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?”

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





About the Author

Adam Shake works in Washington D.C. and spends most of his recreational time hiking and kayaking in Virginia and West Virginia with his wife Laura and their 6 year old Rhodesian Ridgeback, Katahdin. Adam is dedicated to the Environment and maintains a website at www.twilightearth.com
  • Bill

    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.”

  • Bill

    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.”

  • Jenks

    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.

  • Jenks

    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.

    • engine 17

      Yes, the corn sucks up the water. All day everyday the sun is shining, and the entire leaf surface area of the plant is is keeping itself cool by evaporating a buttload of water.

      • Yup. Then the water just disappears. It’s the darndest thing – plants use WATER, then there’s no more water anywhere. EVER!

        Come on, guy – how is that an even remotely reasonable comment?

  • 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.

  • 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.

  • Erik

    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.

  • Erik

    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.

  • Jay Tee

    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)

  • Jay Tee

    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)

  • Dreika

    Who cares?

  • Dreika

    Who cares?

  • Will S.

    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.

  • Will S.

    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.

  • ChuckL

    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.

  • ChuckL

    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.

  • Will S.

    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.

  • Will S.

    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.

  • 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.

  • Misidentifed verification of process water use at Coskata. That was verified by Parsons Engineering. Argonne vouched for two other key elements – 7.7 times more energy created than used in making Coskata’s ethanol and Greenhouse Gas reductions of up to 96 percent (vs. gasoline) depending on the feedstock used.

  • Misidentifed verification of process water use at Coskata. That was verified by Parsons Engineering. Argonne vouched for two other key elements – 7.7 times more energy created than used in making Coskata’s ethanol and Greenhouse Gas reductions of up to 96 percent (vs. gasoline) depending on the feedstock used.

  • larryhagedon

    What is this article, A joke?

    Excluding the fact that 2.5 gallons of hooch per bushel of corn is outdated 1970s technology, we still get much more than Ethanol from a bushel of corn.

    In addition to the Ethanol, Bio-Diesel and Methane or Syngas we get massive quantities of human food, Pharmaceuticals, industrial chemicals and animal feeds as corn derived coproducts, often more than we have markets for.

    Food is especialy problematic. We can not market anywhere near as much corn based people food as we can grow and produce as a coproduct of the hundreds of other corn based products.

    Here is the list of products coming out of Iowa Corn Processing Center in Eddyville Iowa; High Fructose Corn Syrup, Corn Syrup, Dextrose, Crude Corn Oil, Corn Gluten Meal, Sweet Bran®, Dry Sweetners, Acidulants, Citric Acid, Anhydrous Citric Acid, Liquid Citric Acid, Sodium Citrate, Potassium Citrate, Itaconic Acid, Natural Vitamin E, D-Alpha Tocopheryl Acetate, Mixed Tocopherols, Phytosterols, FFA, Citrous Salt, CO2, Monosodium Glutamate, Threonine and Cyclodextrins, bio-diesel, Ethanol.

    In modern corn processing plants, corn is processed, like many other commodities including petroleum, for best uses. Just as gasoline is only one of many petroleum products, so Ethanol is only one of many value added products derived from corn.

    This babble about water usage is simply a red herring. If we actualy used up water the earth would have gone bone dry long ago. All water is endlessly recycled. In fact it evaporates endlessly from plants, soil and the ocean and falls again as rain.

    Rain distribution; rain forests and deserts, come and go, but the water is always on earth somewhere and is constantly being naturally repurified and redistibuted.

    What is true is that with both water and petroleum, we are using up the easy to reach ancient underground pools and aquifiers. Not the first time, or the hundredth time that has happened. Lots of ancient cities are now burried under desert sands.

    In the future we will be using solar, wind, wave, ocean current and tidal power to desalinate trillions of gallons of ocean water and send it thru pipelines all over the world. That has already started in a few places and then even natures spotty water redistribution will be conquered and controlled by man.

    larry

  • larryhagedon

    What is this article, A joke?

    Excluding the fact that 2.5 gallons of hooch per bushel of corn is outdated 1970s technology, we still get much more than Ethanol from a bushel of corn.

