Company to Provide Update on Newly Announced LOI Business Combination

ESS Tech, Inc. (ESS) (NYSE:GWH) ("ESS" or the "company"), a leading provider of non-lithium energy storage solutions, today announced that its second quarter 2026 conference call will now take place on Tuesday, August 11, 2026 at 5:00 p.m. EDT to discuss financial results for the quarter ended June 30, 2026. The company will be providing updates on commercial progress, customer deployments, anticipated technology milestones, and the recently announced signing of a non-binding Letter of Intent for a proposed business combination. A press release detailing these results will be issued prior to the call.

ESS Tech CEO Drew Buckley and CFO Kate Suhadolnik will host the conference call, followed by a question-and-answer period. The conference call will be accompanied by a presentation, which can be viewed or access following the call via the investor relations section of the Company’s website here.

To access the call, please use the following information:

Date:		Tuesday, August 11, 2026
Time:		5:00 p.m. Eastern Time (2:00 p.m. Pacific Time)
Dial-in:		1-833-461-5787
International:		1-585-542-9983
Meeting ID:		666 579 401
Webcast:		https://events.q4inc.com/attendee/666579401

The replay can be viewed through the webcast link above and the presentation utilized during the call will be available via the investor relations section of the Company’s website here.

About ESS Tech, Inc.

ESS (NYSE:GWH) is the leading provider of non-lithium 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 materials ESS solutions enable 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 statements may discuss the management team’s goals, beliefs, hopes, intentions and expectations as to future plans, trends, events, results of operations and financial condition, or otherwise, based on current beliefs of the management of the Company, as well as assumptions made by, and information currently available to, the Company’s management. These forward-looking statements can be identified by the use of forward-looking terminology, including the words "anticipate," "believe," "continue," "could," "estimate," "expect," "intends," "may," "might," "plan," "possible," "potential," "predict," "project," "should," "will," "would," or, in each case, their negative or other variations or comparable terminology may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking. These forward-looking statements, which are subject to risks, uncertainties and assumptions about us, may include projections of our future financial performance, our anticipated growth strategies and anticipated trends in our business. These forward-looking statements are based on ESS’ current expectations and beliefs concerning future developments and their potential effects on ESS. Many factors could cause actual future events to differ materially from the forward-looking statements in this communication. There can be no assurance that the future developments affecting ESS will be those that we have anticipated. 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 other risks and uncertainties described more fully in Exhibit 99.2 of the Current Report on Form 8-K filed by the Company on June 23, 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.

View source version on businesswire.com: https://www.businesswire.com/news/home/20260810826105/en/

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

Media

Brad Dore

VP, Marketing

ESS, Inc.

brad.dore@essinc.com

916-207-7355