Comparing studies that involve techno-economic analyses (TEA) and life cycle assessments (LCA) for different hydrogen production technologies is challenging due to inconsistent assumptions across studies. Thus, this research develops a harmonized framework to assess seven hydrogen production pathways - water electrolysis, methane pyrolysis, biomass gasification, steam methane reforming, autothermal reforming, partial oxidation, and dry methane reforming, under consistent U.S.-specific techno-economic, carbon intensity (CI), and policy assumptions. Process models developed with Aspen Plus produce mass and energy balances, informing opensource TEA and cradle-to-gate CI estimates. Thermal conversion pathways produce hydrogen at $0.8-$3.9/kg, while electrolysis-based methods range from $4.5-$18.5/kg, contingent on both electrolyzer and the source of electricity used. Several low-carbon emitting pathways meet emerging clean hydrogen standards, but only some achieve cost parity with conventional hydrogen under current U.S. federal and state incentives. This framework enables consistent cross-technology comparison and supports informed decisions on hydrogen sourcing, including applications such as sustainable aviation fuel production or fuel cell electric vehicles.

Sustainable aviation fuel (SAF) production is an area of intense research, with many production pathways competing for commercialization in a rapidly changing policy environment. Current techno-economic methods to discern minimum selling price (MSP) can require extensive research and be difficult to generalize to the guidance of emerging technologies. There is a need for more flexible methods to guide the evolution of SAF production toward economically and environmentally viable pathways. We present the following technology-neutral heuristic to approximate MSP, then demonstrate its use to evaluate strategies to minimize the cost of CO2 abatement for a given SAF process. We first apply it to stoichiometric cases based on the method of oxygen removal (in the form of H2O, CO2, or O-2), which serves as paradigm targets for technological evolution. Our analysis indicates that in a favorable green hydrogen market (prices below 2.50 $/kg), oxygen removal as H2O is preferable, while removal as CO2 is preferable at current hydrogen prices. Carbon supplements from lower-oxygen-content sources (such as plastic) and sequestration (such as char) were also shown to potentially reduce production and abatement costs for stoichiometric models. These findings held true when applying this heuristic to model a fast pyrolysis process with waste plastic supplements reducing abatement costs while still meeting CI reduction criteria. The heuristic was also used to evaluate potential evolution paths for gasification/Fischer-Tropsch technologies. A similar trend to the stoichiometric models emerged, with a significant reduction in hydrogen cost and CI required to justify supplementing the process. In this way, we demonstrate a novel approach to the screening and evolution of SAF processes toward viability and efficiency.

Cotton is a natural fiber containing more than 95% of cellulose. With worldwide cotton consumption continuously increasing, the amount of cotton waste generated is enormous. Most of the cotton waste ends up in landfill or incinerators, resulting in a huge waste of this excellent natural resource. In this project, cotton waste was recycled to produce polypropylene nanocomposites. Instead of using the traditional two-step nanofiber extraction and compounding technique, an integrated process was adopted to combine nanofibrillation and compounding into one step. Results showed that cotton fibers with a slight prefibrillation and hydrophobic surface modification were successfully fibrillated into tens to hundreds of nanometers in width during compounding. The nanofibers reinforced polypropylene composites exhibited significantly enhanced tensile and flexural strength and moduli. For instance, when 30% fibers from bleached white and indigo-dyed denim fabrics were introduced, the tensile moduli of the resultant composites reached 4.57 and 4.59 GPa, respectively, compared to 1.60 GPa, the modulus of neat PP. Meanwhile, denim fabrics had a remarkable reinforcing effect on the composites’ impact strength attributing to the hydrophobic indigo dyes that improved the interfacial bonding between cotton fibers and the matrix. The highest impact strength of denim reinforced composites was 4.96 kJ/m2 with 20% fiber loading; while the impact strength of neat polypropylene was 2.46 kJ/m2. The low water uptake of the composites further indicated the excellent adhesion at the filler/matrix interface. In general, a very promising processing technique to recycle cotton waste for high-value products was demonstrated.

