Spatial and temporal variation in virtual water transfers on the U.S. electric grid

Nugent, Jennifer Cathryn

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https://hdl.handle.net/2142/129607 Copy

Description

Title

Spatial and temporal variation in virtual water transfers on the U.S. electric grid

Author(s)

Nugent, Jennifer Cathryn

Issue Date

2025-04-30

Director of Research (if dissertation) or Advisor (if thesis)

Stillwell, Ashlynn

Doctoral Committee Chair(s)

Stillwell, Ashlynn

Committee Member(s)

• Konar, Megan
• Zhao, Lei
• Peer, Rebecca A.M.

Department of Study

Civil & Environmental Eng

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• energy-water nexus
• electric grid
• water footprint

Abstract

Water consumed by power plants is transferred virtually between balancing authorities from producers to consumers on the U.S. electric grid. A balancing authority is an entity that is responsible for meeting electricity demands in a region by managing electricity generation and inter-region transfers. This network of virtual water transfers follows seasonal trends, as energy demand, fuel mix, and water availability vary seasonally. Blue water footprints were estimated based on hydropower reservoir evaporation rates and reported thermoelectric cooling water consumption, while grey water footprints were estimated based on thermoelectric cooling water discharge and local thermal discharge regulations. The central research goal of this dissertation is to analyze the sub-annual and spatial variations in virtual water transfers on the U.S. electric grid and their relationships with changes in season, climate, and infrastructure. Objective 1 quantifies monthly virtual water transfers between balancing authorities based on hourly electricity interchange data reported to the Energy Information Administration (EIA) in Form EIA-930 for 2016–2021. Virtual water footprints were calculated using thermoelectric water consumption volumes reported in Form EIA-923, power plant data from Form EIA-860, and water consumption factors from literature. This timescale is limited by a lack of sub-annual electricity transfer data available before July 2015. Objective 2 analyzes the seasonality of virtual water transfers on a longer historical timeline by calculating net electricity transfers for each balancing authority at a monthly timescale from 2010–2020. Electricity data (generation, demand, and interchange) were compiled, cleaned, and aligned to analyze discrepancies between historical annual and modern monthly data. A consistent time series of generation and demand was produced to determine the net electricity transfers, and subsequently the net virtual blue and grey water exports and imports. The results of Objective 1 and Objective 2 show that the water footprint of hydropower generation dominates virtual water transfers. To further understand the impacts of hydropower generation, Objective 3 leverages the historical net electricity transfer data to analyze the impacts of drought on hydroelectric power generation, electricity interchange, and virtual blue water transfers. The results indicate that virtual water transfers follow seasonal trends. Virtual blue water transfers are dominated by evaporation from hydropower reservoirs in arid, high-evaporation regions, and when virtual water transfers peak depends on the methodology for calculating evaporation from reservoirs. Objective 3 illustrates the correlation between drought severity and coverage and the energy-water nexus. Drought has varying impacts on balancing authorities both spatially and seasonally. Hydropower generation sees the greatest impacts in the form of generation reduction, which most heavily impacts balancing authorities with large reliance on hydropower generation. Increased renewable energy development, particularly wind power, could mitigate drought impacts on the grid and associated water resources. Understanding the spatial and temporal transfer of water resources has important policy, water management, and equity implications for understanding burden shifts between regions. By quantifying the virtual water transfers on the electric grid on a longer historic timeline, seasonality and water consumption are analyzed in response to dynamic changes over time, such as long-term drought and changes in grid fuel mix. The results show the complexities of working with disparate data sources to provide consistent data over historical timelines. The discrepancies between existing data sources highlight the importance of high-quality data collection, organization, and availability.

Graduation Semester

2025-05

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/129607

Copyright and License Information

© 2025 Jennifer Cathryn Nugent

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