Washington, April 14 (Inditop) Bioethanol is a clean-burning energy source, but can gobble up to three times more water than previously thought, a major issue given the increasing water scarcity worldwide.

The growing demand for bioethanol, particularly corn-based ethanol, has sparked significant concerns among researchers and a raging public controversy about its impact on water availability.

In the new study, Sangwon Suh, assistant professor at the University of Minnesota (U-M) and colleagues made a new estimate of bioethanol’s impact on the water supply using detailed irrigation data from 41 states.

Previous studies estimated that a gallon of corn-based bioethanol requires the use of 263 to 784 gallons of water from the farm to the fuel pump. But these estimates failed to account for widely varied regional irrigation practices, the scientists say.

Actually the figure is over 2,100 gallons of water for every gallon of bioethanol, from farm to fuel pump, depending on the regional irrigation practice in growing corn.

Suh’s team found that bioethanol’s water requirements can be as high as 861 billion gallons of water from the corn field to the fuel pump in 2007, said an U-M release.

The scientists noted that annual bioethanol output in US is currently about nine billion gallons and is expected to increase in the near future.

The study is being published on Wednesday’s issue of Environmental Science & Technology, a bi-monthly publication.