ESS Reinforces Leadership Position in Long-Duration Energy Storage with Over 20 Additional Patents Awarded

May 2, 2023

Chicago skyline at night image

Company now holds 62 patents for innovative energy storage technology with additional 225 filed  

Wilsonville, Ore. – May 2, 2023 – ESS Tech, Inc. (“ESS”) (NYSE:GWH), a leading manufacturer of long-duration energy storage systems for commercial and utility-scale applications, has been awarded over 20 additional patents for the company’s industry-leading iron flow battery (IFB) technology since the beginning of 2022. This brings the total number of patents held by the company to 62 worldwide with a further 225 applications filed. 

Founded in 2011, ESS has built an extensive portfolio of patents, proprietary knowledge, and experience in scaling the commercial manufacturing and deployment of iron flow battery systems. ESS’s innovations have addressed the critical advancements needed to facilitate mass adoption of IFB technology including the company’s patented Electrolyte Health Management System (EHMS). Collectively, these innovations have created systems capable of delivering unlimited cycling with zero capacity-fade over their operating life. 

“Solving the world’s big energy challenges requires research and innovation,” said Julia Song, CTO of ESS. “We are proud of our team’s work to develop long-duration energy storage solutions and are grateful for the validation of our distinct innovations by U.S. and global officials. We look forward to the continued advancement of our technology and the competitive advantage it creates in the marketplace as we enable the rapid expansion of wind and solar generation and catalyze the clean energy future.” 

ESS systems provide up to 12 hours of long-duration energy storage for utility and commercial-scale applications. The company’s technology has been validated by multiple third parties including the U.S. Department of Energy’s ARPA-E program, global insurer Munich Re, and utility and commercial customers worldwide. ESS recently announced a partnership with Coldwell Solar to deploy Energy Warehouse systems to microgrids that will power multiple wineries in California, safely providing power even during wildfire conditions.  

The company’s battery modules have been ETL certified to conform to UL 9540A and UL 1973 standards, further affirming ESS modules’ quality, resilience and ability to operate safely.   


About ESS 

At ESS (NYSE: GWH), our mission is to accelerate global decarbonization by providing safe, sustainable, long-duration energy storage that powers people, communities and businesses with clean, renewable energy anytime and anywhere it’s needed. As more renewable energy is added to the grid, long-duration energy storage is essential to providing the reliability and resiliency we need when the sun is not shining, and the wind is not blowing.  

Our technology uses earth-abundant iron, salt and water to deliver environmentally safe solutions capable of providing up to 12 hours of flexible energy capacity for commercial and utility-scale energy storage applications. Established in 2011, ESS Inc. enables project developers, independent power producers, utilities and other large energy users to deploy reliable, sustainable long-duration energy storage solutions. For more information visit   


ESS Contacts

Erik Bylin
[email protected]

Morgan Pitts
[email protected]

Forward-Looking Statements  

This communication contains certain forward-looking statements regarding ESS and its management team’s expectations, hopes, beliefs, or intentions regarding the future. The words “estimate”, “expect”, “will” and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. Examples of forward-looking statements include, among others, statements regarding the Company’s ability to execute on orders and the Company’s relationships with customers. These forward-looking statements are based on ESS’ current expectations and beliefs concerning future developments. Many factors could cause actual future events to differ materially. Except as required by law, ESS is not undertaking any obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise. 

Links to third-party articles and/or websites are for general information purposes only and the content of any third-party article or website is solely the responsibility of the author, owner, operator or publisher of that article and/or website. Views expressed in third-party articles and/or websites reflect the opinion of the author, owner, operator or publisher as of the date of publication, and not necessarily those of ESS Tech, Inc. ESS Tech, Inc. has not independently verified such content, makes no warranties, representations or undertakings relating to such content, and bears no responsibility for the accuracy, legality or content of any external site or for that of subsequent links. Any reliance you place on such information is strictly at your own risk. You are encouraged to read and evaluate the privacy and security policies on the specific site you are entering. ESS Tech, Inc. disclaims any loss, damage and any other consequences resulting directly or indirectly from or relating to your access to the third-party website or any information you may provide or any transaction conducted on or via the third-party website or the failure of any information, goods or services posted or offered at the third-party website or any error, omission or misrepresentation on the third-party website or any computer virus arising from or system failure associated with the third-party website.