A large provider of Colorado energy says sagging hydropower production on the Colorado River system, which has raised concern over the long-term reliability of the power source in the West, has not had a significant impact here.
Tri-State Generation and Transmission Association, the largest hydropower customer on the Colorado River system, has received about two-thirds of its normal hydro supply this year. But only 8% of Tri-State’s total energy comes from the Colorado River Storage Project, known as CRSP, and so the reduction only accounts for about 3% of its total system, according to figures the company provided.
Tri-State, which provides wholesale power to 42 cooperatives in four states, including 17 in Colorado, said it has been able to make up for the hydropower loss with other power sources.
“The reduction of any generation resource is a concern,” Tri-State spokesman Mark Stutz said, “but Tri-State has a diversity of power plants that we utilize, including resources that we can turn on or turn up when more power is needed, and a growing portfolio of wind and solar power.”
The assurances come as some parts of the basin worry about the potential impact of the water at Lake Powell falling below a level at which Glen Canyon Dam could no longer generate power. There are immediate impacts if the water at Powell dips below 3,490 feet above sea level. According to the Bureau of Reclamation, at that level, “essential drinking water infrastructure supplying the city of Page, Arizona, and the LeeChee Chapter of the Navajo Nation could not function.”
Stutz said that it’s “difficult to predict at this time how lower water levels will eventually affect Tri-State.”
One of the upsides to hydropower in general is that it can be made available quickly on-demand, essentially flipped on or off by releasing more or less water through a dam.
“It’s our largest low- or no-carbon emissions energy source that we can turn on and off when we need it,” Adrienne Marshall, an assistant professor of geology and geological engineering at the Colorado School of Mines, said. “At the same time, our ability to generate hydropower is significantly threatened by drought.”
Marshal noted that last year all Western hydropower accounted for about 53% of the renewable energy generated in the Western U.S. and about 16% of total Western grid power generation. (Those renewable numbers, she said, do not count nuclear as renewable.)
Losing any carbon-free energy source is not ideal, Tri-State’s Stutz said. Tri-State is aiming to reduce its greenhouse gas emissions at least 80% by 2030.
“Tri-State is concerned about losing access to these emissions-free hydropower resources,” Stutz said, “which could ultimately increase power costs for rural communities and affect how we advance our greenhouse gas emissions reduction goals, while also presenting broader reliability challenges across the Western electric grid.”
The CRSP system — collectively the federal dams and reservoirs that move water around the Upper Basin states of Colorado, Wyoming, Utah and New Mexico — will see a small bump in hydropower production as a result of recent Drought Response Operations Plan drafted by the seven basin states and approved May 3 by the Bureau of Reclamation.
The primary goal of the 2022 drought plan was to protect the infrastructure and power generation capabilities at Lake Powell’s Glen Canyon Dam. The plan includes delivering 500,000 acre-feet of water from Flaming Gorge to Lake Powell to keep the levels up at the Utah reservoir. The bureau also made the unprecedented decision to hold back 480,000 acre-feet of water in Lake Powell. That water had been scheduled for delivery to the lower basin states of Arizona, Nevada and California.
Clayton Palmer, an environmental specialist at Western Area Power Administration, which distributes and markets CRSP power, said the overall result of the bureau’s big water accounting maneuvers is a net positive for hydropower. WAPA, he said, will generate an additional 92,000 megawatt-hours, roughly enough to power 39,000 households.
“We expected we might take some losses because of reduction in releases at Glen Canyon,” Palmer said. “But it turns out the losses are offset.”
The reason, Palmer said, is that as the water level at Lake Powell drops, so does the amount of power per acre-foot of water the dam can generate. In a more-full Powell, he said, 2 acre-feet can generate a megawatt; at the moment, that number is more like 3 acre-feet. With higher water levels at Flaming Gorge reservoir — Palmer called it a “huge battery” — WAPA can more than make up for the losses at Glen Canyon.
That increase, however, is not enough to erase the forecasted drop for this water year, which runs until the end of September. WAPA is forecasting about a 15% overall dip in CRSP hydropower production compared to last year. And last year was about 20% below WAPA’s historical average since 1992.
The water level at Lake Powell is currently at about 3,523 feet above sea level, or about 24% full, the lowest level since the federal government considered the lake full in 1980. The dam cannot generate electricity if the water level dips below 3,490 feet.
“This drought has had significant consequences in the last couple years,” Palmer said.
CORRECTION: This story was updated at 1:44 p.m. on Tuesday, May 17, 2022, to correct the amount of water that can generate 1 megawatt at Glen Canyon Dam.