This is the fourth in a series of blog posts discussing the water-energy nexus.

Natural Gas Wellhead in Pennsylvania

Natural Gas Wellhead in Pennsylvania - Courtesy of Emily Grubert

Hydraulic fracturing, the technique used to extract natural gas from  shale and coalbed reservoirs, typically uses between 2 and 4 million gallons of water per well over the course of a few days – as much as the city of Washington, D.C. consumes in an hour. With such “unconventional” gas contributing a growing share of U.S. natural gas supplies, this water-intensive process has raised concerns that a large-scale shift in the power sector from coal to natural gas could strain the nation’s water supplies. In a new Worldwatch briefing paper, my coauthor Emily Grubert of University of Texas – Austin and I compare the water needs of electricity generated from coal and natural gas, from the point of fuel extraction to the point of power generation. Our analysis shows that generating a kilowatt-hour of electricity from a combined cycle power plant, even if unconventional gas is used, can consume less than half the water that generating the same amount of electricity from a coal steam turbine plant does.

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Barnett Shale, coal, combined-cycle power plant, dry cooling, hydraulic fracturing, Marcellus Shale, natural gas, steam turbine, unconventional gas, United States, water, water-energy nexus

This is the third in a series of blog posts discussing the water-energy nexus.

Luz Solar Energy Generating System (SEGS) III at Kramer Junction, Califoria

Solar Parabolic Trough in Califoria - Courtesy of Sandia National Laboratory

Large-scale solar power is coming to the United States. After much debate about water conservation and land preservation, the California Energy Commission (CEC) recently approved plans for nine concentrating solar power (CSP) plants in the state. Worldwatch found that this group of proposed plants will consume much less water per megawatt-hour than if California was to build typical coal, natural gas, or nuclear power plants instead. These CSP plants minimize water use through dry cooling.

The CEC expedited its commissioning process this fall to approve the CSP projects before their eligibility for a 30-percent cash grant from the U.S. Treasury’s 1603 Program expired at year’s end. Luckily for U.S. solar developers, Congress has since extended the program through 2011, as I discussed in a previous post. The approved projects represent a total of 4.4 gigawatts (GW) of new installed solar power capacity (or 4.6 GW if a tenth project, which should be approved shortly, is included).

The new CSP projects would increase California’s grid-connected solar power capacity fourfold from the 2009 level. Considering that California has the largest solar capacity in the country—about 10 times larger than any other U.S. state—this is all the more impressive. The development will dramatically assist California in meeting its renewable portfolio standard (RPS) target of generating 20 percent of its electricity from renewable sources by 2010, and 33 percent by 2020. More broadly, these projects would increase the nationwide supply of non-hydroelectric renewable power by over 9 percent, based on 2009 figures from the U.S. Energy Information Administration.

Water consumption has been a central issue in the commissioning process. Mindful of water usage, the CEC has recommended the use of dry cooling systems for the new CSP projects, which in some cases could reduce water consumption by up to 90 percent with minor efficiency losses and added costs (as I discussed in a previous post). Of the ten CSP projects in the pipeline, eight rely on dry cooling.

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Abengoa Mojave, ACC, air-cooled condenser, Beacon, Blythe, Calico, California, California Energy Commission, CEC, central tower, concentrating solar power, cooling tower, CSP, dry cooling, Genesis, Imperial Valley, Ivanpah, Millennium Solar, Palen, parabolic trough, Rice, Ridgecrest, solar, Stirling engine and dish, United States, water-energy nexus, wet cooling

This is the second in a series of blog posts discussing the water-energy nexus, a current focus of the Worldwatch Institute’s Climate and Energy team. A Worldwatch study that investigates water consumption over the lifetime of a natural gas power plant will be available soon.

Malta at Sunset - Flickr Creative Commons / ...-Wink-... (Wendell)

The competition between water and energy demands is heightening around the world, from America’s Colorado River, to farms in Australia’s New South Wales, to China’s industrial north. One of the best examples of a contemporary water-energy nexus is in Malta. Acquiring clean water and electricity has been an enduring challenge in the tiny island nation, where most freshwater comes from private wells and desalination plants, and most electricity comes from foreign oil. Malta’s chronic freshwater shortage and heavy dependence on oil has led the government to fundamentally rethink its water and energy policies and to implement several more sustainable policies this year.

In Malta, a small Mediterranean archipelago south of Italy, water and electricity costs are closely linked. The Maltese Water Services Corporation operates three energy-intensive desalination plants, all of which use reverse-osmosis (RO) to filter the salt from readily available seawater. According to a recent report, “Electricity accounts for 75 percent of the cost of the water produced by Water Services’ RO plants.”

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desalination, electricity theft, Enemalta, Gozo, IBM, Malta, reverse osmosis, smart grid, Water Services, water-energy nexus

This is the first in a series of blog posts discussing the water-energy nexus, a current focus of the Worldwatch Institute’s Climate and Energy team. A Worldwatch study that investigates water consumption over the lifetime of a natural gas power plant will be available soon.

Sunrise in Chicago

Sunrise - Flickr Creative Commons / Shutter Runner

In a world with rapidly diminishing natural resources, the interdependence of water and energy is becoming increasingly apparent. According to the Institute of Electronic and Electrical Engineers, an estimated 500 billion liters of freshwater travels through power plants in the United States each day—more than twice the daily flow of the Nile River. Water and energy demands are coming into competition throughout the country, creating water-energy choke points. These competing demands were discussed at a recent event titled “Choke Point US: Understanding the Tightening Conflict between Energy and Water in the Era of Climate Change,” held September 22 at the Woodrow Wilson International Center for Scholars in Washington, D.C.

For the last four months, the communications network Circle of Blue has been investigating the potential impacts of rising U.S. energy demand on the nation’s water resources. At the Wilson Center event, Keith Schneider and J. Carl Ganter from Circle of Blue talked about the possible effects of the Department of Energy’s projected 40 percent increase in U.S. energy consumption by 2050. Schneider warned that if we are not cautious, this new energy development will come at the expense of “the nation’s water, land, and quality of life.”

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ACC, air-cooled condenser, Circle of Blue, concentrating solar power, CSP plant, dry cooling, Heller system, U.S. Southwest, water-energy nexus, wet cooling, Woodrow Wilson International Center for Scholars