Energy versus Water: Solving Both Crises Together
By Michael E. WebberScientific American Special Editions - October 22, 2008
Water is needed to generate energy. Energy is needed to deliver water. Both resources are limiting the other—and both may be running short. Is there a way out?
In June the state of Florida made an unusual announcement: it would sue the U.S. Army Corps of Engineers over the corps’s plan to reduce water flow from reservoirs in Georgia into the Apalachicola River, which runs through Florida from the Georgia-Alabama border. Florida was concerned that the restricted flow would threaten certain endangered species. Alabama also objected, worried about another species: nuclear power plants, which use enormous quantities of water, usually drawn from rivers and lakes, to cool their big reactors. The reduced flow raised the specter that the Farley Nuclear Plant near Dothan, Ala., would need to shut down.
Georgia wanted to keep its water for good reason: a year earlier various rivers dropped so low that the drought-stricken state was within a few weeks of shutting down its own nuclear plants. Conditions had become so dire that by this past January one of the state’s legislators suggested that Georgia move its upper border a mile farther north to annex freshwater resources in Tennessee, pointing to an allegedly faulty border survey from 1818. Throughout 2008 Georgia, Alabama and Florida have continued to battle; the corps, which is tasked by Congress to manage water resources, has been caught in the middle. Drought is only one cause. A rapidly growing population, especially in Atlanta, as well as overdevelopment and a notorious lack of water planning, is running the region’s rivers dry.
Water and energy are the two most fundamental ingredients of modern civilization. Without water, people die. Without energy, we cannot grow food, run computers, or power homes, schools or offices. As the world’s population grows in number and affluence, the demands for both resources are increasing faster than ever.
Woefully underappreciated, however, is the reality that each of these precious commodities might soon cripple our use of the other. We consume massive quantities of water to generate energy, and we consume massive quantities of energy to deliver clean water. Many people are concerned about the perils of peak oil—running out of cheap oil. A few are voicing concerns about peak water. But almost no one is addressing the tension between the two: water restrictions are hampering solutions for generating more energy, and energy problems, particularly rising prices, are curtailing efforts to supply more clean water.
The paradox is raising its ugly head in many of our own backyards. In January, Lake Norman near Charlotte, N.C., dropped to 93.7 feet, less than a foot above the minimum allowed level for Duke Energy’s McGuire Nuclear Station. Outside Las Vegas, Lake Mead, fed by the Colorado River, is now routinely 100 feet lower than historic levels. If it dropped another 50 feet, the city would have to ration water use, and the huge hydroelectric turbines inside Hoover Dam on the lake would provide little or no power, potentially putting the booming desert metropolis in the dark.
Research scientist Gregory J. McCabe of the U.S. Geological Survey reiterated the message to Congress in June. He noted that an increase in average temperature of even 1.5 degrees Fahrenheit across the Southwest as the result of climate change could compromise the Colorado River’s ability to meet the water demands of Nevada and six other states, as well as that of the Hoover Dam. Earlier this year scientists at the Scripps Institution of Oceanography in La Jolla, Calif., declared that Lake Mead could become dry by 2021 if the climate changes as expected and future water use is not curtailed.
Conversely, San Diego, which desperately needs more drinking water, now wants to build a desalination plant up the coast, but local activists are fighting the facility because it would consume so much energy and the power supply is thin. The mayor of London denied a proposed desalination plant in 2006 for the same reason, only to have his successor later rescind that denial. Cities in Uruguay must choose whether they want the water in their reservoirs to be used for drinking or for electricity. Saudi Arabia is wrestling with whether to sell all its oil and gas at rec_ord prices or to hold more of those resources to generate what it doesn’t have: freshwater for its people and its cities.
We cannot build more power plants without realizing that they impinge on our freshwater supplies. And we cannot build more water delivery and cleaning facilities without driving up energy demand. Solving the dilemma requires new national policies that integrate energy and water solutions and innovative technologies that help to boost one resource without draining the other.
Vicious Cycle The earth holds about eight million cubic miles of freshwater—tens of thousands of times more than humans’ annual consumption. Unfortunately, most of it is imprisoned in underground reservoirs and in permanent ice and snow cover; relatively little is stored in easily accessible and replenishable lakes and rivers.
