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1. A Two-Stage Stochastic Programming Approach for the Design of Renewable Ammonia Supply Chain Networks

   https://doi.org/10.3390/pr12020325  

   Mitrai, Ilias; Palys, Matthew J; Daoutidis, Prodromos (February 2024, Processes)

   This work considers the incorporation of renewable ammonia manufacturing sites into existing ammonia supply chain networks while accounting for ammonia price uncertainty from existing producers. We propose a two-stage stochastic programming approach to determine the optimal investment decisions such that the ammonia demand is satisfied and the net present cost is minimized. We apply the proposed approach to a case study considering deploying in-state renewable ammonia manufacturing in Minnesota’s supply chain network. We find that accounting for price uncertainty leads to supply chains with more ammonia demand met via renewable production and thus lower costs from importing ammonia from existing producers. These results show that the in-state renewable production of ammonia can act as a hedge against the volatility of the conventional ammonia market. 

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2. Distribution-level markets under high renewable energy penetration

   https://doi.org/10.1145/3538637.3538846  

   Ju, Peizhong; Lin, Xiaojun; Huang, Jianwei (June 2022, Thirteenth ACM International Conference on Future Energy Systems (ACM e-Energy 2022))

   We study the market structure for emerging distribution-level energy markets with high renewable energy penetration. Renewable generation is known to be uncertain and has a close-to-zero marginal cost. In this paper, we use solar energy as an example of such zero-marginal-cost resources for our focused study. We first show that, under high penetration of solar generation, the classical real-time market mechanism can either exhibit significant price-volatility (when each firm is not allowed to vary the supply quantity), or induce price-fixing (when each firm is allowed to vary the supply quantity), the latter of which leads to extreme unfairness of surplus division. To overcome these issues, we propose a new rental-market mechanism that trades the usage-right of solar panels instead of real-time solar energy. We show that the rental market produces a stable and unique price (therefore eliminating price-volatility), maintains positive surplus for both consumers and firms (therefore eliminating price-fixing), and achieves the same social welfare as the traditional real-time market. A key insight is that rental markets turn uncertainty of renewable generation from a detrimental factor (that leads to price-volatility in real-time markets) to a beneficial factor (that increases demand elasticity and contributes to the desirable rental-market outcomes). 

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3. A Demand-Responsive Green Ammonia Plant and its Impact on the Electricity Distribution System

   https://doi.org/10.1109/PESGM48719.2022.9917204  

   Edmonds, Lawryn; Liu, Xuebo; Wu, Hongyu (July 2022, 2022 IEEE Power & Energy Society General Meeting (PESGM))

   Most large-scale ammonia production typically relies on natural gas or coal, which causes harmful carbon pollution to enter the atmosphere. The viability of a small-scale “green” ammonia plant is investigated where renewable electricity is used to provide hydrogen and nitrogen via electrolysis and air liquefaction, respectively, to a Haber-Bosch system to synthesize ammonia. A green ammonia plant can serve as a demandresponsive load to the electricity distribution system and provide long-term energy storage through chemical energy storage in ammonia. A coordinated operational model of an electricity distribution system and an electricity-run ammonia plant is proposed in this paper. Case studies are performed on a modified PG&E 69-node electricity distribution system coupled with a small-scale ammonia plant. Results indicate the ammonia plant can adequately serve as a demand response resource and positively impact the distribution locational marginal price (DLMP). 

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4. Inferring sources of substandard and falsified products in pharmaceutical supply chains

   https://doi.org/10.1080/24725854.2023.2174277  

   Wickett, Eugene; Plumlee, Matthew; Smilowitz, Karen; Phanouvong, Souly; Pribluda, Victor (January 2023, IISE Transactions)

   Substandard and falsified pharmaceuticals, prevalent in low- and middle-income countries, substantially increase levels of morbidity, mortality and drug resistance. Regulatory agencies combat this problem using post-market surveillance by collecting and testing samples where consumers purchase products. Existing analysis tools for post-market surveillance data focus attention on the locations of positive samples. This article looks to expand such analysis through underutilized supply-chain information to provide inference on sources of substandard and falsified products. We first establish the presence of unidentifiability issues when integrating this supply-chain information with surveillance data. We then develop a Bayesian methodology for evaluating substandard and falsified sources that extracts utility from supply-chain information and mitigates unidentifiability while accounting for multiple sources of uncertainty. Using de-identified surveillance data, we show the proposed methodology to be effective in providing valuable inference. 

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5. Supply Chain Strategies in Virtually Distributed Supply Chain Project Teams During and Post-COVID-19

   https://doi.org/10.20545/isctj.v06.i11.01  

   Jones, Erick; J.L, Goldston (November 2020, International Supply Chain Technology Journal)

   Due to the COVID-19 pandemic, a number of employees transitioned into virtually distributed supply chain project team environments for the first time in their careers due to shelter-in-place and social distancing mandates that impacted industries around the world. With project managers implementing processes and procedures remotely to employees fielding calls from home while caring for children, the world entered into an unprecedented time and an unknown unknown. As the pandemic required organizations to implement agile practices, project managers within various industries had to adjust operational processes, while at the same time had to ensure project team needs were addressed. In an effort to mitigate the risk of transitioning back to conventional management approaches, a qualitative survey method was performed in this study to understand supply chain project team member experiences during this transition period. The results of the survey uncovered that the creation of a supply chain uncertainty management plan, demonstrating the benefits of virtual supply chain project teams, and the continuous integration of collaborative technology tools may contribute positive outcomes from the COVID-19 pandemic. 

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