Figure 1 provides a comparative picture of the water consumption of primary and transportation fuels, excluding unconventional gas. This comparison, based on gallons per million British Thermal Units (MMBTU), shows that for the transportation fuels:
Water for soy and corn irrigation and ethanol processing is far greater than for all other fuels;
Water consumption to turn coals into transportation fuels is comparable to that for oil from tar sands;
Water for petroleum extraction is fairly low but quite high for refining;
EOR requires wide ranges and potentially very large quantities of water;
And while water for in situ oil production...