The Water-Energy Nexus

Dr. Robert M. Gresham, Contributing Editor | TLT Lubrication Fundamentals July 2016

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© Can Stock Photo Inc. / Tinka
“WATER, WATER, EVERYWHERE, NOR ANY DROP TO DRINK,” is a line from the Rime of the Ancient Mariner by Samuel Taylor Coleridge, circa 1797. Ole Sam was writing in a slightly different context but prescient nonetheless.

I expect STLE members are well aware that STLE’s board of directors commissioned an Emerging Trends report in 2014 that is available for free on at www.stle.org. Somewhat buried in that report, under the trend topic of human and societal needs, was the observation that even though two-thirds of the world’s surface is covered by water, only about one percent of the world’s reasonably available water is potable. Thus, as populations increase and emerging economies grow and thrive, both developed and emerging nations will have to learn to more efficiently manage their water resources.

Coupled with this observation, the U.S. Department of Energy in the same time frame issued a report titled The Water-Energy Nexus: Challenges and Opportunities. Of course, there has been much discussion and, sadly, some blather, about the growing global energy again in both developed and emerging nations.

This has led to the emphasis on, or the emergence of, so-called renewable energy sources (wind, solar, hydroelectric and burning our food in the form of ethanol), the slow re-emergence of nuclear power, more efficient drilling practices, hydro-fracturing of oil shales and the discovery of vast natural gas reserves to fill this growing need. What I had not considered, and the DOE report highlights, is the interdependence of water and energy systems.

Historically at the national and international levels, water and energy have been developed, managed and regulated independently. Indeed, in the U.S. this has occurred regionally, as well. Water management east of the Mississippi River is very different from water management in the west. Further, the U.S. population continues to migrate toward the southwest, where water is a far more scarce commodity.

Indeed, in the west much water comes from the melting of snow (surface water) versus the east where much of the water comes from wells and springs (groundwater) as well as surface water and is much more available. In fact, the two areas evolved from two entirely different legal/regulatory environments. In the east the terms are Pure Riparian, Riparian and Mixed-Pure Appropriation, where in the west the terms are Pure Appropriation, Prior Appropriation (formerly Riparian) and Other. In dealing with water rights in the east, the riparian doctrine states that water belongs to the person whose land borders a body of water. Riparian owners are permitted to make reasonable use of this water provided it does not unreasonably interfere with the reasonable use of this water by others with riparian rights.

In the west, the legal doctrine stipulates that the first person to take a quantity of water from a water source for “beneficial use” (agricultural, industrial or household) has the right to continue to use that quantity of water for that purpose. Subsequent users may take the remaining water for their own beneficial use provided that they do not impinge on the rights of previous users. Sort of a first-come, first-served concept.

This doctrine of water rights is very different from riparian water rights, which are applied in the rest of the U.S. Water supplies are very limited in western states and must be allocated sparingly based on the productivity of its use. The right is also allotted to those who are “first in time of use.” Thus, it is pretty easy to see why the historic growth of the west was pock-marked with water rights wars and litigation—and easy to see the inherent differences in the two regions.

Given the water situation in the U.S., the water-energy nexus identified by DOE is that the flows of water and energy are intrinsically interconnected due to the fact that water’s inherent physical properties make it uniquely useful for producing energy and the use of energy to treat and distribute water for human use create this interdependence. For example, thermoelectric power generation withdraws, from surface or ground sources, large quantities of water for cooling and dissipation of tremendous quantities of waste energy (thermal pollution) due to inefficiencies in converting thermal energy to electricity. The intensity of water use and heat dissipation varies with the generation and cooling technology.

To my great surprise, agriculture, the largest consumer of water, competes directly with the energy sector for water which is consumed—defined as with drawn from surface and/or ground sources and not returned because it has been evaporated, transpired into plants, incorporated into products, etc. Further, the treatment, distribution and waste treatment of water requires considerable energy.

This nexus is very complicated, especially when one considers the various intended and unintended consequences of the varied water-energy systems and interactions. Overlaying these consequences is the significant regional variability in the water and energy systems, their interactions and resulting variations. Further, the energy requirements of water systems vary regionally due to the inherent water quality and pumping needs. Understanding this nexus is not prone to 30-second sound bites from the talking heads community. Perhaps that is why I had previously not considered this.

However, in the U.S., these dichotomies provide a unique opportunity to learn how to manage this nexus on a global scale. Like the U.S., the rest of the world varies tremendously in the availability of water; this likewise has impacted various regions and nations from developing their energy systems as well. If we can develop different but efficient water-energy systems that work well in our different regions, then these technologies also can be applied to other parts of the globe as appropriate. This is a lofty but necessary goal.


Like the U.S., the rest of the world varies tremendously in the availability of water.
© Can Stock Photo Inc. / pyzata

Some parts of the world already have begun to deal with these issues. For example, Israel gets about half its water from unconventional sources relying heavily on desalinization, and it has a very efficient agricultural water system that greatly reduces both the amount of water used and the amount lost to evaporation. Israel, which also reclaims wastewater for appropriate re-uses, likely leads the world in managing its water supply and probably will do the same with the water-energy nexus. Qatar is oil-rich and water-poor, relying on desalinization for water, and it is moving to reclaim waste heat and use renewable energy sources. China is coal-rich but water-poor and is adopting direct and indirect methods to reduce water usage in energy production.

The DOE has identified six pillars to address the water-energy nexus:
1. Optimize freshwater efficiency of energy production, electricity generation and end-use systems.
2. Optimize the energy efficiency of water management, treatment, distribution and end-use systems.
3. Enhance the reliability and resilience of water-energy systems. (Resistance to interruptions due to breakdowns, natural disasters, etc.)
4. Increase safe and productive use of nontraditional water sources.
5. Promote responsible energy operations with respect to water quality, ecosystem and seismic impacts.
6. Exploit productive synergies among water and energy systems.

Now is the time for organizations like DOE, the National Science Foundation and others to fund research into various kinds of technologies to mitigate the water-energy nexus problems. Such research also should include technologies that reduce thermal pollution and can sequester and recycle carbon oxides in the context of the water-energy nexus. For the tribologically oriented community, there are many opportunities to provide enabling technologies to realize these human and societal needs. Success in these critical areas will allow for continued growth and quality of life in both developed and emerging nations.

Success is critical.


Bob Gresham is STLE’s director of professional development. You can reach him at rgresham@stle.org.