GWHWW

These forward-looking statements are made as of the date - 2 - of this Annual Report on Form 10-K and involve a number of risks, uncertainties (some of which are beyond our control) and other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements.
Should one or more of these risks or uncertainties materialize, or should any of our assumptions prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements.
On March 31, 2024, Legacy ESS merged with ESS Tech, Inc. leaving ESS Tech, Inc. as the successor legal entity.
We design and produce long-duration batteries predominantly using earth-abundant materials that we believe can be cycled over 20,000 times without capacity fade based on lab-scale results.
Because our batteries are designed to operate using an electrolyte of primarily salt, iron and water, our products are environmentally sustainable and substantially recyclable or reusable.
We design and build this core technology, including battery stacks, electrolyte and electrolyte health management solutions into a core power train that is then sold in our current product focus: the gigawatt-hour scale, fully configurable Energy Base and core power trains that can be assembled at the customer site into complete storage solutions.
Our original product offering included the Energy Warehouse and Energy Center, which we are not currently offering for sale.
Examples of use cases range from localized energy storage at commercial and industrial sites to grid-scale use cases, such as peaker plant replacement and grid stabilization.
Our proprietary solution to eliminate the - 4 - hydroxide formation is known as the Proton Pump, which works by utilizing hydrogen generated by side reactions on the negative electrode.
This process eliminates the hydroxide and stabilizes the electrolytes’ pH level.
Using our iron flow battery technology, we have developed products to provide reliable, safe, long-duration energy storage solutions.
Our third and current offering, the gigawatt-hour Energy Base storage product, is designed with a fully configurable layout that integrates with any site location and that allows the power (the rate of electricity flow) to be decoupled from the capacity (the total amount of energy held).
This, combined with an expectation of 20,000 cycles and rapid response time, means that the performance of each Energy Base can be tailored to meet individual customer needs.
We continue to perform warranty and maintenance activities for our first and second product generations, the Energy Warehouse and Energy Center, that remain under contract in the field.
ESS has developed and will continue to expand its documentation, reference design and recommendations to allow customers and partners to build and operate integrated storage solutions based on our core technology.
For all of our energy storage products, the intellectual property and points of differentiation are contained within the core technology components, the Proton Pump, power module, Battery Management System and electrolyte.
Customers Our current and potential customers include utilities, Independent Power Providers (“IPPs”) and Commercial and Industrial (“C&I”) end users.
Behind-the-meter customers may include data centers, microgrids, critical infrastructure assets and commercial and industrial customers.
These customers use our energy storage products to store energy on a utility scale that they can then utilize or sell to their customers when needed and ensure overall grid reliability at a time of increasing demand for - 5 - energy and grid reliability.
Partnerships We have various partnerships, including: • OneBeacon Insurance : Through OneBeacon, we offer project surety capacity and corporate bonding options to our customers. • Export-Import Bank of the United States : The Export-Import Bank of the United States (“EXIM”) is the official export credit agency of the United States.
Research & Development Since January 1, 2019, we have invested approximately $184.7 million in improving our technology and bringing our energy storage products to market.
Our research and development efforts are conducted in Oregon and supported by our approximately 21 research and development employees.
We have over 315 patents that are granted, applied for or in the pipeline for application, and an undisclosed number of trade secrets.
Without taking into account any possible patent term adjustments or extensions, the earliest our current, issued patents will begin to expire in 2028.
The proliferation of intermittent generating resources has created new challenges to electric grid stability, and thus an opportunity for an - 6 - increased role for long-duration energy storage solutions.
Our key competitors include different energy storage technologies such as lithium-ion batteries, lithium metal batteries, lithium iron phosphate batteries, sodium-ion batteries including those developed by Contemporary Amperex Technology Co., Limited, vanadium or zinc bromine batteries, sodium sulfur batteries, compressed air, hydrogen, fuel cell and pumped-storage hydropower.
Key competitors in the non-lithium-ion space include EnerVenue, Inc., Invinity Energy Systems, CellCube, CMBlu Energy AG, Energy Dome, Energy Vault, Enerox GmbH, Eos Energy Enterprises, Inc., Form Energy, Highview Power PTY Ltd., Hydrostor, Lockheed Martin (GridStar Flow), and Malta Inc.
Although we may be small compared to some of our competitors, we believe we are well-positioned to compete with them in the market supported by our innovative iron flow battery technology, strategic partnerships and premier leadership team with a proven track record of success.
New technologies may enter the market that may have additional or superior advantages to our offerings.
We believe there remains significant government support available for energy storage technologies, and a variety of newer and emerging companies have announced plans to develop energy storage products using a variety of technologies, including compressed air, thermal energy, and solid-state batteries among others.
Our operations are subject to a variety of federal, state and local regulations governing manufacturing, project development, transportation, environmental, grid interconnection, and market participation matters.
As a participant in the renewable energy sector specifically, there are federal and state regulations, tax incentives and support mechanisms that impact our business.
In addition, renewable energy and energy storage is a priority for many national, state and local governments.
On the U.S. federal level, tax credits remain in place that incentivize both the manufacturing and deployment of renewable energy and battery storage.
The Inflation Reduction Act of 2022 established advanced manufacturing production credits and investment tax credits for energy storage.
The One Big Beautiful Bill Act (H.R. 1) (the “OBBB”), enacted in July 2025, preserved these tax credits but introduced complexity by requiring compliance with certain “foreign entity of concern” (FEOC) rules.
Beginning in 2026, energy storage technology will need to comply with these rules, which generally restrict entities linked to adversarial nations, particularly China, from accessing the benefits of U.S. tax credits including by placing limitations on the eligibility of equipment procured from such entities for such credits.
As a manufacturer of energy storage systems, we may be eligible for advanced manufacturing production credits to produce eligible battery components.
For project deployments, battery energy storage systems are eligible for investment tax credits.
These credits are available for standalone storage systems regardless of whether they are charged by renewable energy sources, allowing project developers to monetize and sell the tax credits they receive from the creation of their projects.

