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Water-Energy Nexus

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Energy Intensity (EI) is a measure of the amount of energy required per unit of production.  EI is a measure of the amount of energy required to take a unit of water from its origin (such as a river or aquifer) and extract and convey it. Within California, the EI of water varies greatly depending on geography and water source.  The Department of Water Resources subdivides the State into specific geographical study areas for planning purposes, corresponding to the State’s major drainage basins. Click on any of the 10 regions in the interactive map below to see a summary of the EI to extract and convey (not treat or deliver) many of the water supplies available in that region. Right mouse click on the energy intensity figures to save.

Energy intensity information is designed to help inform the public and water utility managers about the relative energy requirements of major water supplies used to meet demand. Because energy usage is closely related to greenhouse gas (GHG) emissions, this information can support measures to reduce GHGs, as mandated by the State.


Note:  Energy Intensity (EI) for each regional figure is the estimated energy required for the extraction and conveyance of one acre-foot of water. The figures reflect only the amount of energy needed to move water from a supply source to a centralized delivery location (not all the way to the point of use). Small light bulbs are for EI greater than zero, and less than 250 kilowatt hours per acre foot (kWh/AF). Large light bulbs represent 251-500 kWh/AF of water (e.g., four light bulbs indicate that the water source has EI between 1,501-2,000 kWh/AF). Energy intensities of regional water supplies calculated here include only embedded energy from extraction and conveyance of water. Additional energy would be required to treat and deliver the water to end users. Treatment and delivery energy varies considerably based on treatment technology used and incoming water quality, delivery distance and geography. Treatment alone can add between 50 and 650 kilowatt-hours per acre-foot (kWh/AF) of water. 

*The percent of regional water supply may not add up to 100% because not all water types are shown in this figure. EI values of Desalinated and Recycled Water have not been included in the regional figures because the EI of these water supplies depends more on very localized factors rather than regional factors. Additional information about the EI’s of desalinated and recycled water see California Water Plan Update 2013 Volume 3, Resource Management Strategies 10 and 12. (For detailed descriptions of the methodology used to calculate EI in this figure click here)


For further climate change information, please check out the Regional Reports from the California Water Plan Update 2013.