Design for Flexibility in the Forest Biorefinery Supply Chain

Le climat d’affaires de industrie papetière nord américaine et européenne change présentement. La baisse de la demande, la volatilité des prix, l’augmentation de la compétition pour l’accès aux matières premières et le contrôle du marché, ainsi que des couts énergétiques passablement élevés poussent les entreprises forestières à rechercher de nouveaux modèles d’affaires afin d’être plus compétitives sur le long terme. Une des alternatives pour ces entreprises est de se tourner vers le secteur émergent de la bioéconomie et du bioraffinage. Possédant déjà un système d’utilité, un réseau d’approvisionnement de matières premières, un réseau de distribution de produits ainsi qu’un savoir-faire technique ouvrant la porte à de nombreuses possibilités d’intégration massique et énergétique, l’industrie forestière possède plusieurs avantages compétitifs pouvant améliorer la performance économique de l’implantation du bioraffinage. Plusieurs stratégies différentes peuvent être adoptées pour implanter des activités de bioraffinage au sein d’une entreprise. Par contre, en raison des risques technologiques et des risques de marché associés aux nouveaux procédés et produits, et le manque en capital des entreprises forestières, l’implantation du bioraffinage devrait être effectuée par phase. Des outils d’analyse appropriés sont toutefois requis afin d’identifier les stratégies possibles et les phases d’implantation. Puisque la chaine logistique (SC) d’une entreprise est critique pour la compétitivité à long terme des bioraffineries, un outil d’analyse de la SC peut donc jouer un rôle clé pour une transformation d’entreprise réussie. Une analyse de la SC calcule le bénéfice pour l’ensemble de la chaine logistique et prend en compte les différents contributeurs de couts qui sont typiquement ignorés dans les analyses économiques, tel que les couts d’inventaire, de transition, etc. Elle peut aussi être utilisée pour prendre en considération la volatilité du marché, et détermine comment la flexibilité inhérente d’un système de production peut être exploitée pour atténuer les risques et maximiser le profit. À cet effet, une analyse de la SC peut aussi être utilisée pour cibler le niveau de flexibilité souhaité d’un système afin d’atténuer les risques de volatilité du marché. De plus, cette analyse offre une meilleure compréhension des couts et de la rentabilité d’une stratégie d’implantation donnée. Ainsi, une analyse de la SC peut être utilisée à deux fins différentes : v • Pour la prise de décision au niveau de conception, et plus précisément, pour cibler le niveau de flexibilité d’un procédé de fabrication, • Pour comparer différentes stratégies pouvant être poursuivies par une entreprise, en évaluant leur performance selon différentes conditions de marché. L’objectif de cette recherche est d’illustrer une telle méthodologie de conception, soit une méthodologie qui cible un niveau de flexibilité manufacturière préférable à avoir, qui aide à concevoir le réseau de la SC, et qui permet d’évaluer différentes stratégies de bioraffinage pour transformer une entreprise forestière. Cette méthodologie est démontrée en utilisant une étude de cas qui inclut deux options de produits/procédé, dont des procédés thermochimiques et biochimiques, et plusieurs stratégies d’implantation à implanter au fil du temps. Le point d’ancrage de cette méthodologie est basé sur les principes de gestion de la chaine logistique centrée sur les marges. Plutôt que d’appliquer une approche traditionnelle centrée sur la production, où la gestion de la capacité des équipements et la minimisation des couts de production prime, une approche centrée sur les marges vise plutôt à maximiser le profit. Pour ce faire, tous les couts encourus au long de la SC doivent être considérés de façon intégrée. De même, le potentiel de flexibilité au sein de la SC, particulièrement au niveau de la production, doit être exploité pour maximiser le profit. Une formulation mathématique d’optimisation est développée pour représenter une telle mentalité. Selon cette dernière, une méthodologie de conception est proposée afin d’aider le processus de prise de décision stratégique reliée au design de la chaine logistique du bioraffinage. Cette méthodologie est alimentée par d’autres méthodologies qui identifient un ensemble d’options de procédés/produits prometteurs. Elle comprend quatre étapes principales : 1. La définition des alternatives de procédés représentant différents potentiels de flexibilité, 2. La définition d’options de réseau de SC, en tenant compte des caractéristiques des alternatives de procédés, de même que les politiques, les forces et les faiblesses de l’entreprise étudiant ces alternatives procédés/produits, 3. Le ciblage d’un degré de flexibilité manufacturière et d’un réseau de SC associé, 4. L’analyse de stratégies d’implantation des alternatives procédés/produits retenues vi Un ensemble d’indicateurs de performance représentant la rentabilité de la SC, la robustesse et la flexibilité des différentes options de bioraffinage est utilisé pour évaluer la performance de stratégies de bioraffinage selon différents scénarios de marchés. Les résultats montrent que lorsque la flexibilité d’un système est améliorée, le profit augmente. Cependant, cela ne mène pas nécessairement à une amélioration de la rentabilité. Pour que la rentabilité d’un système flexible augmente, les investissements supplémentaires déboursés pour augmenter le degré de flexibilité doivent être compensés par une amélioration au niveau des profits. Ainsi, pour certains cas, la rentabilité augmente avec la flexibilité du procédé, et dans certains cas non. De plus, la robustesse d’une option est directement liée à sa flexibilité. Plus le degré de flexibilité augmente, plus le système devient robuste envers la volatilité du marché. De même, les résultats montrent l’importance de l’analyse de la SC lors de la prise de décision reliée à la conception. Ils illustrent le fait qu’un changement dans le degré de flexibilité manufacturière d’un procédé affecte directement les opportunités de l’entreprise. Ainsi, des stratégies de marché et des degrés de flexibilité différents impliquent une configuration de réseau de SC et une stratégie de gestion spécifiques. Il devrait donc y avoir une intégration entre la conception de procédés et la conception du réseau de la SC. Il est aussi montré que les produits chimiques à valeur ajoutée sont prometteurs pour le succès futur du bioraffinage. Les options de procédés fabriquant ces derniers obtiennent une rentabilité en termes de taux de retour interne considérablement plus élevée que les options fabriquant des produits de commodités.