The Water-Energy Nexus

Image courtesy of U.S. Department of Energy

Saving water saves energy. Saving energy saves water. There is a growing awareness that water and energy issues are closely connected. What's not yet widely understood is just how much water we can save by saving energy, and how much energy we can save by saving water. The potential is enormous. With demand for water and energy continuing to grow, addressing the water-energy nexus is an opportunity we can't afford to miss.

The more energy we save, the easier it is to reduce the harmful effects of our greenhouse gas emissions. The more water we save, the easier it is secure precious freshwater resources and maintain a healthy, climate-resilient environment. Understanding these relationships between water and energy is more important than ever in today's changing world.

Energy for Water

At a minimum, the United States uses the equivalent of 520 billion kilowatt hours per year--equivalent to 13% of the nation's total electricity use--to pump, heat and treat water. This is double what is generated by all of the nation's hydroelectric dams in an average year and equal to the output of over 150 typical coal-fired power plants! The bad news is that saving energy through water conservation, efficiency and reuse is not currently being utilized as a major strategy for addressing climate change. The good news is that this is one of the largest categories of energy use that we could reduce quickly and significantly, with the added benefit of protecting our water resources from the threat of a changing climate.

We can't eliminate all water-related energy use, of course, but we could reduce a great deal of it in just a few years through water conservation, efficiency and low impact development. We could reduce a great deal more of it over the next few decades if we begin now to replace many uses of treated drinking water with harvested rainwater or treated wastewater. Explore the menu to the right to learn more about the energy savings that can be obtained through better water use and management.

Water for Energy

Water is used in almost every aspect of energy production. In a 2006 report, the Department of Energy estimated that “in calendar year 2000, thermoelectric power generation [coal, nuclear, natural gas] accounted for 39% of all freshwater withdrawals in the U.S., roughly equivalent to water withdrawals for irrigated agriculture.” The report also states that consumption of water for electrical energy production could more than double by 2030 if current trends persist, equaling the United States' entire domestic water consumption in 1995!

As we shift towards cleaner energy, some alternatives - including biofuels and coal with carbon sequestration - can significantly increase freshwater demands. Luckily, other clean energy technologies such as wind and photovoltaic solar power use virtually no water, which means clean air and healthy rivers in your community. Explore the menu to the right to learn more about the river and freshwater benefits of clean energy.