involving much larger capacities are being studied 

 by France and by the U.S.S.R.; England, Argen- 

 tina, and Canada have sites with large potential. 



The only practical opportunities for economic 

 development of tidal power are in the vicinity of 

 Passamaquoddy Bay, Maine and at some locations 

 along the Alaskan coast. The capacity that might 

 be installed has been estimated at 300 to 1,000 

 Mw. 



The Passamaquoddy project has been carefully 

 investigated and analysed as long ago as 1922 and 

 again in the early 1960's. However, the latest 

 report, published in 1965,^ indicated an unfavor- 

 able benefit/cost ratio of .86 to 1 . At current 1968 

 interest rates and costs the ratio is even lower. 



Some of the problems include: 



—Meshing the output generated during periods of 

 high tide with periods of maximum needs, i.e. 

 peaking power requirements. 



—The average high tide is 18 feet but only 12 feet 

 of this head can be used. Designing turbines to 

 operate cheaply enough at low heads is still a 

 problem. 



-The dikes necessary to form a high pool are 

 expensive in that they must extend 300 feet 

 through unconsolidated material to hit bedrock. 



—Political problems arise from the fact that 

 Passamaquoddy would be a Federal development 

 in a non-Federal, i.e. private utility area— and also 

 its international location. 



B. Thermal Differences 



The possibility of generating power from tem- 

 perature differences between tropical surface 

 waters and cold waters from the ocean depths 

 recently has been given serious consideration. This 

 process, in effect, utilizes the sun's radiant energy 

 with the ocean acting as the collector of that 

 energy. It has been estimated" that the potential 

 energy recoverable from thermal differences would 

 provide a continuous source of energy 200 times 



as great as the projected world needs in the year 

 2000. However, methods to harness this source of 

 energy have not been competitive because sea 

 water itself was utilized as the working fluid in 

 order to avoid the problem of transferring large 

 quantities of heat into and out of the fluid at small 

 temperature drops. 



This is a high-cost operation because at the low 

 temperatures inherent in a sea thermal plant steam 

 volumes are so large that turbomachinery becomes 

 excessively bulky and expensive.' Rusting of 

 machinery and equipment is also a serious prob- 

 lem. 



It has recently been suggested* that use of low 

 cost noncorrosive propane as a power fluid (in- 

 stead of sea water), and use of a floating power 

 plant making short water lines possible, may make 

 sea thermal power economically feasible. 



C. Currents and Waves 



Vast amounts of energy are contained in ocean 

 currents and waves. However, studies indicate little 

 possibility of developing power in commercial 

 quantities from these sources except for ocean 

 buoys to supply signals and light. ^ 



D. Geothermal Energy 



A type of energy whose potential is wholly 

 unknown and cannot be evaluated is geothermal 

 energy derived from thermal springs and subsur- 

 face steam reservoirs. Electric power is being 

 generated from geothermal energy at the geysers in 

 California, and a wholly unsuspected geothermal 

 field was discovered near the Salton Sea a few 

 years ago. These geothermal fields appear to be 

 related to tectonically active belts and to areas of 

 relatively recent volcanic activity. It is possible 

 that such fields may be present in the continental 

 shelves off the Pacific and Gulf Coasts. 



II. PRESENT LEVEL OF GOVERNMENT AC- 

 TIVITY 



The Department of the Interior is currently 

 making studies on the feasibility of obtaining 

 power economically from thermal differences. 



Conservation of the Natural Resources of New 

 t'nglanU-The Passamaquoddy Tidal Power Project and 

 Upper St. John River Hydroelectric Development, Report 

 to President Lyndon B. Johnson (1965), p. 5. 



John Isaacs and Walter k. Schniitt, "Resources from 

 the Sea," International Science and Technology, June 

 1963, p. 44. 



J. llilbert Anderson and James H. Anderson, Jr., 

 "Power from the Sun by Way of the Sea?" Power ( 1 965). 



^Ihid 



Conversation with Joseph Guidry, Department of the 

 Interior, Oct. 4, 1967. 



VII-234 