Aviation contributes to global warming through CO2, non-CO2 compound emissions, and aviation induced cloudiness. A suite of measures is needed to decarbonize the aviation sector, the most important being developing and deploying sustainable aviation fuel (SAF). Considerable interest exists in the impact of policies that incentivize the environmental services provided by SAF, and their influence on the return on investment to secure capital investment for production facilities. This paper uses financial analysis and a system dynamics approach to analyze the effect of various policies on 1) the time required for a project to reach a positive net present value (NPV), 2) the magnitude of the NPV at the end of plant life, 3) investment risk and 4) potential regional supply development. Production of SAF from municipal solid waste through gasification Fisher-Tröpsch in the U.S. is used as a case study, and the U.S. Northwest for regional development. The results indicate that a successful industry deployment entails strong support during the first three years of production to reach a positive NPV metric, after which it might be competitive with market-based initiatives or by leveraging economies of scale. Initiatives that target CO2e reductions, through criteria or purpose, generate a major impact. Alignment of strategies to increase fuel yield and emission reduction maximize profits. Stacking policies and programs, when maximizing SAF production, reduces the probability of financial loss under 13% for the three plant sizes assessed. This study demonstrates the importance of the valuation and inclusion of environmental services for project success.

The goal of this paper is to develop a quantitative resilience assessment framework for a supply chain system exposed to multiple risk factors. Most existing studies on supply chain resilience have primarily focused on assessing the system’s ability to withstand and recover from disruptions caused by a single type of hazard. However, a supply chain system is exposed to multiple exogenous and endogenous events and conditions over a planning horizon, and a comprehensive assessment of resilience should take into account multiple risk factors. Moreover, contrary to the conventional resilience assessment methods focusing on the short duration during which the system is impacted by a disaster event, the proposed framework measures the resilience capacities of the system over a long-term horizon through multi-risk assessment and multi-component resilience assessment. Specifically, a new multi-component resilience index is proposed to measure (a) hazard-induced cumulative loss of functionality, (b) opportunity-induced cumulative gain of functionality, and (c) non-hazard-induced cumulative loss of functionality. The case study results indicate that all three types of risk factors contribute to the overall resilience index significantly and ignoring any one of them may result in inaccurate supply chain performance and resilience assessment.

Sustainable aviation fuel (SAF) is vital for the reduction of the environmental impact of the aviation industry while decreasing the dependence of the USA on foreign petroleum fuels. To date, SAF, especially from cellulosic feedstocks, have struggled to overcome two barriers: (1) meeting price parity with their petroleum counterparts and (2) the large capital investment required for industrial‐scale biorefineries. Repurposing of industrial facilities has been suggested as a means of addressing both challenges. In this study we look at the financial impact of manufacturing SAF using three repurposing value levels. To demonstrate the application of this methodology, we examine case studies based on a wood‐based alcohol‐to‐jet process. Each level evaluated assumes a different portion of the existing facility is useable. The impact on capital costs and minimum fuel selling price is estimated for generalized case studies as well as for specific case studies spread across multiple regions of the USA. The best economic outcomes are achieved when large‐scale facilities have both inside and outside battery limit assets that can be repurposed. The geospatially explicit variables that have the largest economic impact are feedstock price, feedstock composition, and industrial natural gas price. However, the scale and value of repurposing both outweigh the geospatial variables within reasonable limits. Of the locations studied, the lowest minimum selling price (MSP) of $1.16/L was calculated at the Washington facility, a nearly 19% reduction from a matching scaled greenfield facility, a result of existing equipment and infrastructure reducing total capital investment by one‐third and plentiful feedstock. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

Chitin, the second most abundant biopolymer in nature, is available in the seafood industry's waste streams. In this pioneering study, chitin from waste shrimp shells was processed into chitin nanocrystals and nanofibers (Ch-NCs and Ch-NFs) for evaluation in the cement paste. The results show Ch-NCs delayed the final set time by up to 106 min, likely by electrostatic repulsion of cement particles, but Ch-NFs imparted only a max 78-min delay. Furthermore, the viscosity of fresh cement paste increased with Ch-NFs but did not significantly change with Ch-NCs. These different outcomes are attributed to more mobility of Ch-NCs rods versus the Ch-NFs network. In addition, nanochitin forms at 0.05 wt% of cement significantly increased 28d flexural strength by-40% and compressive strength by up to-12%. The encouraging results of this study indicate the promise of nanochitins in tailoring fresh and hardened properties of cement-based materials for target applications.

