Actually he says in the interview considering the current technology that it can yield 20 times what corn ethanol can, unless he lying in the interview.
I've read intervies with him where he laments not having the "proper" funding for his projects. Now maybe he's preaching a differant message depending on whose chior he's in front of but everything I've seen on switchgrass says twenty years and craploads of money away from efficent production.
10 tons of SG ... which yields 100 gallons of ethanol
20,000 pounds of mass makes (roughly) 700 pounds of product? That's more efficient than corn ethanol?
An acre of U.S. corn yields about 7,110 pounds of corn for processing into 328 gallons of ethanol.