The "Water-Energy Nexus"

As I continue to learn more about the world’s energy supply, I naturally bump up against water issues, as the two subjects are closely connected across different axes – the so-called “water-energy nexus.”

Of course, energy can be extracted from moving water; in fact, hydro-electricity accounts for about 7% of our power in the U.S. (19% worldwide).  Having said that, we usually consider the ways in which energy is used to provide the water we need – largely pumping and purifying.  I live in California, which, granted, is an extreme case, but here, 19% of all electricity (about 30% of all energy) is consumed in conveying and distributing water, and in treating waste water. 

Virtually all experts believe that water issues will become more severe as:

• world population rises to a peak of about 10 billion,

• droughts and other extreme weather events become worse and more frequent, and

• the energy required to deliver potable water becomes more precious. 

Currently, 1.5 billion people (about 20% of the world’s population) have no access to clean drinking water.  As tragic and unacceptable as this may be, it certainly makes one wonder: What happens when this number grows and begins to include populations in regions that have significant military capabilities (like nuclear weapons)? 

The United States has approximately 5% of the world’s population, and almost the same percentage of the world’s fresh water resources (about 10,000 cubic meters per person per year). But, obviously, this parity doesn’t exist in every country around the globe.  Notably, China has one-fifth this resource per person, and India has one-sixth. 

If we don’t get a grasp on this, it seems certain that we face a terrible future.