There are a number of problems with using switchgrass or any of these other cellulosic materials. The main problems relate to the handling, the storing, the transportation, the logistics of getting a huge volume through the system. We live in a country where we have one growing season per year, a relatively short growing season.
So there are a lot of things that stack up against the economics of it. In a small plant it can work, and there are some examples. It will be working in the U.S. However, to do it commercially is pretty difficult. Certainly in a big plant it seems very unlikely that it would actually make much of a difference to the amount of ethanol produced.