1,000 Gallons Water Per 1 Gallon Ethanol - How Green is That?
Water conservation has always been a hot button for aid organizations and environmentalists, and with a world wide lack of drinking water, and third world countries getting involved in the growing bio-economy, I think it’s time to look behind the curtain of the fuel movement that calls itself “green.”
Most of us are familiar with the “food vs. fuel” controversy that’s been making news, but in addition to this, one of the things that many people are taking a good hard look at, is water sustainability in reference to this corn ethanol fuel.
If we look at the raw data, it becomes apparent that it takes 1 bushel of corn to make 2.5 gallons of ethanol. Now that doesn’t seem so bad, until you ask yourself, “How much water does it take to grow that bushel of corn?”
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Let’s look at some more raw data. Did you know that it takes 2,500 gallons of water to produce that one bushel of corn? That’s a lot of water for 2 and half gallons of Ethanol. Let’s take this thinking a step further. If it takes 2,500 gallons of water to create 2.5 gallons of ethanol, then it takes 20,000 gallons of water, to make 20 gallons of Ethanol.
Think of it like this, the average firetruck holds up to 1,000 gallons of water. Now imagine 20 firetrucks lined up side by side, that’s how much water it takes to make 20 gallons of Ethanol.
I realize that not all of the water that’s needed to grow corn, is fed to the crop through irrigation. In the United States, about 15 percent of a crops total water usage comes from irrigation. But the United States is not the only country that’s growing corn for ethanol. In the growing bio-economy, many smaller (and less water laden countries) are jumping on the corn bandwagon, and some of these countries don’t have the average yearly rainfall, or depth of top-soil that the United States has.
The best source of any type of renewable fuel, should be as environmentally friendly as possible, and until other technologies become available, I for one, will keeping my eye out for other options.
Photo courtesy of SouthernPixel via Creative Commons License.
Source: Domestic Fuel
Since I’m in a corn-growing region…I might inform you that most of this 2,500 gallons of water to grow 1 bushel of corn comes free from the sky in the occasional events we call “rain.”
Doesn’t it seem likely that the majority if that water is absorbed by the ground and not the corn? It would then filter it’s way back to an aquifer or possibly even be evaporated. I highly doubt a bushel of corn sucks up 2500 gallons. Another point of interest would be how ethanol is derived from the corn. If they press the corn to make some sort of corn mash then a lot of that water would be regained at that point.
Bill,
you are absolutely correct. Most corn grown in the United States gets 85% of its water from the ground and rain, and 15% from irrigation. So if we take into account only irrigated water, were looking 150 to 1 instead of 1000 to 1. That’s still a lot of water.
But not all of the corn being grown is in the corn belt, (or even in this country) where rain is plentiful and top soil is deep. (Interesting Article in this months National Geographic on world soils)
More and more corn is being grown in area’s of the world where far more than 15% of a corns water consumption, is being “fed” to the corn.
Thanks for you’re comment.
It’s sad that you are positing such an ignorant argument, because a certain number of people will believe it fully makes a case against ethanol.
The 2500 gallons of water are not ‘consumed,’ but returned to the earth. They are not gone forever, not lost, not contaminated.
There is certainly a case to be made comparing ethanol to other alternative fuel sources, but bad science does not a solid case make.
The water never ‘goes away’, it either comes back as rain, through evaporation, or is pumped back out of the ground, or falls as natural rain in the first place.
Corn ethanol is the most inefficient source of ethanol; although it’s becoming more efficient very quickly, it will not remain the source of ethanol in this country.
SO GET OVER IT! Also, expect to see much less criticzim of corn ethanol once Barack Obama is president. (Obama is pro-ethanol)
Who cares?
I work at an ethanol plant and in production we typically average 3-5 gallons of water per gallon ethanol produced. About half of that is make-up for utilities.
And be careful when using a term like inefficient. You can make ethanol very “efficiently” but you would be sacraficing rate in the process. There will be plenty of warts with cellulose. For example, thing about the logistics of moving stover or switchgrass vs a nice packed corn truck.
Forget how inefficient the manufacture of ethanol from corn is. Ethanol is a very inefficient fuel to use for motor vehicles. To cover the same distance as 8 gallons of ethanol, you would use only about 5 gallons of gasoline and less than 4 gallons of diesel fuel.
Ethanol is a bad idea for motor car power. With luck we won’t have to worry about Obama pushing Ethanol from the oval office. He will just go back to being the most liberal senator in existence.
Corn ethanol is grown and processed in a few months while petroleum has sat underground reacting for millions of years or whatever your fancy is. Of course gas is going to have more energy. Still, it has about 93% of the BTU value of gasoline. The big difference is that you are driving a car that has been developed to run primarily on gasoline for nearly 100 years. Putting it in that motor will work but its not apples to apples.
I work in Communications for General Motors and the water issue around ethanol production is one of those that ethanol haters keep raising to help make it the Big Lie - say it enough and people automatically think it is true. Heartening to read here that posts before this one corrected the 2,500:1 premise. Here’s something else to keep in mind: Next-generation carbon-based ethanol from Coskata (a company with which GM has a strategic alliance) uses less than a gallon of water to produce a gallon of ethanol. The bioreactors in the Coskata system produce 99.7 percent fuel-grade ethanol and a little water. Most of the water used is recycled in the process. Don’t take my word for it. Argonne National Laboratory checked and verified this.