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SpaceX linked to a 6 GW data-center proposal in Arizona

Credited to Rackline · Priya Nair · cochise.az.gov

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A developer seeking county approval for a 6-gigawatt AI data-center campus in Cochise County, Arizona, said in a Nov. 4 statement that SpaceX would host the project's community town hall. It is the only mention of SpaceX in the county's case file.

Tombstone Resources L.L.C., which lists an Atlanta address, has applied to the county for a special use permit in case SU26-22. It wants to build up to nine computing buildings on about 747 acres along U.S. Highway 191 near Cochise, next to the Apache Generating Station run by Arizona Electric Power Cooperative, or AEPCO.

The statement, on Tombstone Resources letterhead and posted by the county, set the town hall for that evening at Cochise Elementary School. The 54-page application does not name SpaceX. It says the campus would train and run AI models mainly for the applicant and its affiliates. SpaceX has made no SEC filing that mentions the site, Cochise County or Tombstone Resources.

The application describes four phases reaching about 6,000 megawatts at full build-out, starting with a first phase of about 1,500 MW. Each building would cover about 493,000 square feet. The plan includes 24 gigawatt-hours of battery storage and dry cooling with no cooling towers.

Power would come from the grid. Sulphur Springs Valley Electric Cooperative, or SSVEC, the local distribution co-op, would provide retail service, and AEPCO would supply wholesale power and transmission. There is no on-site power plant, only the batteries and natural-gas standby generators for critical loads.

The applicant says it would pay for about $3.6 billion of transmission and substation work in the county across the four phases, with about $0.5 billion in the first phase. The money would flow through a three-party electric service agreement with the two cooperatives, which would build and own the equipment.

Cochise County campus: first phase and full build-out

Figures from Tombstone Resources' Oct. 30 application in Cochise County case SU26-22.

Table showing the first phase at about 1,500 MW with about $0.5 billion of grid work, growing to about 6,000 MW and $3.6 billion at full build-out.
StageElectric demandApplicant-funded grid work ($bn)Operations staffTiming in application
Phase 11,500 MW1250Construction power targeted March 2027
Full build-out (4 phases, 9 buildings)6,000 MW41,000Not stated
Source: Tombstone Resources L.L.C. Special Use Authorization application, Cochise County SU26-22 (Oct. 30, 2026)All figures approximate as stated by the applicant. SSVEC's Oct. 28 letter gives the applicant's initial-service target as April 2027. Grid figures depend on an agreement not yet filed with the Arizona Corporation Commission.

That agreement still needs the Arizona Corporation Commission. Both co-ops say it will be submitted under a streamlined large-load process the commission approved on Aug. 27 in docket E-01773A-26-0123. Under that process, commission staff aim to issue a recommendation within 90 days, testing whether the deal serves the public interest, whether its rates are reasonable and whether other customers would subsidize the data center. No Tombstone agreement had been filed in the docket as of Nov. 7.

SSVEC's project website says no agreement has been finalized and that all of its figures are estimates. It says the developer would pay for every upgrade needed to serve the campus. The applicant says the deal would cut SSVEC bills by 10% to 40% and send $13 million to $53 million a year to the SSVEC Foundation, figures it ties to commission approval.

AEPCO's Oct. 29 letter says preliminary studies show the first phase can be served with identified network upgrades. Later phases are expected to need more generation and transmission.

The application targets electric service for construction in March 2027, with first-phase computing load following as transmission is finished. SSVEC's Oct. 28 letter gives the applicant's target for initial service as April 2027.

Water use at full build-out would be about 7 to 10 acre-feet a year, mostly for staff, with no new well, according to the application.

The county Planning and Zoning Commission will hear the case on Dec. 9. The county moved the start to 2 p.m. from 4 p.m. because of public interest, and written comments for the meeting packet are due Nov. 27 at noon. The commission's decision is final unless appealed to the Board of Supervisors.

Source · cochise.az.gov

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