Eos Energy Enterprises increased Q2 2026 revenue 351% year-over-year to $68.8 million and ended the quarter with a record $807 million backlog and $24.6 billion commercial opportunity pipeline, although gross margin remained deeply negative at 71% as the long-duration energy storage manufacturer continued scaling production.
Revenue growth was driven by a 207% increase in cube deliveries. Eos said revenue generated during the first half of 2026 exceeded its revenue for all of 2025, illustrating the rapid increase in commercial shipments as manufacturing capacity expands.
The higher volume has not yet produced positive gross profit. Eos recorded a gross loss of $48.8 million compared with $31 million a year earlier, resulting in a negative 71% gross margin. Still, gross margin improved by 132 percentage points year-over-year and seven percentage points sequentially.
Eos attributed that improvement to increased production volumes and lower conversion costs, partially offset by temporary manufacturing underutilization as it ramped operations across two facilities and by higher project costs associated with the growing installed base.
Adjusted EBITDA loss widened to $71.4 million from $51.6 million, although adjusted EBITDA margin improved by 235 percentage points year-over-year and 16 percentage points sequentially because of the much larger revenue base and operating efficiencies.
Net loss attributable to shareholders was $275.7 million, with Eos citing mark-to-market fair-value adjustments on certain liabilities tied to changes in its quarter-end stock price as the primary driver. The company held $364.1 million of total cash, including restricted cash, at June 30.
Commercial demand continued to build despite those losses. Backlog reached $807 million representing 3.4 GWh, increasing 25% sequentially and 20% year-over-year, with orders from four new customers and two repeat customers contributing to the expansion.
There is significant concentration inside that growth. Eos generated $55 million of Q2 revenue from a pre-existing project financed by an affiliate of Cerberus Capital Management, accounting for approximately 80% of total quarterly revenue. That project was subsequently contributed to Frontier Power USA, and the project together with FPUSA represented 49% of Eos’ backlog volume at June 30.
Frontier Power USA itself has raised approximately $263 million of gross proceeds from Eos, Cerberus and Hudson Bay Capital Management, exceeding its original $250 million equity target. Eos expects the platform to have access to more than $1 billion of deployable project capital and said FPUSA has established an approximately 16 GWh development pipeline.
Eos is also increasing manufacturing capacity. Commercial production began on Battery Line 2 at Thorn Hill in mid-June, with battery cycle times running approximately 10% faster and bipolar-line cycle times approximately 11% faster than Line 1. The company remains on track for full Line 2 production capacity during Q4.
After quarter-end, Eos received a $100 million purchase order from FPUSA for Phase I of the Blanquilla project and announced a strategic partnership with the Department of War involving a Golden Dome for America contract to deploy its zinc-based long-duration storage technology at a critical defense installation.
The company tightened 2026 revenue guidance to $300 million to $350 million from a previous $300 million to $400 million range as it evaluates the timing of consolidating production into Thorn Hill. Eos expects the manufacturing consolidation to increase efficiency, improve capacity utilization and support better margins over time.
The central execution challenge is therefore shifting from establishing demand to converting a growing backlog and commercial pipeline into profitable production. Eos’ record backlog and rapid revenue growth show increased market traction, while its negative gross margin underscores the manufacturing economics that still need to improve as volume scales.
KEY QUOTES:
“We delivered more revenue in the first half of 2026 than in all of 2025. The market wants a U.S. supplier of long-duration energy storage that can deliver at scale. Our focus now is converting that demand into profitable growth. The decisions we are making today, including the consolidation of manufacturing into Thorn Hill, are about building a lower-cost operation that can support that demand.”
Joe Mastrangelo, CEO of Eos Energy Enterprises
