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By Robert Rapier on Mar 12, 2008 with 10 responses

Debunking Robert Zubrin

A reader asked me a while back to take a look at the claims of Robert Zubrin, and comment. So I took a look at his claims, and while I found things that I felt were wrong, I was generally in agreement on his big picture stuff. I concluded with:

Overall, Zubrin is not completely in left field. He strays out there now and then, but his methanol argument is OK. I don’t consider him at all a crackpot…

But today he stepped out onto thinner ice with an editorial that spoke out in favor of our current biofuel policies:

The case for more biofuel

Let’s have a look:

Let’s start with the allegedly misbegotten incentives. The United States invests roughly $3 billion a year through a 51-cent per gallon credit to promote the production and use of renewable fuels like ethanol. The return on that investment? Taxpayers are saving approximately $6 billion that would otherwise be spent on counter-cyclical crop price supports, plus an additional $15 billion reduction in the country’s petroleum import bill.

First off, that $3 billion is based on 6 billion gallons of production. That number is now in the rear view mirror. There is no cap on the level of subsidy, so it just keeps growing as the production grows. If we could possibly get to that 36 billion gallon number, we would be spending $18.4 billion per year. Note that this is just direct federal subsidies. There are various state subsidies as well that add to the total subsidy pie.

And to get the number above, Zubrin assumes 6 billion gallons of ethanol production. How much oil will that displace? The BTU value of a barrel of ethanol is just over half that of a barrel of oil. Say 1 barrel of ethanol is equal to about 0.55 barrels of oil. Then the 6 billion gallons of ethanol is worth 3.3 billion gallons of oil (78.6 million barrels). At today’s price of nearly $110/bbl, that only comes out to be $8.6 billion.

But there’s more. Per the most recent USDA publication on the issue, to produce one BTU of ethanol takes over 0.9 BTUs of fossil fuel. Mostly it’s natural gas, but there is some diesel and gasoline for farm trucks and tractors. So let’s say 0.7 BTUs of natural gas and 0.2 BTUs of diesel. That means within that $8.6 billion of “savings”, we still have about $5.3 billion of fossil fuels. (See Calculations at the end).

So Zubrin’s $15 billion savings is down to about $3 billion. On the other hand, there is a value for the DDGS which will add back to the savings, but it falls far short of the number that Zubrin is using to justify the subsidy. But we also haven’t counted up any of the negative externalities, and probably the most important point – you still have to pay for the ethanol. All we have done is add up the fossil fuel inputs. Add up the other costs (water usage, for instance) and Zubrin’s “savings” are now a deficit, but one that is going into certain Midwest states at the expense of everyone else.

Continuing to meander onto the thin ice, Zubrin writes:

Numerous well-documented studies have shown that by replacing oil with fuel made from biomass, America is reducing its net carbon dioxide emissions and thereby taking a bite out of global warming.

Numerous others have shown otherwise. The most recent studies have shown otherwise. And of course the recent Science articles show otherwise. Which to believe?

The claims that biofuel production in the United States might indirectly encourage rainforests to be cut down were published recently in the hallowed pages of the journal Science. But it turns out that “scientific avalanche” is itself being demolished. The studies published in Science offered no new data to substantiate their claim of a causal connection between U.S. ethanol and forest destruction – just a theoretical model that has since been roundly debunked by respected researchers from the U.S. Department of Energy’s Argonne National Laboratory and Biomass Program.

Let me make sure I understand this. The theoretical model for the study in Science has been “roundly debunked” by Argonne? First, Argonne is using a theoretical model as well. Second, note the strong language in the debunking: Michael Wang writes “At this time, it is not clear what land-use changes could occur globally as a result of U.S. corn ethanol production.” Whoa! What a debunking. You publish your study in Science, I reply with “Beats me”, and that’s a debunking! And by the way, was the Argonne model published in a “the hallowed pages of the journal Science” as was the study it presumes to debunk? Was it peer-reviewed? Why no, it wasn’t.

