There’s Ethanol and then there’s Ethanol

In the renewable energy community, Ethanol has a bad rap, due to some often-quoted, seldom checked studies on energy payback.

It’s received wisdom that ethanol from corn has an energy return on energy invested (EROEI) of somewhere between 0.8 and 1.0; i.e. you get less out than you put in.  The persistence of this idea is possibly due to some great cartoons.  I’m probably going to undermine my whole argument here, by including this one…

Then again, I expect that my audience is highly intelligent, and not easily distracted.  If you weren’t, you probably wouldn’t still be reading my extremely dense and often-tortured prose.  You deserve a good cartoon every now and then…

Back in the world of ethanol, times have changed.

Even though cellulosic ethanol is still very much in its technological infancy, a lot of companies and people are doing a lot of interesting things with corn ethanol to make the process more efficient, and, get those energy inputs in the form of “free” waste heat from some other process, or from renewable sources such as cow manure or landfill gas.

I’ve been educating myself a lot about this reading C. Scott Miller’s Bioconversion blog.  I admit I’m having to do a lot of catch up on this, because I was one of those people who believed ethanol was a total government subsidized boondoggle until recently.

All that said, even at an EROEI of 1.25 to 1.8, ethanol is not much of an energy “source.”  Sure, we’re getting a little energy out of the process, but one way to think about EROEI is how much effort it takes to get our energy. 

As a rough illustration, at an EREOI of 2, there has to be one person working to get energy for every person doing something else.  So if civilization were to exist one out of every 2 people would have to be employed in the energy sector… the other 50% would then have the energy they needed to do other useful things, like be doctors, politicians, soldiers, engineers, builders, investment advisers, bloggers, artists, manufacturers, scientists, psychologists, food farmers (as opposed to energy farmers), talk show hosts, etc.

 You might argue that some of those professions aren’t very useful (investment advisors and politicians perhaps), but even if we eliminate all those “useless” professions, I think the more useful professions like talk show hosts and artists might start finding themselves a little squeezed.

There is a reason that the human race was 95%+ farmers or hunter gatherers for most of of our history: the energy sources we were using were not powerful enough, with too low EROEI to sustain higher forms of civilization, such as talk show hosts.

If you don’t believe me, read this great article on “Peak Wood,” the cause of the iron age.

Back to ethanol: it’s not going to solve our world energy problem.  It’s a useful way to turn non-liquid fuels (manure, biogas, or coal) into something you can put in your car, but if we in the U.S. are  looking for a domestic source of energy that will wean us off the Middle Eastern oil teat, we can do it, only if we want to be a nation of farmers, witha much smaller population and lower standard of living than we have now.

Ethanol is big business these days, and it will make a tiny dent in our oil addiction, so all the investment is probably doing some good.  I predict that the biggest beneficiaries will be the farmers, and considering how hard farming is, that’s not a bad thing.  It’s probably better than out-and-out farming subsidies.

Basically, I’m no longer worked up about ethanol subsidies and mandates.  There are a ton of better ways we could be spending the money, but it’s hardly the stupidest thing our government does with our money.   I’d even be happy about it if they’d simply replace the money spent on all farm subsidies with subsidies for farm based energy.

I just don’t want it to distract from the important work we have to do to deal with the twin probems of peak oil and global warming:

  1. Improve energy efficiency (especially of our vehicle fleet.)
  2. Develop high ERoEI energy technologies: Wind, Solar concentrating, Geothermal.  PV will probably make it on this list as the technology improves.
  3. Displace some of that oil in transport with renewable electricity, via plug-in hybrids.  (Economic fuel cells are still too far away to make hydrogen a viable transportation fuel in the next 20 years)


  1. Okay, pretty interesting stuff. I was wondering if ethanol was just a momentum play for a while there. Here’s my question: You mention “peak oil.” What do you think about that in the light of the recent oil discovery deep in the Gulf of Mexico by Exxon (or whoever) that is supposed to be the source of a huge amount of oil? Just curious. Thanks for the read.