Furthermore, the available water is often not clean or not located close to population centers. Phoenix gets a large share of its freshwater via a 336-mile aqueduct from, of course, the Colorado River. Municipal supplies are also often contaminated by industry, agriculture and wastewater effluents. According to the World Health Organization, approximately 2.4 billion people live in highly water-stressed areas. Two primary solutions—shipping in water over long distances or cleaning nearby but dirty supplies—both require large amounts of energy, which is soaring in price.
Nationwide, the two greatest users of freshwater are agriculture and power plants. Thermal power plants—those that consume coal, oil, natural gas or uranium—generate more than 90 percent of U.S. electricity, and they are water hogs. The sheer amount required to cool the plants impacts the available supply to everyone else. And although a considerable portion of the water is eventually returned to the source (some evaporates), when it is emitted it is at a different temperature and has a different biological content than the source, threatening the environment. Whether this effluent should be processed is contentious; the Supreme Court is set to hear a consolidation of cases about the Environmental Protection Agency’s requirements that power plants retrofit their systems to minimize impact on local water supplies and aquatic life.
At the same time, we use a lot of energy to move and treat water, sometimes across vast distances. The California Aqueduct, which transports snowmelt across two mountain ranges to the thirsty coastal cities, is the biggest electricity consumer in the state. As convenient resources become tapped out, provi_ders must dig deeper and reach farther. Countries that have large populations but isolated water sources are considering daunting megaprojects. China, for example, wants to transport water from three river basins in the water-rich south over thousands of miles to the water-poor north, consuming vast energy supplies. Old-guard investors such as T. Boone Pickens who made their billions from oil and natural gas are now putting their money into water, including one project to pipe it across Texas. Cities such as El Paso are also trying to develop desalination plants positioned above salty aquifers, which require remarkable amounts of energy—and money.
In addition, local municipalities have to clean incoming water and treat outgoing water, which together consume about 3 percent of the nation’s electricity. Health standards typically get stricter with time, too, so the degree of energy that needs to be spent per gallon will only increase.
From Imported Oil to Domestic Water The strains between the resources manifest themselves in tough choices at the local level—especially in land- and water-locked regions such as the desert Southwest. Is it better for a city to import fresh_water or to import electricity to desalinate brackish water in deep aquifers below? Or is it better yet to move the people to where the water is? With infinite energy, freshwater can be reached, but even if the public coffers were unlimited, policymakers are under pressure to limit carbon emissions. And with climate change possibly altering the cycles of droughts, floods and rainfall, burning more energy to get more water might be doubly dire. The challenges get even tougher because the U.S. has finally conceded that the best way to fix its energy and security problems is to break its dependence on imported oil. This new view is reflected in the Energy Independence and Security Act of 2007 and other legislation. Because the transportation sector is a major oil consumer—and a major carbon emitter—it is on the short list of targets for radical change by policymakers, innovators and entrepreneurs. The two most popular choices to replace gasoline appear to be electricity for plug-in vehicles and biofuels. Both paths have merits, but both are more water-_intensive than our current system.
Plug-in vehicles are particularly appealing because it is easier to manage the emissions from 1,500 power plants than from hundreds of millions of tailpipes. The electrical infrastructure is already in place. But the power sector swallows water. Compared with producing gasoline for a car, generating electricity for a plug-in hybrid-electric or all-electric vehicle withdraws 10 times as much water and consumes up to three times as much water per mile, according to studies done at the University of Texas at Austin.
Biofuels are worse. Recent analyses indicate that the entire production cycle—from growing irrigated crops on a farm to pumping biofuel into a car—can consume 20 or more times as much water for every mile traveled than the production of gasoline. When scaling up to the 2.7 trillion miles that U.S. passenger vehicles travel a year, water could well become a limiting factor. Municipalities are already fighting over water supplies with the booming biofuels industry: citizens in the Illinois towns of Champaign and Urbana recently opposed a local ethanol plant’s petition to withdraw two million gallons a day from the local aquifer to produce 100 million gallons of ethanol a year. Resistance will grow as ranchers’ wells run dry.
