ESS Tech Inc Completes Acquisition of VoltStorage GmbH

Why It Matters

The cost cuts and high‑profile collaborations signal ESS’s attempt to transition from cash‑burn to a scalable, revenue‑generating model in the fast‑growing long‑duration storage market.

Key Takeaways

• FY2025 net loss narrowed to $63.4M
• Revenue fell 75% to $1.6M
• Operating expenses cut 33% to $29.7M
• Google partnership drives Project New Horizon
• VoltStorage acquisition adds German IP portfolio

Pulse Analysis

The long‑duration energy storage (LDES) sector is entering a critical phase as utilities and data‑center operators seek multi‑hour solutions to balance renewable intermittency. ESS Tech Inc., one of the few publicly traded flow‑battery firms, has struggled with high cash burn, reflected in a $63.4 million loss for FY 2025. By slashing operating expenses by a third and improving gross profit, the company demonstrates disciplined cost management, yet revenue contraction underscores the challenge of converting pilot projects into commercial sales.

A decisive catalyst for ESS is its partnership with Google and Arizona’s Salt River Project on the 5 MW/50 MWh Project New Horizon. The collaboration validates the Energy Base platform’s suitability for data‑center and utility workloads, while Google’s involvement brings credibility and potential access to its vast renewable‑energy portfolio. The project, slated for delivery in late 2027, could serve as a reference deployment, accelerating market acceptance and opening doors to additional utility contracts.

The recent acquisition of VoltStorage GmbH’s intellectual property and engineering team bolsters ESS’s technology stack with European patents and deep electro‑chemical expertise. Integrating these assets may shorten development cycles for the Energy Base system and improve performance metrics that have historically hampered flow‑battery adoption. Combined with the leadership change to CEO Drew Buckley, ESS appears poised to shift from a loss‑making startup toward a niche player capable of capturing a share of the $10 billion LDES market projected for the next decade. Success will hinge on scaling production, securing repeatable revenue streams, and maintaining the cost trajectory needed for profitability.

Deal Summary

Oregon‑based flow‑battery startup ESS Tech Inc announced it has completed the acquisition of the intellectual property and assets of German battery developer VoltStorage GmbH. The deal, disclosed on March 13, 2026, expands ESS’s patent portfolio and technical resources for its iron‑flow Energy Base product line.