So on the one hand I have a model from one of the top universities in the U.S. The researchers, formerly ethanol supporters, have no apparent axe to grind against ethanol. The paper is published in the premier peer-reviewed scientific journal. On the other hand I have a model that comes from a political agency in an administration that is very supportive of ethanol – written by Michael Wang, who has a history of publishing pro-ethanol studies – and a model that was not peer-reviewed in any scientific journal. Tough call.

Meanwhile, real world data from the U.S. Department of Agriculture simultaneously belie claims that American ethanol is causing arable land to be cleared elsewhere and food prices to rise. In fact, the data show that the total acreage devoted to corn in America is not projected to go up, but that annual corn yields are expected to rise steadily – from 155.3 bushels per acre this year to 173.3 bushels per acre in 2017.

They projected that, did they? You know how they make those projections? They use a model. Did the model predict that grain stocks would be at the low levels they are at today?

Those steady corn supplies are just one reason you can’t blame ethanol for food price increases.

You forgot the word “projected.” Those were “projected steady corn supplies.” You know, from the model. Yet you are treating these as actual data points.

If there is any problem with biofuels it is that America needs to produce more, not less, to put an end to the pick-pocketing of our national purse by OPEC.

If this were qualified by specifying methanol from gasification – as your earlier essays indicated – it wouldn’t be a big deal. Coming toward the end of a defense of corn ethanol based on half-baked claims, it isn’t a logical conclusion.

I think Zubrin’s defense of ethanol in this case is unfortunate, because I think he has a contribution to make if he will stick to ideas that are actually defensible and stop defending that which isn’t. Biofuels can be defended — in my opinion — but not like this.

To conclude, I want to emphasize that I think Zubrin has done a lot of good in pushing for wider adoption of methanol as a transportation fuel. I also agree with his pursuit of the Open Fuel Standard, which we do need in order to reduce U.S. dependence upon OPEC. But I think his defense of ethanol in this case was not objective.

Assumptions and Calculations

The basis is six billion gallons of ethanol
One gallon contains 76,000 BTUs
One gallon has an embedded 76,000 (0.7) = 53,200 BTUs of natural gas
Today’s price of natural gas is $10/MMBTU (abnormally high, but so are oil prices)
Then in one gallon of ethanol, there is ($10/1e6)*53200 = $0.53 of natural gas

One gallon has an embedded 76,000 (0.2) = 15,200 BTUs of diesel
Today’s (spot, not retail) price of diesel is $3/gallon.
One gallon of diesel has 130,000 BTUs.
Then in one gallon of ethanol, there is (15,200/130,000)*$3 = $0.35 of diesel

Thus, in one gallon of ethanol we find embedded $0.88 of fossil fuels.
In six billion gallons, there is an embedded $5.3 billion.

  1. By Bert Chadwick on October 6, 2010 at 2:07 am

    And, who Robert Rapier anyway, to debunk engineer Robert Zubrin? What are his credentials and what is his expertise on the subject?
    As far as I know, nobody well known or an authority on the subject.

  2. By Achilleus on May 4, 2011 at 12:38 am

    fortunately we have a synthetic gasoline now that will cost $1.50/gallon so who cares about biofuels now

  3. By Mario on November 12, 2011 at 9:06 pm

    “If Zubrin continues to write essays like this, he will have no credibility at all on this issue.”
    Robert Rapier who are you and when have you had ANY credibility on this issue?

  4. By Robert Rapier on November 12, 2011 at 9:14 pm

    Robert Rapier who are you and when have you had ANY credibility on this issue?

    There are no sacred cows here. If you wish to know who I am, there is a link to my resume over to the right. I actually get paid to do this kind of stuff, so you can take that for what it’s worth.

    But instead of a useless comment, if you wish to engage you could perhaps highlight exactly where you think I have it wrong?


    • By Cobalt on August 13, 2012 at 7:44 pm

      Your assumption that BTU content is an acceptable for the comparison of energy in transportation fuels is incorrect. BTUs (British thermal units) are a measurement of heating value. If you wanted to heat your home, you’d be making a fair comparison. There are much more important attributes of transportation fuels, such as cooling ability and octane rating. An engine with a compression ratio of 14:1 instead of the usual 10:1 will give an efficiency increase of 24%. Even if you lost 20% with E100, you’d have about 4% better fuel economy due to higher compression.

