Craig’s Trapper Mine began operations in 1977. In Severance, Black Hollow Sun is being completed as Colorado moves beyond 50% renewables
by Allen Best
One chapter ended and another began this week in Colorado’s book-length transition from coal combustion to renewable generation of electricity. Both involved Platte River Power Authority, which delivers electricity to four municipalities along the northern Front Range.
On Wednesday, Platte River celebrated completion of a major solar project east of Fort Collins within the municipal limits of Severance. Called Black Hollow Sun, the 257-megawatt project will provide electricity for Longmont, Estes Park, Loveland and Fort Collins. Planned since roughly 2019, it is part of a surge in utility-scale solar projects coming online during the next few years.
About 250 miles to the west, the last coal was scooped from the open-pit Trapper Mine adjacent to the Craig Generating Station on Sept. 25 after 49 years of operation. This milestone is being celebrated this Friday. All three of the adjoining three units are to be closed before 2029. Coal has been stockpiled from Trapper and Colowyo, another coal mine near Craig that closed last year. Tri-State Generation and Transmission, the operator, is evaluating its options if more is needed. Platte River has a minority interest in Trapper.
Also during the last week came news that Colorado altogether had achieved a tipping point in its electricity. For the previous 12 months, according to Energy Information Administration data, more than 50% of electricity had come from renewables. That was a first — and almost certain to be the norm.
Jason Frisbie, CEO of Platte River Power Authority, says the utility by 2030 will be delivering electricity to its four municipal members well in excess of 80% from non-carbon sources. Top, transmission lines are crucial in Black Hollow Sun and other renewable energy projects. Photos/Allen Best
As for Platte River, directors representing the four member municipalities in 2018 adopted a heavily footnoted goal of achieving 100% renewable electricity by 2030. The 544,740 solar panels of Black Hollow alone won’t get Platte River across that finish line but will help immensely. Jason Frisbie, the CEO of Platte River, said at the ribbon-cutting ceremony that he is confident Platte River will get “well in excess of 80% non-carbon energy” by 2030 while maintaining affordability and reliability.
Cost has not been a problem in this big energy pivot, at least not yet. Economics had already aligned in 2019 when state legislators targeted an 80% reduction in emissions from electrical generation by 2030.
ContourGlobal, a company backed by financial giant KKR, erected the 544,640 PV panels in the Black Hollow Sun project. Photo/ContourGlobal
Some politicians blamed renewables for rising rates by Xcel Energy and others. The real causes are far more complex. Consider Holy Cross Energy, which this year has achieved 90% renewables through August while still having some of Colorado’s lowest electricity rates.
Ensuring reliability as we expand the role of renewables in our energy mix will be more challenging. One strategy lies in expanded transmission and broader markets, connecting consumers and producers in areas larger than one time zone or one weather system. Just last week, the U.S. Department of Energy announced two grants of $250 million each for projects that would connect Colorado with Kansas, Oklahoma and other states in the Eastern interconnection grid.
Storage will help. Platte River expects the 100-megawatt four-hour discharge lithium-ion-phosphate battery storage project next to Black Hollow Solar to be completed in December. ContourGlobal developed the solar project and is selling the electricity to Platte River Power in a power-purchase agreement. NextEra Energy is building the storage.
Other battery chemistries being developed may provide longer-duration storage than the lithium-ion batteries.
Some solutions are smaller and closer to home, sometimes literally. For example, several Colorado utilities help homeowners install Tesla Powerwall batteries that can then be tapped by the utilities to meet peak demand, such as from air conditioners on hot summer evenings. EV batteries or, in the case of a new Xcel Energy program in Jefferson County, school buses, can be used in the same way.
A natural gas plant with the ability to respond quickly to needs is expected to be in place before the Rawhide coal plant is retired. Older natural gas plants required 18 minutes, and coal plants 18 to 24 hours. Photo/Allen Best
To the dismay of some environmental advocates, most utilities want natural gas as a backup. For example, Platte River is spending $600 million on a plant that uses newer technology that can generate electricity almost instantly as needed to balance the variability of renewables. It will become available in late 2029 just before Rawhide, the coal plant north of Fort Collins, closes.
