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A leading data center developer and a pioneering Texas battery owner have formed a mutually beneficial partnership that models a new way for energy storage to accelerate the AI infrastructure build-out.
Storage firm Eolian completed the Chisholm Grid battery in 2021, placing 100 megawatts/125 megawatt-hours of capacity next to a substation 7 miles northwest of downtown Fort Worth. The site was able to discharge its full capacity for just over an hour — a design that worked well for the first wave of big Texas grid battery projects, which could make good money by providing rapid-response ancillary services.
Another 15 gigawatts of storage have piled into Texas since then, and revenues from those once-lucrative ancillary services have plummeted given the glut of batteries. Meanwhile, the market managed by the Electric Reliability Council of Texas, or ERCOT, is changing in other ways that reward longer-duration batteries.
So Eolian CEO Aaron Zubaty came up with a plan to meet the moment. “We’ve already taken the battery storage site offline so that we can upgrade the facilities and ultimately expand the usable duration,” Zubaty said. But he added, “Even though the battery is offline, the site is proving that well-placed infrastructure can create ongoing value across multiple use cases.”
That’s right, Zubaty found a way to get paid for not using a battery: by temporarily lending the site’s grid connection to data center developer CyrusOne. The Dallas-based company runs 55 data centers around the world and is currently building 10 more, including one next door to Chisholm. That data center, dubbed DFW7, could come online later this year.
“Getting a new connection to the grid at the scale of this site, more than 100 megawatts, that’s generally a multiyear process,” CyrusOne CEO Eric Schwartz told Canary Media.
But in this case, he noted, CyrusOne will activate its data center campus one to two years earlier by using Eolian’s grid interconnection while that firm renovates its battery plant.
“Time to market matters, but also certainty,” Schwartz said. At Chisholm, “the grid infrastructure is there and ready to go.”
The power sector has become consumed with the question of how to meet the AI industry’s rapidly ballooning electricity needs. One common assumption is that new gas plants will pave the way for the AI revolution, but gas turbines face yearslong backlogs that defy the “speed to power” desired by AI companies. Ask any battery developer today and they’ll tell you they have booming business prospects with data center customers, but hardly any of these have been made public, aside from a deal between energy storage specialist Calibrant and Aligned Data Centers in Oregon, and now the new Eolian–CyrusOne agreement.
This arrangement emerged from discussions in 2023, and CyrusOne broke ground last April. If construction goes to plan, the rebuild of the battery will wrap up around the time that wires utility Oncor finishes its grid upgrades for CyrusOne to get its own hookup. Then Eolian can get back to bidding into ERCOT, with a duration long enough to qualify for the forthcoming Dispatch Reliability Reserve Service, which requires power plants to discharge for at least four hours.
Chisholm runs on Samsung battery cells with the nickel-manganese-cobalt chemistry, and they have sustained very little degradation over five years of service, Zubaty said. The initial plan is to keep those original cells but restructure them: By dropping the capacity to 25 megawatts, Eolian can lengthen the discharge duration to the five-hour mark. Then it can add in new batteries to fill up the remaining space; the site can hold up to 250 megawatts, based on its grid-connection agreement.
It’s not yet clear if this deal will start a new trend or constitute a fruitful anomaly. There are only so many batteries in need of repowering in places eyed by data center developers. If storage developers get too comfortable leasing out their grid connections, they’ll reduce themselves to glorified landlords. But it says something about the interplay between data center development and battery storage, and how the two could work together to make the electricity network more nimble.
Texas generates tens of gigawatts of solar and wind power far from its cities, then has to send that electricity to consumers, which can cause congestion on transmission wires. Years before the Texas storage boom or the recent AI phenomenon, Eolian looked for areas where batteries could improve utilization of the transmission grid by arbitraging electricity between times of plenty and times of scarcity.
“Our primary strategy for developing battery storage sites in 2016 and 2017 was to start ringing every major city we could with queue positions in locations that were likely future transmission constraints or that were a bridge between load growth and far-flung generating resources,” Zubaty said.
CyrusOne also wanted to be near the population center. Some of its customers benefit from running their computation closer to users. And CyrusOne itself sees a major benefit in building near Fort Worth’s population of skilled technicians, both for construction and ongoing operations, Schwartz said. The city’s authorities have also been supportive of data center construction, as has Texas more broadly.
On top of that, CyrusOne was attracted to the same high-capacity power infrastructure that lured Eolian to that node on the grid years ago. Those heavy-duty wires, and what Zubaty called “an epic substation,” make this a good place to charge a battery or power a huge data center without having to do too much upgrading.
“Five to 10 years ago, we would’ve located the site based on other criteria … and worked with the utility to bring power to the site,” Schwartz said. “Now, we’re bringing data centers to the power rather than trying to bring the power to the data centers.”
Other early entrants into the ERCOT battery market face the same pressures that Eolian responded to, and if they decide to repower their batteries, more data center developers could pursue similar opportunities to come online faster. Admittedly, the geography and timing for such a solution have to line up just right, but these partnerships could prove a critical stepping stone in the headlong rush to build computing infrastructure.
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