Biomass Resource Assessment Part I - Gainesville Regional Utilities

than fossil fuel energy, which produces emissions both from the production of the fuel and theuse of the fuel itself. Net energy ratios of some generation options are shown in Figure 30.30160%Net energy ratio (energyproduced/fossil energy input252015105Net energy ratioCarbon closure140%120%100%80%60%40%20%(%)Carbon closure0Coal fired powerplantNatural gascombined-cycleIGCC using energycropsDirect fired frombiomass resiudes0%Figure 30. Net energy ratio (energy output/fossil fuel energy) and percent carbon closure of fourgeneration technologies (adapted from Mann and Spath, 2002).5.2. Literature reviewYoshioka et al. (2006) evaluated the CO 2 emissions associated with harvesting, transporting,and chipping logging residues from forest plantations in Japan. The system evaluated included1) whole-tree yarding/skidding from 100 to 1,000 meters, 2) processor limbing and bucking atthe landing of the logging site, 3) forwarder hauling of debris from the landing to the road, 4)transport of slash and chips by a 4-ton truck from 20 to 80 km, and 5) energy-conversion.Depending on the operation, CO 2 emissions ranged from 17 to 87 kg CO 2 dry Mg -1 , or about 4 to6 kg CO 2 MWh -1 , within the range of emissions shown from a similar study in Finland. Theseemissions are lower that the estimated emissions of 341 and 304 kg CO 2 MWh -1 from coal andoil respectively.Closer to Alachua County, Condon and Putz (2007) evaluated emissions produced fromharvesting, transporting, and chipping hardwoods during longleaf pine ecosystem restorationprojects. They calculated the net carbon balance as the difference between the carbon harvested99