Hydropower production on the Upper Colorado River system for water year 2022, which ended on Sept. 30, was down about 20% compared with the previous year and about 30% compared with the yearly average since 2000, according to a Bureau of Reclamation official who oversees hydroelectric generation.
“The outlook is likely for pretty low generation years,” said Nick Williams, the Bureau’s Upper Colorado River Basin power manager.
The last time hydropower generation from the Colorado River Storage Project, or CRSP system — the federal dams and reservoirs that move water around the Upper Basin states of Colorado, Wyoming, Utah and New Mexico — was this low was in 1967, Williams said. That’s significant, because not all of the CRSP dams were producing energy at that point, he said.
Lake Powell’s Glen Canyon Dam produces most of the CRSP hydropower, about 78%; Blue Mesa Reservoir west of Gunnison accounts for about 5% of the production.
When compared to a pre-drought average from 1988 to 1999, the most recent water year hydroelectric generation is down about 43%, Williams said. The beginning of the 21st century marked what scientists now believe is the driest 22-year stretch in the Southwest in the past 1,200 years.
Recent dips in CRSP hydropower production have officials rethinking how much power generation can reasonably be relied upon from that system long term.
“We’re starting to look really hard at the assumptions that go into what do we base our numbers and historic statistical models on — and questioning the validity of those,” Williams said. “I think the prudent thing to do is to plan for something that’s likely lower long term and then it’s easier to react to more water and power than it is to less.”
The Western Area Power Administration, or WAPA, which distributes and markets the CRSP power, is thinking through the same long-term implications of lower hydropower production, both internally and in discussions with its customers, said Clayton Palmer, an environmental specialist at WAPA.
“Among the issues is are we in a drought that has some limited duration — or are we to expect these drier conditions as the new normal going forward?” Palmer said. “That’s a constant conversation.”
WAPA negotiated long-term contracts with its customers nearly 20 years ago that were based on pre-early 2000s hydropower numbers that were higher than today’s figures. Those contracts run out in 2024. Last year, WAPA negotiated a two-year period during which customers agreed to take less power. It started Dec. 1.
“The electrical generation was so low relative to our contractual commitments and the market prices for replacement power are so high,” Palmer said. “So, we cut a deal that they would take less power than our contractual commitments.”
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In the meantime, WAPA is trying to sort through how to structure its post-2024 agreements. There are a couple of possibilities, Palmer said. One option is an arrangement where WAPA would distribute certain amounts of CRSP power based on the flows on the river.
“That reduces our risk, but it jerks our customers around,” he said. “We don’t consider that a sustainable product.”
The more likely option, he said, is to just plan for lower yields on average so that customers have at least something they can count on. Then, if there’s more, it’s a pleasant surprise.
Planning for less
For now, at least, the impact of all this in Colorado appears to be limited. Although several Colorado energy providers receive CRSP hydropower from WAPA, including several small and medium-size utilities, for many of those companies it amounts to a small slice of a larger energy portfolio.
Hydropower from WAPA accounts for about 3% of the power provided by Holy Cross Energy, an electric cooperative that serves more than 42,000 customers in western Colorado. But even replacing a small percentage has its challenges, Holy Cross president and CEO Bryan Hannegan said.
“Instead of having a reliable, low-cost source of clean hydro we have to go find other power supply resources to meet our consumers’ needs,” Hannegan said. “Today, those are increasingly coming from the wholesale power market — and largely coming from natural gas fire generation.”
A variety of factors, including the war in Ukraine, have recently sent natural gas prices soaring, Hannegan said.
Holy Cross has developed enough small-scale, renewable projects, including a new collaborative solar and battery storage project with Colorado Mountain College, that replacing WAPA hydropower won’t cause rates to jump this winter, Hannegan said.
“Next year, who knows?” he said.
All this raises questions about whether utilities can count on water being available to generate hydroelectric power on this system in the future, Hannegan said.
The situation is similar at CORE Electric Cooperative, which serves roughly 170,000 members in an area that stretches east from Buena Vista, across the Front Range south of Denver and onto the Eastern Plains.
Power supply manager Chris Hildred said WAPA hydropower has been an important, low-cost piece of the co-op’s energy portfolio — but accounts for less than 2% of its energy capacity. Hildred said the company is thinking through what options it has in the future, including replacing this power altogether, if the supply is no longer reliable.
As of this summer, Tri-State Generation and Transmission Association, the largest CRSP hydropower customer, was receiving about two-thirds of its normal hydropower supply. Those numbers are similar through the end of September, according to a company spokesman.
Tri-State, which provides wholesale power to 42 cooperatives in four states, including 17 in Colorado, continues to make up for the losses with other power sources. About 8% of Tri-State’s total energy comes from the CRSP project.
“As we have noted for some time, dealing with decreasing allocations from CRSP continues to reduce a piece of the pie that we have historically depended on for carbon-free energy,” spokesman Mark Stutz wrote in an email. “This loss of a dispatchable resource remains a hardship, especially during our energy transition, but we have and will continue to work to build a reliable and affordable power supply for our rural communities.”
Some Bureau of Reclamation projections show water levels at Lake Powell could drop below the minimum level needed to generate power as early as the end of next year. With water levels that low, loss of hydropower generation at Glen Canyon Dam is one concern — impacts to the infrastructure is another.
Brad Udall, a senior water and climate research scientist at Colorado State University’s Colorado Water Institute, said the ability to continue to get water through Glen Canyon Dam infrastructure is more significant than the power generation itself.
“Dropping below the ability to produce power at Powell is a really bad idea because we need to protect the infrastructure,” Udall said. “If we go below the penstocks we end up using some infrastructure that’s little used over the years. We have no idea how that would work in the long run. Too many people rely on Powell water to trust these four bypass tubes.”
From a power generation perspective, if the levels at Lake Powell drop below minimum power pool, then there’s a situation where their customers are expecting a product that doesn’t exist, Holy Cross’s Hannegan said.
“Then we have a contract but no ability or capability to deliver on it,” Hannegan said.
One option, Hannegan said, might be to replace the hydropower with other clean energy sources on federal land. “We could build solar and build wind and use that to take pressure off the hydro system.”
Regardless, Hannegan said, something will need to change. “We need to find a longer-term solution to this problem, which doesn’t appear to be getting any better,” he said.