Arsenal Data Site (Arconic Massena Operations)

Facility record

Lifecycle

ProposedSource-reported lifecycle

Location precision

approximate

Address as listed

45 County Route 42

Coordinates

44.9528, -74.883

Serving utility, source-reported

New York Power Authority (NYPA) / National Grid

Operational capacity, source-reported

Not published

Planned capacity, source-reported

933 MW

Source record updated

2026-10-09

Source-reported capacity; not metered consumption. Review underlying documents and notes. Planned capacity may include future phases and is not added to operational capacity here. The source may use facility, grid-feed or IT capacity definitions; consult the linked documents.

Coordinate precision is a source label, not an independent parcel survey. A marker does not confirm utility territory or establish an effect on residential bills.

Reported lifecycle history

1. 2025-03-07Proposed

   Arconic Corporation filed three NYISO large-load interconnection requests (#1728 'Arsenal Data Site 250', #1729 'Arsenal Data Site 500', #1730 'Arsenal Data Site 1000'; 250/500/1,000 MW), POI Denniston Substation (NYPA), proposed in-service 03-2027

   Underlying source

Source notes

Lead only: known from three NYISO large-load queue positions filed by Arconic Corporation in March 2025, all at the Denniston/Dennison substation. The queue excerpt in a 2025 St. Lawrence County planning presentation (rows last updated May 31, 2025) lists the three positions at 250, 500 and 1,000 MW. As of October 2026, the NYISO queue lists their peak loads as 233, 233 and 467 MW; the 933 MW recorded as planned capacity is the total of those three figures. As of September 2026, no site plan, permit application or public announcement had been found, and a local report (nny360) that Arconic wants to use excess plant space for a ~933 MW data center could not be retrieved. Apollo Global Management owns both Arconic and Stream Data Centers. Coordinates are the OSM landuse centroid for Arconic Massena Operations, not a data-center parcel.

NYISO queue lists NYPA as interconnecting utility and National Grid as affected transmission owner, POI Denniston Substation.

Sources and provenance

• St. Lawrence County Planning — LGC 2025 Planning & Zoning presentation: NYISO queue excerpt listing Arconic Corporation 'Arsenal Data Site 250/500/1000' (queue #1728–1730, IR 3/7/2025) · source retrieved 2026-09-21
• Data Centers in New York — 'Arsenal Data Site', Arconic Corporation, St. Lawrence, 933 MW planned · source retrieved 2026-10-09
• EPA RCRA profile — ARCONIC MASSENA OPERATIONS, 45 County Route 42, Massena NY 13662 (~2,700 acres) · source retrieved 2026-09-21
• NYISO Interconnection Queue, Load Projects: #1728/#1729/#1730 'Arsenal Data Site 250/500/1000', Arconic Corporation, peak MW 233 / 233 / 467 (DAT-AI), status 5 · source retrieved 2026-10-09

Power Wars capture: 2026-11-02. Compute Atlas, CC BY 4.0. Entries are not independently verified by Power Wars unless stated.