I love this picture this tall grass, miscanthus giganteus.
It is ten times more efficient in creating biomass from sunlight than switchgrass. It is a perennial grass, but it does not produce seed, because it is a sterile hybrid. It is laborious to propagate it by digging the rhizomes. On the other hand, being sterile it cannot displace indigenous flora.
The French company Bical harvests miscanthus and produces a fuel pellet, that can be fed automatically to a furnace.
(photo from allyrose.wordpress.com)