---------- The pulp and paper industry business environment in North-America and Europe is changing. Declining and volatile product price and demand, increased competition for feedstock and market share, growing competition from global low-cost producers and considerably high energy cost are driving companies to seek alternative business models to be competitive over the longer term. One alternative is to enter the bio-energy and biorefinery sectors that have been emerging in recent years. Having the required utility systems in place and the engineering know-how, existing feedstock supply chain networks and product delivery systems as well as the potential for mass and/or energy integration between existing processes and new processes imply competitive advantages for the forestry companies to improve their economic performance via implementing biorefinery. Many different strategies can be pursued for implementing the biorefinery. Due to a lack of capital for implementing such strategies, technological risks and product market immaturities, the implementation should be executed in a phase-wise manner. Proper analysis tools are required to identify feasible strategies and their implementation phases. The design and management of supply chain (SC) is critical for the long-term competitive advantage of companies who would like to implement the biorefinery. In this regard, SC analysis can be used to evaluate the potential SC performance of different biorefinery strategies. It calculates the profit across the entire SC and accounts for cost contributors that are typically ignored in economic analyses, e.g. inventory cost, changeover cost, etc. It can also be used to take into consideration market volatility, and determine how the flexibility of the manufacturing system can be exploited to mitigate market risks in order to maximize profit. In this way, SC analysis can be used to target the desired level of flexibility of a manufacturing system needed to mitigate the impact of market price volatility. Moreover, these capabilities provide better insight into the costs and profit incurred by an implemented strategy. Thus, an SC analysis can be used for two different purposes: • For making design decisions, and more specifically, for targeting the level of flexibility of a system and designing the SC network configuration • For comparing several strategies by evaluating their performance for different market conditions viii The objective of this thesis is to develop a design methodology for targeting the required level of flexibility, designing the SC network configuration, and evaluating different FBR strategies for transforming a forest company. The methodology is demonstrated using a case study that involves two product/process options, including thermochemical and biochemical processes, with several implementation strategies, implemented over the years. The pivot of this methodology is the margins-based thinking used as an operating policy. It is discussed that, instead of applying the traditional manufacturing-centric approach in production which focuses on capacity management and tries to minimize the costs, the margins-based policy must be implemented, which has the following specifications: • It maximizes the profit instead of minimizing costs • It considers all costs incurred by SC activities in an integrated manner and doesn’t only focus on production cost • It exploits the potential for flexibility in the SC, especially in production, to maximize profit A SC optimization formulation is developed to represent such thinking. Using this formulation, a design methodology is proposed for making strategic decisions related to biorefinery SC design. This methodology is fed by separate methodologies which identify the most promising set of product to produce and technologies to employ. Given that, the methodology involves four major steps: • Defining process alternatives representing different potentials for flexibility • Defining SC network alternatives based on the defined process alternatives as well as the policies, advantages and restrictions of the company • Targeting the level of flexibility of processes and determining its associated SC network • Analyzing different implementation strategies for the proposed product/processes with their targeted level of flexibility and defined SC network A set of performance metrics that represents SC profitability, robustness and flexibility is used to evaluate the performance of biorefinery strategies for several market scenarios. The results show that when the flexibility of a system is enhanced, its profit increases. But this does not necessarily end in profitability improvement. For the profitability of a flexible system to ix improve, the extra capital cost paid for increasing the level of flexibility must be compensated by the profit improvement. Thus, for some cases profitability increases with flexibility and for some cases it does not. Moreover, robustness has a direct relationship with flexibility. As flexibility increases, the system becomes more robust against market volatility. The results reveal the importance of SC analysis in making design decisions. They illustrate that changes in the level of flexibility will directly affect the company’s opportunities and strategies in the market, and thus, each level of flexibility implies a specific SC network configuration and management strategy. Therefore, there must be integration between process design and SC network design. It is also shown that added-value chemicals are promising for the long-term success of biorefineries. Their profitability, in terms of internal rate of return (IRR), is considerably higher than that of commodities

