So Thirsty: Corn Ethanol Uses Up to 300% More Water than Previously Thought

corn ethanol water map image

Image: Environmental Science and Technology
University of Minnesota Researchers Find Huge Differences Between States
We already knew that corn ethanol production used lots of water, but according to a new study published in the journal Environmental Science and Technology, it's both worse than we thought, and more confusing then we suspected. Read on for more details.
corn field photo

Photo: Flickr, CC

From MIT's Technology Review:

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.

But that's not even a static drain on water resources. As more corn is used for ethanol, agricultural regions that need more irrigation are used and so the water usage per gallon of corn ethanol goes up.

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.

You can see this one the map at the top of this post. The dark orange states use over 600 billion liters of water, most of it from ground sources.

And this is just water! We're not even talking about all of the other problems with corn ethanol ("pollution from fertilizer, pesticides, and herbicides; soil erosion; greenhouse-gas emissions from production; and competition for agricultural land with food crops.").

The more time passes, the worse corn ethanol looks. Too bad it's subsidized through the wazoo and historically, agricultural subsidies have been almost impossible to repeal...

Via Technology Review
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