With jet fuel consumption projected to more than double by 2050, dramatic expansion of sustainable aviation fuel (SAF) use will be essential to meeting the aviation industry goal of achieving carbon neutrality in the same time frame. However, to date, the SAF price has, in part, been responsible for the lack of widespread adoption signaling the need for strong and stable policy. Multiple pathways have been developed and received ASTM approval to convert a variety of feedstocks into SAF, each with strengths and weaknesses that vary with conversion technology, feedstock, and production location. To assist researchers and governments in understanding the role of policy on fuel pricing, a set of harmonized, techno-economic analyses (TEAs) were developed to assess three ASTM-qualified production pathways: hydroprocessed esters and fatty acids (HEFAs), alcohol to jet (ATJ), and Fischer–Tropsch (FT), with multiple feedstock options. These decision support tools were used to assess the minimum selling price (MSP) for fuel distillates. Both mature (nth) plants and first of a kind (pioneer plants) were assessed using TEAs. Existing and proposed U.S. incentives, at both the federal and state levels, were integrated into the tools to determine the impact on the MSP. Considering the existing federal policies, analysis indicated that HEFAs could achieve a SAF price that would be competitive to conventional fuels when using waste lipid feedstocks, making this the most viable near-term option. However, this feedstock for HEFAs is limited and unlikely to support the production of large quantities of SAF. After stacking federal and state programs, SAF produced using FT with municipal solid waste (MSW) has the lowest MSP, although FT forest residuals, FT agricultural residues, ATJ corn ethanol, and HEFAs using second crop oilseeds all approach the historical range of traditional jet fuel prices for nth plants. Pioneer plants are viable for only ATJ corn ethanol; however, FT-MSW is approaching price parity.

EDITORIAL article Front. Energy Res., 26 September 2022Sec. Bioenergy and Biofuels Volume 10 - 2022 | https://doi.org/10.3389/fenrg.2022.1005493

A large sugarcane mill with a processing capacity of 12,444 metric ton sugarcane per day is used as a host plant for the evaluation of several bio-refinery concepts to produce sustainable aviation fuels (SAF). Five SAF tech-nologies are studied: Virent's BioForming, alcohol to jet, direct sugar to hydrocarbon, fast pyrolysis-bio-oil hydrotreatment, and gasification & Fischer-Tropsch technologies. A standardized methodology is followed to evaluate twenty integrated scenarios to produce fuels using sugarcane mill facilities. In our analyses we assumed that the sugarcane mill operates 6 months but that the SAF unit operates twelve months (with switchgrass, molasses, and ethanol purchases). For each of the scenarios, the minimum fuel selling price (MFSP) and greenhouse gas emissions (GHG) within the integrated scenarios are estimated. Fourteen out of fifteen integrated scenarios resulted in reductions of capital (5 to 86 %) and operational costs (4 to 34 %) compared with the base case processes. These benefits are associated with a better use of sugarcane mill's infrastructure, co-products availability (molasses and ethanol) as well as waste stream feedstocks (surplus bagasse). It was possible to identify conditions reducing MFSPs between 8 and 53 % from corresponding base cases. Twelve scenarios yielded GHG savings from 10% to 97%.

