A good piece here that lucidly illustrates the limits of scaling up on biofuels.

Corn futures are now trading close to a 10 year high.

As the article says . . .

"Rising demand for alternative fuels is eroding supplies of crops normally used for animal feed or food processing. U.S. production capacity for corn-based ethanol, already at a record, may double in the next two years, and the government said last month demand for biodiesel made from soybean oil may rise 17 percent in 2007. The U.S. is the largest producer and exporter of both crops."

This reminds me a bit of the solar industry - the same growing pains and rising prices that come from a competitive shortage of feedstock. For the solar industry it's the shortage of high-grade silicon for which they compete with a more powerful semiconductor industry; for the biofuels industry it's the shortage of crops for which they compete competing with the food industry.