TransForum Vol. 9, No. 1

Water Use in the Production of Biofuels and Gasoline

Just as water is a vital component of biological processes, it is also essential to producing both biofuels and gasoline. In fact, water has even become a key feature of existing energy projects, and a potential issue in new ones. Argonne researcher Michael Wang and his colleagues at the Transportation Technology R&D Center recently completed a study that looks at the water used for the production of energy feedstocks and fuels from the perspective of the fuels’ lifecycles, including resource extraction, feedstock transportation, fuel production, fuel transportation and operation of a vehicle on the fuel.

Their work focused on two major steps of fuel lifecycles: feedstock production (farming or oil recovery) and fuel processing/production (ethanol production or oil refining). Researchers looked at the consumption of irrigation water, oil-well injection water and process water for five fuel pathways: bioethanol from corn, ethanol from cellulosic feedstocks, gasoline from Canadian oil sands, Saudi Arabian crude and U.S. conventional crude from onshore wells.

Their analysis found that water consumption for feedstock and fuel production varies considerably by type of feedstock, soil and climactic condition and production technology for bioethanol; and by age of oil well, recovery technology, and extent of produced water re-injection and steam recycling for petroleum gasoline. There are significant regional differences, however, particularly for corn production. A summary of consumptive water use for the fuels analyzed in this study is presented in Table 1.

The study noted that cumulative impacts are a particularly critical issue for fuel development. Given the rapid development of both oil sands and biofuel globally, it is conceivable that the sustainability of water resources may be affected more by impacts accumulating over time and across numerous nearby projects, than by average gallons-of-water-used-per-gallon-of-fuel-produced as examined in this study. This possibility has important policy implications and suggests that additional studies, including site-specific analyses, are needed to better understand the ramifications of energy development.

The study concludes that conservation measures can reduce water consumption and achieve sustainable bioethanol and gasoline production. Specifically:

• Improved water management is needed for corn irrigation, particularly in those areas where water is scarce.


• Cellulosic feedstocks should be grown in their native habitat to reduce or eliminate irrigation.


• Groundwater management is especially critical in arid regions, and in locations with high concentrations of biofuel or oil production facilities.


• Steam condensate reuse, process water recycling and water-conserving process modifications using existing commercial technologies should be implemented wherever possible.


• For cellulosic ethanol facilities, a process design optimized to reduce water use should be encouraged.


• For oil recovery, produced water re-injection should be used to the maximum extent possible.

This work is supported by the U.S. Department of Energy’s Office of Biomass under Zia Haq.

May 2009