Energy demands and externalities of fresh water produced via desalinization

Fig. 6: The 50×106 gal/day Carlsbad, CA desalinization plant just approved by San Diego regional water authorities. Photo Source: Poseidon Resources.

The problem:
Climate change is expected to produce major shifts in the distribution of precipitation.  While globally the amount of precipitation is expected to increase, much of it will come in more intense episodes, and periods of drought will likely become more frequent.  At the same time, much of the U.S. has been operating with non-sustainable use of fossil water.  Taken together these developments raise the possibility that the future may see much expanded use of water desalinization.  While this technology is becoming more affordable, it can use prodigious amounts of energy, giving rise to a potential interaction with efforts to reduce GHG emissions by limiting growth in demand for electricity.

The research:
Building on the recent assessment performed by the NRC, Matthews, Morgan and colleagues will begin with a technical assessment of the likely future evolution of technologies for water desalinization.  The results will then be combined with regional population and water use projections to perform bounding analysis to estimate an upper bound on the amount of increased power requirement, as a function of technology type, and regional development patterns, that might be required for large-scale deployment.  These results will be merged with results from demand estimates generated in our study of alternative adoption scenarios for plug-electric hybrid vehicles.  In addition to engineering-economic assessment, there will likely be opportunities to apply methods from decision analysis and robust decision making (See Figure).

The decision makers:
BPA, CAT, EPRI, IRGC, NRDC, Westinghouse.