Increasing wildfire risks have significantly disrupted supply chain systems in the United States, which accounts for a large portion of wildfire-induced economic losses and affects the regional and national economies. While it is important to understand wildfire effects on supply chains in meeting customer needs and achieving regional economic stability, such effects have not yet been extensively studied. This paper proposes a probabilistic framework for quantitatively assessing wildfire risk to a supply chain network. It provides rigorous probabilistic descriptions of wildfire ignition likelihood and growth, the interaction between supply chain components and wildfire, consequent component damage, and network-level performance reduction. A hypothetical forest -residuals-to-sustainable-aviation-fuel supply chain network is utilized as an illustrative example to demonstrate the capability and applicability of the proposed framework. The simulation re-sults indicate that wildfire-induced damages to feedstock nodes are insignificant (i.e., 0.1% re-duction in total feedstock availability per year), whereas total supply chain cost still increases considerably due to high unmet demand penalty and detours. Moreover, the findings further demonstrate the weakness of network configuration under wildfire risk: a failure of the process-ing facility located in the Inland Northwest of the United States results in significant increases in total transportation costs and time, which suggests that the construction of additional processors in this region could reduce wildfire risk significantly. Thus, the proposed framework can be used as a planning tool to evaluate network performance subject to a set of what-if scenarios and assess the effect of pre-and post-wildfire risk mitigation measures.

Nanomaterials have been widely researched for use in construction materials. Numerous studies demonstrate that nanomaterials in small quantities can significantly improve the macroscopic properties of cement paste, mortar, or concrete through various mechanisms. Nanomaterials retrieved from biomass sources have recently gained particular research interest due to remarkable structural properties and the source material’s abundance and renewability. Cellulose and chitin are the most abundant polysaccharides in nature; thus, they are candidates for nanomaterials extraction as multifunctional additives in cementitious systems. In recent years, cellulose nanomaterials in cementitious composites have been extensively investigated, but chitin nanomaterials and starch derivatives for cement and concrete are still emerging research areas. This review article starts with an overview of polysaccharide nanomaterials’ (PNMs) physicochemical properties as a result of different chemical and mechanical extraction processes. Next a brief overview of cement hydration chemistry and microstructure and the interfacial interactions between the cement and the various surface chemical functionalities of PNMs are discussed. Then, the key mechanisms governing the cement strength enhancement by PNMs, such as bridging, nucleating and filling effect, and internal curing, are described. Finally, the impacts of PNMs on other properties of the cement are discussed.

Every year ~ 6–8 million tonnes of shrimp, crab, and lobster shell wastes are generated, requiring costly disposal procedures. In this study, the chitin content of shrimp shell waste was oxidized to produce chitin nanocrystals (ChNC) and mechanically fibrillated to obtain chitin nanofibers (ChNF) and evaluated as additives for mortar. ChNF (0.075 wt%) and ChNC (0.05 wt%) retarded the final setting time by 50 and 30 min, likely through cement dispersion by electrostatic repulsion. ChNF (0.05 wt%) with a larger aspect ratio than ChNC resulted in the greatest improved flexural strength and fracture energy by 24% and 28%. Elastic modulus increased by up to 91% and 43% with ChNC and ChNF. Solid-state nuclear magnetic resonance (NMR) showed ChNF (0.05 wt%) enhanced calcium–silicate–hydrate structure with a 41% higher degree of polymerization, 9% more silicate chain length, and a 15% higher degree of hydration at 28 days. Based on the findings, chitin seems a viable biomass source for powerful structural nanofibers and nanocrystals for cementitious systems to divert seafood waste from landfills or the sea.

The efficient configuration of supply chains is a current challenge for deploying sustainable aviation fuel (SAF), a key element of the decarbonization of the aviation industry. Despite advances in the modeling of biorefinery location siting, transportation network design, and co-products use, current supply chains and business models for renewable fuel production do not result in costs that are competitive with fossil fuels. Various elements for process efficiency enhancement, risk mitigation, total cost reduction, and profit maximization have been studied in supply chain design. In this work, we study the conceptual components needed for the design and analysis of supply chains. We emphasize the impact that monetization of environmental and social services could have on the overall viability of SAF production. The current state of the supply chain configuration of SAF is compared with other supply chain and value-chain strategies, mainly: (1) lean, used for staple commodities, (2) agile, intended for innovative products and services, (3) green, meant to reduce the environmental impacts, and (4) risk-adverse, used to minimize supply risk disruptions. A summary of models and simulation approaches used to synthesize and solve supply chain problems is included. Our review highlights the uniqueness of the supply chain for SAF and proposes ways to enrich the existing approach with methods used by other industries. The SAF business model could be improved by including ecosystem and social services to generate additional revenue. New strategies accounting for the dynamic interactions between the components of the supply chain of SAF, including services, are needed.

