Northwest Fisheries Science Center

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Document Type: Chapter or Section
Center: NWFSC
Document ID: 7354
Type of Book: Technical
Section or Chapter Title: Problems of thermal effluents in marine and estuarine waters
Book Title: Pacific Marine Fisheries Commission Meetings. 21 November 1968, Coeur d'Alene, Idaho
Author: Anthony J. Novotny
Publication Year: 1968
Pages: 1-29

The rapid expansion of plants for the thermal generation of electricity in small countries such as Great Britain has placed a serious burden on the limited supply of fresh water to cool condensers.  By the end of this decade, Great Britain's electric power stations will be discharging 2.2 × 10" BTU per hour in the form of waste heat.  The United States will be discharging 12.5 × 10" BTU of waste heat per hour by 1970.  Both of these countries will have stretched their hydroelectric capacities to the planned limit by the early 1970s and are now looking for sites for additional thermal power generating stations.  The greatest sources of cooling water for steam turbine condensers in the two countries are the coastal estuarine and marine waters.  Undoubtedly, marine and estuarine waters will be utilized by the larger, nuclear–fueled plants which require the greatest quantities of cooling water.  This appears to be the practice in Great Britain, and there is no reason to believe it will be much different in the United States.

J. R. Adams1 lists 12 marine thermal power plants in Great Britain and 15 in the United States (some of these are in estuarine waters).  These plants will require quantities of cooling water ranging from 50,000 to 1,800,000 gallons per minute (gpm); temperatures range from about 3 to 16°C over ambient.  The 1.8–million gpm flow is from the relatively new Turkey Point plant on Florida's Biscayne Bay.

The nuclear–fueled thermal electric station at Biscayne Bay is of interest to us in the Northwest because its size (1,440 MWe) is fairly typical of the first marine and estuarine generating stations to be built here.  The Bonneville Power Administration's Thermal Task Force Committee has recently reported that a minimum of 20 nuclear–fueled thermal power generating stations will be built in the Pacific Northwest by 1990.  The minimum plant size is about 1,000 MWe.  A plant this size would use about 700,000 gpm of cooling water, with a water temperature rise of at least 10°C over ambient.  It must be anticipated that at least several of these plants will be on marine or estuarine sites.  The recent Battelle report (1967) lists seven possible marine and estuarine sites in Oregon and Washington suitable for minimum sized stations.  Direct discharges of waste heat from these power stations will cause some disturbances to the environment.  The direct environmental impact of such large volumes of heated water could be more severe if the plant were located on a river with runs of anadromous fish, for example.  The disturbances to a marine environment receiving such thermal discharges may not be as direct, but they will be more complex.

It is the complexity of these disturbances that I wish to emphasize in this paper—most specifically, complex situations in the Pacific Northwest and some possible solutions.