Global food systems must be a part of strategies for greenhouse gas (GHG) mitigation, optimal water use, and nitrogen pollution reduction. Insights from research in these areas can inform policies to build sustainable food systems yet limited work has been done to build understanding around whether or not sustainability efforts compete with supply chain resilience. This study explores the interplay between food supply resilience and environmental impacts in US cities, within the context of global food systems’ contributions to GHG emissions, water use, and nitrogen pollution. Utilizing county-level agricultural data, we assess the water use, GHG emissions, and nitrogen losses of urban food systems across the US, and juxtapose these against food supply resilience, represented by supply chain diversity. Our results highlight that supply chain resilience and sustainability can simultaneously exist and are not necessarily in competition with each other. We also found a significant per capita footprint in the environmental domains across Southern cities, specifically those along the Gulf Coast and southern Great Plains. Food supply chain resilience scores ranged from 0.18 to 0.69, with lower scores in the southwest and Great Plains, while northeastern and Midwestern regions demonstrated higher resilience. We found several cities with high supply chain resilience and moderate or low environmental impacts as well as areas with high impacts and low resilience. This study provides insights into potential trade-offs and opportunities for creating sustainable urban food systems in the US, underscoring the need for strategies that consider both resilience and environmental implications.
This content will become publicly available on January 1, 2025
Policies and Power Systems Resilience Under Time-Based Stochastic Process of Contingencies in Networked Microgrids
Given the increasing occurrence of high-impact low-probability (HILP) contingencies in existing power systems, strengthening the resilience of these systems has become of paramount importance. Enhancing the resilience of power systems is not solely a technical issue but also a socio-economic and policy concern. Therefore, improving the performance of power systems greatly relies on the guidance provided by energy policies. While the decarbonization response, supported by these policies to mitigate climate change, influences the adoption of energy technologies, its impact on the resilience of the system remains uncertain. To uncover the interactions between technologies, policies, and economics concerning power systems resilience, this study focuses on constructing resilience-oriented networked microgrid systems. It develops a two-stage stochastic programming model by integrating a method for selecting power outage scenarios identified by users, in the presence of emissions policies. The results confirm the contributions of integrated systems in enhancing resilience, but they also reveal that low-carbon emissions policies play an inhibiting role by increasing the financial costs associated with resilience planning and operations. Nevertheless, a 30% emissions reduction threshold can still be achieved from the integrated network, facilitating the dual benefits of maximizing emissions reduction and minimizing the burden of emissions taxes. The study's contributions are threefold: firstly, it incorporates techno-economic incentives and regulations simultaneously; secondly, it quantifies the unintended consequences of policies on resilience; and thirdly, it provides constructive guidance for future energy policymaking, particularly in maintaining system resilience.
more »
« less
- Award ID(s):
- 1847077
- NSF-PAR ID:
- 10492339
- Publisher / Repository:
- IEEE
- Date Published:
- Journal Name:
- IEEE Transactions on Engineering Management
- ISSN:
- 0018-9391
- Page Range / eLocation ID:
- 1 to 21
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Abstract -
Highlights Aquatic vegetation-based nutrient recovery offers an alternate approach for treating agricultural wastewater. Microalgae and duckweed can upcycle waste nutrients into valuable bio-based products. Producing feed, fertilizer, and fuel from manure-grown aquatic vegetation promotes a circular N-bioeconomy. Abstract . The massive amounts of nutrients that are currently released into the environment as waste have the potential to be recovered and transformed from a liability into an asset through photosynthesis, industry insight, and ecologically informed engineering design aimed at circularity. Fast-growing aquatic plant-like vegetation such as microalgae and duckweed have the capacity to enable local communities to simultaneously treat their own polluted water and retain nutrients that underlie the productivity of modern agriculture. Not only are they highly effective at upcycling waste nutrients into protein-rich biomass, microalgae and duckweed also offer excellent opportunities to substitute or complement conventional synthetic fertilizers, feedstocks in biorefineries, and livestock feed while simultaneously reducing the energy consumption and greenhouse gas emissions that would otherwise be required for their production and transport to farms. Integrated systems growing microalgae or duckweed on manure or agricultural runoff, and subsequent reuse of the harvested biomass to produce animal feed, soil amendments, and biofuels, present a sustainable approach to advancing circularity in agricultural systems. This article provides a review of past efforts toward advancing the circular nitrogen bioeconomy using microalgae- and duckweed-based technologies to treat, recover, and upcycle nutrients from agricultural waste. The majority of the work with microalgae- and duckweed-based wastewater treatment has been concentrated on municipal and industrial effluents, with <50% of studies focusing on agricultural wastewater. In terms of scale, more than 91% of the microalgae-based studies and 58% of the duckweed-based studies were conducted at laboratory-scale. While the range of nutrient removals achieved using these technologies depends on various factors such as species, light, and media concentrations, 65% to 100% of total N, 82% to 100% of total P, 98% to 100% of NO3-, and 96% to 100% of NH3/NH4+ can be removed by treating wastewater with microalgae. For duckweed, removals of 75% to 98% total N, 81% to 93% total P, 72% to 98% NH3/NH4+, and 57% to 92% NO3- have been reported. Operating conditions such as hydraulic retention time, pH, temperature, and the presence of toxic nutrient levels and competing species in the media should be given due consideration when designing these systems to yield optimum benefits. In addition to in-depth studies and scientific advancements, policies encouraging supply chain development, market penetration, and consumer acceptance of these technologies are vitally needed to overcome challenges and to yield substantial socio-economic and environmental benefits from microalgae- and duckweed-based agricultural wastewater treatment. Keywords: Circular bioeconomy, Duckweed, Manure treatment, Microalgae, Nitrogen, Nutrient recycling, Wastewater treatment.more » « less