    In addition to the Ethanol, Bio-Diesel and Methane or Syngas we get massive quantities of human food, Pharmaceuticals, industrial chemicals and animal feeds as corn derived coproducts, often more than we have markets for.

    Food is especialy problematic. We can not market anywhere near as much corn based people food as we can grow and produce as a coproduct of the hundreds of other corn based products.

    Here is the list of products coming out of Iowa Corn Processing Center in Eddyville Iowa; High Fructose Corn Syrup, Corn Syrup, Dextrose, Crude Corn Oil, Corn Gluten Meal, Sweet Bran®, Dry Sweetners, Acidulants, Citric Acid, Anhydrous Citric Acid, Liquid Citric Acid, Sodium Citrate, Potassium Citrate, Itaconic Acid, Natural Vitamin E, D-Alpha Tocopheryl Acetate, Mixed Tocopherols, Phytosterols, FFA, Citrous Salt, CO2, Monosodium Glutamate, Threonine and Cyclodextrins, bio-diesel, Ethanol.

    In modern corn processing plants, corn is processed, like many other commodities including petroleum, for best uses. Just as gasoline is only one of many petroleum products, so Ethanol is only one of many value added products derived from corn.

    This babble about water usage is simply a red herring. If we actualy used up water the earth would have gone bone dry long ago. All water is endlessly recycled. In fact it evaporates endlessly from plants, soil and the ocean and falls again as rain.

    Rain distribution; rain forests and deserts, come and go, but the water is always on earth somewhere and is constantly being naturally repurified and redistibuted.

    What is true is that with both water and petroleum, we are using up the easy to reach ancient underground pools and aquifiers. Not the first time, or the hundredth time that has happened. Lots of ancient cities are now burried under desert sands.

    In the future we will be using solar, wind, wave, ocean current and tidal power to desalinate trillions of gallons of ocean water and send it thru pipelines all over the world. That has already started in a few places and then even natures spotty water redistribution will be conquered and controlled by man.

    larry

  • LonnieB

    To ChuckL,

    I respectfully disagree with your assessment of the efficiency of ethanol (E85). The inefficiency you cite is a result of the engines on the road today not being set up for ethanol useage. E85 requires a compression ratio of approx. 13.0 to 1. Most cars and trucks barely break 9.0 to 1, if they do that. Even my high performance Mach 1 only has 10.0 to 1. It isn’t difficult to gat the ratios E85 requires. Far less expesive and complicated than CNG conversion.

    Drag racers have been using alcohol blends for decades and the Indy Racing League mandated E85 useage, exclusively. NASCAR is under pressure to do the same. The first internal combustion engines were powered by ethanol, the same fuel Henry Ford used in his first cars, like the original Model T’s.

    Corn is the least efficient fermentation stock. Sugar cane, sugar beets and best of all, Jerusalem Artichokes are far better, don’t require the amount of water to grow and refine and are not food commodities that threaten the world’s food supply.

    E85 is an excellent “bridge” fuel, until more efficient alternatives come on line. No drilling required and no supertankers to belch out pollution along the world’s coastlines or to be fought over.

  • LonnieB

    To ChuckL,

    I respectfully disagree with your assessment of the efficiency of ethanol (E85). The inefficiency you cite is a result of the engines on the road today not being set up for ethanol useage. E85 requires a compression ratio of approx. 13.0 to 1. Most cars and trucks barely break 9.0 to 1, if they do that. Even my high performance Mach 1 only has 10.0 to 1. It isn’t difficult to gat the ratios E85 requires. Far less expesive and complicated than CNG conversion.

    Drag racers have been using alcohol blends for decades and the Indy Racing League mandated E85 useage, exclusively. NASCAR is under pressure to do the same. The first internal combustion engines were powered by ethanol, the same fuel Henry Ford used in his first cars, like the original Model T’s.

    Corn is the least efficient fermentation stock. Sugar cane, sugar beets and best of all, Jerusalem Artichokes are far better, don’t require the amount of water to grow and refine and are not food commodities that threaten the world’s food supply.

    E85 is an excellent “bridge” fuel, until more efficient alternatives come on line. No drilling required and no supertankers to belch out pollution along the world’s coastlines or to be fought over.

