• ESS Energy Warehouse™ system will showcase central role of non-lithium, long-duration energy storage technologies in a decarbonized grid.

BURBANK, Calif. / May 31, 2024 / Business Wire / ESS Tech, Inc., (ESS) (NYSE: GWH) a leading manufacturer of long-duration energy storage (LDES) systems for commercial and utility-scale energy storage applications, and Burbank Water and Power (BWP) today celebrated the commissioning of BWP’s first LDES system.

“This project represents a major step toward achieving our goal of 100% carbon free power by 2040,” said Mandip Samra, General Manager of BWP. “The Energy Warehouse™ battery will enable our team to gain experience with iron flow long-duration energy storage technology which will be a linchpin of the renewable grid of the future.”

Local elected officials and business and community leaders were on hand to celebrate the installation and commissioning of the 75 kW / 500kWh ESS Energy Warehouse™ iron flow battery on the BWP EcoCampus. The ESS iron flow battery system has been installed and connected to a 265 kW solar array. Once fully operational it will provide power equivalent to the consumption of ~300 homes and will demonstrate the critical role of iron flow technology in a renewable, resilient energy system.

“Visionary utilities like Burbank Water and Power are leading the way to the clean energy future by incorporating advanced long-duration energy storage technologies today,” said Eric Dresselhuys, CEO of ESS. “We look forward to working with BWP and other leading utilities in California and beyond for years to come.”

LDES will play a critical role in achieving California’s ambitious decarbonization goal: 100% zero-emission electricity by 2045. The California Energy Storage Alliance estimates that the state will need 13,571 MW of LDES by 2028 to integrate intermittent renewable energy and optimize assets for a cleaner, more affordable and reliable grid.

This commissioning follows ESS’ recent attainment of IEEE 693 seismic certification for its Energy Center product line and builds on other recent commissioning and delivery milestones with customers including the U.S. Army Corps of Engineers, Sacramento Municipal Utility District and Turlock Irrigation District.

About ESS

At ESS (NYSE: GWH), our mission is to accelerate global decarbonization by providing safe, sustainable, long-duration energy storage that powers people, communities and businesses with clean, renewable energy anytime and anywhere it’s needed. As more renewable energy is added to the grid, long- duration energy storage is essential to providing the reliability and resiliency we need when the sun is not shining and the wind is not blowing.

Our technology uses earth-abundant iron, salt and water to deliver environmentally safe solutions capable of providing up to 12 hours of flexible energy capacity for commercial and utility-scale energy storage applications. Established in 2011, ESS Inc. enables project developers, independent power producers, utilities and other large energy users to deploy reliable, sustainable long-duration energy storage solutions. For more information visit www.essinc.com.

Forward-Looking Statements

This communication contains certain forward-looking statements regarding ESS and its management team’s expectations, hopes, beliefs, or intentions regarding the future. The words “estimate”, “expect”, “will” 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 status of ESS product development and performance of equipment. These forward-looking statements are based on ESS’ current expectations and beliefs concerning future developments. Many factors could cause actual future events to differ materially from such expectations, including, but not limited to, disruptions, or quality control problems in the Company’s manufacturing operations; as well as those risks and uncertainties set forth in the section entitled “Risk Factors” in the Company’s Annual Report on Form 10-K for the twelve months ended December 31, 2023, filed with the Securities and Exchange Commission (the “SEC”) on March 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.