to any large extent with the cobs at present. They are producing Some in their pilot plant. Here's Another Story. about a company attempting to do "stover" to ethanol.

    Comment by rufus | June 17, 2009

  10. King, I might have misunderstood your comment. It is true that you will still have to use some nat gas in the process. Just not nearly as much. And, you will get more ethanol. It should be a net positive contribution. In essence, corn ethanol leverages nat gas with sunshine, and rain to get more miles. Theoretically, one could use more lignin from the kernel, and cobs, and perhaps, stover and eliminate the use of fossil fuels altogether; but, I don't think we're looking at that right away (although, you could throw in some "wood waste" and achieve that ala Poet's Chancellors plant.)

    Comment by rufus | June 17, 2009

  11. "The cob is already being collected with the corn (analogous to bagasse) so a portion of that logistics battle is already included in the deal."R-Squared,They are part way there. The test will be when they transition to running their tractors, corn pickers, and the trucks they use to haul the corn and cobs from the field to ethanol plant and digester on a portion of the ethanol they distill. If they can power their system using nothing more than the ethanol they produce, I will become a believer.

    Comment by Wendell Mercantile | June 17, 2009

  12. It would make more sense to mount a corn cob/stover gasifier on the combine and offset the harvesting fuel and dump the charcoal in the field than any of this.

    Comment by Bob Rohatensky | June 17, 2009

  13. Wendell, those tractors cost $50,000.00 and up. They cost a fortune to repair. John Deere will warrantee a small amount of biodiesel, but they have no interest in warranteeing the use of any ethanol in their diesel tractors. Until they do farmers will be forced to use diesel.It's just a matter of time until some manufacturer introduces an E85-powered tractor. When they do it will take about 5 gallons of E85 to raise an acre of corn (about the same as diesel.)That acre will yield about 160 bushels this year. 2.8 X 160 = 448 gallons of ethanol. Of course, you've got to charge .4 acre back against the DDGS which would translate out to around 745/5 gal of ethanol per gal of diesel.

    Comment by rufus | June 17, 2009

  14. Rufus:Can you clue me in? The Indianapolis 500 runs on ethanol. Why not ethanol tractors etc?

    Comment by Benny "Boom, No Doom" Cole | June 17, 2009

  15. Another Anaerobic Digestion/Biogas Scheme.

    Comment by rufus | June 17, 2009

  16. Benny, the Indy 500 was already running on "spark" engines. In fact, they've been running on Methanol for many years. The conversion was simple.The tractors in the field are diesel (the big ones, anyway.) The life expectancy of a big diesel farm tractor is measured in multiple decades. Benny, a lot of people don't realize that the "average" farmer farms about 500 acres. In spite of the very large amount of money that he turns over in a year, the average farm family income is around $68,000.00. Here's the Kicker. Only about $27,000.00 of that Comes From the Farm. The bulk of a farm family income is from working "in town."These people can't just discard a fifty thousand dollar tractor because they want to use a different fuel. Nor can they take a chance on voiding a warrantee because they want to convert their diesel to ethanol (this can be done. Check out SCANDIA.)Anyway, look for the first E85 powered tractors in a year, or two. Especially if diesel gets back to $5.00 again.

    Comment by rufus | June 17, 2009

  17. anaerobic digestion processes are well known/in place worldwide for various agriculture inputs. can not the potential ranges of energy output given ranges of corncob inputs be calculated to determine the bounds on this process without awaiting test results? or has this been done? awaiting test confirmation?fran

    Comment by Anonymous | June 17, 2009

  18. Rufus-You gotta love the diesel engine. Some people swear if you buy a Dodge truck with a Cummins diesel, do some adjustments, you can run it on veggie oil for the rest of your life. Having seen a Cummins diesel, I tend to believe it.

    Comment by Benny "Boom, No Doom" Cole | June 17, 2009

  19. I was sad to learn that you can not use B100 biodiesel in the current VW TDIs because it messes up the emissions system. I wouldn't be surprised if the same applies to SVO

    Comment by Clee | June 18, 2009

  20. Benny, I was helping my daughter look for a car a couple of years, ago, and was surprised to find that Mercedes warranteed their cars for diesel, biodiesel, or straight vegetable oil.We're going to be running the big diesels for many years to come. The problem is you only get about 12, or 13 gallons of diesel from a barrel of oil, and the good biodiesel crops only grow well in the tropics.

    Comment by rufus | June 18, 2009

  21. Still, back to farm equipment, why not build new tractors ethanol only? Will farmers only buy diesel?

    Comment by Benny "Boom, No Doom" Cole | June 18, 2009

  22. FArmers will buy whatever makes the most economic sense. John Deere has spent many decades "perfecting" their diesel tractors. They're not going to change until some niche player comes along and forces change on them. Sometimes we forget just how new E85 is. I saw a chart while ago. Chicago didn't have a single E85 station in 2006. Today, I guess it has thirty-five, or forty. Maybe more. Case, or Kubota, or someone will build an E85 tractor one of these days. They'll sell a bunch of them, and John Deere will be on the market with one within a year, or so.

    Comment by rufus | June 18, 2009

  23. Aww… so I look to see what kind of biodiesel Mercedes warranties their engines for, and on page 399 of this 408 page pdfhttp://www.mbusa.com/mercedes/data/pdf/ownersmanual/2009_e320_e350_e550_e63amg.pdfthey say, "Mercedes-Benz USA, LLC approves the use of B5 biodiesel (standard diesel with a maximum of up to 5% biodiesel content) in all Common Rail Injection (CDI) and BlueTEC diesel engines. Diesel fuels containing a higher percentage of biodiesel content will cause damage to your engine and are not approved." I wasn't expecting them to take B100, but I thought maybe B20.

