Graduation Date

Fall 2020

Document Type

Thesis

Program

Master of Science degree with a major in Environmental Systems, option Energy, Technology, and Policy

Committee Chair Name

Dr. Sintana Vergara

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Dr. Kevin Fingerman

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Dr. Charles Chamberlin

Third Committee Member Affiliation

HSU Faculty or Staff

Subject Categories

Environmental Systems

Abstract

Biomass energy plays a small but significant role in the current renewable energy portfolio and is a promising alternative pathway for woody residues that would otherwise be considered waste. These woody residues are often stored in large piles prior to combustion, and greenhouse gas emissions from this storage phase of the bioenergy supply chain are uncertain and understudied. This incubation study investigates the effects of three environmental factors on emissions from decomposition of woody biomass stored in chip piles. Incubation experiments were conducted, subjecting chambers of Sequoia sempervirens woodchips to different levels of temperature, oxygen concentration, and moisture content, and measuring the resulting greenhouse gas emissions (CO2, CH4, N2O) over thirty days. Notably, CH4 was detected in concentrations above ambient levels, indicating that environmental conditions used in this study were conducive to anaerobic decomposition. Using a three-way repeated measures ANOVA, we found that temperature and moisture had significant effects on CO2 emissions (p < 0.005 and p < 0.001, respectively). Oxygen and moisture had significant effects on CH4 emissions (p < 0.05). No significant effects of these variables were detected for N2O emissions. High temperature and high oxygen treatments were found to be positively correlated with increased total CO2 and CH4 emissions. Understanding the key drivers of emissions from woody biomass can allow for better estimation of greenhouse gas emissions from the storage phase of the bioenergy supply chain.

Citation Style

APA

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