The potential for petroleum refineries (PRs) to integrate sustainable aviation fuel (SAF) technologies is manifold, unlike with other existing industrial infrastructures that lack such technical similarities. A midsize PR with a crude oil capacity of 120,000 barrels per day was analyzed in this study to determine the feasibility of integrating five well-known lignocellulosic SAF technologies, namely, Virent’s BioForming (VB), alcohol to jet (ATJ), direct sugar to hydrocarbon (DSHC), fast pyrolysis (FP), and gasification and Fischer–Tropsch (GFT) methods, as well as one novel concept referred to as integrated carbonization-gasification-Fischer–Tropsch (ICGFT). The following three integrated scenarios were studied to derive the costs and environmental impact reductions: sharing of infrastructures from outside battery limits (OSBL), co-processing of SAF technology-derived intermediates with PR-derived gas oil inside battery limits (ISBL) and repurposing of an idle or shutdown PR. Sharing OSBL infrastructures resulted in reductions of the minimum fuel selling price (MFSP) by 3–14% relative to the corresponding standalone cases. Co-processing of intermediate products such as VB-derived long chain hydrocarbons, ATJ-derived ethanol, DSHC-derived farnesene, pyrolysis-derived bio-oil, and GFT-derived FT products reduced the MFSP by 10–19% from corresponding standalone cases. Moreover, repurposing scenarios reduced the costs by 16–34%. Greenhouse gas (GHG) estimations showed that 17 of 21 integrated scenarios resulted in GHG savings (7–92%). Lignocellulosic SAF technologies are limited by low fuel yields, which are governed by the high oxygen content of the feedstock. However, ICGFT was found to be advantageous in terms of fuel production at a maximized fuel yield.

This detail the economics of Catalytic Hydrothermolysis (CH), an approve pathway for sustainable aviation fuel (SAF) production. Techno-economic analysis was conducted with the assumption of CH processing facility that process 832 metric tonnes per day of feedstock into renewable fuels such as SAF, gasoline and diesel. Economic data includes estimation of renewable fuel production plant cost such as capital and operating cost; cost benefit analysis model to predict the SAF or jet fuel price; regression models to evaluate the cost for co-product such as diesel and petroleum in relation to SAF price. Estimated SAF, gasoline and diesel cost for the feedstock such as carinata oil, soybean oil, yellow grease and brown grease feedstock is included in the data.

A typical Dry Grind Corn Ethanol Mill (DGCEM) with a capacity of 230 ML of ethanol per year is used as the baseline for the evaluation of biorefinery concepts for sustainable aviation fuels (SFAs). The main goal is to identify SAF cost reduction opportunities as well as environmental benefits by integrating with existing DGCEM infrastructure. Five SAF production technologies are studied: Virent's BioForming (VB), Alcohol to Jet (ATJ), Direct Sugar to Hydrocarbon (DSHC), Fast Pyrolysis (FP) and Gasification & Fischer-Tropsch (GFT). We built SAF unit cases with capital cost equal to the studied DGCEM ($115 M). Larger SAF units are unlikely to synergize well with existing DGCEMs. Twelve co-location and repurposing scenarios are evaluated where SAF technologies utilize intermediate products, auxiliary facilities, or unit operations from DGCEM. For each of the scenarios, the minimum fuel selling price (MFSP) and greenhouse gas (GHG) emissions are estimated. Our aim is to identify which SAF technologies can be most efficiently integrated with a corn ethanol mill. Eleven scenarios result in lowered MFSPs in the range of 3-67% reduction, from their corresponding greenfield design cases. The highest reduction is observed when ATJ is produced in a repurposed facility. In the case of GHG we were able to identify one scenario with lower GHG emissions compared with greenfield units. SAF in thirteen scenarios have GHG emission ranging from 13 to 93% of fossil fuel. One of the repurposed scenarios of ATJ is the concept with the best overall performance parameter.