ESS

What ESS does

ESS Tech, Inc. (NYSE: GWH) is a Wilsonville, Oregon-based energy storage company that designs, manufactures, and sells iron flow battery systems for commercial, industrial, utility, and government customers. Founded in 2011 and taken public in October 2021 through a SPAC merger with ACON S2 Acquisition Corp (implied valuation ~$1.07 billion), the company's core technology uses circulating liquid electrolytes of iron, salt, and water to store and discharge electricity, enabling 8–22 hour long-duration storage with no thermal runaway risk, unlimited cycling, and a 25-year design life. The product portfolio comprises three iron flow platforms — Energy Warehouse® (5+ hours, C&I scale), Energy Center™ (8 hours, utility-scale containerized), and Energy Base™ (8–22 hours, gigawatt-scale modular, launched 2025) — plus a planned sodium-ion BESS line added in 2026 through an 8.5 GWh letter of intent with Alsym Energy, positioning the company across the full non-lithium duration curve from a single manufacturer.

Revenue is generated primarily from hardware sales of complete storage systems configured to customer power and duration requirements, supplemented by project engineering, integration, and installation oversight services, with a potential future licensing stream from the VoltStorage IP acquired in February 2026. The go-to-market is enterprise field sales to utilities, independent power producers, AI data centers, and C&I customers (notably Salt River Project, Google, U.S. Air Force, Burbank Water and Power, Turlock Irrigation District, Stanwell, Energy Queensland, Schiphol Airport, and Sycamore International), combined with channel partnerships (ESI Asia-Pacific for Australia) and event-driven demand generation. Pricing is not publicly disclosed and requires NDA execution; contracts are multi-year and project-based.

Operationally, the company is in a transition year: FY2025 revenue was $1.6M (down from $6.3M) as legacy business activities wind down ahead of the Energy Base platform and sodium-ion launches, while the net loss improved 26% to $63.4M and adjusted EBITDA improved 38% year-over-year to negative $44.3M. Management is guiding to substantial revenue beginning 2027 from existing tier-one contracts, supported by a tripling of Wilsonville manufacturing capacity funded by a $50M EXIM Bank loan, $63M+ in recent financings (Yorkville Advisors and a January 2026 registered direct offering), 103 patents awarded across the U.S., Australia, China, Germany, India, and Japan, and a refreshed executive team led by CEO Drew Buckley (effective January 2026).

Name

ESS

Legal name

ESS Tech, Inc.

Website

https://essinc.com

Company type

Public

Founded year

2011

Operating status

Operating

Headcount range

251–500 employees

Short description

ESS Tech, Inc. designs and produces iron flow battery energy storage systems (Energy Base, Energy Center, Energy Warehouse) for utilities, AI data centers, commercial/industrial customers, and government/military applications, using non-flammable iron, salt, and water chemistry for 5–22 hour long-duration storage.

Ownership category

akta.pro rank

Product category

Long-Duration Energy Storage (Iron Flow Battery Systems)

NAICS

Battery Manufacturing (33591), Electric Power Generation (22111)

SIC

Motors & Generators (3621)

akta.pro primary industry

Electrochemical LDES (Flow Batteries & Other Long-Duration Batteries) (EUAFADAA)

akta.pro secondary industries

Energy Storage Systems (BESS, Flywheels, Batteries) (HDABAKAC), Energy Storage Asset Management (BESS/PCS/EMS) (EUAEAMAE)

Keywords

• Iron flow batteries
• Long-duration energy storage
• Grid-scale battery systems
• Non-flammable battery technology
• Commercial and industrial storage

Headquarters

HQ city

Wilsonville

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Technology or R&D, Supply Chain, Operations, Infrastructure, Marketing or Sales

Revenue model

1. Energy Storage System Sales: ESS generates revenue primarily from selling complete iron flow battery energy storage systems (Energy Base, Energy Center, Energy Warehouse) to utilities, IPPs, data centers, and C&I customers. Systems are custom-configured based on customer power capacity and duration requirements.
2. Project Engineering & Integration Services: Revenue includes engineering services for custom system design, installation oversight, and integration with customer infrastructure. Professional services for deployment and commissioning.
3. Technology Licensing: Following VoltStorage acquisition, ESS may generate revenue from licensing iron-salt battery technology and intellectual property to partners.

