There is an old joke in the energy business that advanced biofuels are the fuel of the future, and always will be. A Spanish company, Abengoa Bioenergy , has bet $500 million on robbing that joke of its punch line. In the middle of a cornfield here it is building a 38-acre Erector set of electrical cable and pipe that will soon begin producing cellulosic ethanol, which it calls a low-polluting alternative to petroleum products. This is just as the George W. Bush administration and Congress intended seven years ago with legislation promoting energy independence. But even as Abengoa and other companies prepare to produce significant amounts of cellulosic ethanol, using corn stalks and wheat straw as opposed […]