Life Cycle Assessment of Biomass for Generation of energy : Case Studies of Poplar Management in the Pacific Northwest of the U.S.A.

approved: ________________________________ Michael R. Milota A Life Cycle Assessment (LCA) of the production of poplar biomass grown under four management conditions in the Pacific Northwest (PNW) of the U.S.A. was conducted. While the extraction of fossil fuels and the subsequent generation of energy have environmental impacts, the alternative of extracting poplar biomass also has impacts due to electricity for irrigation, fuels for machinery, chemical application, and water consumption. Two management conditions were short rotation and no irrigation (Site 1) or irrigation with river water (Site 2). The others were long rotation and irrigation with wastewater from a treatment facility (Site 3) or irrigation with landfill leachate (Site 4). Questionnaires were used to obtain operating data for the production of cuttings and four processes in each site. These were land preparation, plantation management, harvesting, and land restoration. SimaPro v.8 and the USLCI and Ecoinvent v.3 databases were used to create a Life Cycle Inventory and the TRACI 2.1 v 1.01/US 2008 model was used to determine impact indicators. Biomass yield for future harvests was estimated using the 3-PG model. Plantation management and harvesting had the greatest contributions to environmental impacts due to fuel consumption. Utilization of chemicals during land preparation and land restoration were also important contributors. Short rotations resulted in lower global warming potential (79.5 and 54.5 kg CO2 eq· t-1) and energy consumption (1381.8 and 877.4 MJ ·t-1) than long rotations (93.1 and 81 kg CO2 eq· t-1 and 1406.9 and 1343.5 MJ· t-1). This was mainly due to diesel use during plantation management. Higher planting density resulted in greater water consumption and electricity use due to irrigation when cuttings are produced. Site 2 had the lowest environmental impacts compared to the other sites due to a low planting density, no on-site irrigation, and low chemical and energy consumption. Chemical use, such as applying pesticides and herbicides, strongly affected ozone depletion and eutrophication while fuel consumption, such as diesel use, had strong effects on global warming, smog and acidification. Increasing biomass yield reduces impacts. The biosolids applied in Site 3 reduced ozone depletion by 65% and other impacts by 19 to 24% compared to applying an equivalent amount of nitrogen fertilizer. The increased proportion of hydroelectricity in the PNW results a reduction in almost all impact categories compared to the typical electricity mix for the Western U.S. When the electricity was all from biomass, ozone depletion, smog and eutrophication increased. This research provides the opportunity for environmental impacts to be considered when making decisions for plantation management. ©Copyright by Marcia A. Vasquez Sandoval June 30, 2015 All Rights Reserved LIFE CYCLE ASSESSMENT OF BIOMASS FOR GENERATION OF ENERGY: CASE STUDIES OF POPLAR MANAGEMENT IN THE PACIFIC NORTHWEST OF THE U.S.A. by Marcia A. Vasquez Sandoval A DISSERTATION Submitted to Oregon State University In partial fulfillment of the requirements for the degree of Doctor of Philosophy Presented June 30, 2015 Commencement June 2016 Doctor of Philosophy dissertation of Marcia A. Vasquez Sandoval presented on June 30, 2015.