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T H E E N E R G Y WAT E R C O L L I S I O N - page 3 / 6

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Water required to produce transportation fuels

Running a typical car (getting the equivalent of 24 miles per gal- lon of gasoline) on corn ethanol can require one-half to 20 gallons of water per mile—or more—de- pending on the water used for irri- gation. “Cellulosic” biofuel would require less than one gallon of wa- ter per mile. Gasoline, while not a renewable resource, requires the least water: less than half a gallon for extracting and rening oil.

0.6–20GPM

corn ethanol

0.1–0.6GPM

cellulosic biofuel

0.1–0.3GPM

gasoline

Unconventional fossil fuels— such as “liquid coal” or oil from tar sands or shale—can have serious water implications. A coal-to-liquids plant supplying 50,000 barrels of fuel per day would withdraw al- most 5 billion gallons of water in a year21—a gure similar to the highest water use seen for gasoline—but does not account for the large volumes of water needed to mine and wash the coal before processing.

THE FLIP SIDECalifornia uses 19 percent of its electricity and 32 percent of its natural gas for water.22 Just as energy produc- tion requires large amounts of water, the inverse is also true: substantial amounts of energy are used to pump, transport, treat, and heat the water we use every day. Nationwide, the EPA estimates, treating and distribut- ing drinking water and wastewater together account for 3 percent of en- ergy use. In some parts of the coun- try, the energy toll is much higher. 7

California’s single biggest user of electricity is the State Water Project.23

  • is system, serving 29 local water

agencies, consumes enough to power more than 450,000 households24—or a city roughly the size of San Di- ego. Similarly, the Central Arizona Project, a 336-mile aqueduct deliver- ing water to Phoenix and Tucson, is Arizona’s largest electricity user.25

WATER UNRESTWater supply conicts are growing across the United States. Particu- larly in the West, conicts between competing water users—e.g., farmers, electric utilities, cities—are building. Such conicts, many of which have an energy dimension, are expected to intensify, especially during periods of drought or other water stress.26 Even without factoring in the exacerbating role of climate change, water sup- ply conicts involving several major Southwest cities—including Denver, Albuquerque, Las Vegas, and Salt Lake City—are considered highly 8

Electricity and Water Pollution

Thermal pollution is not the only way thermoelectric power plants aect water. The arsenic, mercury, lead, and other toxic substances contained in the 120 million tons of coal plant waste produced every year can severely contaminate drinking water supplies.35 Coal mining in the United States uses an estimated 80 million to 230 million gallons of water each day—the equivalent of 10 million to 20 million showers. The EPA estimates that strip mining of coal by moun-

taintop removal has buried almost 2,000 miles of Appalachian headwater streams—some of the most biologi- cally diverse streams in the country.36

Natural gas-red plants are less water-intensive than coal or nuclear plants. Still, extracting gas from shale deposits, such as those found in Texas, Pennsylvania, and New York, through a process known as hydraulic fractur- ing can potentially lower local water quality, as well as strain local water supplies.37

1 gallon of = water per mile (GPM)

likely by 2025.27 Such tensions are not conned to arid regions. In the Southeast, for example, prolonged drought brought simmering disputes between Georgia, Tennessee, and other stakeholders over the rights to Tennessee River water to a boiling point in 2008.28 By 2030, electric capacity is predicted to grow nearly 30 percent in the western United States and 10 percent in the South- east,29 a trend that would force the question: With what water?

9 CLIMATE COMPLICATIONS As the climate changes, so does the water cycle. Increas- ing climate variability—extreme heat and extended drought, in particular— is already testing the resilience of energy and water systems in the South- west and other regions. Further climate change will pose far-reaching chal- lenges. e Northeast and Midwest can expect more spring ooding and extended summer drought.30 In the Southeast, where both air and water temperatures are expected to rise,31 in- stances where water is too warm to be used to cool power plants may become far more frequent. Other regions— notably the Southwest—can expect far less runo and precipitation, especially in the warm months. Longer, more se- vere droughts will leave arid areas even drier.32 With declining snowpack, for example, ows in the Colorado River are projected to decrease 20 percent be- low current averages by 2050.33 e net eect nationally will be a more variable and unreliable water situation.34

Union of Concerned Scientists

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