      • By Robert Rapier on August 13, 2012 at 7:51 pm

        Study after study — done by the US DOE — has shown a decline in fuel economy “commensurate with the decline in energy content.” It may be possible to design engines with a high enough compression ratio to compensate, but they won’t be flex fuel. They would have to be ethanol all the way. (Some partially compensate, but most E85 flex fuels still lose 20-25% fuel efficiency).

        I have in fact written at length about this issue:  All BTUs are not Created Equally.

        • By Cobalt on August 14, 2012 at 2:41 pm

          I never said that BTU content had nothing to do with fuel economy, just that it isn’t an acceptable measurement for comparing transportation fuels. Gasoline might have a higher BTU content than ethanol, but ethanol can take advantage of higher compression ratios. Gasoline would knock and cause engine damage in high compression engines.

          Brazil has ethanol-only cars and my home state of Utah has tons of dedicated CNG cars and trucks. I could see a market for dedicated ethanol cars in the States after ethanol becomes more available.

          • By Tom G. on August 16, 2012 at 1:17 pm

            I am not sure Cobalt will ever see this posting but I found the below link/site very interesting back in 2010.  The author uses simple math and existing automotive principles to explain how vehicle efficiency can be determined.  

            The site is has been static [mostly unchanged] for about a year or so since the author was unemployed for some period of time.  The following link compares CO2 emissions per mile to gasoline and electric vehicles.  Other sections of the site address other subject matter some people interested in automotive technology might find interesting.  Hope you enjoy the link.  


      • By Tom G. on August 14, 2012 at 1:17 am

        Cobalt said in part: “Your assumption that BTU content is an acceptable [method?] for the comparison of energy in transportation fuels is incorrect. BTUs (British thermal units) are a measurement of heating value.

        Here is my take on the subject and my definition of a BTU.

        The amount of heat required to raise the temperature of one pound of water (at or near 39.2 degrees Fahrenheit) by one degree Fahrenheit or in practical terms, the amount of heat generated by one lighted stick of match.  One Btu is also equal to about 252 small calories or 0.252 kilo calories.  A gallon of liquid propane contains about 92,000 Btu, a gallon of fuel-oil about 140,000 Btu and an average ton of coal about 20 million Btu.  One kilowatt-hour of electricity contains about 3,400 Btu.  To read more about how the BTU is used in business and industry please go to:

        Here is another way to look at BTU.  We measure the quantity of energy (or force) with the units kilowatt hour, BTU, or Joule. These are all measurements of units of energy.  Conversely, the same units can be used to measure how much energy a process [or a vehicle for example] has used.  Example – We used so many BTU’s of fuel therefor we must have used and equivalent number of kilowatt-hours of electricity or an equivalent number of gallons of some type of fuel.

        Let’s take an example.  If our vehicle uses one gallon of gasoline to go 60 miles in one hour that means we have achieved 60 miles per gallon.  It also means that since there are 3414 BTU’s in a kilowatt-hour and a gallon of gasoline has about 110,000 BTU’s of heat energy; we would have consumed and equivalent of 32.2 Kilowatt Hours of electric power.  It really doesn’t make any difference – horsepower, watt, or the BTU – they can all be the same since each can be represented by each units equivalent value.

        You could use BTU’s to tell your neighbor how much heat energy you used last winter to heat your home instead of the number of gallons of heating oil.  Actually that would be far more accurate measure since heating oils vary in heat content just like the difference in the energy content of gasolines.  Your neighbor could then convert the BTU number you gave him into an equivalent number of gallons of fuel you used if he knew the BTU content of the fuel you were using.  


  5. By Reticuli on November 7, 2012 at 4:06 pm

    Horsepucky.  It’s not even a technical or cost hurdle anymore.  All new gas-using models are now already designed and certified with fully flex engines due to the Brazilian mandate.  The car companies, which are in bed with the oil companies, keep the feature switched off in the American market.  You’re living in the past.  A mandate on new vehicals would now cost us NOTHING and destroy OPEC overnight. 

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