Tuesday, April 8, 2008

Is Corn Ethanol Really Economically Infeasible?

Is Corn Ethanol Really Economically Infeasible?

One of my readers insists that the claims that corn-based ethanol is too energy inefficient to make sense points to the "State Average Fuel Ethanol Rack Prices" table. The prices range from around $2.52 to $2.83 per gallon. These are the wholesale prices, so I would expect them to be a bit more expensive at retail. But how much more?

I know that ethanol fuel is generally exempt from motor vehicle fuel taxes--and at some point, if enough vehicles switched over, we would have to start taxing it--but these prices would suggest that corn-based ethanol may not be that inefficient. If large amounts of energy were going into refining ethanol, I would expect the prices to be higher. How much tax subsidy is there in these prices?

I really, really like the idea of ethanol as a fuel. While the global warming thing is probably hype, corn is a renewable resource--we aren't going to run out, and the net carbon dioxide change over several years is zero. I also like the idea that it doesn't come from places where the people have their turbans wound too tightly.

Even if sugar cane based ethanol makes more sense than ethanol from corn, that's okay. Just about any moist tropical country can grow sugar cane, and the number of potential growers would mean that a cartel like OPEC would difficult to maintain. In addition, the U.S. has Hawaii, Puerto Rico, and the U.S. Virgin Islands. In addition, Louisiana at one time was a major grower of sugar cane (and the graveyard of many slaves who were worked to death to bring in the crop). I would be surprised if we can't grow sugar cane in a number of other Gulf Coast states.

UPDATE: A reader points out that this table at Wikipedia (for what that's worth) showing the energy content per volume and per weight of various fuels. One problem with ethanol is that the energy density of ethanol is quite low compared to gasoline. Unless you can take advantage of its very high octane number (perhaps with very high compression engines), the amount of ethanol you are going to burn to get the same energy output as gasoline means that even at the wholesale prices listed in the table above, the stuff is still quite a bit more expensive than gasoline.

UPDATE 2: A number of readers expressed their concern about rising demand for corn to make ethanol is driving up the cost of food, not just in America, but in the Third World. Another reader asks about jojoba. This March 6, 2003 New Scientist article points to biodiesel based on jojoba oil:

An oil frequently found on your bathroom shelf may prove a viable alternative to diesel fuel for cars and trucks. Early tests show that jojoba-fuelled engines kick out fewer pollutants, run more quietly and for longer, and perform just as well as diesels.

The search for alternative fuels, driven by dwindling oil reserves and concerns over exhaust emissions, has lead researchers to investigate more sustainable sources such as vegetable oils. Sunflower oil, soybean oil and even opium poppy oil have all been tested as potential fuels.

Now it is jojoba's turn. Jojoba is a desert shrub that can reach up to 4.5 metres high and typically lives more than 150 years, producing nuts that yield half their volume in oil. The non-toxic oil is widely used as a non-greasy skin-smoothing ingredient in cosmetics, and as a base for shampoos and make-up.

Engineers think the oil has potential as a motor fuel because it releases a lot of energy when it burns and is chemically stable at the high temperatures and pressures in a working engine.

Dash of methanol

To test jojoba in engines, Mohamed Selim and his colleagues at the United Arab Emirates University in Al-Ain and at the Helwan University in Cairo, connected an array of sensors to a diesel engine and monitored its performance while burning regular diesel fuel.

They then ran the engine on a fuel called jojoba methyl ester, which they made simply by adding a dash of methanol and a catalyst to raw jojoba oil.

Selim's team reveals in the journal Renewable Energy (vol 28, p 1401) that the jojoba fuel matched diesel for torque and power over the engine speeds they tested, between 1000 and 2000 revolutions per minute. What is more, the jojoba combustion gases took slightly longer to reach maximum pressure in the cylinder, which Selim believes may explain why the engine runs more quietly on the nut oil.

And of course, here's the jojoba oil web page!

The reader who sent these links suggests:
Jojoba yields 194 gallons of oil per acre and can be planted in desert conditions that won't support most other crops. It yields approximately the same BTU per acre as ethanol without the high cost of cultivation while not distorting feed grain markets and food supplies dependent upon them. It's safe to assume it would yield more BTU per acre with even rudimentary cultivation, thus making it much more efficient than ethanol.

I've read that the U.S. could easily grow enough jojoba to power every diesel vehicle in the country by simply fostering the plants growth in areas that it would naturally inhabit. I've felt for years that jojoba is the 'hidden answer' to many our energy problems, that along with promoting diesel as an alternative to gasoline instead of trying to legislate it out of existence.
If jojoba is really the future, what's holding it up? There are a lot of good ideas out there, but I suspect that gasoline is still cheap enough to make a lot of these great ideas not go anywhere.

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