A Comprehensive Optimization Framework for Designing Sustainable Renewable Energy Production Systems

As the world has recognized the importance of diversifying its energy resource portfolio away from fossil resources and more towards renewable resources such as biomass, there arises a need for developing strategies which can design renewable sustainable value chains that can be scaled up efficiently and provide tangible net environmental benefits from energy utilization. The objective of this research is to develop and implement a novel decision-making framework for the optimal design of renewable energy systems. The proposed optimization framework is based on a distributed, systematic approach which is composed of different layers including systems-based strategic optimization, detailed mechanistic modeling and operational level optimization. In the strategic optimization the model is represented by equations which describe physical flows of materials across the system nodes and financial flows that result from the system design and material movements. Market uncertainty is also incorporated into the model through stochastic programming. The output of the model includes optimal design of production capacity of the plant for the planning horizon by maximizing the net present value (NPV). The second stage consists of three main steps including simulation of the process in the simulation software, identification of critical sources of uncertainties through global sensitivity analysis, and employing stochastic optimization methodologies to optimize the operating condition of the plant under uncertainty. To exemplify the efficacy of the proposed framework a hypothetical lignocellulosic biorefinery based on sugar conversion platform that converts biomass to value-added biofuels and biobased chemicals is utilized as a case study. Furthermore, alternative technology options and possible process integrations in each section of the plant are analysed by exploiting the advantages of process simulation and the novel hybrid optimization framework. In conjunction with the simulation and optimization studies, the proposed framework develops quantitative metrics to associate economic values with technical barriers. The outcome of this work is a new distributed decision support framework which is intended to help economic development agencies, as well as policy makers in the renewable energy enterprises

Economic and Environmental Optimization in the Supply of Switchgrass in Tennessee

The low efficiency of collection, storage and transportation in the switchgrass supply chain has hindered the commercialization of a switchgrass-based biofuel industry, even given its ecological and environmental advantages in carbon sequestrate, soil quality, water use, and pollution pressure. Thus, designing a switchgrass-based supply chain balancing both environmental and economic performance is important to expedite the development of the cellulosic biofuel industry to meet the national energy plan. The objectives of this study are to 1) determine economic cost and multiple environmental outcomes in feedstock supply chains and 2) identify the relation between the economic and environmental performances. The first paper considers three objectives: minimization of economic cost, greenhouse gas (GHG) emissions, and soil erosions. The second paper focuses on the relation between economic cost and abated greywater footprint for industrialized supply of cellulosic biofuel in west Tennessee. The improved augmented epsilon method and compromise solution method were applied to high-resolution spatial data to determine the optimal placement of the feedstock supply chains. Results in the first paper indicated that land change into switchgrass production is crucial to both plant-gate cost and environmental impact of feedstock supply. Converting croplands to switchgrass incurred higher opportunity cost from land use change but stored more soil carbon and generated less soil erosion. Tradeoffs in higher feedstock costs with lower GHG emissions and lower soil erosion on the frontier were captured. Soil erosion was found more cost effective criterion than GHG emission in general. The compromise solution location for the conversion facility generated at 63% increase in feedstock cost but improved the environmental impact in lowering 27 % GHG emission and decreasing soil erosion by 70 times lower in the feedstock supply chain compared with cost minimization location. Results in the second paper showed that tradeoff between feedstock costs and greywater footprint was mainly associated with the changes of land use, while ambient water quality condition was also influential to the selection of feedstock production area. The average imputed cost of lowering grey water footprint in the most preferred feedstock supply chain in west Tennessee was $0.94 m-3 [per cubic meter]

