PNNL

Abstract

This study analyzes the strength of interconnections between multiple resources across the United States. Concepts from graph theory and Input-Output analysis are used to identify and quantify key intersectoral linkages using two new indices: the ‘Interconnectivity Magnitude Index’ (Magnitude) and the ‘Interconnectivity Spread Index’ (Spread). The future evolution of resource interconnectivity in the U.S. will be driven by a range of socioeconomic, natural and technological changes. In this study we focus on a subset of these in four scenarios developed using the Global Change Assessment Model (GCAM-USA): (i) Reference scenario (ii) Low Pop/GDP (iii) High Pop/GDP and (iv) Low Carbon. Analysis is conducted at both national and state level spatial scales from 2015 to 2100. Reference scenario results for the U.S. show that resource interconnectivity is primarily driven by water used for agriculture, while changes in interconnectivity are driven by a decoupling of the water and electricity systems as powerplants become more water efficient. A higher population and GDP result in relatively more decoupling as a larger share of water and energy are used directly use by industrial and municipal end-users as compared to amongst resource systems themselves. Lower population and GDP show the opposite trends. The Low Carbon scenario increases interconnectivity as a result of the expansion of purpose-grown biomass connecting water and energy systems. These results complement other studies looking at the distribution of critical resource hotspots such as the increase in water scarcity, biofuel expansion into other crop lands, and shifts in water use for power-plant cooling. Even in regions with similar levels of projected resource stress, an analysis of the variable characteristics of interconnectivity across these regions highlights the need for distinct co-management strategies to maximize efficiency and plan more resilient systems.