The Interrelations of Water and Energy
Deason, Deputy Director
Center for Sustainable Environments
Water and energy are rarely considered together
although their infrastructures are inextricably linked. This is
especially true in the West where water is used for cooling electrical
generating plants and where electricity is used to move water over
vast distances and high elevations. On the average in the eight
Intermountain western states, fossil fuel generation of 1
kilowatt-hour of electricity requires one-half gallon of water.
Dominated by coal and gas fired steam generating plants, electrical
generation in the Intermountain West consumes over 650 million gallons
of water per day, primarily for condensing steam that has been used to
drive turbines (Last Straw, p. 1). This is enough water to meet the
needs of four million people, about the population of the state of
Conversely, enormous pumps moving water throughout the
West use extensive amounts of electricity to raise groundwater to the
surface, transport it over long distances (even over mountain ranges),
distribute it for agricultural and urban uses, move it to waste
treatment plants, and return it to surface streams after processing.
In arid regions of the Southwest, the largest users of electricity are
invariably companies that transfer and distribute water such as the
California State Water Project (“Energy Down the Drain,” p. v).
The interdependency of water and energy exacerbates all
of the major environmental problems of the West. With steady
population growth, states such as Arizona and Nevada require
increasing amounts of water which, in turn, require more energy to
access and distribute. Since this increased electrical demand is
largely met by fossil fuel- fired electrical generation plants,
significant amounts of additional water are required for cooling the
plants. More greenhouse gases are emitted, which contribute further to
global warming. Atmospheric warming eventually decreases water
supplies and forces more intensive pumping from deeper sources or
longer distances, resulting in even greater demands for electricity.
These interdependencies, which are usually ignored in water and energy
planning, create a downward spiral among electrical generation,
climate change and water supplies that is cumulative and non-linear.
Seventy percent (70%) of water used in the United
States goes to agricultural production with some states such as
California using as much as 85% of water for irrigation. Currently in
the United States, it takes an average of 1000 liters of water to
produce 1 kg of cereal grain and 43,000 liters for 1kg of beef. About
65% of irrigation water comes from underground aquifers, where
uncontrolled withdrawal in some areas has caused a fall in the water
table of 30m or more (Pimental, BioScience, 2004, p. 910). Withdrawal
from the Ogallala Aquifer through the Midwest from southern Minnesota
to Texas is three times faster than recharge, creating a rapid
depletion of groundwater that threatens future water availability for
food production and ranching operations.
Most estimates suggest that as much as 50% of water
used for irrigation is wasted due to inefficient technologies, system
leaks, evaporation and over-watering. Thus, significant opportunity
exists for efficiency improvements and economic benefits. Government
water subsidies, which artificially suppress true costs, as well as
the failure of planning and policy to associate electrical costs with
water use, have diverted attention from this problem. Most farmers
know that excess water leads to salting and water-logging which
significantly decrease crop production and income. Coordinating exact
watering levels with crop types is essential for efficient and
profitable farming operations.
Excess water adds significantly to electrical costs, as
electricity used for irrigation typically represents 90% of all
electricity used on farms (Energy Down Drain, p. v). Depending on
local conditions, installation of efficient irrigation systems may
save a landowner as much as 45% of overall electrical costs. Even in
an urban setting such as San Diego, it has been estimated that 25% of
electrical costs can be saved by water conservation measures (“Energy
Down the Drain,” p. vi).
As continual pumping decreases water levels, water
sources must be found deeper or further away, sharply increasing
pumping demands and electrical costs sharply. Depending on local
conditions, electrical costs increase about 32 times for each 100m of
pumping depth. It is estimated that 150,000 ha of agricultural land in
the United States has already been abandoned because of high pumping
costs (Pimental, et al, Water Resources, Agriculture and Environment,
04-1). In recent years, drought has intensified water scarcity and
pumping needs, causing skyrocketing electrical costs alongside reduced
crop yields. Since 2002, the Southwest has seen record numbers of
foreclosures and involuntary sales of farms and ranchlands due to
drought, high electricity bills, and reduced income from low crop
Because of the interdependency of water and energy,
water conservation has the double benefit of saving both water and
electricity. Water saved at the consumer end, such as high efficiency
clothes washers or drip irrigation, results in significant energy
savings because less water needs to be accessed, conveyed, treated,
distributed, removed and treated again as waste, all of which are
highly energy intensive. There is even a triple benefit in that
electricity savings also means less water is needed to cool generating
plants. Water use creates a domino effect and so does water savings.
Finally, reducing water use and associated energy
needed to move water increases the portion of future energy needs that
can be met by renewable energy resources. In a word, the less energy
we need, the more likely renewables can supply it. In addition,
renewable technologies use less water and produce less pollution than
fossil fuel generating plants. By conserving water and reducing or
eliminating greenhouse gases, renewables decrease the likelihood of
future water shortages driven by climate change. The fact that
renewable energy technologies use less water and produce fewer
greenhouse gases are two major reasons why the Southwest, and indeed
the U.S., should increase renewable energy production as rapidly as
“Energy Down the Drain: the Hidden Costs of California’s
Water Supply,” National Resources Defense Council and Pacific
Institute, April, 2004.
“The Last Straw: Water Used by Power Plants in the Arid West,” Hewlett
Foundation Energy Series, April, 2003.
“Water Resources: Agricultural and Environmental Issues,” David
Pimental, et al, BioScience, Vol. 54, No. 10, October 2004.
Water Resources, Agriculture, and the Environment. D. Pimentel, B.
Berger,, et al, Ithaca New York: New York State College of Agriculture
and Life Sciences, Cornell University Environmental Biology Report.
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