energy requires water; water requires energy

So far, I have not directly addressed the relationship between energy and water, which is the subject of this blog. This weekend I was reading Energy Demands on Water Resources, Report to Congress on the Interdependency of Energy and Water (US Department of Energy, December 2006).

"Water is an integral element of energy resource development and utilization. It is used in energy-resource extraction, refining and processing, and transportation. Water is also an integral part of electric-power generation. It is used directly in hydroelectric generation and is also used extensively for cooling and emissions scrubbing in thermoelectric generation. For example, in calendar year 2000, thermoelectric power generation accounted for 39 percent of all freshwater withdrawals in the U.S., roughly equivalent to water withdrawals for irrigated agriculture . . . " (p9)

Later, "A 2003 General Accounting Office study showed that most state water managers expect either local or regioal water shortages within the next 10 years under average climate conditions (GAO, 2003). Under drought conditions, even more severe water shortages are expected." (p10) Meanwhile, "The Energy Information Administration (EIA) projects, . . . the U.S. population to grow by about 70 million in the next 25 years and electricity demand to grow by approximately 50 percent (EIA, 2006). . . . Much of this growth is expected to occur in the Southeast, Southwest, and Far West, where water is already in limited supply." (p10)

It is important to note that unlike irrigated agriculture which consumes roughly 50% of the water "withdrawn" for that purpose, thermoelectric power plants often return almost 100% of the "withdrawn" water after it is used. However, the quality of the water and its increased temperature can have negative impacts on the plant and animal life living in the water.

To offset the increased demand on both energy and water resources, managers may be able to take advantage of efficiencies between the two with careful planning. New technologies are being developed that hold promise of at least partially ameliorating the problem.

At present, energy and water resource planning are often done separately. This presents an important systemic problem. If resource managers take into account the interrelated needs for both resources, they will be able to take advantage of efficiencies in developing both. For example, ". . . significant improvements in energy and water conservation can often be realized through implementation of innovative processes or technologies, colocation of energy and water facilities, or improvements to energy and water infrastructures." (p49)

of pumps and pressure

Those aquifers that we are so assiduously mining in the West: why weren't they exhausted long ago? After all, surface waters in New Mexico have been fully appropriated since at least 1848.
The answer lies in well technology. With the development of more powerful pumping technology, the deeper waters became accessible. This has led to a temporary, illusory increase in water supply.

It also explains why the water situation in Roswell, New Mexico in the early part of the 20th century was so noteworthy. The deep aquifer there is a special kind, an artesian aquifer. This means that there is so much pressure on the water in the aquifer, that when you drill a well into it, the pressure sends the water shooting skyward. In Roswell a pump wasn't necessary. Mother Nature would pump the water for you.

Unfortunately for the people living along the Pecos River, excessive mining of the shallow and deeper groundwater led to a lowering of the pressure in the aquifer, a lowering of the water table, and along with it, the Pecos River. This reduced the amount of water available to downstream users in Carlsbad and also Texas and created all sorts of water management problems, including a huge lawsuit between Texas and New Mexico.

blogoworld connections of interest

Here are a couple related blogs that may interest readers of H2OE:

John Fleck of the Albuquerque Journal blogs New Mexico Science: A reporter's notebook about science and technology. http://www.abqjournal.com/abqnews/index.php?option=com_content&task=view&id=2429&&Itemid=31

and

Michael Campana, who is now Director of the Institute for Water and Watersheds at Oregon State University blogs WaterWired!
http://aquadoc.typepad.com/waterwired/

Enjoy!

salinity: irrigation and steaming brine

I've been reading Water, the Fate of Our Most Precious Resource, by Marq de Villiers (c2000, ISBN0-618-03009-3).

In the chapter on irrigation, de Villiers discusses the growing salinity of the soil and indicates that the American Southwest is an area vulnerable to saline degradation. "It is where irrigation is intensive, the soils naturally poor, and the drainage either inadequate or nonexistent that the most serious problems will occur. The American West . . . is the most notorious example." (p143) In the Imperial Valley in California this is beginning to render the farmland unusable.

Then he mentions the geothermal aquifer beneath the Imperial Valley:

"Water temperatures in the huge underground pool rise as high as 280C. Researchers are developing methods to use the steaming brine to generate electrical power. They believe it is feasible that the clean wastewater produced by a power plant could be used to dilute the salty water in the fields." (p140)

The above is an example of how to take advantage of the energy-water nexus.

Later, he talks about methods for preventing saline buildup in the soil:

"But what can be done? More efficient irrigation would help -- the large-scale application of the methods my grandfather had worked out intuitively. The Israelis, always searching for better techniques, have improved efficiencies sixfold by using laser technology to get fields absolutely level, and by reusing surplus water from one crop on other, more salt-resistant crops. Israeli water engineers have taken "water stress management" of crops to a high art, and water only when necessary." (p144)

Perhaps this is incentive for Southwest American farmers to invest in laser-levelling, even though it may reduce the amount of water they put to beneficial use, it can also preserve their soils so they remain productive over a longer time-frame.