The Bureau of Reclamation has initiated a program to modify turbines at 2,078-MW Hoover Dam in Arizona and Nevada to increase generating capacity at lower lake levels. BuRec said it is pursuing the program because the level of Hoover’s reservoir, Lake Mead, has dropped since 1999.
“The turbines at Hoover Dam were originally built with cast steel wicket gates,” BuRec Commissioner John Keys III said. “Newer materials and designs allow for more water flow through the gates, which results in additional available electric capacity. The lower lake elevations resulting from the drought make this is an opportune time to investigate and proceed with wicket gate modifications.”
In 2005, BuRec installed stainless steel wicket gates in Unit A-1, one of 17 commercial turbines. By installing the new wicket gates, which control the amount of water flowing past the turbine, BuRec said it can operate the unit with an additional 8 MW of available capacity when surface elevation of Lake Mead is at 1,145 feet above sea level or lower. Similar results are expected for two other units, one of which received new stainless steel gates this year, and another that will receive new gates in 2007, BuRec said.
BuRec said it consulted power customers before deciding to launch the program. Power customers include the city of Los Angeles, which is allotted more than 15 percent of the project’s firm energy. Los Angeles is one of 11 cities that are allotted power from Hoover Dam. Other power users include the states of Arizona and Nevada, the Metropolitan Water District of Southern California, and Southern California Edison Co.
Precision Machine to study boosting capacity, performance
BuRec announced March 21 it awarded a $195,648 contract to Precision Machine &Supply Inc., Lewiston, Idaho, to study maximizing generating capacity and performance of seven units (HYDROWIRE, Nov. 21, 2005). Three of the units are on the project’s Arizona side; the other four are in Nevada.
After evaluating the study, BuRec could purchase new wicket gates for one or more additional units. If all contract options were exercised, the contract would exceed $5 million over three years.
Turbine runner modifications are excluded from study. All original turbines were replaced in a 1986-1993 uprating program.
Hoover Dam was completed in 1936 in Black Canyon on the Colorado River, 30 miles southeast of Las Vegas, Nev.