Photograph by Taylor S. Kennedy
Energy and water are inextricably linked. Water generates power, and, on the other side of the same coin, it takes large amounts of energy to clean and deliver water.
Nearly 6 percent of electricity in the U.S. comes from hydroelectric sources, which capture the natural energy stored in moving water and convert it into electricity. Hydropower has been in play for thousands of year—an original use was to grind grain at small mills.
But now huge dams associated with hydropower are under fire for altering natural flows and water quality.
In most developing countries, elaborate systems are in place to treat and transport water into our homes, onto agricultural fields, and into factories. All of this pumping and disinfection, especially of salt water, can be very energy intensive, requiring large amounts of nonrenewable resources, such as coal.
Understanding this energy-water nexus can help shine a light on our dependency on both and lead us toward conservation.
- A U.S. Congressional mandate to produce 15 billion gallons (56.8 billion liters) of corn ethanol by 2015 would annually require an estimated 1.6 trillion gallons (6 trillion liters) of irrigation water (and even more direct rainfall)—a volume exceeding the state of Iowa’s annual water withdrawals.
- Transferring Colorado River water into southern California requires about 1.6 kilowatt-hours (kWh) of electricity per cubic meter (35 cubic feet) of water; the same quantity sent hundreds of kilometers from north to south through California’s State Water Project takes about 2.4 kWh, primarily for pumping. Because of these delivery mechanisms, the energy required to provide drinking water to a typical southern California home can rank third behind that required to run the air conditioner and refrigerator.
- Producing 35 cubic feet (one cubic meter) of drinkable water through desalination reverse osmosis (the process of forcing salty water through a membrane to remove the salts) requires about 2 kWh of electricity. Although that’s down from 5-10 kWh 20 years ago, it is still energy intensive.
Did You Know?Currently, the roughly 15,000 desalination plants worldwide have the capacity to produce 540.3 billion cubic feet (15.3 billion cubic meters) of water per year—less than 0.5 percent of global water demand. Some 47 percent of this capacity is in the Middle East, where many nations can afford to turn oil into water.
More About Energy and Water
The power of water has been harnessed for energy since the ancient Greeks. Today, hydropower provides about one-fifth of the world's electricity.
As climate change throws Earth's water cycle off-kilter, the world's energy infrastructure is in trouble—and the U.S. is in particularly "bad shape."
Companies, including beer giant SABMiller, are starting to account for their water use. But will consumers get to see this information on labels?
A research center slated to be built in 2010 as part of the Sahara Forest Project is meant to serve as a proving ground for new technologies designed to bring green living to the desert.
Help Save the Colorado River
You can help restore freshwater ecosystems by pledging to cut your water footprint. For every pledge, Change the Course will restore 1,000 gallons back to the Colorado River.
Sandra is a leading authority on international freshwater issues and is spearheading our global freshwater efforts.
He's paddled the Colorado River from its headwaters to the delta in an effort to bring awareness to this mighty river at risk.
For more than 15 years, Osvel Hinojosa Huerta has been resurrecting Mexico's Colorado River Delta wetlands.
Change the Course Infographic
Check out this infographic and learn how you can conserve water and save the Colorado River, as well as other freshwater ecosystems.
Water Currents, by Sandra Postel and Others
Arizona's Verde River gets a boost from an innovative partnership.
Farmers in the Verde River Basin employ new technology to benefit a desert environment.
Funny viral video series hopes to get people thinking about the importance of water.