Coal-powered water woes

Circle of Blue, which should be one of the news feeds you follow via RSS reader, has posted an excellent summary of the interaction between coal and water, A Desperate Clinch: Coal Production Confronts Water Scarcity, that begins with a focus on the Dump Creek tributary of the Clinch River in Virginia, and then broadens out to the coal and water portion of the energy/water nexus (emphasis added):

Within Dumps Creek’s 20,000- acre watershed there are two active and two abandoned deep mines. There’s also a scraped off mountaintop, that fully comprises one-fifth of the watershed, where miners blasted away the overburden to get at coal. Dumps Creek is critical to these operations—hundreds of thousands of gallons of water are used daily to cool and lubricate mining machinery, wash haul roads and truck wheels to reign in airborne particulates as well as to suppress underground dust that otherwise could ignite.

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These production practices are just the first stages of an economically essential and ecologically damaging accord between coal and water that is coming into sharper national relief. It’s not just that mining and combustion of coal could not occur without using vast amounts of water; it’s occurring in the era of climate change, population growth and an increasing demand for energy. The result is that the competition for water at every stage of the mining, processing, shipping and burning of coal is growing more fierce, more complex and much more difficult to resolve.

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Slowing down the vortex of coal’s conflicted outcomes has only gotten harder. The Energy Information Administration, a research unit of the federal Department of Energy, forecasts that by 2050 the demand for energy in the U.S. will be 40 percent higher than it is today. As the nation considers what it will take to cool the planet and serve the country’s steadily increasing energy appetite, federal scientists and policy makers are taking a fresh look at how long the coal era will persist, and by necessity the tumultuous space where water and coal intersect.

Nothing about what they see is pretty. Scientists define water use by two basic measurements. One is how much water is “withdrawn” from America’s rivers, lakes, and aquifers for domestic, farm, business, and industrial use, most of which is returned to those same sources. The second is how much water is actually “consumed” in products, by livestock, plants and people, or evaporates in industrial processes. In both measurements of withdrawal and consumption coal is at the top of the charts.

The U.S. withdraws 410 billion gallons of water a day from its rivers, lakes and freshwater aquifers. About half is used to cool thermoelectric power plants, and most of that cools coal-powered plants, according to the most recent assessment by the United States Geological Survey (USGS).

Similarly, the U.S. consumes about 100 billion gallons of water a day; nearly 85 percent is used for crop and livestock production. Of the 16.1 billion gallons that remain: industrial, mining and power plants use nearly 8 billion gallons a day, most of that for mining, processing and burning coal, according to the Department of Energy.

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Coal industry executives insist their favorite fuel will be part of the energy mix for at least the next generation, and likely beyond. And they are readying a favored fix for climate change, an unproven technology to snare all the carbon emissions at coal-fired plants and store them deep underground—so-called “carbon capture and sequestration” or CCS.

But there’s a big problem there, too. Scientists with Sandia National Laboratories who’ve studied carbon capture and storage say CCS will increase water withdrawal and use by 25 percent to 40 percent. In other words, without significant advances in a technology that is only now being tested in a handful of applications, the path to a low-carbon economy that still burns coal will put enormous new pressure on America’s declining supply of fresh water.

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The numbers—like a splash of cold water—are a national wakeup call: Mining companies use from 800 to 3,000 gallons of water to extract, process, transport and store one short ton of coal and dispose of mining waste, according to estimates by researchers at Virginia Tech University.

The typical 500-megawatt coal-fired utility burns 250 tons of coal per hour, uses 12 million gallons of water an hour—300 million gallons a day—for cooling, according to researchers at Sandia National Laboratories.

To produce and burn the 1 billion tons of coal America uses each year, the mining and utility industries withdraw 55 trillion to 75 trillion gallons of water annually, according to the USGS. That’s roughly equal to the torrent of water that pours over Niagara Falls in five months.

It almost seems like piling on poor old coal. We’ve known for a long time that it’s a dangerous and filthy way to move electrons down a wire, but now this growing awareness of its share in the energy/water nexus should make it clear to even the most hardened coal advocate just how bad an idea it is. The issue with water is not merely the amount that coal plants (and all other thermoelectric generation facilities) consume or how much heat pollution they cause when water is returned to a lake or river, but the long-term dependency that’s created when we build a coal plant. If any thermoelectric plant can’t get enough water that’s sufficiently cool it can’t run at full capacity and might not be able to run at all.[1][2] Our decision to build a new generating plant is based on numerous factors — e.g. do you build a plant here, near a big city that needs the electricity but has a questionable water supply, or would it be prudent to build it hundreds of miles away where the water supply seems much more secure, but with the added expense of adding new transmission lines to deliver the juice? These decisions are all based on assumptions about the future, and in the case of climate-dependent issues, like the availability of cooling water, those assumptions are riskier now thanks to the changing rules of the game. It’s almost as if someone delivered a swift jolt to the environment and knocked it out of its old, comfortable (to us) and predictable (by us) equilibrium…

[1] This is talking about once-through cooling systems, which are still in widespread use, and account for just over half of US thermo plants. See the stats at Annual Steam-Electric Plant Operation and Design Data, especially the spreadsheet F767_COOLING_SYSTEM.xls available from that page. Closed-loop or recirculating cooling systems can dramatically reduce water consumption. For more than you ever thought you would need or want to know about cooling systems, see Water Use Benchmarks for Thermoelectric Power Generation [PDF].

[2] The US Dept. of Energy report Impact of Drought on U.S. Steam Electric Power Plant Cooling Water Intakes and Related Water Resource Management Issues says, page 2:

During the summer and fall of 2007, a serious drought affected the southeastern United States. As shown in Figure 1, a part of this area of the country is still experiencing extreme drought. In 2007, river flows in the southeast decreased, and water levels in lakes and reservoirs dropped. In some cases, water levels were so low that power production at some power plants had to be stopped or reduced. The problem for power plants becomes acute when river, lake, or reservoir water levels fall near or below the level of the water intakes used for drawing water for cooling. A related problem occurs when the temperature of the surface water increases to the point where the water can no longer be used for cooling. In this case, the concern is with discharge of heated water used for cooling back into waterways that are just too warm to keep temperatures at levels required to meet state water quality standards. Permits issued under the Clean Water Act (CWA) National Pollutant Discharge Elimination System (NPDES) program limit power plants from discharging overly heated water. For example, the Tennessee Valley Authority (TVA) Gallatin Fossil Plant is not permitted to discharge water used for cooling back into the Cumberland River that is higher than 90°F (WSMV Nashville 2007).

The southeast experienced particularly acute drought conditions in August 2007. As a result, nuclear and coal-fired plants within the TVA system were forced to shut down some reactors (e.g., the Browns Ferry facility in August 2007) and curtail operations at others. This problem has not been limited to the 2007 drought in the southeastern United States. A similar situation occurred in August 2006 along the Mississippi River (Exelon Quad Cities Illinois plant). Other plants in Illinois and some in Minnesota were also affected (Union of Concerned Scientists 2007). Given the current prolonged drought being experienced in the western United States (see also Figure 1), and also the scarcity of water resources in this region in general, many western utilities and power authorities are also beginning to examine the issue. The problem has also been experienced in Europe as well. During a serious drought in 2003, France was forced to reduce operations at many of its nuclear power plants (Union of Concerned Scientists 2007)