The Water-Energy Nexus - An Overview

“THE WATER-ENERGY NEXUS – AN OVERVIEW”

 Two commodities in short supply in the southwestern United States are water and energy.   Water supply and energy development can be conflicting interests, where both are competing for the same water resource.  But water and energy development can be complimentary.  Water is required for most electrical energy production, and energy availability can increase useable water supplies through desalination.
For the foreseeable future, large-scale electric power generation will depend mostly on coal-fired or nuclear power plants, both of which have large cooling-water demands.  Even newer, greener technologies, like concentrated solar power (CSP) generation, require substantial quantities of water.  However, steam-power generation can tolerate only limited salinity to avoid corrosion and/or scaling.  Any large-scale electrical power project requires many thousands of acre-feet of moderately good-quality water.
Producing energy from biomass, tar sands, oil shale, and other sources is also water-use intensive.  For example, it is generally assumed that three barrels of water will be required to produce one barrel of oil from oil shale.
 Co-location of power and desalination plants will reduce the traditional competition between water supply and power production.  Power plants tend to be located in sparsely populated areas where the ground water is brackish or saline.  These areas may become the preferred sites for joint production of both power and fresh water, providing inexpensive power for desalination and reliable water supplies for power.   Co-location of CSP and desalination plants is common in the Middle East, with both power and water often available for export.
Co-location of large nuclear power and desalination plants is obtaining serious attention in coastal areas around the world.   This approach should also be considered for inland areas where abundant brackish ground water is available.