Water everywhere: Total water requirements for the irrigation and conversion of one liter of ethanol by state, as well as the total water used in ethanol production by state. (See full image on page 2.)
Environmental Science and Technology
Ethanol from corn consumes three times more water than previously thought.
Ethanol derived from corn consumes up to three times more water than previously thought, according to a new study.
Prior studies have estimated, based on national production averages, that one liter of corn-derived ethanol should require 263 to 784 liters of water to both grow the crop and convert it into fuel. Now, researchers at the University of Minnesota have concluded that the amount of water used in ethanol production varies hugely from state to state, ranging from 5 to 2,138 liters of water per liter of ethanol, depending on regional irrigation needs.
Corn ethanol is already plagued by environmental concerns such as pollution from fertilizer, pesticides, and herbicides; soil erosion; greenhouse-gas emissions from production; and competition for agricultural land with food crops.
The new study, published in the journal Environmental Science and Technology, also found that as corn-based ethanol production has approximately doubled nationwide between 2005 and 2008, related water use has more than tripled.
"Ethanol consumes more water over time as corn production extends to regions that need extensive irrigation," says Sangwon Suh, an assistant professor of biosystems engineering at the University of Minnesota and coauthor of the study. "That means more water is needed to produce a given unit of ethanol over time."
Suh and his colleagues examined state and county records on irrigation use for growing corn, both as food and for fuel, as well as the location, production levels, and water usage of existing corn-ethanol facilities. The researchers found that more than 80 percent of the corn used to make ethanol is harvested within a 64-kilometer radius of the refinery where it is converted into fuel. Using this information and data on local rates of irrigation, the researchers were able to estimate the water requirements of individual corn-ethanol production facilities.
In some states, such as Ohio, Iowa, and Kentucky, where corn can grow with little to no irrigation, only five to seven liters of water are required to turn the foodstuff into fuel. Almost all of this water is used to boil, ferment, and distill the biofuel. As ethanol production has increased, however, more corn is being grown in western states such as Nebraska, Colorado, and California, where irrigation needs raise the fuel's water requirements significantly.
"This is one more nail in the coffin for ethanol," says David Pimentel of Cornell University, in Ithaca, NY, whose own studies have shown that ethanol requires more energy to produce than it releases when burned, and that the fertilizer used to grow corn for ethanol has contributed significantly to dead zones in the Gulf of Mexico (areas of the ocean with low oxygen content due to increases in chemicals in the water).
Rain and floods in the corn-growing Midwest could drive up the costs of producing the biofuel.
Demand for corn-derived fuel is driving up food prices, but new technologies could help.
I wonder how much worse this is compared to producing a barrel of oil from the oil sands in Alberta.
http://en.wikipedia.org/wiki/Athabasca_Oil_Sands#Water
Beef takes 25 times more water per lb than what it takes to grow a lb of corn.
I wish the farm industry would put a little more money toward research into Cellulosic ethanol.
Or just another plant that requires less fertilizer/water/pesticides.
They spend all this time and energy trying to perfect corn, and it is a dead end for producing fuel.
It is a perfect example of entrenched interest being to stupid to see the writing on the wall.
Sweet Sorghum grows well all the way to Canada and can produce as much molasses sugar per acre as sugar cane. You can feed the waste to cattle after the sugars are squeezed. You could also use the waste for cellulose to sugar technology and produce more ethanol. Sweet sorghum also requires much less water and chemical additives than corn or sugar cane. Algae, switchgrass, and other plants are also much better for producing biofuels of many kinds.
Politicians, lawyers, bean counters, and farmers unwilling to try new ideas are the problem.
The main areas where corn is grown and processed have a superabundance of rainfall. I live in the middle of Illinois corn country. We have so much rain that it is not even possible to get the equipment in the field some springs. We had over 50 inches last year! None of these posts refer to the simple fact that nature uses water over and over again. Pull out your Jr. High School text book and look up transpiration!
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
Our list of the 50 most innovative companies, including the following:
On Twitter
Become a Fan on Facebook
Subscribe to the Feed
lasertekk
146 Comments
Once again
With each report, the deck continues to stack against ethanol. Production should have been outlawed yesterday.
Reply
USABORN1
1 Comment
Re: Once again
It only takes 3 gallons or less to convert corn to 1 gallon of ethanol. Anybody can inflate numbers to make it look bad. How much water does it take to make a gallon of gas?? Or even a ream of paper?? I guarantee it is much less than ethanol.
It takes an average of 2 gallons of water to brush you teeth, over 7 to flush the toilet,37 per gallon of crude, or 16 to convert beets to sugar. So 3 gallons to convert corn to ethnol is squat, and all the money is staying in the USA...
Reply
mfolbe
49 Comments
Re: Once again
You really believe it uses that much water to brush your teeth. Next time, try it with the water turned off while you are brushing.
Ethanol is just bad stuff all around. It can't be transported. It's energy content sucks. It relies on federal subsidies to be profitable. It takes special engines to even use it because it gunks up our old engines. You have to have congress mandate its use or it would just go away. Maybe if gas was $4 a gallon again, it would be considered, but not at $2. Nobody wants it.
Reply
bill_paterson47
1 Comment
Re: Once again
1 gallon of Ethanol = 3 gallons of water; POET's less than that.
1 lb of hamburger = 4 gallons of water
1 chicken = 11.6 gallons of water
1 gallon of oil = 41.5 gallons of water
Know your facts before you start spreading rumors. Alot of lives, jobs, and reputations are at stake. All because big oil has more money and power to inflate the information conveyed to our public, we are all fools for not giving credit where it's due.
My statistics are from Iowa State University Extension/epa/usgs
Reply
MarionMeads
9 Comments
Re: Once again
There is something wrong with the statistics on the hamburger figure.
Consider this:
How much water does a cow drink before it is processed into Hamburger? Then add to it the many pounds of water to produce the many pounds of grass, corn or alfalfa that the cow eats.
Fred Pearce, author of When the Rivers Run Dry, helps us quickly understand it by the few numbers he gives:
* to grow a pound of rice: 250 to 650 gallons of water
* to grow a pound of wheat: 130 gallons
* to produce a quart of milk: 500 to 1000 gallons
* to produce a pound of cheese: 650 gallons
* to produce a 1/4 pound of burger: 3000 gallons
He kindly puts water use into perspective in annual terms:
* 1 ton (265 gallons) for drinking
* 50 to 100 tons (13,250 to 26,500 gallons) around the house
* 1500 to 2000 tons (397,500 to 530,000 gallons) for food and clothing
Reply