Guest Opinion by Kip Hansen — 6 December 2023

One of the absolutely nuttier ideas to come out of the climate change / anti-fossil fuels mania of modern times comes from the international airlines business.  They are being pushed by governments and getting  unending pressure to signal their virtue by visibly climbing aboard the “Stop Fossil Fuels Now” bandwagon.  The hitch is, as we all know, is that airplanes need fuel to fly and currently, fossil fuels are the only choice.

But, thanks to the venerable Old Gray Lady, we are now informed, with interactive media,  that:

“Airlines Race Toward a Future of Powering Their Jets with Corn”

“Carriers want to replace jet fuel with ethanol to fight global warming. That would require lots of corn, and lots of water.”

The headline is simultaneously literal and tongue-in-cheek – the (I am fighting the urge to use the phrase “corny idea”) concept is to replace the more usual jet fuels  with ethanol made from corn. 

“Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound with the chemical formula CH3CH2OH. It is an alcohol, with its formula also written as C2H5OH, C2H6O or EtOH, where Et stands for ethyl. Ethanol is a volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. It is a psychoactive recreational drug, and the active ingredient in alcoholic drinks.”  [ source The Wiki ]

 Ethanol is “alcohol” of the same type one finds in their whiskey, vodka, gin, moonshine, beer and now fruit drinks.  

Ethanol is a fairly simple hydrocarbon composed entirely of Carbon, Hydrogen and Oxygen.   Products of its complete combustion are CO₂ and H₂O.

“Wait,” you say, “replacing fossil fuels with ethanol will still produce CO₂?”  Of course it will, they are both, jet fuels and ethanol, primarily hydrocarbons. 

So why make the switch?  Already, in the U.S.A., “Today, nearly 40 percent of America’s corn crop is turned into ethanol, up from around 10 percent in the mid-2000s. This was largely because of government mandates that began in 2005 requiring gasoline to be mixed with minimum amounts of renewable fuel.” [ NY Times, linked article – hereafter just NYT ]

How much ethanol are they talking about for automotive gasoline each year?  “14 billion gallons”.  “….the 135 billion gallons of finished motor gasoline consumed in the United States contained about 14 billion gallons of fuel ethanol.”  [ source – US EIA ]

How much fossil fuel-based jet fuel is burned each year?  In 2019 commercial 95 billion gallons of jet fuel were consumed. [ source ]. The Covid panic reduced that somewhat, but the total is expected to reach that again this year.

To replace all of the fossil-fuel-based jet fuel would require, if all things were equal (which they are not) another 95 billion gallons of ethanol.

The U.S. already uses up to 40% of its total corn crop to produce the measly 14 billion gallons of ethanol mixed into gasoline.  It would take 250% of today’s total U.S.  corn crop to produce the 95 billions gallons of ethanol to replace jet fuels – not even considering the number of additional ethanol plans that would be needed.  Of course, the U.S. need not carry the whole ethanol load necessary to replace worldwide jet fuel use, but it gives us some idea of the magnitude of the suggestion.

In acreage of land planted in corn, that would be an increase from 100 million acres to 250 million acres.  Much of that acreage would have to be irrigated and aquifers in the mid-west corn belt are famously overtaxed already.

Other sugar crops such as sugar cane and sugar beets can be used to make ethanol using the same processes as for corn.  Ethanol can also be produced from almost any plant materials even  cellulosic feedstocks, such as crop residues and wood—though this is not as common. 

But wait, there’s more:  ethanol does not contain the same amount of energy per gallon as jet fuel. 

Jet Fuel contain approximately 135,000 BTUs per gallon.  Ethanol contains only 76,330 Btu/gallon which is only 56% of the energy in jet fuel.  Thus, many more gallons of ethanol will be needed – around 130 billion gallons of ethanol to replace the 95 billion gallons of jet fuel.

On the CO₂ emissions side, burning 1 kg of jet fuel produces about 9.3 kg of CO₂ whereas burning 1 kg of ethanol only produces 5.7 kg of CO₂.  That’s about 2/3s as much CO₂ per kg….but, as above, ethanol doesn’t have as much energy per kg (or BTUs per gallon) as jet fuel – only about 2/3s as much, to the actual reduction in CO₂ has to be calculated taking into account the extra ethanol that has to be burned or the same energy return. 

Then there is the idea of burning food to power jet airplanes.  Of the world’s current 8 billion humans, just under 10% do not get enough food to eat – do not get enough basic calories, not to mention vitamins, proteins, micro-nutrients – they just plain do not get enough food.  Corn is good food.  Land used to grow corn for jet fuel could grow other food or other basics grains which, if transported to areas of need, would help resolve that problem.  Corn and other grains are also food for animals raised as food – chickens, pigs, cattle, sheep, rabbits and goats that provide high quality protein around the world. 

Remember, because this idea touches on the topics of fossil fuels, the environment, agriculture, animals as food and fresh water use, there is and will be a great deal of controversy.

Bottom Lines:

1.  It is my opinion that it is ill-advised, bordering on criminally negligent, to convert much needed food into fuels for cars or for airplanes, when so many people are in want of basic calories.

2.  Whether or not any real world net reduction in CO₂  would result from a shift from jet fuels to ethanol in air transportation is questionable.  

3.  Arable land is just too precious to be wasted in the misguided effort to grow corn in order to replace jet fuel with ethanol – given that arable land could be used to grow better food for the underfed peoples of the world.  

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Author’s Comment:

In short, growing five times more corn so that it can be turned into ethanol is just a stinking rotten idea when there are plentiful fossil fuels.

Revisiting the idea if and when fossil fuels ‘run out’ might get my vote – but I doubt it.

If we must, for some as yet unknown reason, restrict emission from airplanes, then forbidding our governments from flying politicians around the world all the time would be my first suggestion.  Junketing businessmen and women would be next on the list – let them have video conferences. 

OK, in truth, whole books and journals full of research would be needed to cover this topic and do it justice.  I’m just sticking with “Bad Idea”.

Thanks for reading.

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