Life cycle energy and environmental benefits of generating electricity from willow biomass

摘要

Biomass is a key renewable energy source expected to play an important role in US electricity production under stricter emission regulations and renewable portfolio standards. Willow energy crops are being developed in the northeast US as a fuel source for increasing biomass energy and bioproduct demands. A life cycle inventory is presented that characterizes the full cradle-to-grave energy and environmental performance of willow biomass-to-electricity. A willow biomass production model is developed using demonstration-scale field experience from New York. Scenarios are presented that mimic anticipated cofiring operations, including supplemental use of wood residues, at an existing coal-fired generating facility. At a cofiring rate of 10% biomass, the system net energy ratio (electricity delivered divided by total fossil fuel consumed) increases by 8.9% and net global warming potential decreases by 7-10%. Net SO_2 emissions are reduced by 9.5% and a significant reduction in NO_x emissions is expected. In addition, we estimate system performance of using willow biomass in dedicated biomass gasification and direct-fired generating facilities and demonstrate that the pollution avoided (relative to the current electricity grid) is comparable to other renewables such as PV and wind.