July 21, 2014

Energy and Water 4: Water Needy Fuel Production

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Figure 1: Water Consumption of Different Fuel Types. Union of Concerned Scientists.

Figure 1: Water Consumption of Different Fuel Types. Union of Concerned Scientists.

With the energy industry established as the biggest water guzzler, using more water than agriculture, industry and public utilities, the next question to address is: Which source of energy, or fuel, is the worst water offender?

A study conducted by Tamim Younos, previously an associate director at the Virginia Water Resources Research Center based at Virginia Tech, looked at the water consumption of 11 different types of fuel sources and five power generating methods. Basing their calculations on government reports, the scientists found that, in terms of power generation, geothermal and hydroelectric energy types use the least amount of water, while nuclear plants use the most.

The study also found that the most water-efficient energy sources were natural gas and synthetic fuels produced by coal gasification. The least water-efficient energy sources were fuel ethanol and biodiesel.

The results were no surprise to the Union of Concerned Scientists who state that powering your car with ethanol might use dozens of gallons of water per mile. Creating a single gallon of corn ethanol requires about 100 gallons of freshwater. In some regions, where farming relies on irrigation, the production of one gallon may use three times that amount.

On a more hopeful note, other forms of biofuel may not need as much water for production—it may only take 2 to 10 gallons of water to produce each gallon of “cellulosic” biofuel.

Looking at figure 1, you can see that gasoline is the most water-friendly of the three compared fuels, using less than half a gallon in the extraction and refining process. But gasoline comes with other costs as it is not a renewable resource.