A Modeling, Optimization, and Analysis Framework for Designing Multi-Product Lignocellulosic Biorefineries

The objective of this research is to propose a methodology to develop modular decision analysis frameworks to design value chains for enterprises in the renewable fuels and chemicals sector. The decision support framework focuses on providing strategic decision support to startup and new product ventures. The tasks that are embedded in the framework include process and systems design, technology and product selection, forecasting cost and market variables, designing network capacities, and analysis of risks. The Decision support system (DSS) proposed is based on optimization modeling; systems design are carried out using integer programming with multiple sets of process and network configurations utilized as inputs. Uncertainty is incorporated using real options, which are utilized to design network processing capacity for the conversion of biomass resources. Risk analysis is carried out using Monte Carlo methods. The DSS framework is exemplified using a lignocellulosic biorefinery case study that is assumed to be located in Louisiana. The biorefinery utilizes energy crops as feedstocks and processes them into cellulosic biofuels and biobased chemicals. Optimization modeling is utilized to select an optimal network, a fractionation technology, a fermentation configuration, and optimal product recovery and purification unit operations. A decision tree is then used to design incremental capacity under uncertain market parameters. The valuation methodology proposed stresses flexibility in decision making in the face of market uncertainties as is the case with renewable fuels and chemicals. The value of flexibility, termed as “Option Value” is shown to significantly improve the net present value of the proposed biorefinery. Monte Carlo simulations are utilized to develop risk curves for alternate capacity design plans. Risk curves show a favorable risk reward ratio for the case of incremental capacity design with embedded decision options. The framework proposed here can be used by enterprises, government entities and decision makers in general to test, validate, and design technological superstructures and network processing capacities, conduct scenario analyses, and quantify the financial impacts and risks of their representative designs. We plan to further add functionality to the DSS framework and make available the tools developed to wide audience through an “open-source” software distribution model

Integrated Forest Biorefinery Network Design Under Uncertainty

The Canadian Pulp and Pulp (P&P) industry has been recently confronted by shrinking markets and tighter profit margins. Transforming P&P mills into Integrated Forest Biorefineries (IFBR) is a prominent solution to save the struggling industry and allow diversification towards the promising bioproducts markets. The implementation of such a strategy is a complex process that faces many sources of uncertainty. Therefore, the industry is in need for a planning tool that facilitates the IFBR network design by taking the uncertain market conditions into consideration. First, we propose a mixed integer programming model to optimize the investment plan in addition to other tactical decisions over a long term planning horizon. We test the model using a realistic case study for Canadian P&P companies, where we perform a set of sensitivity analysis tests in terms of bioproduct demand and energy prices. Our results showcase the potential of the IFBR to help the P&P industry and highlight the substantial impact of the bioproduct demand on its profitability. Second, we develop a Multi-stage Stochastic Programming model which explicitly incorporates the demand uncertainty. We also develop a simulation platform to validate the model and compare its performance with alternative decision models. We assess the value of incorporating demand uncertainty in the planning process and we also elaborate on the value of flexibility in terms of adjusting the investment plan in response to changes in market trends. Our results demonstrate the significant value of explicitly incorporating the uncertainty in IFBR network design as well as flexibility in the investment plan

Progress of social assessment in the framework of bioeconomy under a life cycle perspective

