3and 7

3. Caballo Dam is located on the Rio Grande in south-central New Mexico, some 25 miles downstream from the Elephant Butte hydroelectric plant. Caballo was built to impound water discharged from Elephant Butte during winter power generation for irrigation use during the summer. Caballo Dam is an earthfill structure 96 feet high and 4,590 feet long. The reservoir has capacity of 343,990 acre-feet of water. According to the U.S. Army Corps of Engineers, Caballo has a maximum head of 78 feet and a maximum flow rate of 5000 cubic feet per second. Calculate the hydroelectric potential of the Caballo site. 4. A run-of-the-river hydroelectric plant is proposed for a site where the elevation change is 75.5 feet. The project would divert 3960 GPM through a steel penstock designed to produce a frictional head loss that is 25% of the total head. Compute the power output from the plant if the turbine efficiency is 0.85 and minor losses are negligible. 5. Suppose a 4-inch ID penstock delivers 150 GPM of water through an elevation change of 100 feet. The pressure in the pipe is 27 psi when it reaches the powerhouse. What fraction of the available head is lost in the pipe? What power is available for the turbine? (Masters, 2004) 6. Suppose 150GPM of water is taken from a creek and delivered through 1000 feet of 3-inch polyethylene pipe to a turbine 100 feet lower than the source. Estimate the power delivered by the turbine/generator, assuming an efficiency of 50%. In a 30 day month, how much electric energy would be generated? (Masters, 2004) 5.14. PROBLEMS 5-15 7. Find the optimum flow rate (in gallons per minute) for the system described in the previous