WILSONVILLE, Ore. – August 14, 2025 – 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 financial results for its second quarter ended June 30, 2025.

The second quarter marked a pivotal period in ESS’s strategic reset, with significant progress on both commercial execution and capital discipline. During July, the Company secured up to $31 million in new capital through a combination of immediate cash inflows and a $25 million Standby Equity Purchase Agreement, providing flexibility to scale deployments. Further, commercial momentum accelerated following launch of the Energy Base, ESS’s proprietary long-duration, non-flammable iron flow battery platform. The Company closed its first Energy Base sale, has entered into contracting for additional Energy Base projects and submitted proposals totaling over 1.1 GWh during the quarter. ESS’s Made in the USA manufacturing model—with over 98% domestically sourced components—continues to provide a competitive edge in navigating evolving trade policy and tariff environments. Recent federal legislation, including the One Big Beautiful Bill Act, maintains key Section 45X Production Tax Credits while expanding incentives for domestically manufactured energy storage, positioning ESS products as even more attractive to customers seeking long-duration solutions with minimal supply chain risk.

Operationally, ESS continued to enhance efficiency and reduce costs while maintaining delivery readiness. “Q2 reflects the early results of the operational reset we began earlier this year,” said Kelly Goodman, Interim CEO of ESS. “We are building a business with sharper focus, disciplined execution, and a stronger financial foundation. We are excited to welcome Jigish Trivedi as our new Chief Operating Officer and Kate Suhadolnik as interim Chief Financial Officer – two proven leaders who will help drive the next phase of our growth. We continue to see growing demand from Tier 1 customers and with a robust pipeline, ESS is well-positioned to deliver safe, sustainable, long-duration storage solutions at scale while creating long-term value for our customers and shareholders.”

•GAAP revenue of $2.4 million, up 294% from Q1 2025

•GAAP cost of revenues of $7.5 million, down 15% from Q1 2025

•GAAP operating expenses of $6.5 million, down 35% quarter-over-quarter

•GAAP net loss and adjusted EBITDA improved 50% year-over year

In addition, the Company ended July with $7.2 million in cash and cash equivalents, up from $0.8 million at the end of Q2.

ESS will hold a conference call on Thursday, August 14, 2025 at 5:00 p.m. EDT to discuss financial results for its second quarter 2025 ended June 30, 2025. Interested parties may join the conference call beginning at 5:00 p.m. EDT on Thursday, August 14, 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 271308. A telephone replay will be available until August 21, 2025, by dialing (866) 813-9403 in the U.S., or for international callers, +1 (929) 458-6194 with conference ID 482125. 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/.

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.

In this press release and the accompanying earnings call, the Company includes Non-GAAP Operating Expenses and Adjusted EBITDA, which are non-GAAP performance measures that the Company uses to supplement its results presented in accordance with U.S. GAAP. As required by the rules of the Securities and Exchange Commission (“SEC”), the Company has provided herein a reconciliation of the non-GAAP financial measures contained in this press release and the accompanying earnings call to the most directly comparable measures under GAAP. The Company’s management believes Non-GAAP Operating Expenses and Adjusted EBITDA are useful in evaluating its operating performance and are similar measures reported by publicly-listed U.S. companies, and regularly used by securities analysts, institutional investors, and other interested parties in analyzing operating performance and prospects. By providing these non-GAAP measures, the Company’s management intends to provide investors with a meaningful, consistent comparison of the Company’s profitability for the periods presented. Adjusted EBITDA is not intended to be a substitute for net income/loss or any U.S. GAAP financial measure and, as calculated, may not be comparable to other similarly titled measures of performance of other companies in other industries or within the same industry. Further, Non-GAAP Operating Expenses are not intended to be a substitute for GAAP Operating Expenses or any U.S. GAAP financial measure and, as calculated, may not be comparable to other similarly titled measures of performance of other companies in other industries or within the same industry.

The Company defines and calculates Non-GAAP Operating Expenses as GAAP Operating Expenses adjusted for stock-based compensation. The Company defines and calculates Adjusted EBITDA as net loss before interest, other non-operating expense or income, and depreciation and amortization, and further adjusted for stock-based compensation and other special items determined by management, including, but not limited to, fair value adjustments for certain financial liabilities associated with debt and equity transactions as they are not indicative of business operations.

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 Company’s manufacturing plans, the development and launch of the Energy Base product, the Company’s order and sales pipeline, the Company’s ability to successfully bid on projects and execute on orders, the Company’s ability to effectively manage costs, the Company’s partnerships with third parties, relationships with current and potential customers, and potential capital raising measures, including under the Company’s Standby Equity Purchase Agreement.

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, 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 successfully bid on projects and acquire customers; issues related to the Company’s partnerships with third parties; risk of loss of government funding for customer projects; failure to raise additional capital, including under the Company’s Standby Equity Purchase Agreement, on acceptable terms or at all; and the Company’s need to achieve significant business growth to achieve sustained, long-term profitability. 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.

Erik Bylin

investors@essinc.com

Source: ESS Tech, Inc.