The bioeconomy is positioned as a sustainable pathway to address the climate crisis and decrease the consumption of fossil resources. Life cycle methodologies are recognised as useful tools for assessing sustainability issues of production and consumption patterns. Nevertheless, the Social Life Cycle Assessment (S-LCA) methodology is less explored despite its potential, although it is true that social sustainability assessment in promoting bioeconomy strategies requires more attention. This study describes the state of the art of the S-LCA methodology under the bioeconomy framework, critically analysing the main procedural and practical issues of its implementation, and the eventual specificities, as well as providing some of the challenges for future studies. This review highlights methodological weaknesses that require further research, related to the definition of system boundaries and cut-off criteria, the method of impact assessment, and the selection of societal issues and stakeholders, as well as uncertainty, among others. In addition, particularities of the bioeconomy in the life perspective were noted, such as multifunctionality and allocation issues of bio-based products, as well as the strong interest in biofuel production systems. Therefore, more efforts are desirable to address the diversity of challenges towards the progress of the S-LCA method in line with other life cycle approaches (environmental and economic). However, the updated S-LCA Guidelines represent a useful and valuable starting point on the way towards a comprehensive (i.e., diverse social concerns) and standardised social assessment under a life cycle perspectiveThis research has been supported by the project Enhancing diversity in Mediterranean cereal farming systems (CerealMed) project funded by PRIMA Programme and FEDER/Ministry of Science and Innovation–Spanish National Research Agency (PCI2020-111978). R.R.L., S.G.G. and M.T.M. belong to the Galician Competitive Research Groups (GRC)_ED431C-2021/37, co-funded by Xunta de Galicia and FEDER (EU)S

Sustainability Assessment of the Hot Water Extraction Biorefinery Process Using a Phased Implementation Approach

