How Holy Cross Energy got to 85%

And what it’s doing now for the more difficult and complex parts of its clean energy journey

by Allen Best

Holy Cross Energy in 2025 achieved a breakthrough notable across the nation. Averaged over the year, 85% of the electricity delivered by the Glenwood Springs-based electrical cooperative to its 46,500 member-owners came from renewable sources.

Other, smaller electrical utilities have achieved 100% through the artifice of buying renewable energy credits. Holy Cross did it by investing in renewable energy early, before the disruption of covid and supply chain constrictions.

By late 2024 the work on wind and solar projects in eastern Colorado had paid off. So had several smaller solar and storage projects within the Holy Cross service territory in the Vail, Aspen and Rifle areas.

Holy Cross’s achievement was also the result of an agreement made in 1992, long before the cooperative set out to end its dependence upon fossil fuels. In that agreement, Xcel Energy agreed to share use of a transmission line that crosses the Continental Divide at Hagerman Pass, near Leadville, with Holy Cross. That shared use transmission has allowed Holy Cross to import large volumes of now inexpensive wind- and solar-generated energy from Colorado’s eastern plains. Holy Cross is 3% of the size of Xcel.

Oh, it’s Aspen and Vail, you might say — they can afford stuff like this. Please note that Holy Cross did this while delivering electricity at 11 cents a kilowatt-hour. That is 40% below the national average. In Colorado, which tends to have lower electricity rates, it’s a third below the state average. As for reliability, Holy Cross members average one outage per year.

Those statistics were delivered by Bryan Hannegan in an hour-long Zoom session on Monday. He joined Holy Cross as chief executive in 2017. At the time, 38% of the portfolio of Holy Cross came from renewable sources, much of it hydro. It was also part owner of Comanche 3, the youngest and largest coal plant in Colorado.

In 2017, directors of Holy Cross approved what was then seen as the ambitious goal of achieving 70% clean energy. It was a time of tumbling costs for wind and solar. In 2019, directors realized Holy Cross could move faster. They upped the goal to 100% by 2030.

It’s not clear that Holy Cross can achieve this. Hannegan told me years ago that getting to 85% or 90% would be the easiest part. Getting to 100% would likely become more difficult and expensive.

Recently, Hannegan and others — including Ron Sinton of Boulder in a session sponsored by the Colorado Renewable Energy Society several weeks ago — have made the argument that being hyper-focused on 100% “clean” electricity may be not the best use of time and other resources. We have other segments of our economy to decarbonize, some of them far more difficult nuts to crack than electricity.

From meteorology to electricity

Hannegan is atypical of utility executives. Reared in southern California, he got his first degree in meteorology from the University of Oklahoma. At the University of California at Irvine, he created climate models while earning a master’s degree in mechanical and aerospace engineering. He has a Ph.D. in earth systems science.

A decade ago, Hannegan was at the former National Renewable Energy Laboratory where he served as associate laboratory director. While there, he co-founded the Department of Energy’s Grid Modernization Initiative.

In 2017, when I read the short story in The Aspen Times announcing his hiring, I knew none of his background. I did know of the grassroots pressure for the cooperative to pick up its pace. I had a hunch I would be paying greater attention to Holy Cross. I have never been disappointed. The story just keeps getting more interesting.

Hannegan is generous with his public outreach. I have heard him speak at least four times in the last year. Last November he presented for an Empower Hour session. Responding to dozens of questions, he spoke for nearly two hours. It was all worthwhile. You can watch/hear it here.

On Monday, he spoke on Phil Nelson’s Zoom at Noon session, a weekly gathering.

“There’s a lot going on,” he said at the outset. “In fact, I’ll argue that probably within the next decade we’ll see more change in the electricity space than we’ve seen in the last 20 to 50 years.”

You can watch and hear Hannegan’s Zoom-at-Noon session by going here. Password: V^91qaR5.

In the session on Monday, Hannegan detailed the parts of what he called “our clean energy journey.” The journey started in 1992, when most people believed coal was the story far into the future. Directors at that time forged a partnership with Xcel Energy to share transmission capacity.

Use of that transmission has allowed Holy Cross in the last two years to import large amounts of wind from the Bronco Plains II wind farm about 130 miles east of Denver. To best advantage, Holy Cross gets a larger share of the electricity in winter, when it needs it. A partner, Guzman Energy, gets a larger share in the summer, when the cooler mountain towns don’t need it

Holy Cross also shares production with another electrical cooperative, CORE Electrical Cooperative, from a solar farm about 30 miles east of Denver called Hunter Solar.

