The Water Drain
Take Ethanol. When produced from corn that requires irrigation, it can use nearly 1,000 gallons of water per gallon of fuel, according to a 2007 report from Sandia. The same report said extracting and refining oil consumed an average of just 1.5 gallons of water per gallon of fuel.
“You can look at the water-use ratios, and if you include the corn production, ethanol is going to use more water than pulling up and refining petroleum,” said Otto Doering, a professor of agricultural economics at Purdue University.
Water consumption for ethanol produced from rain-watered corn consumes, on average, just four gallons per gallon of fuel produced, according to the Sandia study. Hightower estimates that between 4 percent and 7 percent of ethanol comes from irrigated corn.
But that adds up.
In fact, even assuming just 4 percent of the 8.5 billion gallons of ethanol expected to be produced in 2008 will come from irrigated corn, approximately 360 billion gallons of water will be consumed this year to make ethanol. That’s roughly equivalent to the amount of water used to refine the entire volume of gasoline American drivers yearly use.
When the energy produced from the fuel is considered — ethanol is not currently as energy efficient as gas — the same amount of water is used to generate about 2.5 percent of the country’s transportation fuel as is used to produce gasoline, the source of nearly 95 percent of the country’s transportation fuel.
That’s because while ethanol is now blended in more than 50 percent of gasoline, the majority of it is still E10, which is 10 percent ethanol and 90 percent gasoline. So ethanol is currently trimming just 7.2 billion gallons of gasoline off America’s annual appetite of 140 billion gallons, according to the U.S. Department of Energy.
Doering, Hightower and others speaking out about freshwater use are not advocating a return to oil for all liquid fuels. But there is a growing concern that water must be factored into the energy equation.
“It’s always been a problem, but it’s more of a problem now because the stresses on both water and energy have grown,” said Peter Gleick, president of the Pacific Institute for Studies in Development, Environment and Security in Oakland, Calif.
And with population growth added into the mix, drinking water supplies could come into competition with water use for energy.
Different regions — the South, the West, Midwest, Northeast — will have to develop plans tailored to their water supply, Gleick said. But no region is immune to freshwater shortages.
“People look at the Great Lakes,” Gleick said, “and think, ‘Wow, look at all that water. Why can’t we put it to use here or elsewhere?’ But the Great Lakes are a vulnerable, sensitive system as well. It turns out that if you take out just a little more water than nature puts in, the lake levels drop.”
The lake levels have dropped, which is very disconcerting to people like Mary Ann Dickinson, executive director of the the Alliance for Water Efficiency, a Chicago-based nonprofit.
“Really, the Great Lakes only have 1 percent of their water that’s renewable,” Dickinson said. “So if you’re taking out of the Great Lakes more than 1 percent of its total mass, you’re mining the Great Lakes.”
The problem is even more dire in Southeastern cities like Atlanta where droughts and population gains have stressed water resources to the point where the states are fighting over water use rights and citizens are asked to cut their water use to essential needs. But personal water use only accounts for about 20 percent of total freshwater use in Georgia, nowhere near thermoelectric power at 50 percent — the top consumer of water in the state. The numbers are even more tilted in the Southeastern region as a whole.
Many scientists suspect the water shortages in the Southeast and elsewhere are tied to global warming. While ocean levels would rise precariously from melting sea ice, lake levels are forecast to drop by two to five feet over the next few decades in nearly all the climate models, according to Cameron Davis, president of the Chicago-based Alliance for the Great Lakes.
Warmer winters mean less ice cover and more evaporation from the lakes, Davis said. Lake Michigan and Lake Huron’s level rose six inches in June thanks to above-average precipitation. But the level of the connected lakes is still expected to be 11- to 14 inches below the long-term average at the end of the year, according to the U.S. Army Corps of Engineers.
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