L'industrie canadienne des pâtes et papiers (P&P) est confrontée à une concurrence mondiale sans précédent. Ceci l'oblige à développer des solutions innovantes pour maintenir sa compétitivité. dans un contexte où les préoccupations environnementales sont grandissantes, en particulier celle du réchauffement climatique et celle de la consommation des ressources fossiles, qui ont mené à l'établissement de réglementations environnementales plus strictes. Le concept de bioraffinage est de plus en plus considéré comme une solution prometteuse pour améliorer la rentabilité et la performance environnementale des usines de P&P ainsi que pour soutenir la transformation du modèle d'affaire des compagnies forestières. La rétro-installation d'un procédé de bioraffinage dans une usine existante présente de nombreux défis dus à l’incertitude dans la conception de procédé, la mise à l'échelle de technologies émergentes, le choix des matières premières, le choix de la technologie de conversion, la performance des bioproduits en adéquation avec les besoins du marché ciblé, les problèmes potentiels d'intégration avec les procédés existants, le manque de capitaux et le financement. Ces incertitudes engendrent de nombreux risques commerciaux et technologiques. Des stratégies d'implantation incrémentale basées sur une approche systématique par phase peuvent être suivies pour atténuer les risques associés aux projets de transformation en bioraffinerie. Les projets de bioraffinerie ont l'objectif de développer des produits et de l’énergie provenant de sources renouvelables. L'identification de la stratégie la plus durable est donc critique pour la mise en œuvre réussie des projets de bioraffinerie. L’évaluation de la durabilité d’une stratégie de bioraffinage peut être faite en considérant les facteurs les plus importants identifiés par une analyse systématique. Une stratégie de bioraffinage peut être considérée comme durable lorsqu'elle apporte de la rentabilité, de la performance environnementale, de la compétitivité à long terme et qu'elle présente des mesures d'atténuation des risques technologiques et de marché. L'objectif de cette thèse est de mettre en oeuvre une méthodologie pratique et systématique pour l'évaluation des stratégies d’implantation du bioraffinage basé sur l'extraction à l'eau chaude (HWE) des hémicelluloses, considérant la durabilité et le potentiel de réduction des risques commerciaux et technologiques. La méthodologie est validée en utilisant une étude de cas impliquant l'intégration à une usine existante d'un procédé de bioraffinage basé sur HWE. Les procédés considérés incluent l’extraction des hémicelluloses et son traitement ultérieur selon différentes applications: production de biogaz, production d'hémicelluloses pour l'alimentation animale, production d'hémicelluloses pour la fabrication d'un sucre à cinq carbones (sucre C5), production d'un sucre C5 et production de furfural. Le sel d'acétate est coproduit dans toutes les options de traitement à l'exclusion du celle pour le biogaz. Suite à l'identification des couples procédé/produit prometteurs, des scénarios d'implantation par phase sont définis pour atténuer les risques financiers, commerciaux et technologiques. Ensuite, les outils d'ingénierie des systèmes sont utilisés pour évaluer la performance en durabilité des options de procédé et de leurs scénarios d'implantation par phase à court et à long terme. Finalement, les résultats économiques, environnementaux et d'analyse des risques sont analysés ensembles afin d'identifier la stratégie de bioraffinage HWE la plus durable. Les résultats de l'analyse économique ont prouvé que sans subvention du gouvernement aucune des options de bioraffinage HWE ne semble économiquement prometteuse, sauf celle produisant le sucre C5 qui obtient un taux de retour interne (TRI) de 25%. Néanmoins, considérant l'évaluation préliminaire des risques, les risques associés à cette option ont été identifiés comme étant relativement élevés. En incluant les subventions, les résultats économiques sont radicalement changés et toutes les options de bioraffinage définies ont montré une rentabilité attrayante - à l'exclusion du biogaz. Il a été montré que le TRI est particulièrement sensible à l'inclusion des subventions, en particulier dans le cas des stratégies à faible coût en capital. Considérant les résultats de l'analyse des scénarios d'implantation, il a été prouvé que la stratégie implantée en deux phases (Phase I : sirop d'hémicelluloses pour fabrication de sucre C5 et sel d'acétate, Phase II : sucres C5 et sel d'acétate) présente une meilleure atténuation des risques que les stratégies implantées en une seule phase directement. En ce qui concerne l'analyse des impacts environnementaux (analyse de cycle de vie conséquencielle "du berceau à la porte"), l'écorce, les produits chimiques et le transport des produits ont été identifiés comme étant les principales sources d'impacts. Les options de bioraffinage, y compris le sirop d'hémicelluloses pour les sucres C5 et les sucres C5 présentent respectivement des réductions des gaz à effet de serre (GES) de 80 % et 68 %. En outre, les résultats montrent une amélioration considérable de la performance (plus de trois fois) dans la catégorie d'impact sur la santé humaine. En raison de la cohérence entre les résultats économiques, environnementaux et d'analyse des risques, l'identification de la stratégie la plus durable est simple. La coproduction du sel d'acétate et d'hémicellulose pour la fabrication de sucre C5 en phase I suivi par la coproduction du sel d'acétate et du sucre C5 en phase II, apparaît comme étant la stratégie de bioraffinage la plus prometteuse et durable. ---------- Canadian pulp and paper (P&P) industry has encountered the challenge of an ever-growing level of global competition in the product market. This in turn implies the necessity for innovative solutions for the P&P industry to maintain its competitive position. In addition, P&P companies have faced further restrictions due to the existence of strict environmental regulations; increase of environmental concerns regarding the global warming and limitations in the fossil-based resources. Biorefining is increasingly considered as an alternative solution for enhancing P&P mill’s profitability, improving their environmental performance and facilitating their market transformation. Retrofitting a biorefinery process into an existing mill introduces numerous challenges due to uncertainties in process design and scale-up, various types of feedstock, different biorefinery conversion technologies, bioproduct properties and market position, potential problems in the mill’s process due to biorefinery integration and lack of capital and financing. These uncertainties result in several market and technology risks. Strategies such as incremental implementation of the biorefinery processes based on a systematic phased approach can be followed for mitigating the risks associated with biorefinery projects. In addition, the main objective of implementing a biorefinery project is to develop sustainable sources of renewable energy and products. Therefore, identification of the most sustainable strategy plays a significant role in the successful implementation of biorefinery projects. Several indicators can be defined for the sustainability evaluation of biorefinery processes, but a systematic analysis can help identifying the most important factors to consider. A sustainable biorefinery implementation strategy is the one that provides profitability and long-term competitiveness, mitigates market and technology risks in a proper manner and presents remarkable environmental performance. The objective of this thesis is to apply a systematic and practical methodology for evaluating the hot water extraction-based (HWE) biorefinery implementation strategy, using a perspective of sustainability and assessing the potential for technology and market risk mitigation. The methodology is demonstrated by using a case study that involves the integration of HWE pretreatment process into an existing P&P mill. The biorefinery process includes hemicellulose extraction and its further processing for different applications including biogas, hemicellulose for animal feed, hemicellulose for C5-sugars, C5-sugars and furfural. Acetate salt is the by-product of all the process options excluding the biogas. Following the identification of feasible HWE-based process-product alternatives, phased approach scenarios are developed to mitigate the financial, market and technology risks. Then, systems engineering tools are employed to assess the economic, environmental and risk performance of the developed process options in short-term and long-term and to evaluate metrics for the sustainability evaluation. Finally the results of the analysis are interpreted and analyzed to identify the most sustainable HWE-based biorefinery process option. Results of the economic analysis proved that before the inclusion of government subsidy and except for C5-sugars option with the Internal Rate of Return (IRR) of 25%, none of the HWE-based biorefinery options looked economically promising. Nonetheless, according to a preliminary risk assessment, market and technology risks associated with C5-sugars option were identified to be relatively high. By including subsidy, the economic landscape changed drastically and all the defined biorefinery options, excluding biogas, showed considerable project profitability. It was realized that IRR was particularly sensitive to subsidy, specifically in the case of low capital cost process options. Considering the results of risk analysis, it was proved that the two-phase strategy, which aggregated the production of acetate salt and hemicellulose for C5-sugars in phase I and C5-sugars and acetate salt in phase II, had better risk mitigation performance, when compared with single-phase strategies. Regarding the environmental analysis (“Cradle-to-gate” consequential LCA), bark, chemicals and product transportation identified to be as main sources of impacts. Biorefinery options including hemicellulose for C5-sugars and C5-sugars presented GHG reduction of 80% and 68%, respectively. Also, these options proved a considerable improvement of more than three times in the human health impact category, relative to the existing processes at the mill. Due to the consistency between the economic, environmental and risk analysis results, identification of the sustainable process option is straight-forward. The two-phase option including acetate salt and hemicellulose for C5-sugars application in phase I and acetate salt and C5-sugar in phase II was identified to be the most promising and sustainable biorefinery process option

