LAS VEGAS (KLAS) — Power production at Hoover Dam is down about 33% and will continue to drop as the “megadrought” affecting the Southwest continues, according to a U.S. Bureau of Reclamation spokesman.
The declining level at Lake Mead is the reason, according to Doug Hendrix, Deputy Public Affairs Officer with the Bureau of Reclamation’s Lower Colorado Regional Office.
At full capacity, the turbines at the dam can produce 2,074 megawatts, but as the water level has declined during the drought, power production has been affected and efficiency of the power plant is down 33%. The dam is currently producing enough electricity for 675,000 homes, Hendrix said. That’s down from a million homes at peak production.
“When you have less water in the reservoir, you have less hydraulic force — water falling through the penstocks. There’s less hydraulic force spinning the turbines,” Hendrix said. Penstocks refers to the system of pipes that take water to the turbines.
A recent decision to keep more water in Lake Powell — at the expense of a higher water level at Lake Mead — was based in part on preserving power production at Glen Canyon Dam.
Generating power at Lake Mead hasn’t changed much since the dam was put in place in the 1930s. Water drops through 30-foot-diameter pipes in four intake towers on the lake side of the dam. The higher the lake level, the higher the force of the water as it drops to spin the turbines.
There are 17 turbines — nine fed by the two towers on the Arizona side and eight fed by the Nevada towers. The technology and the design of the turbines has improved over the years. All the original turbines were replaced between 1986 and 1993.
And recent design improvements have been put in place as five turbines were rebuilt over the past decade, Hendrix said. The rebuilt “wide-head” turbines operate more efficiently and have a higher tolerance as hydraulic force drops.
Hendrix said the dam can continue normal power production until Lake Mead drops to 950 feet — about 100 feet lower that its current level. And even then, the dam can still generate power, but the turbines that have not been upgraded will be operating in the “rough” zone.
Power production and water supply are two different ballgames. While Las Vegas residents have watched nervously as Lake Mead’s level has dropped, the effect on power production has been invisible to some degree. But it’s a problem.
“Crisis mode? No,” Hendrix said. “Are we concerned? Yes.”
So power production will become a problem before the valley’s water supply. The third “straw” that brings water to the Las Vegas valley will operate until Lake Mead drops to 895 feet.
The lake level is expressed as an elevation above sea level. The surface of Lake Mead is currently just under 1,049 feet.
Hendrix has watched Lake Mead’s drop since he joined by Bureau of Reclamation 22 years ago.
“The drought we’re in … we’re in the 23rd year of a record drought,” he said. He fields a lot of questions about the drought as part of his duties with the Public Affairs Office.
Hoover Dam has been one of the top tourist attractions in the region since it was built, and the dam’s operations have fascinated people for decades. It’s the most visited dam in the world, with about 7 million tourists a year.
When the dam was built, it provided a source of electricity for the boom in Southern California. Southern Nevada’s population has exploded since the early 1980s.
About 50% of the power produced at Hoover Dam still goes to California. Nevada gets about 22% and Arizona gets 20%. Contracts managed by the Department of Energy control the distribution of the power, and Native American tribes are also among the dam’s customers.
