Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies 5-2014 Global Evaluation of Biofuel Potential from Microalgae Jeffrey W. Moody Utah Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Mechanical Engineering Commons Recommended Citation Moody, Jeffrey W., "Global Evaluation of Biofuel Potential from Microalgae" (2014). All Graduate Theses and Dissertations. 2070. https://digitalcommons.usu.edu/etd/2070 This Thesis is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. GLOBAL EVALUATION OF BIOFUEL POTENTIAL FROM MICROALGAE by Jeffrey W. Moody A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Mechanical Engineering Approved: Dr. Jason Quinn Dr. Byard Wood Major Professor Committee Member Dr. Rees Fullmer Dr. Mark McLellan Committee Member Vice President for Research and Dean of the School of Graduate Studies UTAH STATE UNIVERSITY Logan, Utah 2014 ii Copyright © Jeffrey Moody 2014 All Rights Reserved iii ABSTRACT Global Evaluation of Biofuel Potential from Microalgae by Jeffrey W. Moody, Master of Science Utah State University, 2014 Major Professor: Dr. Jason C. Quinn Department: Mechanical and Aerospace Engineering Traditional terrestrial crops are currently being utilized as a feedstock for biofuels but resource requirements and low yields limit the sustainability and scalability. Comparatively, next generation feedstocks, such as microalgae, have inherent advantages such as higher solar energy efficiencies, larger lipid fractions, utilization of waste carbon dioxide, and cultivation on poor quality land. The assessment of microalgae-based biofuel production systems through lifecycle, technoeconomic, and scalability assessments has been forced to extrapolate laboratory-scale data due to the immaturity of the technology. This type of scaling leads to large uncertainty in the current near-term productivity potential and ultimately the results from modeling work that rely on this type of modeling. This study integrated a large-scale validated outdoor microalgae growth model that utilizes 21 species and reactor-specific inputs that accurately account for biological effects such as nutrient uptake, respiration, and temperature with hourly historical meteorological data from around the world to determine the current global productivity potential. A global map of the microalgae lipid and biomass productivity has iv been generated based on the results of annual simulations at 4,388 global locations spread over the seven continents. Maximum annual average yields between 24-27 m3·ha-1·yr-1 are found in Australia, Brazil, Colombia, Egypt, Ethiopia, India, Kenya, and Saudi Arabia with the monthly variability (minimum and maximum) yields of these locations ranging between 14 and 33 m3·ha- 1·yr-1. A scalability assessment that leverages geographic information systems data to evaluate geographically realized microalgae productivity, energy consumption, and land availability has been performed highlighting the promising potential of microalgae-based biofuels compared to traditional terrestrial feedstocks. Results show many regions can meet their energy requirements through microalgae production without land resource restriction. Discussion focuses on sensitivity of monthly variability in lipid production compared to annual average yields, biomass productivity potential, effects of temperature on lipid production, and a comparison of results to previous published modeling assumptions. (157 pages) v PUBLIC ABSTRACT Global Evaluation of Biofuel Potential from Microalgae The objective of the proposed work is to determine the productivity potential of microalgae around the world based on the current large uncertainty of the productivity potential found in literature. To achieve this objective, a validated thermal and biological growth model was utilized coupled with weather data files from weather stations around the world. This enabled a realistic assessment of the productivity potential based on actual climatic variables. Sensitivity of microalgae lipid productivity to biomass production, temperature, and variability was performed illustrating the importance of biological and temporal resolution. Results from modeling work were leveraged for a scalability assessment based on transportation fuel consumption and land availability statistics from around the globe. A comparison of the results from this study to the current assumption in literature shows the community has dramatically overestimated the current near term productivity potential in literature. As research into microalgae continues to grow, many studies are being performed to understand the energetic and economic feasibility of converting microalgae to biofuel. The large variability as to the true current productivity potential of microalgae has detrimentally affected large-scale assessments of the microalgae-to-biofuels system. The large uncertainty has resulted in favorable skewing of the environmental impact, economic feasibility, and resource requirements of the microalgae-to-biofuel process. The results from this study offer a better understanding of the true large-scale near term productivity of microalgae based on light, nutrient, and temperature factors to better inform future energetic and economic assessments of biofuel from microalgae. Jeffrey W. Moody vi ACKNOWLEDGMENTS I give special thanks to my supportive wife, Allison, for her patience as I worked long days and late nights to finish this work. I could not have done it without her. I would like to thank Dr. Jason Quinn for his encouragement, support, and assistance throughout the entire process. Financial support was provided by the Department of Energy (grant number DE-EE0003114) and Utah State University. Jeffrey W. Moody vii CONTENTS Page ABSTRACT ........................................................................................................................................ iii PUBLIC ABSTRACT ............................................................................................................................ v ACKNOWLEDGMENTS ..................................................................................................................... vi LIST OF TABLES .............................................................................................................................. viii LIST OF FIGURES .............................................................................................................................. ix LIST OF SYMBOLS ............................................................................................................................. x INTRODUCTION ................................................................................................................................ 1 MATERIALS AND METHODS ............................................................................................................. 4 Photobioreactor Thermal and Biological Growth Models ........................................................... 5 Weather Data ............................................................................................................................. 11 Simulation Architecture ............................................................................................................. 12 Harvest Technique and Reporting Metrics ............................................................................ 12 Temperature Sensitivity ......................................................................................................... 13 Productivity Variability ........................................................................................................... 13 Geographical Information System (GIS)..................................................................................... 14 RESULTS AND DISCUSSION ............................................................................................................ 18 Global Productivity Potential and Variability ............................................................................. 18 Temperature Sensitivity ............................................................................................................. 22 Scalability Assessment ............................................................................................................... 23 Literature Comparison ............................................................................................................... 26 CONCLUSION .................................................................................................................................. 30 FUTURE WORK ............................................................................................................................... 31 REFERENCES ................................................................................................................................... 32 APPENDIX ....................................................................................................................................... 37 viii LIST OF TABLES Table Page 1 Average microalgae lipid yields in m3·ha-1·yr-1of various regions around the world with respective high and low variability ……………………………. 21 2 Amount