From the “no surprise there” news desk comes word that generating ethanol from lignocellulosic sources like paper wastes and agricultural residues is still probably a decade or more away from being competitive with ethanol production from starch from sources like corn and sugar cane.
Lignocellulosic sources are plentiful, and unlike starch sources, are not edible, so their use in ethanol production would not divert materials from the food stream. But the sugars in lignocellulosic material are more complex, and thus they require a far costlier assortment of enzymes to process. Furthermore, the wide array of feedstocks, all with different properties, means that each feedstock would have to be processed under different conditions, significantly adding to the complexity of the production system at large.
Even staunch proponents of ethanol agree that starch-based ethanol production is at best a stepping stone, and that in order for ethanol production to really be a smart use of resources, lignicellulosic ethanol production will have to come on line.
There are reasons that starch-based ethanol production is considered first-generation technology. Among other things, demand for corn as a feedstock drives up the cost of feed and food products, and makes it hard for soil conservation programs aimed at taking cropland out of production difficult to compete.
There are, of course, many opportunities for research to identify technological advancements in ethanol production. But in the meantime, policies like the federal renewable fuel standard will require the use of starch-based ethanol.