Eos Energy Enterprises is to consolidate its Pittsburgh-area zinc battery manufacturing at its 4GWh Thorn Hill facility in Warrendale, Pennsylvania.
The US long-duration energy storage manufacturer began commercial production at the 432,000 square foot plant in June, less than six months after taking possession of the building. Its Line 1 equipment will now be transferred from Building 700 at the company’s original Turtle Creek site to join Line 2 at Thorn Hill.
Cube assembly, testing and shipping will remain at Building 200 in Turtle Creek. Both locations are in Allegheny County, in the wider Pittsburgh area.
Eos said bringing battery manufacturing together at one site would shorten material flows, improve the use of factory space and reduce manufacturing overheads. It expects the consolidation to cut conversion costs by approximately 10–15%, with the benefits beginning in 2027.
The transition and its associated costs were included in the company’s existing 2026 revenue guidance of $300–350 million. Eos said it did not expect the move to affect customer delivery commitments.
Around 250 employees will be affected, including approximately 205 represented by the United Steelworkers. Eos said each would be offered a position or assigned a workplace at Thorn Hill, Building 200 or its corporate offices, subject to collective bargaining requirements.
Chief executive officer Joe Mastrangelo said: “We built our manufacturing foundation in Turtle Creek, and we have outgrown the footprint we started with. Bringing battery manufacturing together at Thorn Hill gives us the space and capacity we need for the next phase of growth while keeping jobs, investment and opportunity right here in Allegheny County.”
The company’s Eos Z3 battery uses a non-flammable, zinc-based chemistry intended for storage durations ranging from four to more than 16 hours. Eos said the product had approximately 91% US domestic content and was supported by a predominantly US-based supply chain.
Photo: Pittsburgh skyline reflected in the Allegheny River by Lance Anderson on Unsplash
