Researchers In Denmark have been looking hard at the amount of biomass that will be available for biofuels after 2030 is going to become tight. This is what they say in a peer-reviewed paper in Environment Science Technology, produced by the American Chemical Society.
We show that toward 2030, regardless of whether a global or European perspective is applied, the amount of biomass, which can become available for bioethanol or other energy uses, will be physically and economically constrained. This implies that use of biomass or land for bioethanol production will most likely happen at the expense of alternative uses. In this perspective, we show that for the case of a new advanced bioethanol technology, in terms of reducing greenhouse emissions and fossil fuel dependency, more is lost than gained when prioritizing biomass or land for bioethanol. Technology pathways involving heat and power production and/or biogas, natural gas or electricity for transport are advantageous.
There's more, but you have to subscribe. The bit that interests me is the parts about heat and power production, that is static power generation. I guess there could be real benefits in this area because potentailly at least you could build power plants in the middle of agricultural areas. There would be transmission losses, but this would probably be less than the energy needed to transport liquid fuels around.