Subscribe free to our newsletters via your
. Earth Science News .

Rivers Act As 'Horizontal cooling towers'
by Staff Writers
Durham NH (SPX) Apr 23, 2013

File image.

Running two computer models in tandem, scientists from the University of New Hampshire have detailed for the first time how thermoelectric power plants interact with climate, hydrology, and aquatic ecosystems throughout the northeastern U.S. and show how rivers serve as "horizontal cooling towers" that provide an important ecosystem service to the regional electricity sector - but at a cost to the environment.

The analysis, done in collaboration with colleagues from the City College of New York (CCNY) and published online in the current journal Environmental Research Letters, highlights the interactions among electricity production, cooling technologies, hydrologic conditions, aquatic impacts and ecosystem services, and can be used to assess the full costs and tradeoffs of electricity production at regional scales and under changing climate conditions.

Lead authors of the study are Robert Stewart of the UNH Institute for the Study of Earth, Oceans, and Space (EOS) and Wilfred Wollheim of the department of natural resources and environment and EOS.

Thermoelectric power plants boil water to create steam that in turn drives turbines to produce electricity. They provide 90 percent of the electricity consumed nationwide and an even a greater percentage in the Northeast - a region with a high density of power plants.

Cooling the waste heat generated during the process requires that prodigious volumes of water be withdrawn and makes the thermoelectric sector the largest user of freshwater in the U.S. - withdrawing more than the entire, combined agricultural sector. Water withdrawals are either evaporated in cooling towers or returned to the river at elevated temperatures. Rivers can help mitigate these added heat loads through the ecosystem services of conveyance, dilution, and attenuation - essentially acting as horizontal cooling towers as water flows downstream.

Says Stewart, a research scientist in the EOS Earth Systems Research Center, "Our modeling shows that, of the waste heat produced during the production of electricity, roughly half is directed to vertical, evaporative cooling towers while the other half is transferred to rivers."

The study also shows that, of the waste heat transferred to rivers, only slightly more than 11 percent wafts into the atmosphere with the rest delivered to coastal waters and the ocean.

"We were surprised to find that relatively little of the heat to rivers is exchanged back to the atmosphere," notes Wollheim, an assistant professor and co-director of the Water Systems Analysis Group at EOS. Wollheim adds, "Reliance on riverine ecosystem services to dispense waste heat alters temperature regimes, which impacts fish habitat and other aquatic ecosystem services."

The researchers quantified the various dynamics using a spatially distributed hydrology and water temperature model developed at UNH known as the Framework for Aquatic Modeling in the Earth System, or FrAMES model, coupled with the Thermoelectric Power and Thermal Pollution Model developed by collaborators at CCNY.

The combined models showed that there are roughly 4,700 river miles in the region potentially impacted by power plants. The study found that, in general, the impact to river temperatures, and thus fish habitat, is "considerable" and disruptions in river flow "minimal," in part because so many of the region's power plants are located well down river near coastal areas.

But the study also noted that in the face of changing climate and increasing energy demand, "it is essential to assess the capacity and associated environmental trade-offs of heat regulating ecosystem services that support the electricity sector."

Indeed, last summer a reactor at the Millstone nuclear power plant in Waterford, Conn. was shut down because the water in Long Island Sound was too warm to cool it-something utterly unanticipated when the plant was designed in the 1960s. And in July 2012, a nuclear plant in Illinois had to obtain special permission to continue operations because its cooling water pond reached 102 degrees in the wake of low rainfall and high air temperatures.

By means of the study, notes Wollheim, "We can better understand the unintended consequences to other ecosystem services as we rely on rivers to support generation of electricity. Integrative, regional approaches will be needed to help plan as society adapts to changing climate and hydrology while demand for power continues to increase."

Project collaborators and co-authors on the Environmental Research Letters paper include UNH's Richard Lammers, and Ariel Miara, Charles Vorosmarty, Balazs Fekete, and Bernice Rosenzweig of CCNY. Read the paper here.


Related Links
University Of New Hampshire
Water News - Science, Technology and Politics

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

New technique measures evaporation globally
New York NY (SPX) Apr 17, 2013
Researchers at Columbia Engineering and Boston University have developed the first method to map evaporation globally using weather stations, which will help scientists evaluate water resource management, assess recent trends of evaporation throughout the globe, and validate surface hydrologic models in various conditions. The study was published in the online Early Edition of Proceedings of the ... read more

U.S. lawyer defends Australian asylum seekers

Landslide kills 14 in Ecuador

Pakistan quake victims burn tyres at angry protests

Hong Kong searches for 6 missing crew after boat crash

US eases export rules on aerospace parts

MEADS Low Frequency Sensor Cues Multifunction Fire Control Radar in Test

Ontario Air Cadets Take Flight in Lockheed Martin's Prepar3D Simulation Software

Softening steel problem expands computer model applications

Rivers Act As 'Horizontal cooling towers'

New Caledonia bans shark fishing

New NASA Satellite Takes the Salton Sea's Temperature

Climate scientists say Asian monsoon forecasts could improve

Sea stalactites provide clues to origin of life

Chinese ship sinks off Antarctica: Chile

Age matters to Antarctic clams

An SwRI-led remote-sensing study quantifies permafrost degradation in Arctic Alaskan wetlands

Deep, Permeable Soils Buffer Impacts of Agricultural Fertilization on Streams and Rivers in Southern Amazon

Ecology, economy and management of an agro-industrial Amazon frontier

Double cropping helps Brazil develop

New studies explore mango's potential health-affirming properties

Measuring the hazards of global aftershock

Calculating tsunami risk for the US East Coast

A global murmur, then unusual silence

Superstorm Sandy shook the US

Nigeria amnesty panel says talks possible with Islamists

Scaled down US-Morocco war games resume: embassy

S.African leaders at odds on C.Africa troop re-deployment

France hands Timbuktu mission to Burkina Faso troops

Ancient skeletons reveal genetic 'history' of Europe's peoples

From mice to humans, comfort is being carried by mom

DNA study suggests human immunity to disease has ethnicity basis

Fascinating rhythm: The brain's 'slow waves'

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement