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Biofuel Production

Technology pathway designs may be selected as candidates for process integration and possibly for experimental verification at engineering and/or pilot scale after component technologies are deemed sufficiently developed. The technology pathways are not meant to serve as a business model, but are used to guide and focus R&D on the largest cost and sustainability barriers, as well as inform stakeholders and researchers of quantitative progress on specific pathway elements.

University of Florida's Stan Mayfield Demonstration Biorefinery DatasetThe University of Florida's Stan Mayfield Demonstration Biorefinery enabled the study of the most effective ways to convert sugarcane and sorghum agricultural residues into cellulosic ethanol. This dataset provides details on 23 campaigns run at the biorefinery between 2012 and 2016. The data were published using GitHub, allowing interested users to browse the documentation, download specific files, download the entire dataset.

This workshop examines the potential benefits, feasibility, and barriers to the use of biofuels in place of heavy fuel oil (HFO) and marine gas oil for marine vessels. More than 90% of world’s shipped goods
travel by marine cargo vessels powered by internal combustion (diesel) engines using primarily low-cost residual HFO, which is high in sulfur content. Recognizing that marine shipping is the largest source of
anthropogenic sulfur emissions and is a significant source of other pollutants including particulates, nitrogen oxides, and carbon dioxide (CO2), the International Maritime Organization enacted regulations to
lower the fuel sulfur content from 3.5 wt.% to 0.5 wt.% in 2020. These regulations require ship operators either to use higher-cost, low-sulfur HFO or to seek other alternatives for reducing sulfur emissions (i.e.,
scrubbers, natural gas, distillates, and/or biofuels). The near-term options for shipowners to comply with regulations include fueling with low-sulfur HFO or distillate fuels or installing emissions control systems.
However, few refineries are equipped to produce low-sulfur HFO. Likewise, the current production rates of distillates do not allow the necessary expansion required to fuel the world fleet of shipping vessels
(which consume around 330 million metric tons). This quantity is more than twice that used in the United States for cars and trucks. The other near-term option is to install emission control systems, which also
requires a significant investment. All of these options significantly increase operational costs. Because of such costs, biofuels have become an attractive alternative since they are inherently low in sulfur and
potentially also offer greenhouse gas benefits. Based on this preliminary assessment, replacing HFO in large marine vessels with minimally processed, heavy biofuels appears to have potential as a path to
reduced emissions of sulfur, CO2, and criteria emissions. Realizing this opportunity will require deeper knowledge of (1) the combustion characteristics of biofuels in marine applications, (2) their compatibility
for blending with conventional marine fuels (including HFO), (3) needs and costs for scaling up production and use, and (4) a systems assessment of their life cycle environmental impacts and costs. It is
recommended that a research program investigating each of these aspects be undertaken to better assess the efficacy of biofuels for marine use.

Publication Date
Bioenergy Category
Mike Kass , Zia Abdullah , Mary Biddy , Corinne Drennan , Troy Hawkins , Susanne Jones , Johnathan Holladay , Dough Longman , Emily Newes , Tim Theiss , Tom Thompson , Michael Wang
Funded from the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Bioenergy Technologies Office.

The 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy is the third in a series of national biomass resource assessments commissioned by the U.S. Department of Energy. This report aims to inform national bioenergy policies and research, development, and deployment strategies. It is the first volume in a two-volume set. Volume 2 evaluates the potential environmental sustainability effects of a subset of production scenarios described in Volume 1.

Producing renewable fuel from dedicated energy crops, such as switchgrass, has the potential to generate localized environmental benefits. This study uses high-resolution spatial data for west Tennessee to quantify the effects of producing switchgrass for cellulosic ethanol on the grey water footprint (GWF), or the amount of freshwater needed to dilute nitrate leachate to a safe level, relative to existing agricultural production. In addition, the estimated cost and GWF are incorporated in a mixed-integer multi-objective optimization model to derive the efficient frontier of the feedstock supply chain and determine a switchgrass supply chain that achieves the greatest reduction in GWF at the lowest cost. Results suggest that background nitrate concentration in ambient water and the types of agricultural land converted to switchgrass production influence the extent of the GWF. The average GWF of switchgrass in the study area ranges between 131.8 L L−1 and 145.9 L L−1 of ethanol, which falls into the range of estimated GWF of other lignocellulosic biomass feedstock in the literature. Also, the average cost of reducing GWF from the feedstock supply chain identified by the compromise solution method is $0.94 m−3 in the region. A tradeoff between biofuel production costs and reduced nitrate loading in groundwater is driven by differences in the agricultural land converted to feedstock production. Our findings illustrate the energy-water-food nexus in the development of a local bioenergy sector and provide a management strategy associated with land use choices for the supply of energy crops. However, the water quality improvements associated with displacing crop with feedstock production in one region could be offset by expanded or more intensive agricultural production in other regions.

Publication Date
Contact Person
Jia Zhong
Contact Organization
University of Tennessee, Knoxville
Bioenergy Category
Zhong, J. , T. E. Yu , C. D. Clark , B. C. English , J. A. Larson , C. L. Cheng

Switchgrass (Panicum virgatum L.), a native of the North American prairies, has been selected for bioenergy research. With a focus on biomass yield improvement, this study aim (i) to estimate the genetic variation in biomass yield and important agronomic traits in ‘Alamo’, (ii) to determine correlations between biomass yield and agronomic traits, and (iii) to compare efficiency of phenotypic selection from a sward plot and advanced cycle half-sibs (ACHS) on the basis of space-plant performance. Sixty-two Alamo half-sib families (AHS) from a 4-yr-old Alamo sward and 20 advanced cycle half-sib families (ACHS) were evaluated in replicated field trials under simulated swards in Knoxville and Crossville, TN. Results showed significant variation (P < 0.05) among AHS for biomass yield, tillering ability, and spring vigor, suggesting the importance of additive genetic variation in these traits. Overall mean biomass yield of AHS was not different from the Alamo control, demonstrating the inefficiency of phenotypic selection from swards. Mean biomass yield of ACHS was 15 and 20% less than that of the control and AHS, respectively. Such results could be attributable to the influence of environment and genotype × environment interaction. However, results showed great potential for biomass yield improvement through selection on the basis of family performance. Using 10% selection intensity, parental control of two, and a narrow-sense heritability estimate of 0.11, gain per cycle selection from half-sib family selection is estimated to be 23%. Spring vigor showed potential use for indirect selection due to its high genetic correlation (rG = 0.75) with biomass yield. However, it is impeded by the low heritability estimate (h2 = 0.34).

Publication Date
Bioenergy Category
Dalid, C. , A. M. Saxton , F. L. Allen , V. R. Pantalone , S. Nayak , H. Bhandari

on environment friendly and socio-economically sustainable renewable energy sources. However, commercial production of bioenergy is constrained by biomass supply uncertainty and associated costs. This study presents an integrated approach to determining the optimal biofuel supply chain considering biomass yield uncertainty. A two-stage stochastic mixed integer linear programming is utilized to minimize the expected system cost while incorporating yield uncertainty in the strategic level decisions related to biomass production and biorefinery investment.

Publication Date
Bioenergy Category
Sharma, B. P. , T. E. Yu , B. C. English , C. Boyer , J. A. Larson
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