Regional Differences in Water Quality Impacts from the Bioenergy Mandate: A Scenario-Based Approach to Quantifying the Impacts from RFS2

The Renewable Fuels Standard (RFS2) under the Energy Independence and Security Act (EISA 2007) mandates the production of 36 billion gallons of biofuel by 2022 for use in the transportation sector. Although the mandate seeks to reduce greenhouse gas emissions by reducing our dependence on oil, there is concern that consequent land-use/cover (LULC) changes could result in significant unintended environmental impacts. The evaluation of water quality impacts from the mandate is challenging, especially for cellulosic and other advanced biofuels because the bioenergy supply chain is an emerging system with inherent uncertainties. This research addresses several gaps in the literature on the water quality impacts of the mandate and is organized into three chapters. The first chapter addresses the regional differences in impacts to water quality from a similar land-use change for two watersheds in the Midwest (Upper Cedar) and Southeast (Lumber). The Soil and Water Assessment Tool, a hydrological model that is able to simulate crop growth and water and nutrient outputs is set up, calibrated and validated. The potential reduction in nitrogen loading per potential gallon of ethanol to surface waters, for a change from baseline corn/soy to switchgrass, is about 40% in the Midwest and around 80% in the Southeast. Although, the trend in reduction is similar in both watersheds, this study shows that results extrapolated from the Midwest, where a lot of the bioenergy literature is based, may not be representative of other bioenergy producing regions. The second chapter investigates the impact of uncertainties in production costs of perennials on three objectives incentivizing different aspects of the biofuel industry – maximizing farmer profitability, surplus from feedstock production and ethanol production and land-use efficiency, using a Monte-Carlo Analysis. The study also investigates the impact of current farmer safety net for corn-soy production and bioenergy subsidies on the feedstock choice in each region. The analysis indicates that the three objectives result in different feedstock options in the two regions. Further, results indicate that the current incentive structure for perennial biomass is insufficient to encourage production on cropland, especially because the commodity crop alternative has better risk management. The final chapter of the dissertation links the feedstock production and ethanol production stages of the bioenergy supply chain. A Mixed Integer Linear Programming (MILP) optimization is used to drive land-use change at the Hydrologic Response Unit (HRU) level for the three objectives investigated in the second chapter. Results indicate there are tradeoffs between profitability and water quality for the three objectives. When the location of the biorefinery was considered, the supply of biomass and changes to water quality were localized around it, and these changes were significant at the sub-watershed scale. Optimization of biorefineries is usually done at the county or other large administrative scales. Our results indicate that such a scale would miss the localization of impacts which could be especially sub-optimal for sensitive watersheds. Any optimization of the biofuel supply chain system for water quality will therefore have to be at a watershed or sub-watershed resolution. A limitation of this work is the use of a single water quality indicator to quantify water quality impacts. Optimizing the supply chain must also involve development of appropriate multi-metric indicators of water quality for the region under consideration.PHDNatural Resources and EnvironmentUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/137155/1/skeerthi_1.pd