ESS Global Fleet Achieves Operational Milestone Surpassing 2 GWh of Transacted Energy

Additional Energy Center™ products are delivered to Florida utility and product line achieves safety and operational certifications.

ESS Global Fleet Achieves Operational Milestone Surpassing 2 GWh of Transacted Energy

Investors:
Erik Bylin
Investors@essinc.com?

Media:
Morgan Pitts
503.568.0755
morgan.pitts@essinc.com?

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 the company’s global fleet of LDES solutions has transacted nearly 2.5 GWh of transacted energy. This operational milestone was achieved as the company continues to deliver and begin commissioning of its Energy Center™ products and earns new safety and operational certifications, underscoring the company’s leadership in the LDES industry.

In December, ESS completed construction and initial testing of two Energy Center™ units for Portland General Electric and began shipment of Energy Center™ systems to a major Florida utility. Eight Energy Center™ systems have now been delivered for the Florida project. Both projects are expected to become fully operational this year.

“These milestones illustrate the value that ESS systems are delivering to our customers and our steady progress in scaling the business,” said Hugh McDermott, ESS SVP of Business Development. “The Energy Center^TM is our 8+ hour product and we continue to build on the evolution of our systems. We’re now looking to add 12+ hour projects with our Energy Base^TM product line while continuing to grow the overall ESS fleet to provide safe and sustainable LDES, including delivering green baseload, for decades to come.”

Underscoring the safety and sustainability of the solution, the Energy Center™ product line recently earned industry-leading certifications including ETL certification to the UL 9540 standard. UL 9540 is a comprehensive safety standard for grid-connected energy storage systems which affirms the safety of the battery system and its environmental performance. The standard covers stationary energy storage systems for both outdoor and indoor installations.

To facilitate deployment and operation of ESS products, the Energy Center™ product line also recently passed the Modular Energy System Architecture (MESA) Standards Alliance’s MESA-Device profile test, the first energy storage technology to demonstrate compliance, and has also received SunSpec Alliance Modbus Certification.

The Energy Center’s software was rigorously assessed against the MESA-Device profile test to confirm its ability to reliably communicate and share data between systems at a project site and to enable clean, predictable command and control operation.

These new certifications are in addition to IEEE 693-High certification, which the Energy Center product line received in 2024. IEEE 693 is a widely accepted seismic rating for energy infrastructure. ESS was the first non-lithium LDES provider to receive the certification, providing assurance that the Energy Center product line qualifies for deployment as critical infrastructure in seismically active regions.

If you would like to learn more about these developments, including information about ESS’ new Energy Base^TM product line, representatives from ESS will be exhibiting at Intersolar North America in San Diego from February 25-27 in booth number 2405. For more information or to schedule a meeting, please visit https://www.essinc.com/essevents.

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” 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 leadership team, expectations regarding future activities, the exploration of strategic alternatives and the installation of energy storage systems for applications in the 12 to 24 hour long duration storage market, which are currently at the RFP stage. 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, our product specifications and performance and customer installations, as well as those risks and uncertainties set forth in the section entitled “Risk Factors” in the Company’s Quarterly Report on Form 10-Q for the three and nine months ended September 30, 2024, filed with the Securities and Exchange Commission (the “SEC”) on November 14, 2024, and its other filings filed with the SEC. 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.