Ethanol's Water Use

So much has been made of the amount of water being used in the production of ethanol. As I am sure everyone is aware, water is a precious resource and management and conservation efforts are needed to ensure the continued supply of fresh usable water in this nation. But since ethanol is competing with gasoline as a transportation fuel, it's water use should be put in perspective with the water use of the petroleum industry.

The estimates for the amount of water used in the conversion of corn into ethanol is 3 to 4 gallons of water for each gallon of ethanol produced.

Now let's see how this compares to the petroleum industry. It is estimated that for every barrel of oil refined that 65 to 90 gallons of water are used resulting in 20 to 40 gallons of water being discharged. That means that 45 to 50 gallons of water are consumed in the production of each barrel of petroleum. There are 42 gallons of crude oil per barrel, so that amounts to 1.1 to 1.2 gallons of water for every gallon of crude oil processed.

So at the present time ethanol uses more water per gallon produced than gasoline production does. But as the easy to process oil is becoming more limited, oil production is beginning to shift to oil that is harder to process. A great example is the tar sands of Canada.

The tar sands of Canada, the oil shale here in our country and various other similar deposits around the world are most likely going to be the long term future of the oil industry. And to process tar sands into fuel, 2 to 4.5 barrels of water are required to produce one barrel of fuel. In other words 2 to 4.5 gallons of water are required for every gallon of fuel produced.

So at the moment gasoline production is not as water intensive as is ethanol production. But as more and more production is shifted to tar sands and oil shale deposits, gasoline production will become more water intensive than ethanol production.

To a certain extent this explains why the amount of articles criticizing ethanol has gone up so much over the last few months. Not only is the water intensity of gasoline production going to increase in the future, so is the pollution emitted during the production process. And the environmental damage done through the extraction of these deposits is much greater than traditional oil drilling techniques. As time passes ethanol will look better and better in comparison to gasoline. So if the oil industry is going to be able to kill ethanol off it has to be now.

Sources:

Water Usage for Current and Future Ethanol Production
The Harm the Tar Sands Will Do