Integrating embedded resources and network analysis to understand food-energy-water nexus in the US

Tasnuva Mahjabin; Alfonso Mejia; Seth Blumsack; Caitlin Grady

doi:10.1016/j.scitotenv.2019.136153

Integrating embedded resources and network analysis to understand food-energy-water nexus in the US

Sci Total Environ. 2020 Mar 20:709:136153. doi: 10.1016/j.scitotenv.2019.136153. Epub 2019 Dec 17.

Authors

Tasnuva Mahjabin¹, Alfonso Mejia¹, Seth Blumsack², Caitlin Grady³

Affiliations

¹ Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, United States of America.
² John and Willie Leone Family Department of Energy and Mineral Engineering, The Pennsylvania State University, University Park, PA, United States of America; Santa Fe Institute, Santa Fe, NM, United States of America.
³ Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA, United States of America; Rock Ethics Institute, The Pennsylvania State University, University Park, PA, United States of America. Electronic address: cgrady@psu.edu.

PMID: 31905549
DOI: 10.1016/j.scitotenv.2019.136153

Abstract

To find a sustainable way of supplying food, energy, and water (FEW) while simultaneously protecting the ecosystem services, it is imperative to build greater understanding on interconnections, feedback, and dependencies in FEW systems. The FEW nexus has developed as a field of study to provide frameworks for such pursuits. Building upon previous work in this paper, we analyze FEW resources through the development of a virtual water trade network using the US network of food and energy flows and their associated virtual water contents. Our main objective is to provide a quantitative estimation of the virtual water embodied in the internal US food and energy transfers and analyze the associated interdependencies of these connections. Three methodological advancements demonstrate the novelty of this work. First, unlike existing FEW virtual water modeling studies, our work separates corn into both food and energy resources accounting for the significant use of corn for ethanol in the United States. Second, we apply recently published water consumption values for energy commodities confirming the variation between previous water footprint studies and these more accurate accounting procedures. Third, we examine network properties of the trade flows furthering FEW nexus literature and showcasing avenues for future research. Our results indicate that accounting for the transfer of corn from the food commodity network to the energy commodity network leads to a virtual water footprint decline of 11% for the cereal grain virtual water network. Additionally, the food trade network shows highly dense and connected properties compared to the energy trade network. Finally, our results indicate that transfers of water footprints between water scarce and water abundant states differ substantially between food and energy virtual water networks. A quantifiable understanding of the water footprint network embodied in the food and energy trade can help in developing policies for promoting conservation and efficiency in the context of the FEW nexus.

Keywords: Ethanol; Food-energy-water nexus; Network analysis; Virtual water; Water footprint.