"Ethanol from corn is not a good way to go for many reasons," he said. "Water is just one reason." Other researchers have found that ethanol production removes vast amounts of acreage from food production, and it is one of the reasons the price of food is rising so rapidly. It is a huge problem in Brazil, where forested regions are being converted to cornfields, thus releasing more greenhouse gases into the atmosphere.
However, there are other sources of ethanol, like switch grass, which would require much less water than corn, Younos said.
But let's go back to that 60-watt light bulb, because it puts the researchers' findings in perspective.
If the bulb is lighted by a fossil-fueled power plant (coal, natural gas, oil) it will require 8 to 16 gallons of water to keep it lit for one 12-hour day. Based on an estimated 111 million occupied housing units in the U.S., if everybody kept one bulb on 12 hours a day for a full year, the amount of water used would add up to 336 to 656 billion gallons of water.
That's just for one light bulb, in each home, for one year. If we knew the total number of light bulbs across the country, the amount of water used would be staggering, or perhaps drowning.
But here's the good news. According to Rachelle Hill, Younos's collaborator, if just one incandescent bulb is switched to a compact fluorescent bulb, it will save 2,000 to 4,000 gallons a year.
If the numbers compiled by Younos and Hill are anywhere near accurate, growing energy demands will place huge demands on fresh water supplies, which are already stretched to the limit in many areas of the world, even the United States. It's a double whammy in the Southwest, where a prolonged drought has robbed a desert region of vast amounts of water at a time of explosive growth in population.
That's a conflict that could someday make the current energy crisis seem like the "good old days."
Lee Dye is a former science writer for the Los Angeles Times. He now lives in Juneau, Alaska.