Whether proponents realize it or not, any plan to switch from gasoline to electricity or biofuels is a strategic decision to switch our dependence from foreign oil to domestic water. Although that choice might seem more appealing than reducing energy consumption, we would be wise to first make sure we have the necessary water.
New Mind-set Needed, Too Regardless of which energy source the U.S., or the world, might favor, water is ultimately more important than oil because it is more immediately crucial for life, and there is no substitute. And it seems we are approaching an era of peak water—the lack of cheap water. The situation should already be considered a crisis, but the public has not grasped the urgency.
The public has indeed become more open-minded about the risks of peak oil, which vary from the dire (mass starvation and resource wars) to the blasÈ (markets bring forth new technologies that save the day). Supply shortages and skyrocketing prices have ratcheted up confidence in the claims of the “peakers.” Policy levers and market forces are being deployed to find a substitute for affordable oil.
What will it take for us to make the leap for water and, better yet, to consider both issues as one? When the projections for declining oil production are overlaid with the increasing demand for water, the risks become severe. Because water is increasingly energy-intensive to produce, we will likely be relying on fossil fuels for pumping water from deeper aquifers or for moving it through longer pipelines. Any peak in oil production could force a peak in water production. Peak oil might cause some human suffering, but peak water would have more extreme consequences: millions already die every year from limited access to freshwater, and the number could grow by an order of magnitude.
Perhaps signposts will wake our collective minds. Kansas lost a lawsuit to Missouri recently over interstate water use, causing Kansan farmers to reconfigure how they will grow their crops. Rationing should certainly put society on notice, and it is beginning. My hometown of Austin, Tex., now imposes strict lawn-watering restrictions. California, suffering record low snowfalls, has issued statewide requirements for municipal water conservation and rationing of water that are reminiscent of gasoline controls in the 1970s.
Someday we might look back with a curious nostalgia at the days when profligate homeowners wastefully sprayed their lawns with liquid gold to make the grass grow, just so they could then burn black gold to cut it down on the weekends. Our children and grandchildren will wonder why we were so dumb.
Forcing Solutions The rising tension between water and energy is troubling, but it also presents an opportunity. We can tackle the problem. The first step is to integrate U.S. policymaking processes. Although the two resources are highly interdependent, energy and water regulators operate separately, with different funding streams, accountability mechanisms, government oversight and legislative committees. Instead of water planners assuming they will have all the energy they need and energy planners assuming they will have all the water they need, we must get them in the same room to make decisions.
The federal government has long had a Department of Energy but does not have a Department of Water. The EPA oversees water quality, and the U.S. Geological Survey is responsible for collecting data and monitoring supply, but no federal agency ensures the effective use of water. Congress should create a single overseer, possibly in the Department of the Interior (because of water’s environmental importance) or the Department of Commerce (because of its role in the economy). Partly because water has historically been produced locally, most regulatory responsibility has been pushed down to the state and municipal levels. Local policies can readily fail, however, when aquifers, rivers and watersheds span multiple cities or states. What happens when another city takes your water?
Federal energy and water agencies should then develop a plan for integrated policy making. For example, when power plant owners seek building permits for a given site they must show that the new installations will meet EPA air-quality standards; similar requirements from a new agency should have to be met for water usage. Energy planners should be in the room when their counterparts debate issuing water permits, to raise concerns about greater electricity demand. When siting and permitting are considered for power plants, water experts should be there to comment on any potentially elevated risk of scarcity. These interactions can take the form of simple collaborations.
The same cross talk should inform climate change legislation. In May, Michael Arceneaux, deputy executive director of the Association of Metropolitan Water Agencies, began a one-person campaign to educate Congress that high-profile bills under consideration, notably those involving carbon cap-and-trade systems, had serious effects on water supplies that were not being considered.
