As many as 100 million acres of cropland and pastures would have to be dedicated to cultivating biomass fuels like switchgrass to support a national goal of 25 percent renewable energy use by 2025, a University of Tennessee study says.

Moreover, new commercial technologies will be needed to turn switchgrass, wheat, rice and forest products into ethanol fuel, now principally made from corn, and their byproducts into feedstock for power generation.

And on that note, see: Robert Rapier, "Cellulosic Ethanol Reality Check