ESS to Present in Clean Energy Group’s Beyond Lithium Webinar Series on June 3, 2026

Key Terms

long-duration energy storage technical

Long-duration energy storage is technology that can store large amounts of electricity for many hours to days and release it when needed, like a very large rechargeable battery that can power a neighborhood through the night or during multi-day cloudy periods. It matters to investors because it enables more reliable use of wind and solar, reduces the need for backup power plants, creates new revenue opportunities from capacity and grid services, and can change the economics of energy projects and utilities.

ldes technical

Long-duration energy storage (LDES) describes technologies that store large amounts of electricity for many hours to days, not just minutes, allowing power to be shifted from times of surplus to times of need. For investors it matters because LDES can unlock greater use of renewable energy, reduce the risk of blackouts, create new revenue streams for utilities and storage companies, and influence long-term capital and policy decisions in the energy sector.

WILSONVILLE, Ore.--(BUSINESS WIRE)-- ESS Tech, Inc. (NYSE: GWH) ("ESS" or the "company"), a leading manufacturer of iron flow, long-duration energy storage (LDES) systems for commercial and utility-scale applications, today announced that management will participate in Clean Energy Group’s Beyond Lithium webinar series.

ESS CEO Drew Buckley will participate in the webinar from 3:00 PM ET to 4:00 PM ET. Buckley will discuss an overview of the company and its iron flow technology, including target applications and related services, market readiness, the path to commercialization, and other key topics.

Clean Energy Group Beyond Lithium webinar series
Date: Wednesday, June 3, 2026
Format: Webinar
Time: 3:00 – 4:00 PM ET
Registration: Click here
Attendee: CEO Drew Buckley

For more information on Clean Energy Group’s Beyond Lithium webinar series, please email your request to ESS@mzgroup.us or call Chris Tyson at (949) 491-8235.

About ESS Tech, Inc.

ESS (NYSE: GWH) is the leading manufacturer of long-duration, iron flow energy storage solutions. ESS was established in 2011 with a mission to accelerate decarbonization safely and sustainably through longer lasting energy storage. Using easy-to-source iron, salt, and water, ESS iron flow technology enables energy security, reliability and resilience. We build flexible storage solutions that allow our customers to meet increasing energy demand without power disruptions and maximize the value potential of excess energy. For more information visit www.essinc.com.

Cautionary Language on Forward-Looking Statements

This communication contains forward-looking statements (including within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, and Section 27A of the Securities Act of 1933, as amended) concerning the Company and other matters that involve substantial risks and uncertainties. These forward-looking statements are based on ESS’ current expectations and beliefs concerning future developments and their potential effects on ESS. These forward-looking statements involve a number of risks, uncertainties (some of which are beyond ESS control) or other assumptions that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements, which include risks and uncertainties described more fully in the section titled “Risk Factors” in the Company’s Quarterly Report on Form 10-Q filed on May 7, 2026, and the Company’s other filings with the U.S. Securities and Exchange Commission. 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.

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Company 
investors@essinc.com

Investor Relations 
Chris Tyson 
Executive Vice President 
MZ Group - MZ North America 
Phone: (949) 491-8235 
GWH@mzgroup.us
www.mzgroup.us

Source: ESS, Inc.