Kelly Sanders
University of Southern California
Dr. Kelly T. Sanders is an Assistant Professor in the University of Southern California’s Sonny Astani Department of Civil and Environmental Engineering. Her research aims to ease tensions between human and natural systems through technical, regulatory and market intervention, with particular emphasis on analyzing opportunities at the nexus of energy and water. She has authored more than two dozen publications and has given dozens of invited talks on topics at the intersection of engineering, science,and policy. Sanders has been recognized in Forbes’ 30 under 30 in Energy and MIT Technology Review’s 35 Innovators Under 35 for her contributions to the energy field. Her research and commentary have been featured in media outlets such as Forbes,The Washington Post, The Los Angeles Times, The Huffington Post, Bloomberg, The Wall Street Journal and Scientific American. Sanders received her B.S. in Bioengineering from the Pennsylvania State University, as well M.S.E and Ph.D. degrees in Mechanical Engineering and Environmental Engineering from the University of Texas at Austin, respectively. She teaches classes related to energy and the environment.
Water is a critical input to the United States energy economy. Large volumes of water are required throughout the lifecycle of energy systems from primary energy extraction through ultimate waste disposal and site remediation. Despite the coupled relationship between energy and water resources, to date there exists no comprehensive national estimate of the water consumed and withdrawn for the US energy economy. Furthermore, existing water use intensity factors of energy systems in the literature, typically defined as the water consumed (or withdrawn) per unit of energy produced (or delivered), often utilize data that are decades old, reflect a small sample size of facilities, are unclear in their accounting of primary versus secondary quantities of energy, or are interpreted incorrectly from study to study in the literature.
This analysis quantifies the water withdrawn, consumed and produced for the US energy economy in the year 2014. Results are differentiated by water source type (surface water, groundwater and reclaimed) and quality (fresh, brackish, reclaimed and hypersaline). The data analyzed through this effort were prioritized such that recent, raw empirical datasets were used whenever possible, followed by recent data published in peer-reviewed and non peer-reviewed (e.g. governmental reports) publications, personal communication with operators, and finally, environmental impact studies. When data were not available, values were calculated based on physical relationships. Water intensity factors were calculated for 16 fuel classifications across five lifecycle stages including primary fuel extraction, processing, transportation, conversion, and waste management. All results are reported in terms of primary energy and delivered energy (i.e. post-conversion and transportation losses), so that various energy systems can be compared across consistent units and methods of normalization.
Results indicate that 220 billion cubic meters, representing about 40% of total annual US water withdrawals, were dedicated to energy systems in 2014, primarily for thermal power plant cooling. Approximately, 16 billion cubic meters of water were consumed by energy systems in that year, representing about 10% of total US water consumption. Evaporative losses from thermal power plant cooling and hydroelectric reservoirs represented approximately 37% and 17% of annual water consumption across the energy sector, respectively. The majority of water consumed (76%) and withdrawn (86%) for energy systems was freshwater, with the energy extraction stage representing the largest amount of energy-related water consumption and the conversion stage, dominated by power plant cooling, representing the largest amount of energy-related water withdrawals. Our results suggest that recent freshwater consumption for fossil fuel extraction is higher than literature estimates and the water consumed per unit of energy produced varies considerably depending on the extraction site and method of production, underscoring the importance of regional context when estimating lifecycle water use implications of energy systems.
• Food, energy, water, and nutrient material flows and footprints
