How Much Energy is Embedded in Local Water Use?

Extensive research on this topic has been done in California, but the question remains largely unanswered for the rest of the United States and Canada. The amount of energy embedded in drinking water and wastewater likely varies greatly from region to region due to different water pumping and treatment requirements, and national averages are not very helpful. Each water utility will need to calculate these values for their own systems.

Using California as an example, the 2005 California Energy Commission Staff Report Paper  that accompanied the 2005 Integrated Energy Policy Report  estimated that 19 percent of the state’s electric energy load and 32 percent of the state’s gas load was water related, measured at both the utility level and at the consumer level.  River Network’s 2009 report, The Carbon Footprint of Water,  estimates “that U.S. water-related energy use is at least 521 million MWh a year—equivalent to 13% of the nation’s electricity consumption.” The Water Efficiency Committee of the Illinois Section of AWWA conducted a study to determine the energy intensity of the state’s water suppliers. Utilities were surveyed and the results were compiled in the Water-Energy Nexus Survey Summary Report,  which was later used by Illinois regulators to financially reward energy saved from water conservation programs.

Reducing energy consumption with water efficiency also lowers greenhouse gas emissions associated with that water consumption. In its report, The Carbon Footprint of Water, River Network estimates that the carbon emissions related to water in 2005 were approximately 290 million metric tons, or 5% of all carbon emissions in the United States.

Related resources:

• Alliance to Save Energy’s Watergy Website 
• Electric Power Research Institute and Water Research Foundation (2013) Electricity Use and Management in the Municipal Water Supply and Wastewater Industries 
• Environmental Law Institute (2010) Mapping the Energy-Water Policy Landscape 
• National Conference of State Legislatures (2009) Overview of the Water-Energy Nexus in the United States 
• Natural Resource Defense Council and Pacific Institute (2004) Energy Down the Drain 
• U.S. Department of Energy Watergy Software