This story is part of a special series that explores the global water crisis. For more clean water news, photos, and information, visit National Geographic's Freshwater Web site.
As climate change throws Earth's water cycle off-kilter, the world's energy infrastructure may end up in hot water, experts say.
From hydropower installations in the Himalaya to nuclear power plants in Western Europe, energy resources are already being impacted by flooding, heat waves, drought, and more. (Explore an interactive map of global warming effects.)
Traditionally power plants and energy facilities have been built for the long haul—the circa-1936 Hoover Dam in Nevada is still a major hydroelectric generator.
But in a rapidly warming world, a site that looks ideal when it's built may be in a much different environment 50 years later. For instance, a facility built on permafrost in the Arctic may collapse due to the melting tundra. (See Arctic warming pictures.)
"There's a growing understanding about the need to assess our impact on the environment," said Cleo Paskal, an environmental-security expert at London's Royal Institute of International Affairs and author of the book Global Warring.
But "there's not enough of an emphasis on the changing environment's impact on us."
U.S. in "Bad Shape"
Climate change is predicted to raise global sea levels, for example, between 7 and 23 inches (18 and 59 centimeters), according to a 2007 report by the United Nations' Intergovernmental Panel on Climate Change.
Of the areas most at risk, the United States is in particularly "bad shape," Paskal noted. More than half of the U.S. population—and its associated energy facilities—lives along the coasts, where sea level rise is predicted to hit hardest.
Strong storm surges, for instance, could easily inundate much of the energy grids and other small-scale infrastructure in Washington D.C. and parts of New York City, which sit fewer than ten feet (three meters) above sea level.
In fact, most of the world's major oil and gas facilities, from Niger to Singapore, sit only slightly above sea level.
The U.S. Gulf Coast is home to many offshore and coastal energy facilities—more than a quarter of U.S. oil production and nearly 15 percent of natural gas production comes from the Gulf of Mexico, for instance. Yet the coast is also vulnerable to flooding and extreme weather events, which are predicted to increase in the region due to climate change.
In 2005, Hurricane Katrina damaged more than 450 oil pipelines and 113 platforms along the Gulf Coast, slashing oil production by half and causing a spike in global oil prices, Paskal said. Most of the infrastructure was later rebuilt—in the same places.
In Hot Water
In addition, nuclear power plants—which must draw water from seas, rivers, lakes, or reservoirs to cool their reactors—are logically situated near water, putting them in the path of sea level rise and storm surges, Paskal said.
Flooding has already affected production in some plants in the U.S., France, and India. For instance, in 1992 Hurricane Andrew caused major damage to the Turkey Point nuclear power plant on Biscayne Bay, Florida.
But perhaps more troubling for nuclear facilities are heat waves, which will be commonplace in Europe by 2040—well within the life spans of reactors now coming online, according to the Met Office Hadley Centre, a climate-research center in the U.K.
In a normal scenario, as cold water from nearby water bodies enters the plant, it's circulated to absorb excess heat and released from the plant at a higher temperature, Paskal said.
But during a heat wave, hotter air warms the water even before it goes into the plant. So when wastewater is pumped back into the environment, it can reach temperatures blistering enough to kill off ecosystems.
That's why the French government has set a temperature limit—75 degrees Fahrenheit (24 degrees Celsius) on how hot nuclear-plant water outflow can be. When waste water exceeds this temperature—for instance during a heat wave—reactors must shut off or power down, which means keeping the plant running at a lower energy level.
But sometimes governments will temporarily allow wastewater to exceed that temperature limit: During a record-breaking heat wave in France in 2003, the government upped the temperature maximum to 86 degrees Fahrenheit (30 degrees Celsius).
Eventually, though, France decided to shut down or power off 17 nuclear reactors during the 2003 event, costing the country about U.S. $408 million (300 million Euros). More recently, during a 2009 heat wave, a third of the country's plants powered down, requiring France to buy energy from the United Kingdom.
Changing the Norm
Infrastructure built around what used to be predictable water flows is also in trouble, experts say. (Learn about the global water crisis.)
For instance, glacier-dependent hydropower installations, widespread in Nepal, India, China, and the European Alps, depend on a seasonal flow of glacial runoff, just as precipitation-dependent dams operate based on seasonal rainfall and snowfall.
(Related: "Melting Himalayan Glaciers May Doom Towns.")
But climate change is blowing such constants out of the water, experts say. Melting glaciers due to warming temperatures are sending more runoff to the dams associated with hydropower stationsthan the facilities were designed to handle.
Erratic rainfall is also wreaking havoc: In the Indian city of Surat in 2006, unusually heavy rains overwhelmed an upstream hydroelectric dam, flooding most of the city and killing hundreds. By contrast, a lack of rainfall between 2008 and 2009 caused hydroelectricity generation in India to fall by nearly 9 percent during those years.
"The unusual or what was seen outside the norm may become the norm," said Geoff Dabelko, director of the Environmental Change and Security Program at the Woodrow Wilson International Center for Scholars, a Washington, D.C.-based research center.
"We're used to having a fixed amount of water, and [planners] don't take into account variability nearly enough," he said. "Installations have to be designed with that warmer world and that variability in mind."
Shortsighted Power Plans
Such capricious water cycles may spur innovation into new energy technologies, such as renewables, experts say.
"We've reached a point where we can no longer assume that we have enough water to build the old kind of energy systems," said Peter Gleick, co-founder and president of the Pacific Institute for Studies in Development, Environment, and Security in Oakland, California.
But even alternatives such as solar power have their own challenges. "Solar thermal plants are great if your only concern is reducing greenhouse gas emissions," Gleick said. But "there are other environmental issues that we worry about, and one of them is water."
That's why some energy companies, such as California-based solar company BrightSource Energy, are experimenting with solar plants that use dry cooling. During dry cooling, steam turbines create exhaust that enters an air-cooling condenser, where water is condensed from steam and returned to the boiler. This replaces the need for an influx of fresh water to cool the plant.
For instance the proposed Ivanpah Solar-Energy Generation Station in the Mojave Desert would reduce water usage by 90 percent as compared with wet cooling, according to BrightSource. Water usage at Ivanpah—limited just to washing mirrors—would amount to the equivalent annual water use of 300 homes in the region.
Yet renewable sources such as solar aren't immune to forces of nature, environmental-security expert Paskal noted: A solar-powered plant in Cedar Rapids, Iowa, was inundated during historic 2008 floods.
"There's no point in erecting an array of solar panels if it's in a floodplain."
Such lack of foresight in planning energy infrastructure is common, especially in the U.S., where billions of stimulus dollars are being poured into new energy projects that haven't factored in future catastrophes, Paskal added.
"We are underestimating our own vulnerabilities," she said, "quite dramatically."