Eos Energy Launches Commercial Production at Second U.S. Battery Manufacturing Facility

Eos Energy Enterprises has started commercial production at its second U.S. manufacturing facility, marking a significant step in the Pittsburgh-based company's push to scale domestic zinc-based battery production.

The new Battery Line 2, located at Eos' Thorn Hill facility in Marshall Township, Pennsylvania, completed Site Acceptance Testing (SAT) and has begun producing commercial batteries. The line will ramp throughout the year, with subassemblies coming online in early Q3 and full production targeted for Q4 2026.

What's New at Thorn Hill

Battery Line 2 was designed using operational lessons from the company's first production line. The facility incorporates single-piece flow architecture, enhanced process redundancy, and advanced pick-and-place gantry systems to improve throughput. Compared to Line 1, the new layout reduces raw material travel by 86% and shortens overall production line length by 40%.

"Battery Line 2 demonstrates our ability to continuously improve as we scale," said John Mahaz, Chief Operating Officer of Eos. "We took the lessons learned from commissioning and operating Line 1 and incorporated them directly into the design of this facility and production line. The result is a more efficient manufacturing environment with better flow and a stronger foundation for future expansion. Most importantly, it validates that our manufacturing system can be replicated and scaled with discipline."

Why It's Happening Now

Eos is working to meet a growing contracted backlog. Line 1, at its original facility, surpassed its full-year 2025 production output in just the first 164 days of 2026—a pace that underscored the need for additional capacity. Together, the two lines are intended to move Eos toward its goal of 4 GWh of annualized manufacturing capacity by end of 2026.

Demand is being driven in part by a 2 GWh capacity reservation agreement with Frontier Power USA (FPUSA). In May 2026, FPUSA acquired a 480 MWh battery project portfolio in Texas and signed a strategic framework agreement with Stella Energy Solutions to advance a 2 GWh pipeline built around Eos technology. In the U.K., Frontier Power Energy Holding Ltd. acquired rights to two projects in Scotland expected to utilize approximately 2.8 GWh of Eos Z3 Indensity systems.

What It Means for the Industry

For plant operators and energy managers evaluating long-duration energy storage, Eos' expansion signals growing domestic supply of zinc-based battery systems—an alternative to lithium-ion that the company positions as non-flammable and stable, suited for 4 to 16-hour storage applications at utility, microgrid, commercial, and industrial scales. The ability to replicate and scale a second production line also reduces the execution risk that has historically slowed battery manufacturers trying to move from pilot to full production.