  2. CSMiller said

    Thanks for reading my blog – that’s what it’s there for. I appreciate your patience.

    I don’t think we need to replace gasoline from oil so much as we have to come up with a plan for lowering our dependence by replacing fossil resources with biomass feedstock. It is also important that whatever technolog(ies) we use be deployable throughout the globe using a variety of feedstocks.

    People I talk to say that this technology already exists in the form of synthesis gas fermentation (look it up on my site or Wikipedia) – capable of burning blends of cheap feedstock (like municipal solid wastes, autofluff, tires, sulfurous coal, etc.) and fermenting the resulting syngas into ethanol and other biofuels. There are untapped masses of this type of cellulosic feedstock available that do not require cultivation.

    Due diligence run by major engineering companies on some of the pilot plants using syngas fermentation has resulted in yields of about 125 gallons/ton with effectively no emissions.

    The DOE should secure funding for commercial-scale deployment of these technologies. Just the beginning of a shift to renewables of this type will chasten the oil industry – like the threat of SDI humbled Russian ambitions in the 80s.

  3. tomkonrad said

    I response to PK-

    1. The Exxon oil “discovery” wasn’t a discovery… more, what the did was prove that you could actually get oil from this deep.  But it was an amazing feat.

    2. Peak oil is not about oil reserves, it’s about oil *Production.* Peak Oil= the moment when production is at it’s maximum.
    3. This Jack oil feild will not be in real production until 2012. And that’s when it’s scheduled to start producing. Considering this is the deepest ever producing well, we can expect problems.
    4. This is going to be *very* expensive oil to produce, since, again, it’s the deepest anyone has ever gone. So much for making a dent in oil prices.
    5. US oil reserves, even when increased by 50%, are miniscule compared to demand. US oil peaked in 1970… we’re dragging out the tail end. It’s like saying Canada has the second biggest oil reserves afer Saudi Arabia because of oil sands. Sure, it’s there, and we’ll get it eventually, but it is very slow and expensive to extract.  Except that there is a lot less of this than there are of the oil sands.

    Peak oil review had a section on this if you want to hear the skeptic’s side of the story.

  4. tomkonrad said

    In response to CSMiller-

    I agree, ethanol technology is coming along. I was more trying to convince my old-line environmentalist readers than I was trying to convince you (Miller) of anything. Giving a boost to cellulosic technology would certainly be a better use of our tax dollars than subsidising corn ethanol. From my perspective as an investor, though, cellulosic is too early stage for me to invest… I’m too cautious, because of the however many versions out there, only 1 or 2 will end up being economic. Once again, this is a good role for government intervention.

    One question for you: if we use all the available crop residues, forestry waste, and switchgrass, how much of our current gas demand could we displace at 125 gallons/ton? I’ve seen some numbers out of NREL ( that don’t look good, at least before 2030.

  5. CSMiller said

    There is plenty of feedstock available from the sources you define but that is not as plentiful or expendable as landfill biomass. Check out,71757-0.html?tw=wn_story_page_prev2. And I quote:

    Louis Circeo, director of Georgia Tech’s plasma research division, said that as energy prices soar and landfill fees increase, plasma-arc technology will become more affordable.

    “Municipal solid waste is perhaps the largest renewable energy resource that is available to us,” Circeo said, adding that the process “could not only solve the garbage and landfill problems in the United States and elsewhere, but it could significantly alleviate the current energy crisis.”

    He said that if large plasma facilities were put to use nationwide to vaporize trash, they could theoretically generate electricity equivalent to about 25 nuclear power plants.

  6. tomkonrad said

    CSM: I think we’re talking across each other a bit here: we have different time frames for this technology, which is why I’m happy to see the various cellulosic technologies out there, but I don’t think they’ll be big players before 2015 (see that presentation by John Sheehan from NREL I referenced in my last comment.)
    My biggest worry about ethanol is that our government is using it as an excuse not to act on making our cars more efficient. There seems to be talk in Washington of allowing automakers to have less efficient fleets if there are a large enough proportion of flex fuel vehicles in them. Energy efficiency (lighter, more aerodynamic vehicles and hybrids) is something that we have the technology to do on a large scale today; cellulosic is not ready yet, and getting off oil is going to require both. I feel we need to be emphasizing what works now.

