There have always been non-food crops grown and they have always competed with food crops for resources because both are produced using the same intensive agriculture methods. Energy crops are no different. They too will require the same resources as other intensive agriculture crops and they will all share North America's resources and work under the same market economics that drive every commodity crop. The food vs fuel argument is heavily distorted and primarily driven by politics not logic.

We are getting very impressive in our biomass yields. Our current yields of corn and sorghum biomass in North America are pretty much as high as what the rainforest in Brazil achieves. That is quite a biomass yield and something we should be proud of, however it does call into question how much higher it can go. If billions of years of evolution have suggested a pseudo-upper limit for land based biomass productivity in the rainforest, how much higher can we go? Clearly it is not an actual limit because sugar cane and miscanthus have been grown at a higher yield, but at what cost? And what is a reasonable upper limit? Its safe to say we aren’t sure yet, but we are certainly entering new territory in terms of biomass yields/acre and good or bad its very impressive.