Author: [email protected]

Project to Deploy up to 27 MWh American-Made Large Capacity Energy Storage (LCES) System at U.S. Clear Space Force Station in Alaska

Wilsonville, Ore.– January 29, 2026 – ESS Tech, Inc. (“ESS,” “ESS, Inc.” or the “Company”) (NYSE: GWH), a leading manufacturer of long-duration energy storage systems (LDES) for commercial and utility-scale applications, today announced the execution of a $9.9 million contract with Concurrent Technologies Corporation (“CTC”) and the United States Air Force Research Laboratory (“AFRL”) for a large capacity energy storage (LCES) system at the U.S. Clear Space Force Station in Alaska.

The Air Force Research Laboratory is the primary scientific research and development center for the Department of the Air Force. AFRL plays an integral role in leading the discovery, development, and integration of affordable warfighting technologies for its air, space, and cyberspace force. The prime contractor, Concurrent Technologies Corporation, is an independent, nonprofit, applied scientific research and development professional services organization, and provides comprehensive energy and sustainability solutions for military installations.

Under the contract, ESS will deploy up to 27 MWh of its American-made iron flow battery (IFB) systems to support operations at Clear Space Force Station in Alaska. The project is part of an AFRL initiative to demonstrate new and emerging advanced energy storage and energy efficiency technologies capable of meeting demanding military requirements in some of the harshest environments on earth, including temperatures below -40°C. ESS’s iron flow battery technology will integrate with microgrids, advanced controls and complementary systems to optimize energy use and provide continuous, reliable power for mission critical operations at the station.

“This project is a significant validation of ESS battery technology and its ability to provide reliable energy every day and support grid resiliency when it matters most,” said Drew Buckley, Chief Executive Officer of ESS. “Building on our recent 50 MWh project for Salt River Project in Arizona, our technology is being chosen for essential grid resilience capabilities and optimized energy consumption at mission-critical infrastructure including defense installations and data centers.

“The Department of Defense is actively seeking long duration resilient microgrids to improve readiness, with a keen interest in ‘Made in USA’ software and systems to reduce risk of foreign cyber security vulnerabilities. We believe this award will further unlock long duration storage opportunities with the DoD and the growing microgrid market,” concluded Buckley.

Kevin Merichko, Director, Infrastructure at CTC added, “By enabling localized power (islanding), rapid recovery and a stable electricity supply during grid instability or disruptions, resilient grids help avert severe safety, operational and financial consequences while assuring critical missions continue without interruption. We look forward to working with ESS, AFRL and the U.S. Space Force, to further improve Clear Space Force Station resilience.”

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.

Forward-Looking Statements

This communication contains certain forward-looking statements, including statements regarding ESS and its management team’s expectations, hopes, beliefs, intentions or strategies regarding the future. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intends,” “may,” “might,” “plan,” “possible,” “potential,” “predict,” “project,” “should,” “will,” “would” 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 timing of the closing of the offering, the expected gross proceeds and the expected use of the net proceeds. 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, but are not limited to, whether or not ESS will be able to raise capital through the sale of securities or consummate the offering; the final terms of the offering; the satisfaction of customary closing conditions; prevailing market conditions; general economic and market conditions as well as geopolitical developments; and other risks. 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.

Contacts

Investor Relations
Chris Tyson
Executive Vice President
MZ Group – MZ North America
Phone: (949) 491-8235
[email protected]
www.mzgroup.us

Media
Brad Dore
VP, Marketing
ESS Tech, Inc.
Phone: (916) 207-7355
[email protected]

Wilsonville, Ore.– October 9, 2025 – Salt River Project (SRP), a not-for-profit public power utility serving the greater Phoenix metropolitan area, and ESS (NYSE:GWH), a leading manufacturer of iron flow long-duration energy storage (LDES) systems, today announced an agreement to add Project New Horizon, a five megawatt (MW), 50 megawatt-hour (MWh) battery system, to the grid. The pilot project will be installed at SRP’s Copper Crossing Energy and Research Center in Florence, Arizona and sell capacity to SRP under a ten-year energy storage agreement.

The ESS Iron Flow Battery (IFB) project will be part of SRP’s effort to evaluate emerging, non-lithium ion LDES technologies and support SRP’s reliability and sustainability goals. The system, which will utilize ESS’ Energy Base technology, will store enough energy to power 1,125 average-size homes for 10 hours. This project is the result of an RFP issued by SRP in 2024 for LDES pilots.

SRP is working to at least double the number of generating resources on its power system in the next 10 years to meet increasing energy demand in the Phoenix metropolitan area. SRP has nearly 1,300 MW of energy storage currently supporting its grid, which includes 1,100 MW of battery storage— spanning eight facilities— and 200 MW of pumped hydro storage. 

“As the Valley continues to see rapid commercial and residential growth, projects like this allow us to better understand the efficacy and impact of different kinds of LDES technologies as they mature,” said Chico Hunter, SRP Manager of Innovation and Development. “This is another opportunity for SRP to evaluate the real-world performance of emergent technologies on our grid and in the Arizona climate.”

ESS’ technology uses a combination consisting mainly of iron, salt and water to store and discharge energy. The Energy Base will be designed to deliver 10 hours of discharge with “fast charging” of 10 hours or less.  ESS’s products are safe and sustainable with no risk of thermal runaway, operate in a wide range of temperature environments and are Made in America with over 90% domestic content. They further offer a competitive levelized storage cost with a 25-year life expectancy.

“SRP once again demonstrates its leadership with its commitment to non-lithium, long duration energy storage,” said Kelly Goodman, Interim Chief Executive Officer of ESS. “This project is a significant validation in both the LDES industry and ESS as a technology provider.  We are thrilled to be working with SRP to deliver more hours of clean energy to its customers.”  

The Copper Crossing Energy and Research Center currently includes a 99-MW flexible natural gas facility. A 55-MW utility scale solar project is currently under construction at the site. The site will also host CMBlu Energy’s “Desert Blume”, a 5 MW, 10-hour LDES project.

ESS will be partnering with industry leaders to deliver the project by December of 2027. Design is already underway, and manufacturing will begin in 2026. SRP and ESS will work with the Electric Power Research Institute (EPRI) to monitor performance data of the project.

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.

About SRP

SRP is a community-based, not-for-profit public power utility and the largest electricity provider in the greater Phoenix metropolitan area, serving about 1.1 million customers. SRP provides water to about 2.5 million Valley residents, delivering more than 244 billion gallons of water (750,000 acre-feet) each year, and manages a 13,000-square-mile watershed that includes an extensive system of reservoirs, wells, irrigation laterals, and 131 miles of canals.

This release contains certain forward-looking statements, including statements regarding the Company and its management team’s expectations, hopes, beliefs, intentions or strategies regarding the future. The words “anticipate”, “believe”, “continue”, “could”, “estimate”, “expect”, “intends”, “may”, “might”, “plan”, “possible”, “potential”, “predict”, “project”, “should”, “will” and “would” 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 productization, manufacturing and delivery of the Energy Base and operational scaling. These forward-looking statements are based on the Company’s current expectations and beliefs concerning future developments and their potential effects on the Company and involve a number of risks, uncertainties (some of which are beyond the Company’s 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, but are not limited to, delays, disruptions, or quality control problems in the Company’s manufacturing operations; issues related to the development and launch of the Energy Base product; failure to raise additional capital on acceptable terms or at all; and other 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 15, 2025, and the Company’s other filings with the U.S. Securities and Exchange Commission. Except as required by law, the Company is not undertaking any obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise. 

Contacts

Investor Relations
Chris Tyson
Executive Vice President
MZ Group – MZ North America
Phone: (949) 491-8235
[email protected]
www.mzgroup.us

Media
Brad Dore
VP, Marketing
ESS Tech, Inc.
Phone: (916) 207-7355
[email protected]