    I rolled my eyes at a couple things Circeo says above:

    1. Our “largest renewable energy source” is always going to be solar, in the long term at least.  At the moment, the technology is too expensive to be deployed on the gigantic scale required (Tens of square miles rather than acres), but when it is there is enough solar energy hitting the Earth to meet all our energy needs hundereds of times over. – you can also get this link in my Aug 8 blog.

    As a side note, while this waste to energy is good, it’s not totally renewable- part of the fuel for their plasma generator is coming from stuff in the landfill; eventually that will be empty, according to the article.  Does he mean the equivalent of 25 nuclear plants burning the contents of old landfills, which we might profitably recycle (especially as “energy prices soar”), and is he counting on the reduction of waste as we increase recycling, again as a response to rising energy prices (recycling saves energy compared to making things from raw materials.  Somehow I doubt he takes these factors into account.

    2. “As energy prices soar” can make any technology economic. “As energy prices soar” it makes sense for me to cook my breakfast on a fire of $1 bills. I want to know what price point(s) makes the technology economic when all costs are taken into account. Also, “As energy prices soar” our economy grinds to a halt and we start to starve. I’m interested in solutions to peak oil and global warming that work “as energy prices gradually increase.”

    Thanks for this discussion. You’re really made me think.

  7. CSMiller said

    And you are making me think.

    The objective of the waste-to-energy “bioconversion” crowd is, first, to reduce the rate at which we landfill. In California we have had a very productive period of recycling and yet, it has only managed to eliminate the growth in landfilling – not the original tonnage that gets landfilled. If source reduction could make a dent in the tonnage, that would be terrific, but for that to be successful would require a huge education process and draconian regulations levied on California businesses – which would only give out of state and out of country competitors a clear manufacturing advantage.

    Most bioconversion is being contemplated for newly collected and sorted trash that is not currently recyclable. Since the biorefineries are clean (almost zero emissions) and can be sited at the MRF centers (established city facilities where trash is sorted for recyclables) the city would save the fees and pollution for trucking trash to the landfills (which are being located further and further away from the source of the trash). And save trucking the recyclables to recycling centers and polluting ships to China (see “Recycling’s China Syndrome” at

    L.A. City is leading this new waste management innovation and has unanimously passed a 20-year plan called RENEW L.A. to deploy the biorefineries. The first will probably use anaerobic digestion with the other six using syngas fermentation. Simultaneously, the L.A. County Bureau of Sanitation is issuing an RFP this month for their own commercial-scale (probably syngas) plant.

    So even if these plants don’t produce a drop of biofuel, they are still fulfilling a social need by extending recycling (even Ed Begley, Jr. agrees), reducing landfill use, reducing air and ground contamination, reducing gHg (global warming), while employing thousands of Angelenos throughout the city.

    Without even considering mining landfills, California has about 40 million tons per year of non-recyclables – 75% of which could be cleanly bioconverted to biofuels. The technology exists in pilot plants, it just has to be deployed commercial-scale. This is a solution that could have major global impact on waste management and liquid fuel production.

    Solar energy will not touch the current demand for ethanol in this state which is already at 900 million gallons per year – 95% of which is imported. And we don’t grow much corn here – but we generate alot of waste biomass.

    I’ve written extensively on these subjects. Just use my search engine to find my references.

  8. […] I wrote a blog a couple months back talking about how environmentalists should avoid lumping all ethanol together as “bad” renewable energy because the Energy Return on Energy Investment (EROEI) is very low.  First of all, new ethanol plants being built today do have a net energy gain on a well-to-wheels basis (the critics are using decade old data), and so long as the energy inputs come from renewable sources, ethanol looks like a decent way to turn other forms of renewable heat energy into something we can put into our tank and drive around with. […]

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