and 253 more.

Gone since FY2024

These forward-looking statements are made as of the date of this Annual Report on Form 10-K and involve a number of risks, uncertainties (some of which are beyond our control) and other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements.
Should one or more of these risks or uncertainties materialize, or should any of our assumptions prove incorrect, actual results may vary in - 2 - material respects from those projected in these forward-looking statements.
On March 31, 2024, Legacy ESS merged with ESS Tech, Inc. leaving ESS Tech, Inc. as the sole remaining legal entity.
As of April 1, 2024, the Company does not have any subsidiaries.
We design and produce long-duration batteries predominantly using earth-abundant materials that we believe can be cycled over 20,000 times without capacity fade.
Because we designed our batteries to operate using an electrolyte of primarily salt, iron and water, our products are environmentally sustainable and substantially recyclable or reusable.
We design and build this core technology, including battery stacks, electrolyte and electrolyte health management solutions into a core power train that is then sold in a variety of configurations to create distinct products that meet the various needs of the industry.
These include our smaller-scale Energy Warehouse, larger containerized Energy Centers, gigawatt-scale fully configurable Energy Base and core power trains that can be assembled at the customer site into complete storage solutions.
Our batteries and technology can be purchased with an extended ten-year warranty which is backed by investment-grade, warranty and project insurance policies from Munich Re, a leading provider of reinsurance, primary insurance and insurance-related risk solutions, which stands behind the performance of our energy storage products.
To our knowledge, we are the first long-duration energy storage company to receive this type of insurance, which provides a warranty backstop for our proprietary flow battery technology, supporting our performance obligations regardless of project size or location and de-risking the technology for our customers.
We have also collaborated with Munich Re to develop separate project coverage for our customers.
This project coverage provides warranty continuity insurance in the event of our insolvency, providing long-term assurance of project performance to our customers and their investors and lenders.
Bonding and surety capital is provided through OneBeacon Insurance Group (“OneBeacon”) as well as qualification from the U.S.
Export-Import Bank, which provides additional product assurance.
We believe each of these elements allows us to increase our total addressable market, as potential customers have reduced technology risk, financing risk and importing risk.
Examples of use cases range from localized - 4 - energy storage at commercial and industrial sites to grid-scale use cases, such as peaker plant replacement and grid stabilization.
Our proprietary solution to eliminate the hydroxide formation is known as the Proton Pump, and it works by utilizing hydrogen generated by side reactions on the negative electrode.
This process eliminates the hydroxide and stabilizes the pH level of the system.
Using our iron flow battery technology, we developed a variety of products to provide reliable, safe, long-duration energy storage solutions.
Our first energy storage product, the Energy Warehouse, is designed as a ‘behind-the-meter’ solution and is often used for initial testing and technology verification.
Our second, larger scale energy storage product, the Energy Center, is designed to be a complete battery solution delivered in a modular, stackable form factor that can be deployed either ‘behind-the-meter’, at commercial/industrial sites or in micro-grid deployments, or ‘front-of-the-meter’ for large-scale grid applications.
The Energy Center is designed to allow customers to connect multiple units in a variety of configurations, supporting energy storage projects ranging from sub-megawatt to tens-of-megawatt scale.
The Energy Center is configured with higher power and longer duration than the Energy Warehouse, and the modular design allows customers to meet the specific requirements of their application as needed.
