This post is by Mary Kelly, Attorney and Co-Director, Land, Water, and Wildlife Program at Environmental Defense.
If you've been watching the news, you know we have a climate problem, and you may also know we have a drinking water problem in some parts of the country. What you may not realize is that these two problems are related. Yes, global warming can impact rainfall, but that's not all. The water supply sector uses large amounts of energy to transport, treat, and deliver water. On the flip side, vast quantities of water are required to generate power.
Every year, the U.S. thermoelectric industry uses 3.3 billion gallons of water [PDF]. That's 20 percent of all the water used in the country, excluding agriculture. And this number is projected to more than double to 7.3 billion gallons by 2030. Water is used in all stages in the creation of energy: extracting, processing, refining, and transporting fuel to power generation plants. Power plants themselves also uses vast amounts of water, particularly for the towers that cool the water heated in the generators.
Then there's the energy used to treat and deliver water. California was among the first states to take a close look at this, and they discovered that supplying municipal water accounted for almost 20 percent of the electricity used in the state [PDF]. On average, 75 percent of the cost of municipal water comes from the electricity used to capture, treat, distribute, and use the water. After the water is used, more energy is required to treat the wastewater.
As cities grow, particularly in water-scarce areas, supplying municipal water uses increasingly more energy. Understanding this relationship highlights the importance of conserving water and practicing energy efficiency. For every kilowatt saved, water also is saved. For every gallon of water not used, energy usage is reduced. Investments in and incentives for energy and water conservation must be our highest priority.
In addition to bolstering our conservation efforts at all levels, states and the federal government need to better integrate water and energy supply planning. Other states should follow California’s example and quantify the local relationship between energy and water. Environmental Defense is partnering with the Jackson School at the University of Texas to quantify this relationship in Texas. This information will help the state evaluate water and power projects to ensure that these resources are available to citizens in the future.