hydroelectric installation; with an installed capacity of 2.08 million kW, it is still one of this
country’s largest.
The $165 million cost of Hoover Dam has been repaid, with interest, to the federal trea-
sury through the sale of its power. Hoover Dam energy is marketed by the Western Area Power
Administration to 15 entities in Arizona, California, and Nevada under contracts that expire
in 2017. More than half, 56%, goes to southern California users; Arizona contractors receive
19%, and Nevada users get 25%. The revenues from the sale of this power now pay for the dam’s
operation and maintenance. The power contractors also paid for the uprating of the power
plant’s nameplate capacity from 1.3 million to over 2.0 million kW.PROBLEMS
- Calculate the water pressure at the bottom of the dam when the water level is two- thirds of
the height of the dam. Express your result in lb/in
2
and Pa. Also, calculate the magnitude
of the force due to water pressure acting on a narrow strip (1 ft by 100 ft wide) located at
the base of the dam. - As mentioned in the article describing Hoover Dam, Lake Mead contains 28,537,000 acre-
feet of water (an acre-foot is the amount of water required to cover 1 acre to a depth of 1 ft).
Express this water volume in gallons and m
3
. - Hoover Dam generates more than 4 billion kWh a year. How many 100-watt light bulbs
could be powered every hour by the Hoover Dam’s power plant? - How much coal must be burned in a steam power plant with a thermal efficiency of 34%
to generate enough power to equal the 4 billion KWh a year generated by Hoover Dam?
Assume the coal comes from Montana (see Chapter 8 for heating value data).
Hoover Dam 415
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