Our third, gigawatt-scale storage product, the Energy Base, is designed with a fully configurable layout that integrates with any site location and that allows the power (the rate of electricity flow) to be decoupled from the capacity (the total amount of energy held).
This, combined with an expectation of unlimited cycling and rapid response time, means that the performance of each Energy Base can be tailored to meet individual customer needs.
ESS has developed and will continue to expand its documentation, reference design and recommendations to allow customers and partners to build and operate integrated storage solutions based on our core technology. - 5 - For all of our energy storage products, the intellectual property and points of differentiation are contained within the core technology components, the Proton Pump, power module, Battery Management System and electrolyte.
ESS’ Critical Technology Customers Our current and potential customers include utilities, IPPs and C&I end users.
Behind-the-meter customers may include data centers, microgrids, critical infrastructure assets and small-scale C&I customers.
These customers use our energy storage products to store energy on a utility scale that they can then utilize or sell to their customers when needed and ensure overall grid reliability at a time of increasing demand for energy and grid reliability.
Partnerships • Munich Re : We offer our customers the opportunity to purchase our batteries and technology with a ten-year warranty which is backed by investment-grade warranty and project insurance policies from Munich Re, a leading - 6 - provider of reinsurance, primary insurance and insurance-related risk solutions, which stands behind the performance of our energy storage products.
This project coverage provides warranty continuity insurance in the event of our insolvency, providing long-term assurance of project performance to our customers and their investors and lenders. • OneBeacon Insurance : Through OneBeacon, we offer project surety capacity and corporate bonding options to our customers. • Export-Import Bank of the United States : The Export-Import Bank of the United States (“EXIM”) is the official export credit agency of the United States.
Research & Development Since January 1, 2019, we have invested approximately $176.4 million in improving our technology and bringing our energy storage products to market.
Our research and development efforts are conducted in Oregon and supported by our approximately 41 research and development employees.
We have over 333 patents that are granted, applied for or in the pipeline for application, and an undisclosed number of trade secrets.
Without taking into account any possible patent term adjustments or extensions, the earliest our current, issued patents will begin to expire is 2028.
The proliferation of intermittent generating resources has created new challenges to electric grid stability, and thus an opportunity for an increased role for long-duration energy storage solutions.
Our key competitors include different energy storage technologies such as lithium-ion batteries, lithium metal batteries, vanadium or zinc bromine batteries, sodium sulfur batteries, compressed air, hydrogen, fuel cell and pumped-storage hydropower.
Key competitors in the non-lithium-ion space include CellCube, CMBlu Energy AG, Energy Dome Energy Vault, Enerox GmbH, Eos Energy Enterprises, Inc., Form Energy, Highview Power PTY Ltd., Hydrostor, Lockheed Martin (GridStar Flow), Malta Inc., and VoltStorage GmbH.
Although we may be small compared to some of our competitors, we believe we are well-positioned to compete with them in the market supported by our innovative iron flow battery technology, strategic partnerships and premier leadership team with a proven track record of success. - 7 - New technologies may enter the market that may have additional or superior advantages to our offerings.
We believe there is significant government support available for energy storage technologies, and a variety of newer and emerging companies have announced plans to develop energy storage products using a variety of technologies, including compressed air, thermal energy, and solid-state batteries among others.

and 235 more.

Sentence-level comparison of Item 1A in the two most recent 10-Ks (FY2024 ↗, FY2025 ↗). A reworded sentence counts as one dropped and one added, so heavy edits read as low “kept”. Headings and page furniture are stripped; nothing is summarised by a model.

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