I think America makes enough biofuel to meet incremental gasoline demand. I've been wrestling with Excel for two days to produce this graph, which uses data from RITA, to give the volume of gasoline consumed historically in the US, the US renewable fuel authority for ethanol stats, the National Biodisel Board for volumes of biodiesel and the American Ethanol Coalition for volumes of ethanol produced in the US and the amount of the corn crop used to generate it. Their figures apply for 2004, 2005 and 2006, I've extrapolated them in the graph.
Here's the results of the hard work.
I've calculated the in compound annual growth in ethanol at of 2%/year since 1990, and ethanol production's compound annual growth of 10.2% in that time, and assumed that these are going to continue. In part of that calculation I've ignored a possibly rogue data point in the Rita numbers for 2004 which show a big spike in gasoline demand that year, and I've calculated the avearge of the 2003 and 2005 numbers and inserted it instead.
What is clear is that by 2013, about 40% of the US corn crop will be being used to make ethanol, and that will account for 5% of the total fuel consumption in the US. I am also assuming that cellulosic and other technology will make a negligible impact in that time. That there is no change in the US' stance on imports of ethanol from other low cost producers during that time.
What I'd really appreciate is for some one to run a ruler over the figures I've used...
By the way I posted this yesterday and realised that I'd forgot to make clear that I'd projected the data from the American Ethanol Coalition into the future. I've made that clear now.