Crops grown for biofuel would use up more water than problematic sources of petroleum, such as tar sands and oil shale.
The great advantage of biofuel over petroleum is that the sources of biofuel are so widely available. The geologic fates may not have endowed your corner of the world with oil or gas deposits, but just about everyone can grow plants to make fuel. Unfortunately, some of the places these crops are grown require irrigation, and when water enters the equation, biofuels are a lot less attractive than the stuff they’re replacing.
Perhaps, a better idea is to use crops that don’t require any more water than what local rains provide. Oil palms in Indonesia and sugarcane in Brazil are already being used to produce biofuels in large quantities without irrigation. It’s not that these plants don’t need lots of water; it’s just that the tropical lands they are grown on receive abundant rains. Indeed, it might make more sense to import biofuels from such water-rich regions of the globe than to try to grow them where there’s not enough water. One thing’s for sure: The future of any crop now being touted as a good source of biofuel will hinge on how it slakes its thirst.
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