In Modesto, Calif., utility records chart an 18 percent rise in farmers’ energy use in 2014 compared with 2013. No evidence shows exactly why this happened, but California’s drought, now in its fourth year, sent many farmers to their wells to pump from hidden aquifers water that normally would be found at ground level.
Such measures are a timely illustration of the way water needs power — not just to move it, but to clean it and even, with desalination, to create it from brine. A large desalination plant being built to provide 7 percent of San Diego’s water will require about 38 megawatts of power, enough for more than 28,000 homes. And it is no coincidence that primary owners of the 2,250-megawatt, coal-fired Navajo generating station near Page, Ariz., are water managers; they need the power to move water.
The converse is also true: Water is required for power — for hydropower; for extracting oil, natural gas and coal; and, most of all, for cooling power plants. A report from the Congressional Research Service projects that 85 percent of the growth in domestic water consumption from 2005 to 2030 will come from the power sector.
In 2011, Texas suffered its own blistering drought. Kent Saathoff, then a vice president of the Electric Reliability Council of Texas, warned at the time that without rain in the coming months, “there could be several thousand megawatts of generators that won’t have sufficient cooling water to operate.” Rain eventually arrived to avert that disruption, but this year the R.W. Miller 403-megawatt plant in Palo Pinto, west of Fort Worth, went off-line because it lacks sufficient cooling water.
Coiled throughout the American economy, energy and water are forever linked, an economic version of DNA’s double helix. As populations grow and climate change and droughts take their toll, resource managers and environmental advocates are warning that scarcity of either water or energy could set off shortages and escalating costs for both.
“One of the serious risks is that we accelerate a very damaging negative feedback loop both in protecting the environment and impacts to our economy,” said Vickie Patton, general counsel at the Environmental Defense Fund. She worries that “we will be using energy and water alike in a fashion that only leads to more serious impacts, greater use and much higher cost.”
The situation was born of assumptions from the last century about the abundance of both power and water, according to the Pacific Institute, a nonprofit research center based in Oakland, Calif. Now those assumptions are in doubt.
For almost four years of drought, beginning in October 2011, “California ratepayers spent $1.4 billion more for electricity than in average years because of the drought-induced shift from hydropower to natural gas,” the institute said in a March 17 report. In the same period, hydropower’s share of the electricity market dropped from 18 percent in average years to less than 12 percent, it said.
And even before this drought, experts at the University of California, Davis, estimated that just under 20 percent of California’s total energy use in a typical year went to move and treat water. Nationally, the comparable figure of electricity devoted to water was about 12.6 percent in 2010, according to a report from the University of Texas at Austin.
Power’s claim on water is even more striking. The Congressional Research Service reported that in 2005 water for cooling power plants “represented 44 percent of the water withdrawn nationally.” Of this, 6 percent was consumed; the rest was returned, warmer, to local waterways.
Warren Lasher, the director of system planning at the Electric Reliability Council of Texas, said many of the state’s power plants depend on local resources, like nearby ponds, for cooling water.
The severe water shortages in 2011, he said, meant “a lot of plants had to lower the intake structures in their ponds.”
For those concerned that the interdependence of power and water could lead to higher costs and greater scarcity of both, two energy developments in the last five years offer both good news and bad.
One is the rise of renewables, which can use nominal amounts of water. With solar power, for example, water is needed mostly to clean solar panels.
The other big development is directional mining for shale gas embedded in rock. Fracking, as this is known, has transformed the world’s power landscape. It usually means injecting large amounts of chemically infused water underground at high pressure.
Opponents argue that groundwater is at risk of contamination from the methane released, though a research report last fall questioned whether poor well construction, not fracking, caused the problems.
Still, the sheer volume of water used is an issue. The United States Geological Survey reported that fracking an individual well could take 1.5 million to 5.7 million gallons of water.
With demand for power and water at risk of exceeding supply in places, the new goal is to conserve both.
Air-cooling equipment for power plants could replace water-cooling, Mr. Lasher said. But that, too, requires power. He said that financial experts would have to sort out “over the next 20 years, which is going to be more expensive, power or water.”
Hydropower is also being rethought. The LucidPipe Power System, developed by Lucid Energy, has been adopted by Portland, Ore., and Riverside, Calif., and is planned for San Antonio. It uses the pressure of gravity-driven water flowing through a pipe to turn turbines within the pipes and generate electricity.
Continuing efforts to rethink the use of the two resources are underway at the University of California, Davis’s Center for Water-Energy Efficiency, which has calculated in a report how water is used for power production in 158 national power systems.
The report said, “By benchmarking water consumption for energy to standard measures, policy makers can better understand and track the status of this coupled system.”