Sorry – scale of water use was old & not right logic for the Cellulosic case.
Corn based ETOH uses 785 gal/gal ETOH produced (dry grind method/process) & without corn irrigation (~80% case for most corn growers) and the Actual ETOH proces uses about 3-6 gal/gal ETOH produced.
So for Cellulosic case the corn is grown for food market and cellulosic therefore would not be incremental demand but use of
the byproduct waste and so water consumption is not additive. The Cellulosic process is also more conserative (with recycle case) and only consumes about 1.9 – 3 gal/gal ETOH.
And current figures on gasoline production from crude with current high levels of recycle for water and the ratio is about 2-2.5 gal /gal gasoline. <See some these values in Arizona University PDF ~ 2007 @ http://www.swhydro.arizona.edu/archive/V6_N5/feature4.pdf :>
So now the only hurrdle left is conflict on trying to increase MPG – since ETOH is much lower BTU content and lowers fuel by 3-5 MPG for every additional 3-5% of ETOH blended. And the damage car companies claim ETOH is doing to carburetors/jets & computer fuel use and offsetting their efforts for mechanical improvements in MPG.
