The Water Footprint of California’s Energy System, 1990–2012

Published: February 2015
Authors: Julian Fulton and Heather Cooley
Pages: 18

water-footprint-ca's-energy-systemReceived: October 15, 2014/ Accepted February 26, 2015 by American Chemical Society for Environmental Science & Technology

A new article by Julian Fulton and  Heather Cooley  evaluates the amount of water consumed in meeting California’s energy needs – also referred to as the water footprint of energy. The article, published in Environmental Science and Technology, examines how the water footprint of energy changed between 1990 and 2012 – finding that the amount of water consumed substantially increased over recent decades without utilizing more of the state’s water resources, but rather by relying more heavily on water resources from outside the state. Much of that increase is attributable to the production of bioethanol, which recent energy policies have promoted to meet state greenhouse gas targets. Fulton and Cooley demonstrate that while efforts to mitigate climate change in California have been successful in reducing greenhouse gases, these policies may have shifted burdens from energy to water, rather than alleviate them. They conclude that more integrated analysis and planning of water and energy systems are needed to ensure that climate adaptation and mitigation strategies do not work at cross purposes. 

Abstract: California’s energy and water systems are interconnected and have evolved in recent decades in response to changing conditions and policy goals. For this analysis, we use a water footprint methodology to examine water requirements of energy products consumed in California between 1990 and 2012. We combine energy production, trade, and consumption data with estimates of the blue and green water footprints of energy products. We find that while California’s total annual energy consumption increased by just 2.6% during the analysis period, the amount of water required to produce that energy grew by 260%. Nearly all of the increase in California’s energy-related water footprint was associated with water use in locations outside of California, where energy products that the state consumes were, and continue to be, produced. We discuss these trends and the implications for California’s future energy system as it relates to climate change and expected water management challenges inside and outside the state. Our analysis shows that while California’s energy policies have supported climate mitigation efforts, they have increased vulnerability to climate impacts, especially greater hydrologic uncertainty. More integrated analysis and planning are needed to ensure that climate adaptation and mitigation strategies do not work at cross purposes.

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