    Comment by Clee | June 18, 2009

  24. "It would make more sense to mount a corn cob/stover gasifier on the combine and offset the harvesting fuel and dump the charcoal in the field than any of this."Bob! Where have you been, man?I agree that if you could run your combine off of corn cobs, that would be ideal. As I said above, cellulosic ethanol is an energy hog, and boiling off the water is not an optimal usage of the energy they will get from their digester.RR

    Comment by Robert Rapier | June 18, 2009

  25. OT but in WSJ today:Gas Glut: Why the U.S. Boom Could Mean Cheaper Gas EverywherePosted by Keith JohnsonIn his ads, T. Boone Pickens drawls that natural gas is “abundant, and it’s ours.” He’s quite right.The latest official survey of U.S. natural gas reserves shows how important the latest wave of shale-gas exploration has been: Reserves are the highest they’ve been in the 44-year history of the government survey, and jumped 35% in just the last two years. The Potential Gas Committee estimates U.S. gas supply at more than 2 trillion cubic feet; new shale-gas fields account for 33% of that.And there are already 7 million CNG cars and trucks on the road globally.We are we quibbling about ethanol? How does doom talk make sense?

    Comment by Benny "Boom, No Doom" Cole | June 18, 2009

  26. I'm sure not an expert on this but why can't they use solar power for the heat they need to make the ethanol?–jennifer

    Comment by Anonymous | June 18, 2009

  27. Anonymous Anonymous said… I'm sure not an expert on this but why can't they use solar power for the heat they need to make the ethanol? –jenniferYes, perhaps concentrated solar using fresnel lenses instead of nat gas or methane from cow pies, corn stover, etc,The only problem with solar is that it only works about 8 hrs a day. (so far)Your idea seems to suggest that the distillation process might only be run on the day shift (lots of solar) while the digestion process continues round the clock.John

    Comment by Anonymous | June 18, 2009

  28. Benny – here is the link to the WSJ article: Gas Glut It looks like we have an opportunity to convert coal fired power to natural gas and then to IGCC coal. Not that that is the way the government policies will do it.

    Comment by KingofKaty | June 18, 2009

  29. Anonymous said. I'm sure not an expert on this but why can't they use solar power for the heat they need to make the ethanol? –jennifer__________________________________Perhaps Robert might want to weigh in on this one. I don't know much about ethanol "plant economics" Robert world know more about whether this is a feasible idea or not. John

    Comment by Anonymous | June 18, 2009

  30. From the WSJ article:" Potential Gas Committee, concludes that the U.S. has 2,074 trillion cubic feet of natural gas still in the ground, or nearly a century's worth of production at current rates. That's a 35.4% jump over the committee's previous estimate, in 2007" So the US hasn't actually found hundreds of years worth of recoverable natural gas remaining at current consumption rates. Switch from oil to NG for transportation and that'll probably drop to about 60 years.

    Comment by Clee | June 18, 2009

  31. At least one plant, Corn Plus, is using a couple of windmills.Folks, we are, at present, within a dime, or fifteen cents, of being an economically viable business WO subsidies, or tax credits. A lot of E85 is selling around the U.S. for about $1.75. Without the tax credit it would have to sell for about @2.15/gal. Being pretty conservative you can figure that the average Joe would like to see a 25% discount for lost mileage (a lot of the times it's not that bad, but, perceptions are perceptions,) so, a price of $2.95 gal for gasoline gets you there. Of course, the unseen factor is that without ethanol competing in the marketplace (about 700,000 barrels/day) gasoline would be more expensive. How much more we can argue about, but common sense tells you it would make some difference.

    Comment by rufus | June 18, 2009

  32. i found this explanation of anaerobic digestion helpful.http://www.energysavers.gov/your_workplace/farms_ranches/index.cfm/mytopic=30003 I wasn't exsctly sure what it meant.

    Comment by takchess | June 19, 2009

  33. "Robert world know more about whether this is a feasible idea or not."Feasible? Yes. But there is a reason not to do it. You could produce steam from solar power, but steam has to be very reliable. You can't have your steam fluctuate if clouds cover the sun. So, you need backup natural gas. Since natural gas can run your boilers 24/7, much cheaper just to go that route than try to tie solar into the mix.So it can be done, it just isn't very practical.RR

    Comment by Robert Rapier | June 19, 2009

  34. But FPL is doing it anyway with that 75 MW hybrid solar power plant they're building

    Comment by Clee | June 19, 2009

  35. Robert, why not use molten salt (or equivalent) as a buffer between the solar heat source and the steam usage, as is apparently planned for some of the solar-thermal plants?

    Comment by David | June 19, 2009

  36. “I wasn't exsctly sure what it meant.”It means anaerobic digesters are a very complex way of treating waste that produces energy as a byproduct. A mega landfill or mega dairy would result in a 10 MWe power plant.Anaerobic digesters provide huge environmental benefit but small amounts of generation.Compare this to wind and solar with huge environmental impact but small amounts of generation.

    Comment by Kit P | June 19, 2009

  37. "Robert, why not use molten salt (or equivalent) as a buffer between the solar heat source and the steam usage, as is apparently planned for some of the solar-thermal plants?"It isn't a matter of technical feasibility, it is a matter of economics. With razor-thin margins for ethanol plants right now, the cost to do this will dissuade any companies from doing it. It isn't just ethanol companies; all chemical plants and oil refineries could potentially use solar energy to help with their steam production. It is just very expensive to have a secondary system that only produces energy a portion of the time. The cost per BTU is going to be much, much higher – and the technology isn't well-established.RR

    Comment by Robert Rapier | June 19, 2009

  38. The Corn Belt isn't in the same place as the Sun Belt

    Comment by Clee | June 19, 2009

Sorry, the comment form is closed at this time.

%d bloggers like this: