ESS Tech, Inc. (ESS) (NYSE : GWH), a leading manufacturer of iron flow long-duration energy storage systems (LDES) for commercial and utility-scale applications, today announced that it will hold a conference call on Thursday, May 15, 2025 at 5:00 p.m. EDT to discuss financial results for its first quarter 2025 ended March 31, 2025.

The news release announcing the first quarter 2025 financial results will be disseminated on May 15, 2025 after the market closes.

Interested parties may join the conference call beginning at 5:00 p.m. EDT on Thursday, May 15, 2025 via telephone by calling (833) 470-1428 in the U.S., or for international callers, by calling +1 (404) 975-4839 and entering conference ID 788626. A telephone replay will be available until May 22, 2025, by dialing (866) 813-9403 in the U.S., or for international callers, +1 (929) 458-6194 with conference ID 107029. A live webcast of the conference call will be available on ESS' Investor Relations website at http://investors.essinc.com/.

A replay of the call will be available via the web at http://investors.essinc.com/.

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.

View source version on businesswire.com: https://www.businesswire.com/news/home/20250512197535/en/

Investors:

Erik Bylin

investors@essinc.com

Media:

Morgan Pitts

503.568.0755

morgan.pitts@essinc.com