How Droughts Can Cause Power Outages
Hundreds of millions of people in India lost power this summer, in part because of a delayed monsoon season. Rainfall may seem far removed from power plants, but the fate of water in a region often affects the power there, too. In India's case, the late rains meant farmers took more water from rivers to water their crops. The rivers were left with too little energy for the country's hydropower plants.
In the future, water shortages could lead to simultaneous electricity and fuel shortages, according to a new report from the International Energy Agency. The Paris-based agency studies the global energy market and helps 28 nations coordinate with each other during an oil supply emergency. The agency's findings underscore the limit of the world's supply of fresh water. "It is a growing concern," Kelly Twomey Sanders, a University of Texas doctoral student in Austin who studies water and energy use, told TechNewsDaily.
"We've certainly seen this in the past," said Vince Tidwell, a hydrologist at Sandia National Laboratories in New Mexico. In the past few years, nuclear power plants in the U.S. and France have had to temporarily dial down the amount of electricity they make because they overheated the water they use for cooling, Tidwell said.
France's reduced power production prevented people from turning on their air conditioners and contributed to the thousands of deaths during the 2003 European heat wave, said Sanders, who like Tidwell was not involved in the International Energy Agency report.
Water also could limit how much oil the U.S. extracts, depending on whether U.S. companies perform more hydraulic fracturing, or fracking, in the future. The International Energy Agency expects fracking, which is gaining popularity in the U.S., to help North America become the world's No. 1 producer of oil in 2020.
The rising concerns come out of the intersection of several trends. People around the world are expected to demand more energy as populations grow and more people in developing countries buy cars and get electricity in their homes. At the same time, global warming will cause droughts and other water shortages in certain regions. [SEE ALSO: What Country Faces the Worst Climate Change]
As energy demand goes up, so will the demand for fresh water. The International Energy Agency expects the demand for water just for energy production — not including water for washing, drinking or irrigating crops — to grow twice as quickly as the demand for energy itself.
That is a "reasonable guess," said Mike Hightower, a Sandia engineer who contributed to a 2006 report to the U.S. Congress on how the energy sector uses water.
How energy tech uses water
Fifteen percent of the water the world currently uses goes to making energy, according to the International Energy Agency. Nuclear, coal and other power plants use water to make hot steam to turn turbines, plus more water to cool and condense the steam. In addition, some newer energy technologies, including ones designed to be more environmentally friendly, use more water than their traditional counterparts.
Examples include fracking, an oil and natural-gas mining technique that requires millions of gallons of water per well to release natural gas from shale deposits.
"Greener" biofuels made from plants require water while the plants grow. Driving a mile on corn ethanol uses about 100 times more water than traditional gasoline, Sanders said, while biofuels made from algae can use 1,000 times more water than gas does.
A newer power plant cooling technique, called closed loop cooling, draws less water than traditional open loop cooling but loses more of what it draws to evaporation, so it consumes more water overall.
With closed loop systems, power plants draw in water from a river, reservoir or another source, then reuse the water until it has all evaporated. In open loop systems, power plants continually draw in new water and dump their once-used, warm water back into the source.
Many countries are now building closed loop plants because they trap and kill fewer fish.
For the future
To help relieve the water crunch, power plants may turn to some new water-saving technologies. Solar panels and wind turbines use much less water than coal or gas plants do. Companies could make biofuels from species such as switchgrass that are more water-efficient than corn. Fracking companies could develop methods to use less water or reuse water.
Power plants, the greatest water-users among energy technologies, could use non-potable water or air instead of clean, drinkable water to cool the steam that turns their turbines.
Alternative cooling systems tend to be more expensive to build and maintain, however. Some may be out of reach for developing countries, Hightower said. Nevertheless, developed countries that find themselves needing power plants in drier areas may simply have to pony up for the more-expensive tech. One Texas power plant already has: "They actually had to install dry cooled systems because they just physically didn't have enough water," Sanders said. Dry systems use air instead of water for cooling and are more inefficient.
Sandia is currently helping U.S. cities plan power plants around water availability, Hightower said. Engineers in other countries are likely doing the same, he added.
"This is a concern; we need to look at it and address it, start looking at it now," Hightower said.
Corrected Nov. 20: The original story said corn ethanol is 1,000 times more water intensive than traditional gasoline. Corn ethanol actually uses about 100 times more water than gasoline, while biofuels made from algae use 1,000 times more water.