Localizing energy generation

Another important component of Holy Cross’s strategy has been to create some local projects. Tapping wind in western Colorado is difficult. Solar is easier, if somewhat constrained by the high price of land in many locations. Still, Holy Cross has been able to create three solar-plus-storage projects.

“These resources are inherently more resilient because they are closer to the people they are serving,” said Hannegan.

“I hadn’t heard that voiced before, this equation between closer and more resilient,” said Nelson, the moderator.

Hannegan further explained that localization of power sources might come at a higher cost, but they are less likely to be compromised by equipment failures, cybersecurity hacks, physical infrastructure damage or a storm.

The big pivot underway in the electricity industry — part of the response to climate change — is this diversification and decentralization of power. In 2004, when Holy Cross became part of the Comanche 3 project, the prevailing model was of ever-larger power plants that burned coal.

Even 15 years ago, many electrical cooperatives were chafing at restrictions of their electrical providers. This was prominent in the “family” of Tri-State Generation and Transmission. Tri-State was inflexible. It insisted that the local cooperatives had almost no authority to add localized sources.

United Power was among the most prominent members of Tri-State that chafed under that restriction. Now on its own, United under the guidance of CEO Mark Gabriel has pursued a strategy that he calls “hyper-localization.” Like Holy Cross, United Power has been adding solar-plus-storage projects within its service territory on the northern fringes of metropolitan Denver. One key advantage: it reduced the cost of paying for transmission. As for Tri-State, it has become more flexible in allowing its member coops to localize larger portions of their energy.

As for Holy Cross, it has not abandoned its 100% goal. But, as Hannegan explained, the next phase of this journey — on which it embarked several years ago — is not a simple matter of adding more renewables. If anything, the renewables need to come fromdifferent locations, to dilute the likelihood of wind blowing in one place if not the other, for example.

Too, as Holy Cross informed developers in its 2023 request for proposals, it needs a different matrix of generation. That includes technologies that can deliver electricity at times when the skies are dark and the wind scarcely blows, if at all.

One bidder submitted a proposed for enhanced geothermal, producing electricity from the Earth’s interior heat. It didn’t make the price cut, but Hannegan believes the technology will relatively soon become part of the generating mix in Colorado.

But clean electricity is only part of the Holy Cross story even now. Hannegan and his team in Glenwood Springs for several years have been at work in the task of “fitting clean energy” into what he calls a “smart portfolio of resources.” This includes flexibility, demand-side management and other strategies. Again, that’s a goal, much like renewable energy, that scarcely existed before the 21^st century except in the minds of people like RMI’s Amory Lovins.

This allows the clean energy that you have to go further, to “help spread out the power supply that helps us fit in that white space.”

This part of the Holy Cross journey does get complex, though. Instead of sailing down I-70 in an electric car, it’s more like negotiating a maze of city streets.

Strategies going forward

To get a better grasp of what Holy Cross is doing, it might be best to listen to the Zoom-at-Noon or Empower Hour sessions. Any one component could deservedly get its own story. Here’s an overview:

Water as a storage medium. Here, Holy Cross sees an expanded role in displacing use of natural gas to heat buildings via thermal energy networks, or TENs. One of the things Holy Cross has been exploring is that when it has surplus renewable energy, the energy can be stored via the medium of water. The stored energy can be tapped later, when the heat in the thermal energy network is needed.
Power+ FLEX. Holy Cross provides generous rebates to members who invest in batteries for their homes or businesses that can then be tapped for use by the utility. This can help Holy Cross meet peak demands without the great expense of new transmission lines or other infrastructure.
Storage via electric vehicles. Holy Cross has distributed close to 1,000 home and workplace EV chargers to members. In exchange, Holy Cross will at some point begin tapping the electricity in those EV batteries, once again to help meet demands. The batteries can be restocked when electricity becomes more freely available.
Dynamic pricing. Members have the opportunity to save money by using less electricity during times of peak demand. “Eventually we’ll also be asking them and paying them to use more during times where we have oversupply.”

Does Holy Cross have everything figured out? No, and it should be noted that other utilities are on the move, too.

“One of the great things about working in this space is that when something works, our neighbor utilities are pretty quick to adopt it. And we’ve seen our lessons being used. And we frankly learned lessons from folks throughout the West and across the country.

“Now, we just need to tackle the carbon emissions in the other two-thirds of the economy, the built environment, the transport sector, and industry.”