Archive for July 30th, 2012


Water-Energy Nexus Goes mainstream

Post from Jeffrey Winters:

Jeffrey Winters

Water plays a little appreciated but crucial role in the cooling systems of most thermal electric generating plants—a plant with cooling towers, for instance, will consume about 400 to 500 gallons per megawatt-hour due to evaporation. If water consumption is restricted, due to drought or some other reduction of flow in the source of water nearest the facility, the power plant may have to reduce production or shut down entirely.

Because of this, the connection between power production and water use has become a topic of great interest at ASME. In 2008, the Center for Research and Technology Development published the ASME Water Management Technology Vision and Roadmap, and a research committee on water management technology produced the ASME Water Management Technology Best Management Practices and Innovations for the Process Industries in 2010. And at last year’s congress, there was a whole technical track dedicated to what’s called the water-energy nexus.

The magazine has covered the topic as well, most notably in Mike Hightower’s feature article, “Energy Meets Water,” in July 2011.

Now the connection has made the Op-Ed pages of the New York Times. On July 24, the Times published an article by Michael E. Webber, an assistant professor of mechanical engineering at the University of Texas in Austin, called, “Will Drought Cause the Next Blackout?”

Webber discusses some of the effects the national drought is already having. In Texas, for instance, some cities have declared a moratorium on the use of municipal water in hydraulic fracturing operations to preserve dwindling reserves for domestic use. Fortunately, Webber writes, there are solutions at hand. Some are obvious.

“The government should also invest in water-related research and development (spending has been pitifully low for decades) to seek better air-cooling systems for power plants, waterless techniques for hydraulic fracturing, and biofuels that do not require freshwater irrigation.”

But others are not as obvious, and will likely strike some stakeholders in coal power as controversial.

“New carbon emissions standards can also help save water. A plan proposed by the Obama administration (requiring new power plants to emit no more than 1,000 pounds of carbon dioxide per megawatt hour generated) would encourage utilities to choose less carbon- and water-intensive fuels. Conventional coal plants, which are very thirsty, exceed the standards proposed by the president. But relatively clean, and water-lean, power plants that use wind, solar panels and natural gas combined cycle, would meet them. Thus, by enforcing CO2 limits, a lot of water use can be avoided.”

What is indisputable is that the water-energy nexus left the engineering world to become part of the national discussion.

The Editor

John G. Falcioni is Editor-in-Chief of Mechanical Engineering magazine, the flagship publication of the American Society of Mechanical Engineers.

July 2012

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