Pricing tiers

Go-to-market motion3 records

Distribution channels2 records

Marketing channels8 records

Core offering

ESS designs, manufactures, and sells iron flow battery energy storage systems for long-duration, utility-scale, commercial, industrial, and data center applications. Its portfolio comprises Energy Base™ (8-22 hours, gigawatt-scale modular LDES), Energy Center™ (8-hour utility-scale turnkey containerized system), and Energy Warehouse® (5+ hour commercial/industrial turnkey system), all built on a non-flammable iron-salt-water electrolyte chemistry with a 25-year design life and zero capacity degradation. Revenue is generated primarily through direct hardware sales of these configured systems, supplemented by project engineering and integration services.

Product overview

ESS Tech, Inc. offers a comprehensive portfolio of long-duration iron flow battery energy storage solutions using non-flammable, sustainable iron, salt, and water chemistry. The product portfolio includes three iron flow battery systems: (1) Energy Base™ – next-generation modular LDES platform offering 8-22 hours of storage with decoupled power/energy architecture for gigawatt-scale applications; (2) Energy Center™ – utility-scale turnkey containerized solution providing 8 hours of storage for grid applications; and (3) Energy Warehouse® – commercial/industrial turnkey system delivering 5+ hours of storage. ESS is expanding into short- and medium-duration storage through a partnership with Alsym Energy for sodium-ion batteries (8.5 GWh LOI), positioning itself as a full-spectrum non-lithium energy storage provider across the entire duration curve from a single manufacturer.

Differentiator

Problem solved

Functional benefit

Brands

• Energy Base™: Gigawatt-scale, long-duration energy storage solution offering 8-22 hours of energy storage with modular architecture.
• Energy Center™
• Energy Warehouse®

Products and services

• Energy Base™ Next-generation long-duration energy storage solution offering 8-22 hours of energy storage using iron flow chemistry. The modular platform decouples power and energy capacity so customers can scale each independently, and is designed for gigawatt-hour scale applications serving AI data centers and utility-scale storage projects.
• Energy Center™ Utility-scale iron flow battery solution delivering 8 hours of continuous discharge at rated power. Turnkey, containerized design built on 125 kW DC, 8-hour building blocks with flexibility to extend energy durations, and is designed for rapid deployment at grid-scale applications requiring long-duration storage.
• Energy Warehouse®
• Sodium-Ion Battery Energy Storage System U.S.-made sodium-ion battery BESS targeting short- and medium-duration applications, built on non-flammable technology from Alsym Energy that eliminates thermal runaway risk without complex HVAC systems. Uses domestically sourced materials free from Foreign Entity of Concern (FEOC) concerns, with 135 Wh/kg energy density, over 10,000 cycles, and above 95% round-trip efficiency.

Quantifiable outcome

• Unlimited cycling with no capacity degradation over 25-year design life
• +6 more outcomes

Named customers9 records

Segments5 records

Ideal customer profiles5 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature6 records

Partnerships

Nine partnerships are on record, tiered minor, core, validation and major.

• American Battery Leadership Coalition (ABLC)minorOthers · 18 June 2026ESS is a founding member of the coalition alongside Alsym Energy, Peak Energy, Batri, Ingevity, Mana, Microporous, NAION, and Re:Build Manufacturing. Coalition advocates for federal policies supporting sodium-ion commercialization and domestic supply chain development.
• Juniper EnergyminorStrategic or Co-development Partner · 6 May 2026500 MWh strategic partnership for sodium-ion battery energy storage deployment across California, with focus on high-temperature Mojave Desert sites. Alsym Energy is the technology provider while Juniper develops the projects.
• Alsym EnergycoreStrategic or Co-development Partner · 30 April 2026Strategic partnership through letter of intent to add 8.5 GWh of sodium-ion cells and modules to ESS portfolio. Alsym's Na-Series batteries are non-flammable with 135 Wh/kg energy density, over 10,000 cycles, and above 95% round-trip efficiency. The partnership enables ESS to offer a unified, non-lithium platform spanning short-, medium-, and long-duration storage from a single provider.
• Burbank Water and PowervalidationStrategic or Co-development Partner · 6 April 2026Third-party validation project under American Public Power Association's Demonstration of Energy & Efficiency Developments program. 21-month operation of ESS Energy Warehouse documented successful performance, with BWP concluding iron flow technology works and has a place in utility storage strategy.
• Salt River Project (SRP)coreStrategic or Co-development Partner · 3 March 2026Project New Horizon collaboration for 5MW/50MWh iron flow Energy Base technology deployment at Copper Crossing Energy and Research Center in Florence, Arizona. SRP awarded the project through competitive LDES solicitation. EPRI providing independent oversight of operational testing. Delivery targeted for December 2027.
• GooglemajorStrategic or Co-development Partner · 3 March 2026Cost-sharing participant in Project New Horizon with SRP. Google is funding a portion of project payments to evaluate real-world operational performance of non-lithium LDES. Collaboration aimed at grid reliability, renewable integration, and broader LDES deployment pathways.
• VoltStorage GmbHcoreTechnology or Integration · 18 February 2026Acquisition of intellectual property and assets including iron-salt battery patents, technical development work, and key executive and engineering personnel. The acquisition combines two complementary iron-based battery technologies to create more flexible, cost-effective LDES solutions.
• Concurrent Technologies Corporation / U.S. Air Force Research LaboratorymajorImplementation/ SI/ Consulting Partner · 29 January 2026$9.9 million contract for deployment of up to 27 MWh iron flow battery systems at U.S. Clear Space Force Station in Alaska. Part of AFRL initiative to demonstrate advanced energy storage for harsh environments including temperatures below -40°C. CTC serving as prime contractor.
• Energy Storage Industries – Asia PacificcoreChannel Partner/ Reseller/ Distributor · 1 January 2023Strategic partnership for deployment of LDES in Australia. ESI handling local assembly of Energy Warehouse systems in Australia while ESS continues supplying core technology from US. Initial projects include Stanwell Clean Energy Hub and Energy Queensland network battery project.

