GWHTOTCMiscellaneous Electrical Machinery, Equipment & SuppliesUS GAAP · USD

ESS Tech, Inc.

ESS Tech, Inc. designs and sells long-duration energy storage systems based on iron flow battery technology. Its products use earth-abundant materials and a proprietary Proton Pump architecture to serve utility-scale and commercial customers that need multi-hour storage, grid balancing, and resilience. The company also provides engineering, warranty, and maintenance services around its storage deployments.

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Revenue1.6m USD
−74.9 %y/y
Operating profit (EBIT)-57.4m USD
+36.1 %y/y
EBIT margin-3,626.5%
−2,200.0 ppy/y
Net income-63.4m USD
+26.4 %y/y
Free cash flow-53.7m USD
+32.5 %y/y

Fiscal year 2025 · change from previous year

Development 2020–2025

-125-100-75-50-25025m USD2020: 0.00 m USD2020: EBIT -17 m USD20202021: 0.00 m USD2021: EBIT -61 m USD20212022: 0.89 m USD2022: EBIT -105 m USD20222023: 7.5 m USD2023: EBIT -86 m USD20232024: 6.3 m USD2024: EBIT -90 m USD20242025: 1.6 m USD2025: EBIT -57 m USD20251.6-57
RevenueOperating profit (EBIT)
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Business

Share of revenue
Long-duration energy storage systems75 %

Utility-scale and commercial iron flow battery systems sold as Energy Warehouses, Energy Centers, and Energy Base.

Core technology components10 %

Proton Pump, power module, battery management system, and electrolyte components used in ESS systems.

Engineering and deployment services8 %

Design support and site deployment engineering tied to customer projects.

Extended warranty and maintenance7 %

Service contracts covering warranty support and ongoing maintenance for installed systems.

Products

Reported · share of revenue
65.1%28.0%FY2025100 %
  • Products65.1 %
  • Other Product or Service28.0 %
  • Services6.8 %

Source: 10-K FY2025, revenue the company reports per product line (SEC XBRL). Shares are of the lines shown and add up to 100 %.

Customers

ESS sells primarily to large enterprise customers in the power and energy ecosystem. Its core buyers are utilities, independent power producers, and commercial and industrial users that need grid-scale storage, renewable integration, or backup resilience. The company also targets behind-the-meter customers such as data centers, microgrids, and critical infrastructure operators.

Utilities

Buy front-of-the-meter storage to balance the grid and support renewable penetration.

Independent Power Producers (IPPs)

Buy storage to improve the economics and dispatchability of renewable projects.

Commercial and Industrial (C&I) customers

Buy behind-the-meter systems to reduce energy costs and improve resilience.

Data centers and microgrids

Buy storage for uptime, backup power, and sustainability goals.

Critical infrastructure operators

Buy long-duration storage for reliability and continuity of operations.

Strategy

ESS is focused on scaling its iron flow battery platform while reducing manufacturing cost and improving unit economics. Near-term revenue is expected from Energy Centers, second-generation Energy Warehouses, Energy Base, and core component productization, with cost reduction driven by design optimization, supply chain work, and automation. The company is also trying to preserve liquidity through cost controls while it seeks additional financing to support commercialization.

Lower manufacturing cost and improve gross marginShort term

Commercial viability depends on achieving attractive unit economics at scale.

Scale commercialization of Energy Centers and Energy BaseMedium term

These products are expected to drive near- and medium-term revenue growth.

Secure additional capital and preserve liquidityShort term

The company has negative operating cash flow and needs funding to continue operations.

Geography

ESS is a U.S.-based company with research and development activities in Oregon and a business model that can be deployed in multiple markets. The reports do not provide a country revenue split, but the company highlights U.S. operations, export financing support through EXIM, and the ability to sell into overseas markets. Geography matters because permitting, grid policy, and customer financing conditions can materially affect project timing and demand.

Risks

ESS remains an early-stage commercialization story with substantial execution risk around manufacturing scale, product reliability, and customer adoption. Its project-based revenue is lumpy and depends on large utility and C&I customers, while the company also faces intense competition from better-capitalized rivals and a going-concern financing risk. Policy, permitting, and technology preferences in the energy storage market can materially affect demand and timing.

Sorted by severity
LowMediumHighLowMediumHighImpact →Likelihood →Manufacturing scale-up and product commercialization risk1Liquidity and going-concern risk2Large-customer concentration and long sales cycles3Competitive pressure from alternative storage technologies4Cybersecurity and IT systems disruption5
Impact is the risk’s severity and likelihood how probable it is over the next few years, both assessed from the company’s reports. Numbers match the list.
  1. Manufacturing scale-up and product commercialization riskImpact: CriticalLikelihood: High

    The company is still early in commercialization and must prove it can produce at scale reliably and profitably.

    Exposure: Energy storage systems and core components

  2. Liquidity and going-concern riskImpact: CriticalLikelihood: High

    The company has negative operating cash flow and states that additional financing is needed to meet near-term requirements.

    Exposure: Corporate funding and ongoing operations

  3. Large-customer concentration and long sales cyclesImpact: HighLikelihood: High

    Utilities and C&I buyers are large enterprises with lengthy procurement and approval processes.

    Exposure: Utility and enterprise project pipeline

  4. Competitive pressure from alternative storage technologiesImpact: HighLikelihood: High

    Lithium-ion and newer technologies may be preferred for power density or cost, limiting adoption of iron flow batteries.

    Exposure: Market acceptance and pricing

  5. Cybersecurity and IT systems disruptionImpact: MediumLikelihood: Medium

    Products are remotely monitored and the business depends on internal and third-party systems.

    ExposureRemote monitoringCustomer dataOperations
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Accounting

Judgemental items
Revenue recognition for product and service contracts

Revenue depends on when performance obligations are satisfied, which can create timing volatility across quarters.

Impact: Affects reported revenue, deferred revenue, and contract assets

Warranty and maintenance accruals

Extended warranties and maintenance services require estimates of future service costs.

Impact: Affects cost of revenue and gross margin

Inventory valuation and obsolescence

The company has recognized write-offs and lower realizable value adjustments as product lines transition.

Impact: Affects cost of revenue and inventory carrying value

Purchase commitment and contract loss estimates

Non-cancellable purchase commitments and unfulfilled obligations can require charges or reserves.

Impact: Affects liabilities and operating results

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Last updated: 24/09/2026