Fig. 6

System boundary of bioethanol production by fermentation of sugar from willow hot water extract. Electricity and heat are cogenerated on-site from the combustion of (HWE processed) biomass or natural gas. Site preparation steps of vegetation removal, herbicide applications and plowing (dashed boxes) only apply to grassland. Harvest and storage may occur during the summer or winter seasons. Harvest and fertilizer application occur once during each of the seven 3-year rotations. Headlands around the field are mowed annually. The other site preparation and maintenance steps occur once over the lifetime of the system