Water and Power - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 240

The water industry itself uses a lot of energy. The collection, transportation, treat-
ment, and distribution of water by the nation's sixty thousand water systems and fifteen
thousand wastewater treatment plants account for about 4 percent of America's total
electrical use, according to the Sandia National Laboratories. In a 2007 study by state
agencies, California found that “water-related energy use” —i.e., moving the state's wa-
ter supply across great distances, through the Sacramento-San Joaquin Delta and over
mountain ranges—consumes about 19 percent of the state's electricity, 32 percent of its
natural gas, and 88 billion gallons of diesel fuel a year. Energy was required for each step
of the value chain, from storage to conveyance, treatment, distribution, and wastewater
collection. As more long-distance aqueducts and pipelines are planned, regulators will
have to factor in the power needed to build and operate them and the water costs asso-
ciated with that power.
Climate change is affecting power supplies because sudden shifts in temperature lead
to surges in power use, and because generators are vulnerable to drought or flood. As
Lake Mead's water levels sank in the early 2000s, managers worried that the hydroelec-
tric turbines in Hoover Dam would stop spinning. Farther down the Colorado River, a
debate brewed over San Antonio's wish for billions of gallons of water to alleviate the
drought in Texas, while Austin requested water to supply new power plants for its ex-
panding suburbs. There isn't enough blue gold to satisfy both demands.
Roughly half of the freshwater drawn from sources in the United States is used by
industrial cooling towers. Many older power plants use inefficient “once-through” cool-
ing (OTC) systems, in which large amounts of water are drawn from a waterway, circu-
lated through the system, then discharged. Of the water used to cool power plants, 2 to
3 percent is lost to evaporation , which works out to a loss of 1.6 trillion gallons a year
of water that would otherwise be used by the ecosystem. As they suck water into plants,
OTC systems kill fish and other aquatic organisms; when the heated water is pumped
back out of the plant, it causes further damage.
During the heat wave of 2008, for instance, Texas used approximately 157,000 milli-
on gallons of water a year—enough to supply drinking water to 3 million people—just
for cooling the state's power plants.
As we approach the limits of how much water can be extracted from the environ-
ment, growth may be held in check. By 2050, the US population is expected to reach
440 million , and energy demand will increase by 40 percent, according to the Depart-
ment of Energy. This will require adding at least sixteen hundred new power plants. But
these plants use tons of water, which may not be available unless other users are sacri-
ficed. Most of the new growth is projected for the water-stressed West, and regulators
in Idaho and Arizona have denied permits for new power plants because of concerns
about water use.