Benefits from this transition have been unequal. The town of Severance will benefit from $500 million in the assessed valuation of Black Hollow on land previously used for low-value livestock grazing. Mayor Matthew Fries says the project will help Severance start several other projects in the town’s core, but did not provide details.
Craig and Moffat County benefit from cushions extended by departing utilities but the community is still trying to figure out its future.
This big pivot from combustion of fossil fuels to emissions-free renewables in generating Colorado’s electricity hasn’t been as quick or as elegant as a ballet dancer’s pirouette. It’s taking time. On Wednesday, as the solar panels were being celebrated, in the background a drilling rig labored on, looking for fossil fuels. But clearly, there is strong movement forward, as evident in the events this week.
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Given that the power grid infrastructure is already in place at Rawhide, why isn’t solar, wind and storage technologies being planned for the wide open spaces around the plant?
As you know, stringing power lines across the plains or mountainous terrain is expensive. Twenty-five years ago a rural electric coop representative at the Denver Stock Show told me it cost $15,000 per mile to extend the rural electric grid to someone’s stock tank or electric fence (he was trying to sell ranchers small wind turbines or solar panels). With the $15,000 price tag, I imagine the costs involved in connecting remote wind and solar farms to the grid to be astronomical.
Good point, Pete. I know that a solar project exists at Rawhide. As for storage, who knows. It would make sense. Maybe that is something in the pipeline that Platte River isn’t yet ready to talk about, at least not without having questions to answer. I do know that this site in Severance had several pre-existing transmission lines crossing it. The project was conceived, I believe, in 2019. As for wind, I don’t know the technology well enough to even hazard a guess as to the economics let along other considerations.
1. Do all these solar panels pivot to track with the sun?
2. What is the projected lifespan of these solar panels?
3. What is the plan for disposal of the 544,640 used panels when they come of age? Can any of the components be reused?
You can use AI chatbots to answer questions like this or just Google in general.
1. Do the panels pivot to follow the sun? Yes.
The entire Black Hollow Sun Solar Complex uses a single-axis tracking system.
That means the modules aren’t mounted at one permanent angle. The tracker rotates them around one axis during the day to increase solar production as the sun moves across the sky. The public sources I found don’t identify the tracker manufacturer/model or provide its exact rotation limits.
That’s one of the more interesting technical aspects to investigate further because with 544,740 modules over roughly 1,700 acres, the tracker equipment itself represents a substantial amount of steel, motors/drivetrains, bearings and electrical equipment in addition to the PV modules. The 544,740-module and 1,700-acre figures are from Platte River Power Authority.
2. How long are they supposed to last?
Platte River Power Authority gives the project an estimated lifespan of 30+ years.
The project’s two phases entered commercial operation in 2025 and 2026, respectively.
So using PRPA’s stated project life, you’re basically talking about an end-of-life horizon in the 2055-2056+ timeframe, although that shouldn’t be interpreted as an expiration date for every module.
Interestingly, PRPA is buying the electricity from ContourGlobal rather than owning the solar plant. PRPA says it purchases the project’s full energy output, while its March announcement describes a 20-year PPA.
That creates an important distinction:
20-year power contract ≠ 30+ year expected plant life.
What happens to the plant after the PPA therefore becomes an interesting question in its own right.
3. What happens to the 544,740 panels eventually?
This is where the readily available public information gets thin.
The PRPA material I found specifies the 30+ year lifespan, but it doesn’t specify what ultimately happens to the modules or identify a recycling/disposal contractor or process.
In principle, however, a utility-scale PV plant contains substantial potentially recoverable material. That either could be taking the panels apart and recycling the parts or sending the panels somewhere to be refurbished and resold, often for pennies on the $ compared to a new panel. They may be “old” after 30 years, but they still function and probably have 80% or so of their original efficiency.