  • dan s

    http://www.swhydro.arizona.edu/archive/V6_N5/feature4.pdf has slightly different statistics than you are pulling out of your arse

    96% of corn used for ethanol production is not irrigated

    and then in the conversion to ethanol a ratio of 4:1 or 3:1 water per ethanol

    Sure ethanol isn’t a solution for our energy needs, but you sir need to put down the crack pipe

  • dan s

    http://www.swhydro.arizona.edu/archive/V6_N5/feature4.pdf has slightly different statistics than you are pulling out of your arse

    96% of corn used for ethanol production is not irrigated

    and then in the conversion to ethanol a ratio of 4:1 or 3:1 water per ethanol

    Sure ethanol isn’t a solution for our energy needs, but you sir need to put down the crack pipe

  • dave

    Adam, corn is going to be raised one way or another, people used irragation long before ethanol.

    • Randy

      You can argue anything you want, but clean water usage in a age where water shortages are becoming a problem, groundwater levels are being droped faster than they can replentish is very unresponsible. We can live without the ethanol, but not clean water. Corn grower lobbyests and speculators are somehow keeping the EPA from seeing the obvious. In turn using one of our top food comodities as a fuel derivitive has to be one of the worst ideas ever. Win win for farmers though, causes grain prices to rise causing meat, eggs, produce, and milk to high levels while collecting gov’t money(subsities). Wake up America!!

  • dave

    Adam, corn is going to be raised one way or another, people used irragation long before ethanol.

  • marlin

    liars figure and figures lie on both sides of this silly “ethanol” issue. Fact – energy can nether be created or destroyed, meaning: rearrange the molecules however you like, rename them to your own phycological delight and the end of it all human non-intrinisic motion requires energy inputs and they all come from the same place – da sun. Ethanol for cars? the question should be – why cars? Ethanol renewable? – that too is a poor argument – why do farmers carry crop insurance? because when wind and hail damage their corn crop they CAN’T get it back – renew it – its gone. with each crop the anhydrous and all the diesel used to plow, till, spray, truck and store the stuff is consumed – not renewable.

  • marlin

    liars figure and figures lie on both sides of this silly “ethanol” issue. Fact – energy can nether be created or destroyed, meaning: rearrange the molecules however you like, rename them to your own phycological delight and the end of it all human non-intrinisic motion requires energy inputs and they all come from the same place – da sun. Ethanol for cars? the question should be – why cars? Ethanol renewable? – that too is a poor argument – why do farmers carry crop insurance? because when wind and hail damage their corn crop they CAN’T get it back – renew it – its gone. with each crop the anhydrous and all the diesel used to plow, till, spray, truck and store the stuff is consumed – not renewable.

  • Pingback: Electric cars may not be so Green - Smart Car of America Forums : Smart Car Forum()

  • Not-a-Marxist

    Animals (dinosaurs) drank an awful lot of water during their life cycle.

    If we’re comparing total mass balance, that fossil fuel took a huge bit of water for each gallon of gas, didn’t it?

  • George

    I might point out that when Ethanol burns, the by-products are Carbon Dioxide and water, which is returned to the atmosphere as water vapour. The problem comes when ground water is used for irrigation, depleting aquifers that have been in existence for millions of years.

    • ALMOST a fair point, but most aquifers are relatively “stagnant”, in the sense that they don’t move, contribute to plant growth, animal hydration, etc.

  • D Finch

    Another ridiculous anti-ethanol article with no facts. 2500 gallons per bushel… where do you come up with this stuff.

    • Kevin Frey

      Yes where did he come up with those numbers? He is way off. FACT is, based on University of Colorado Ag Sciences Dept. it takes approximately 350,000 gallons of water to grow 1 acre of corn (about 30,000 plants) over a 100 day growing cycle. Since it takes approximately 2.1 acres to produce a bushel of corn, that would mean that in actuality it requires about 294,000 gallons of water to grow enough corn to make 1 gallon of ethanol. If you also calculate the approximate 3-6 gallons used in the distillation process of dissolving the solutes to make 1 gallon of ethanol usable in an internal combustion engine, that brings the total to around 294,004.5 gallons of water per gallon of ethanol. 2500 gallons, yeah right. Good thing you called him out on his ridiculous anti-ethanol rhetoric. Don’t you just love science?