As the U.S. better coordinates policy mak_ing, innovative technologies can reduce the amount of freshwater that society extracts and consumes. Agriculture is the place to start. Drip irrigation (instead of spraying water onto fields, allowing much of it to evaporate) requires much less water and delivers it directly to a crop’s roots. Farmers in the high plains due east of the Colorado River should switch to drip irrigation for their own good. Nearly all of them tap the Ogallala aquifer, the largest in the U.S., and it is being depleted at a rate of 15 billion cubic yards a year—much more than the rainfall and runoff that reaches it to recharge it. Irrigation now accounts for 94 percent of the groundwater used in the entire region.
Consumption by power plants can be significantly reduced by switching from water cooling to air cooling or at least hybrid air-water cooling. Although air systems are more expensive and are less efficient during operation, they virtually eliminate water withdrawal.
Reusing municipal and industrial waste_water will also save supplies and reduce energy consumed to transport them. Although many people cringe at the thought of “toilet to tap” cycles that convert wastewater to drinking water, astronauts onboard the space station and residents in Singapore readily drink treated wastewater every day with no ill effects. Even if that option remains unpalatable to many consumers, municipalities can certainly use reclaimed water for agriculture and industry and, indeed, for cooling power plants.
Engineering advances can also make water treatment much less energy-intensive. For example, Stonybrook Purification in Stony Brook, N.Y., is developing advanced membranes that more efficiently clean wastewater and desalinate saltwater. The inventor who discovered a way to purify water using minimal energy could become the world’s richest person and be forever enshrined.
Intelligent monitors can reduce residential and commercial waste. It is not uncommon to see sprinkler systems spraying lawns at full force in the heat of the afternoon—when evaporation is maximized and irrigation effects are minimized—and in the middle of a rainstorm. Companies such as Accuwater in Austin combine sensors, smart software and Internet connectivity for real-time weather information to better control such systems.
Residents can also spare the energy spent to heat water by widely implementing solar water heating. The simple technology is affordable, reliable, time-tested and pays for itself. But perhaps because the technology doesn’t seem cutting-edge and doesn’t have much backing from the federal government, its market penetration remains small. We may have to make social choices, too. Conserving energy and water means we might need to give up our young love affair with corn-based ethanol.
More than anything, however, we need to value water. We must move away from a long-standing expectation that water should be free or cheap. If we think water is important, we should put a realistic price on it. Without that, we send a confusing signal that everyone can be blasÈ about wasting water.
Once true pricing is in place, the U.S. can perhaps go further and show consumers and regulators how much the price of water raises the price of energy and how much the price of energy raises the price of water. These two metrics will bring us face to face with the dilemma of conserving both resources, prompting effective solutions.
Engineering advances can also make water treatment much less energy-intensive. For example, Stonybrook Purification in Stony Brook, N.Y., is developing advanced membranes that more efficiently clean wastewater and desalinate saltwater. The inventor who discovered a way to purify water using minimal energy could become the world’s richest person and be forever enshrined.
Intelligent monitors can reduce residential and commercial waste. It is not uncommon to see sprinkler systems spraying lawns at full force in the heat of the afternoon—when evaporation is maximized and irrigation effects are minimized—and in the middle of a rainstorm. Companies such as Accuwater in Austin combine sensors, smart software and Internet connectivity for real-time weather information to better control such systems.
Residents can also spare the energy spent to heat water by widely implementing solar water heating. The simple technology is affordable, reliable, time-tested and pays for itself. But perhaps because the technology doesn’t seem cutting-edge and doesn’t have much backing from the federal government, its market penetration remains small. We may have to make social choices, too. Conserving energy and water means we might need to give up our young love affair with corn-based ethanol.
More than anything, however, we need to value water. We must move away from a long-standing expectation that water should be free or cheap. If we think water is important, we should put a realistic price on it. Without that, we send a confusing signal that everyone can be blasÈ about wasting water.
Once true pricing is in place, the U.S. can perhaps go further and show consumers and regulators how much the price of water raises the price of energy and how much the price of energy raises the price of water. These two metrics will bring us face to face with the dilemma of conserving both resources, prompting effective solutions.
Note: This article was originally printed with the title, "Catch-22: Water vs. Energy".
ABOUT THE AUTHOR(S) Michael E. Webber is associate director of the Center for International Energy and Environmental Policy at the University of Texas at Austin and assistant professor of mechanical engineering at the university.
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