-
more » « less
Abstract This article presents a comprehensive study that focuses on the techno-economic analysis of co-located wind and hydrogen energy integration within an integrated energy system (IES). The research investigates four distinct cases, each exploring various configurations of wind farms, electrolyzers, batteries, hydrogen storage tanks, and fuel cells. To obtain optimal results, the study employs a sophisticated mathematical optimization model formulated as a mixed-integer linear program. This model helps determine the most suitable component sizes and hourly energy scheduling patterns. The research utilizes historical meteorological data and wholesale market prices from diverse regions as inputs, enhancing the study’s applicability and relevance across different geographical locations. Moreover, sensitivity analyses are conducted to assess the impact of hydrogen prices, regional wind profiles, and potential future fluctuations in component prices. These analyses provide valuable insights into the robustness and flexibility of the proposed IES configurations under varying market conditions and uncertainties. The findings reveal cost-effective system configurations, strategic component selections, and implications of future energy scenarios. Specifically comparing to configurations that only have wind and battery combinations, we find that incorporating an electrolyzer results in a 7% reduction in the total cost of the IES, and utilizing hydrogen as the storage medium for fuel cells leads to a 26% cost reduction. Additionally, the IES with hybrid hydrogen and battery energy storage achieves even higher and stable power output. This research facilitates decision-making, risk mitigation, and optimized investment strategies, fostering sustainable planning for a resilient and environmentally friendly energy future.
-
With the end of Dennard scaling, power constraints have led to increasing compute specialization in the form of differently specialized accelerators integrated at various levels of the general-purpose system hierarchy. The result is that the most common general-purpose computing platform is now a heterogeneous mix of architectures even within a single die. Consequently, mapping application code regions into available execution engines has become a challenge due to different interfaces and increased software complexity. At the same time, the energy costs of data movement have become increasingly dominant relative to computation energy. This has inspired a move towards data-centric systems, where computation is brought to data, in contrast to traditional processing-centric models. However, enabling compute nearer memory entails its own challenges, including the interactions between distance-specialization and compute-specialization. The granularity of any offload to near(er) memory logic would impact the potential data transmission reduction, as smaller offloads will not be able to amortize the transmission costs of invocation and data return, while very large offloads can only be mapped onto logic that can support all of the necessary operations within kernel-scale codes, which exacerbates both area and power constraints. For better energy efficiency, each set of related operations should be mapped onto the execution engine that, among those capable of running the set of operations, best balances the data movement and the degree of compute specialization of that engine for this code. Further, this offload should proceed in a decentralized way that keeps both the data and control movement low for all transitions among engines and transmissions of operands and results. To enable such a decentralized offload model, we propose an architecture interface that enables a common offload model for accelerators across the memory hierarchy and a tool chain to automatically identify (in a distance-aware fashion) and map profitable code regions on specialized execution engines. We evaluate the proposed architecture for a wide range of workloads and show energy reduction compared to an energy-efficient in-order core. We also demonstrate better area efficiency compared to kernel-scale offloads.more » « less
-
The lack of community-relevant flood informational resources and tools often results in inadequate and divergent understandings of flood risk and can impede communities' ability to function cohesively in the face of increasing flood threats. The current study reports on a set of workshops that the authors conducted with various groups (citizens, city engineers and planners, realtors and builders, and media representatives) within a flood prone community to evaluate how novel hydroinformatic tools that include hydrodynamic modeling, geospatial visualization, and socioeconomic analysis can enhance understanding of flood risk and engagement in flood risk mitigation among diverse community members. The workshops were designed to help identify stakeholder preferences regarding key functionality needed for integrated hydroinformatic technologies and socioeconomic analyses for flood risk reduction. Workshop participants were asked to use and comment on examples of prototype flood risk informational tools, such as: (1) flood damage estimation tool, (2) drivability and emergency accessibility tool, and (3) community-scale social and economic metrics tool. Data gathered from workshops were analyzed using qualitative analysis based on a grounded-theory approach. Data were coded by hand based on themes identified by the research team and incorporated deviant case analysis to ensure minority opinions was represented. The study results are focused on the following main themes and how flood tools can address them: (1) improving the understanding of flood risk and engagement in flood risk mitigation, (2) reducing the gap between individual and community risk, (3) challenges in communicating flood risk information, (4) enhancing relevance to and engagement of the community, and (5) enabling actionable information. Our research demonstrates the need for community-anchored tools and technologies that can illustrate local context, include local historical and simulated events at multiple levels of community impact, enable analyses by flood professionals while also providing simplified tools of use by citizens, and allow individuals to expand their knowledge beyond their homes, businesses, and places of work.more » « less
