Beyond Lithium, Part 2: ESS Tech’s Iron Flow Battery

Beyond Lithium, Part 2: ESS Tech’s Iron Flow Battery

by Clean Energy Group / Clean Energy States Alliance

Applied Sciences & Engineering Energy THYEnergy, power generation, distribution and storageTHYBBattery technology
🎙 Clean Energy Group / Clean Energy States Alliance 👥 2K 📅 June 3, 2026 ⏱ 62 min 👁 341 📄 expert opinion 🧭 2026-08-16
Available in: English (current) Français

Keywords

iron flow batterylong-duration storageESS Techgrid resiliencerenewable integration

Summary

This webinar, part of Clean Energy Group’s ‘Beyond Lithium’ series, features Drew Buckley, CEO of ESS Tech, discussing their iron flow battery technology for long-duration energy storage. Buckley begins by outlining the company’s background, including its IPO in 2021 and strategic reset in 2025, which led to the development of their current product, the Energy Base. He explains the market drivers for long-duration storage, highlighting the rise in electricity demand from AI data centers and the increasing penetration of intermittent renewables, which create a need for storage that can discharge for 10-20+ hours. The technology uses iron, salt, and water, offering advantages in safety, supply chain, and cost scaling with duration, as opposed to lithium-ion which requires stacking more batteries. Buckley presents real-world deployments, including a 21-month demonstration with APA and Burbank Water and Power, and a solar-over-canal project with Turlock Irrigation District. He also mentions significant contracts with Salt River Project, Google, and the US Air Force. The presentation concludes with a Q&A session where Buckley addresses questions about cost, safety, and market positioning.

175 words

Critical Evaluation

Value of the Information & Strength of the Argument

The webinar provides valuable insights into the long-duration energy storage market and ESS Tech’s specific technology. The argumentation is coherent, emphasizing the market gap for storage beyond 10 hours and the unique advantages of iron flow chemistry, such as abundant materials and decoupling of energy and power. Buckley effectively argues that while lithium-ion is suitable for shorter durations, iron flow offers a cost-effective and safe alternative for longer durations, supported by real-world deployments and contracts. However, the presentation is from a company perspective, so it may overstate the technology’s readiness and market potential, lacking independent validation.

Scientific Rigor, Source Quality, Title Accuracy

The webinar maintains a professional tone and references specific projects and reports, such as the APA demonstration and the Turlock project, which add credibility. However, the sources are primarily company-driven, and the presentation does not provide detailed technical specifications or independent verification. The title accurately reflects the content, focusing on ESS Tech’s iron flow battery. The webinar is part of a series that aims to highlight non-lithium technologies, and it fulfills that objective by presenting a compelling case for iron flow storage.

193 words

Title / Content Match

The title accurately reflects the content, which focuses on ESS Tech's iron flow battery as part of the Beyond Lithium series.

Quality & Reliability

7/10

The webinar presents a company's perspective on its technology and market, with claims supported by references to real deployments and contracts, but lacks independent verification and detailed technical data.

Key Moments

Markers derived by PSI from the transcript: the creator did not define chapters.

Cited Sources

  • Webinar Slides — Slides presented during the webinar, containing detailed information on ESS Tech's technology and market analysis.

Concurring Sources

  • APA and Burbank Water and Power Demonstration Report — Referenced in the webinar as a third-party validated 21-month demonstration of iron flow technology.

Contribution & Novelties

The webinar offers an insider perspective on the strategic pivot of ESS Tech from a containerized design to an open architecture, highlighting the importance of aligning product design with market needs. It provides a clear explanation of how iron flow batteries decouple energy and power, enabling cost-effective scaling for longer durations. The presentation also underscores the growing demand for long-duration storage driven by AI data centers and renewable integration.

Pour aller plus loin :

  • Long-duration energy storage — Overview of energy storage technologies and their applications.
  • Iron–air battery — Related technology using iron and air, relevant to the discussion on non-lithium storage.
  • Flow battery — General concept of flow batteries, including iron-based systems.
  • Salt River Project — Utility company mentioned as a customer, providing context on their role in Arizona’s energy grid.

132 words

Radar Profile

The radar profile shows a balanced performance with moderate scores across all dimensions, indicating a solid but not exceptional presentation. The highest score is in information quantity, reflecting the comprehensive coverage of market and technology aspects, while technical depth and reliability are slightly lower, suggesting a need for more detailed data and independent validation.

Reliability 6/10

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