• Residents filed an appeal of the conditional use permit granted earlier this month
• Project plans to use 90 engines from Wärtsilä in BTM arrangement

Project Antelope has stalled in Iron County, Utah, after residents that live west of the planned 1.5 GW project site filed an appeal of the conditional use permit, which was granted by the county’s planning commission earlier this month.

The appeal will be sent to a hearing officer, who will set the schedule to hear the appeal, Uinta County Planner Brett Hamilton said via email.

The June 4 approval cleared the way for Pronghorn Development LLC to pursue the 640-acre, 1.5 GW campus utilizing Wartsila 18V50SF gas engines. The project is a five-building, master-planned AI and hyperscale campus totaling up to 6.75 million square feet of data hall space, to be built in phases over roughly eight-to-ten years.

At the meeting, Hamilton said each phase would include one data center building and a corresponding power block of about 300 MW. He added that each power building would use 18 generators, implying 90 engines across the full campus.

Representatives of Pronghorn Development did not respond to a request for an interview.

Hamilton also stressed during the meeting that the county’s conditions of approval were written so the project is “not allowed to receive power from the grid” and must remain behind the meter, even if some utility interconnection steps are required as part of the process.

Under county code, the facility cannot exceed 65 decibels at the project boundary. Hamilton told commissioners that without mitigation the project would not comply, but with silencers on the generators, sound walls and other controls, it could meet the standard.

The staff recommendation also included conditions covering water rights, road paving, pronghorn habitat mitigation, dark-sky lighting and a Utah Division of Air Quality approval order.

Meanwhile, Iron County is attempting to tighten its oversight of large-load projects. The county commission in May adopted a 180-day moratorium on new or incomplete applications for data centers, data center power plants and utility-scale solar projects.

That pause does not apply to Project Antelope because its application had already been deemed complete. It does, however, apply to the separate Red Butte data center and natural gas plant proposed by Tetra Tech and BrightNight, which county officials said remained incomplete and would be put on hold.