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Clean Power Water Feature at Hopwood Park

Published on August 19th, 2018 | by Steve Hanley


Wind & Solar Conserve Freshwater Reserves That Other Electricity Generators Squander

August 19th, 2018 by  

When we talk about renewables like solar and wind, the focus is often on how much carbon dioxide they keep from being dumped into the atmosphere. That’s an important benefit, but there is another aspect of using renewables to generate electricity that is often overlooked. While coal, natural gas, and nuclear power plants require massive amounts of freshwater to operate, renewables use less of our precious freshwater assets by several orders of magnitude.

Carbon dioxide emissions threaten the Earth’s environment over time, but freshwater supplies are critical to human life in a much more immediate fashion. A person can live without oxygen for about 3 minutes and without food for about 30 days. But the human body cannot exist for more than about 3 days without access to clean drinking water.

Water is one of those things we take for granted. Turn on the faucet and out it comes. We don’t think too much about how it gets there. Of all the water on Earth, 97.5% is saltwater, according to the book Water In Crisis: A Guide To The World’s Fresh Water Resources by Peter Gleick. Of the 2.5% remaining, most of it is locked up in glaciers or is otherwise inaccessible. Only 0.8% is available as freshwater to support human life. With such a limited supply, it makes sense to conserve it rather than squander it, doesn’t it?

fresh water use in US

Credit: Anna Hazard; Source: Estimated Use of Water in the United States in 2010, by Molly A. Maupin et al. U.S. Geological Survey, 2014

A recent article by Scientific American points out that “In the U.S., 45.3 percent of the water withdrawn from lakes, rivers and underground aquifers is used to cool off thermoelectric power plants: nuclear reactors and plants that burn fossil fuels.”

Okay, water is essential to life and is in critically short supply. Yet, in America, nearly half of all the water available is used to cool electric generating plants — more than is used in agriculture and nearly three times more than is used by public water supplies. Scientific American notes the chart above does not take into account the millions and millions of gallons of freshwater used by fracking companies to extract natural gas.

Making enough electricity to power an average American home for a day requires 615 gallons of freshwater if the source of the electricity is a nuclear power plant, 199 gallons for a coal fired plant, and 114 gallons for a generating facility that operates on natural gas. By contrast, solar requires about 1 gallon of water to produce a megawatt-hour of electricity and wind none at all. To access the interactive feature of the chart below, please access the source article.

water use per megawatt

Credit: Anna Hazard; Source: “Operational Water Consumption and Withdrawal Factors for Electricity Generating Technologies: A Review of Existing Literature,” by Jordan Macknick et al., in Environmental Research Letters, Vol. 7, No. 4; December 20, 2012

The current administration likes to claim that nuclear, coal, and natural gas are essential to America’s national security. But access to clean water is one of the primary factors that motivates people to migrate from their homelands. Migration is poised to be one of the principal factors leading to global conflicts as elevated average temperatures around the world bring reduced rainfall to areas that are accustomed to reliable access to freshwater.

In the United States, large numbers of people live in areas that depend on freshwater supplies for their very existence. Most of the American Southwest, including Phoenix and Los Angeles, fits that definition. It’s easy to imagine the political disruptions that will occur if those areas no longer have access to water in the quantities they are accustomed to.

If renewables like solar and wind can reduce water usage to make electricity by several orders of magnitude compared to traditional facilities, that is yet another reason to favor them. Water is something Americans take for granted. That will change suddenly when they turn on their faucet one day and find nothing comes out.

“Failure to plan equals a plan to fail,” according to an old adage. At present, the US has no plan to conserve its freshwater supplies. In fact, it seems hellbent on squandering them as fast as possible. The consequences of such short-sighted policies should be intuitively obvious to the most casual observer. 


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About the Author

Steve writes about the interface between technology and sustainability from his home in Rhode Island and anywhere else the Singularity may lead him. His motto is, "Life is not measured by how many breaths we take but by the number of moments that take our breath away!" You can follow him on Google + and on Twitter.

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