69. Are the rise and fall of tides used to develop power? 



Only in France are the tides used to develop power. There are many 

 reasons why tidal power is not extensively used and probably won't be 

 in the near future. 



There are only a few places in the world where the tidal range is great 

 enough to justify building danns. Even if all these areas were utilized, 

 they could supply only one-tenth of one percent of the world's power 

 requirements by the year 2000. 



Labor costs for such huge construction projects are prohibitively 

 high. Perhaps some of the dams could have been built 30 years ago, but 

 labor costs today make the projects financially unattractive. 



-HYDRO TURBtNCS 



POWER HOUSt 



Wheki Se/k Water at Low Tide 



5LU1CE GATES Vja 2 i 3 OPEN FOR BAr WATER 

 TO FLOW OUT TO THE SEA,. GATE5 N^ \ t^ CLOSED 

 WITHOUT STOPPAGE OF HYDRO- ELECTRIC GENERATORS 

 BY MEANS Of TIDAL GATE CONTROLS. 



Tidal power cannot compete economically with power produced by 

 nuclear fission and other methods. The main reason that tidal power is 

 not used is simply that the need for additional power does not exist now. 



It is interesting to note that extensive use of tidal energy for power 

 stations would bring about a noticeable change in tidal conditions. 

 According to the French engineers Allard and Gibrat, if the utilization of 

 tidal energy is brought to 2 billion kilowatts, the earth would slow its 

 rotation so much that it would lag 24 hours every 2,000 years. 



Deacon, G. E. R. 



Seas, Maps, and Men, Doubleday and Company, 1962. 

 Gaskell, T. F. 



World Beneath the Oceans, American Museum of Natural History. 

 Pell, Claiborne (Senator) 



Challenge of the Seven Seas, William Morrow and Company, 1966. 



85 



