The Complex Relationship and Looming Crisis Between Our Thirst For Water and Our Hunger for Energy
November 16th, 2011
Two articles on a recent Union of Concerned Scientists/Energy and Water in a Warming World report looking at the watergy nexus in the United States.
The first, via the New York Times, notes:
Data from 2008 show that power plants in Texas and Massachusetts consume the most water in the cooling process.
The first chapter of a new report on the effect of power plants on freshwater systems has the feel of a documentary film. Imagine a camera panning the dessicated Texas landscape as a voice intones statistics from the brutal 2011 drought — a dried-up Brazos River, 80 days of 100-degree-plus temperatures in some locations, and so on.And then the punch line: “An energy-water collision wasn’t far behind.”
Cut to a close-up: “One plant had to curtail nighttime operations because the drought had reduced the amount of cool water available to bring down the temperature of water discharged from the plant,” the report says. (The Environmental Protection Agency regulates the maximum temperature of such discharges to ensure that aquatic life is not harmed and fish breeding and migration are not impeded.)
You get the idea. The report was prepared by the Union of Concerned Scientists in collaboration with independent experts. It quotes Kent Saathoff, a vice president of the Electric Reliability Council of Texas, who said last month, “If we don’t get any rain between now and next summer, there could be several thousand megawatts of generators that won’t have sufficient cooling water to operate next summer.”
Texas may offer a preview of what happens in a warming world. In 2007, there were blackouts in parts of North Carolina because a drought affected the Catawba River. “The thirst of the region’s power plants became incompatible with what the river had to give,” the report said.
Complicating matters, not enough is known about how much water power plants use and how the discharge affects the local environment, it adds.
Both the water shortage and the lack of information will become more problematic, the researchers write. In the not-too-distant future, they say, a growing population is likely to want more air-conditioning than the electrical grid can supply because there will not be enough water available to cool thermoelectric plants.
Power plants generally work by converting water into steam to turn turbines; the water then has to be cooled before it can re-enter the environment or be used again.
Coal-fired plants alone account for 67 percent of freshwater withdrawals by the power sector and for 65 percent of the water completely consumed by it, the report said. Newer plants include air-cooling or “dry cooling” technologies, but so many plants rely on water-cooling that they accounted for 41 percent of the withdrawals of freshwater in the United States in 2005, according to the United States Geological Survey.
That said, they return a great deal of the water they use, usually to rivers — although in the case of some California plants like Diablo Canyon, the cooling water is taken from and returns to the Pacific Ocean.
Yet some water is inevitably lost to evaporation or otherwise never gets back to the rivers. The map above, from the report’s appendix, indicates which states lose the most water to operate power plants.
Not all plants provide accurate reports to the federal Energy Information Administration, however. The report suggests that “many operators estimated annual use rather than measuring it.”
The report noted that in 2008, more than 100 water-cooled coal and natural gas power plants “reported to the government that they produced millions of megawatt-hours of electricity yet used no water at all.” And “power plant operators have universally ignored rules requiring them to specify groundwater sources used for cooling,” it added.
Until some of the data gaps are remedied, the full effects of power plants on watersheds will remain unknown
The second, via KQED, note:
For the second time in as many weeks, a major report has emerged warning of consequences from the demand that America’s electricity producers are placing on water supplies.
Today’s findings, from the Union of Concerned Scientists, conclude that water and power are on a collision course in the US, as nearly all major power plants slurp up water for cooling. As of 2008, the UCS study found that across the US, “thermocooled” power plants (which is most of them) took up somewhere between 60 billion and 170 billion gallons of water from rivers, lakes and aquifers. That’s three times the volume of water that pours over Niagara Falls. At least 2.8 billion and as much as 5.9 billion gallons of that was “consumed,” or not put back.
Power Plants are putting strain on watersheds throughout the nation, according to UCS researchers.
“It’s really water that keeps the lights on,” says Kristen Averyt, deputy director of the Western Water Assessment at the University of Colorado, and lead researcher for the report.
Coal, natural gas and nuclear plants — even some solar power plants — produce electricity by generating steam to power turbines (90% of the nation’s electricity is produced in this way), and require “vast volumes” of water for cooling. The authors say this, in turn, is putting stress on watersheds around the country.
Power plants vary widely in their “water intensity.”
The good news is that California and Western plants tend to be less water-intensive than elsewhere in the nation, though the authors say that among Texas plants, nearly half the water used comes from underground aquifers. Here in California, many major power plants are located along the coast and use seawater. But all plants have one thing in common: they tend to put back the water much warmer than when they withdrew it.
“Fish can’t climb out of the hot tub,” says Rob Jackson, who studied the effects on water temperature from plant cooling for the UCS report. Jackson says that despite bans by several states on putting back water hotter than 90 degrees Fahrenheit, eleven of those states have power plants exceeding the limit. Jackson cited one plant in Florida, which was found to be returning water to the Manatee River at 115 degrees, literally Jacuzzi temperature.
The report also points to “significant gaps and errors” in industry figures that purportedly track water use by power plants.
The UCS authors singled out one California solar plant as a paragon of water-efficient design. The Ivanpah thermal-solar array, under construction by Oakland-based Brightsource Energy, will use a “dry-cooling” system. That seems prudent, as it’s located in the middle of the desert.
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Educated at Yale University (Bachelor of Arts - History) and Harvard (Master in Public Policy - International Development), Monty Simus has held a lifelong interest in environmental and conservation issues, primarily as they relate to freshwater scarcity, renewable energy, and national park policy. Working from a water-scarce base in Las Vegas with his wife and son, he is the founder of Water Politics, an organization dedicated to the identification and analysis of geopolitical water issues arising from the world’s growing and vast water deficits, and is also a co-founder of SmartMarkets, an eco-preneurial venture that applies web 2.0 technology and online social networking innovations to motivate energy & water conservation. He previously worked for an independent power producer in Central Asia; co-authored an article appearing in the Summer 2010 issue of the Tulane Environmental Law Journal, titled: “The Water Ethic: The Inexorable Birth Of A Certain Alienable Right”; and authored an article appearing in the inaugural issue of Johns Hopkins University's Global Water Magazine in July 2010 titled: “H2Own: The Water Ethic and an Equitable Market for the Exchange of Individual Water Efficiency Credits.”