Abstract
Economically viable production of biobased products and fuels requires high-yielding, high-quality, sustainable process-advantaged crops, developed using bioengineering or advanced breeding approaches. Understanding which crop phenotypic traits have the largest impact on biofuel economics and sustainability outcomes is important for the targeted feedstock crop development. Here, we evaluated biomass yield and cell-wall composition traits across a large natural variant population of switchgrass (Panicum virgatum L.) grown across three common garden sites. Samples from 331 switchgrass genotypes were collected and analyzed for carbohydrate and lignin components. Considering plant survival and biomass after multiple years of growth, we found that 84 of the genotypes analyzed may be suited for commercial production in the southeastern U.S. These genotypes show a range of growth and compositional traits across the population that are apparently independent of each other. We used these data to conduct techno-economic analyses and life cycle assessments evaluating the performance of each switchgrass genotype under a standard cellulosic ethanol process model with pretreatment, added enzymes, and fermentation. We find that switchgrass yield per area is the largest economic driver of the minimum fuel selling price (MSFP), ethanol yield per hectare, global warming potential (GWP), and cumulative energy demand (CED). At any yield, the carbohydrate content is significant but of secondary importance. Water use follows similar trends but has more variability due to an increased dependence on the biorefinery model. Analyses presented here highlight the primary importance of plant yield and the secondary importance of carbohydrate content when selecting a feedstock that is both economical and sustainable.
| Original language | English |
|---|---|
| Pages (from-to) | 1897-1910 |
| Number of pages | 14 |
| Journal | ACS Sustainable Chemistry and Engineering |
| Volume | 12 |
| Issue number | 5 |
| DOIs | |
| State | Published - Feb 5 2024 |
Funding
This work was supported by the Center for Bioenergy Innovation, a Bioenergy Research Center funded by the U.S. Department of Energy Office of Biological and Environmental Research. It was authored in part by the Alliance for Sustainable Energy, LLC, the manager and operator of the National Renewable Energy Laboratory for the U.S. Department of Energy (DOE) under contract no. DE-AC36-08GO28308, and by Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. DOE under contract no. DE-AC05-00OR22725. The authors appreciate the assistance of Stan Martin in posting the data doi. Switchgrass Common Garden Panel: We thank the Thomas E. Juenger Laboratory for sharing clones to establish the common garden switchgrass panels at the Knoxville (TN), Watkinsville (GA), and Tifton (GA) sites used in these analyses. We acknowledge the contribution of numerous UGA undergraduates for grinding switchgrass samples. We would like to thank Crissa Doeppke (NREL) for all switchgrass sample preparation, Joel Miscall (NREL) for TGA analyses of switchgrass samples for ash content estimates, and Lance Hamilton (UTK) for assistance in the UTK harvest. Our appreciation goes to the numerous graduate students, technicians, and postdoctoral researchers who aided in switchgrass harvests. This work was supported by the Center for Bioenergy Innovation, a Bioenergy Research Center funded by the U.S. Department of Energy Office of Biological and Environmental Research. It was authored in part by the Alliance for Sustainable Energy, LLC, the manager and operator of the National Renewable Energy Laboratory for the U.S. Department of Energy (DOE) under contract no. DE-AC36-08GO28308, and by Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. DOE under contract no. DE-AC05-00OR22725. The authors appreciate the assistance of Stan Martin in posting the data doi. Switchgrass Common Garden Panel: We thank the Thomas E. Juenger Laboratory for sharing clones(32) to establish the common garden switchgrass panels at the Knoxville (TN), Watkinsville (GA), and Tifton (GA) sites used in these analyses. We acknowledge the contribution of numerous UGA undergraduates for grinding switchgrass samples. We would like to thank Crissa Doeppke (NREL) for all switchgrass sample preparation, Joel Miscall (NREL) for TGA analyses of switchgrass samples for ash content estimates, and Lance Hamilton (UTK) for assistance in the UTK harvest. Our appreciation goes to the numerous graduate students, technicians, and postdoctoral researchers who aided in switchgrass harvests.
Keywords
- bioethanol
- biomass yield
- composition
- feedstock variability
- life cycle analysis
- minimum fuel selling price
- switchgrass
- techno-economic analysis
