At the Columbia Water Center we frequently refer to the water/energy nexus. I am often asked what is meant by this term. Broadly speaking, the water/energy nexus refers to the myriad cyclical ways in which water and energy relate to, and impact, each other. Water is necessary in the production of virtually all types of energy, but energy is also needed for many methods of accessing water–most notably for pumping groundwater. The interplay between these two sectors is exceedingly complex.
For environmentalists, a troubling example of the water/energy nexus arises in the American West, a region known for its brilliant sun and high potential for solar energy production. Unfortunately, the region is also known for its short supply of water resources, and water is just what is needed for a popular type of solar energy production–wet cooling of solar thermal plants. While extremely attractive, both economically and because of its minimal carbon emissions, solar thermal energy is also hugely water intensive. As the Times reported on Oct 27, this tension is beginning to come to a head in many water-stressed areas of the region.
This presents a conundrum for many environmentalists (including me). Solar is typically considered to be one of the “good” energy alternatives due to its relatively small environmental footprint. Yet it’s clear that in spite of the many arguments in favor of solar, its drawbacks also need to be considered. The unfortunate reality is that many regions which are so well suited to solar, for reasons related to weather and space, are also water-stressed. This isn’t an argument against solar, but we do need to acknowledge that the potential implementation of solar, especially on a large scale, needs to be carefully evaluated in light of the water constraint. It is also imperative that as a society we work towards breaking down barriers to the adoption of much less water-intensive types of solar production.
There are countless other examples of the interplay between water and energy issues, and while awareness of each individually seems to be on the rise, there is relatively little consideration of the actual connection between the two. At the Water Center, we will continue to research this issue, yet it is my hope that over time, energy and water will come to be seen, not as distinct, but as two sides of the same coin. A myopic focus on only of these is unlikely to lead to good decisions; instead both factors should be considered as part of a holistic approach to–everyone’s favorite term–environmental sustainability.