Scale indicators8 records

Recent moves7 records

Expansion highlights6 records

Direct peers

• Energy Vault: Energy Vault develops long-duration energy storage systems (gravity, kinetic, and hybrid) for utility-scale applications. It is a direct peer to ESS in the non-lithium LDES category, competing for the same utility and data center customers seeking 8+ hour duration storage.
• Form Energy: Form Energy is developing iron-air batteries for multi-day (100+ hour) grid storage, directly competing with ESS in iron-based long-duration chemistry. It targets the same utility and IPP customer base for low-cost, long-duration storage.
• Invinity Energy Systems: Invinity manufactures vanadium flow batteries for utility-scale and commercial LDES applications. It is a direct flow battery peer to ESS, selling containerized long-duration storage to utilities, microgrids, and C&I customers globally.

Broad incumbents

• Sumitomo Electric Industries: Sumitomo Electric is a major industrial conglomerate that has deployed vanadium redox flow battery systems at utility scale globally. It competes with ESS in the same long-duration flow battery category but as part of a much larger diversified industrial portfolio.
• Fluence Energy: Fluence is a leading global energy storage system integrator (backed by Siemens and AES) offering lithium-ion-based grid-scale solutions. It competes with ESS primarily in the 2-4 hour utility storage segment but overlaps in long-duration procurement.
• Tesla (Energy / Megapack): Tesla's Energy business offers Megapack, Powerpack, and Autobidder software for utility and commercial storage. While focused on lithium-ion, Tesla is the dominant incumbent in the broader stationary storage market that ESS targets.
• Wärtsilä Energy Storage: Wärtsilä provides grid-scale energy storage and optimization solutions primarily based on lithium-ion batteries. It competes with ESS in utility and IPP procurement for grid services and is part of a much larger marine and energy technology business.
• Saft (TotalEnergies): Saft, a TotalEnergies subsidiary, manufactures industrial batteries including lithium-ion and nickel-based solutions for grid, microgrid, and mission-critical applications. It overlaps with ESS in utility-scale and military microgrid storage deployments.

Emerging players

• Lockheed Martin (GridStar Flow): Lockheed Martin developed and has been piloting its GridStar Flow redox flow battery for DoD and grid applications. It competes in the same long-duration flow battery niche as ESS, particularly for military microgrid deployments.
• Alsym Energy: Alsym Energy develops non-flammable, low-cost sodium-ion batteries for stationary storage and has entered a strategic partnership with ESS to add 8.5 GWh of cells to ESS's portfolio. It is a complementary technology partner and emerging competitor in non-lithium storage.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks5 records

Key highlights7 records

Customer concentration

• Xx.com/ESS_info
• YouTubeyoutube.com/channel/UC3vNQ7v-VdTQFQ48kP6jUwQ/featured
• Facebookfacebook.com/energystoragesystemsinc
• LinkedInlinkedin.com/company/energy-storage-systems?

Compliance6 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles10 records

Funding overview

Funding rounds17 records

Investors22 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A2 records

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about ESS