UL 1973 certification affirms safety profile of company’s battery technology

ESS Tech Inc. (“ESS”) (NYSE:GWH), a leading manufacturer of flexible, sustainable and responsible long-duration energy storage systems for commercial and utility-scale applications, today announced certification of its S200 battery modules to the Underwriters Laboratories’ (UL) 1973 standard.

UL 1973 is an industry standard for stationary energy storage systems which confirms ESS modules’ quality, resilience and ability to operate safely and effectively in a variety of conditions. S200 modules power the company’s Energy Warehouse and Energy Center product lines and certification to the UL 1973 standard demonstrates the company’s commitment to safety.

In 2022, ESS also achieved certification to the UL 9540A standard, demonstrating that ESS systems pose no risk of thermal runaway and making the company’s energy storage products a preferred choice for installation in regions prone to wildfires or adjacent to populated areas.

Recent use cases illustrate the advantages of ESS’ safe and nontoxic energy storage technology. In January, ESS was selected by Amsterdam Airport Schiphol to provide a battery system that will enable electrification of ground operations. The safety profile of ESS technology was a key factor in system selection given close proximity to passenger aircraft.

In addition, ESS was selected by the Sacramento Municipal Utility District (SMUD) to deliver up to 2 GWh of energy storage systems in support of the utility’s 2030 Clean Energy Vision. To build a resilient, decarbonized energy system, ESS technology will be deployed across SMUD’s grid. The safety and flexibility of ESS technology make it ideally suited for siting in densely populated areas where improved grid resilience is needed and safety is a top priority.

ESS iron flow technology provides cost-effective long-duration energy storage and is ideal for applications that require up to twelve hours of flexible energy capacity. ESS systems provide resilient, sustainable energy storage well-suited for multiple use cases including utility-scale renewable energy installations, remote solar + storage microgrids, solar load-shifting and peak shaving, and other ancillary grid services. ESS technology is safe, non-toxic and has a 25-year design life without capacity fade.

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 Company’s ability to execute on orders and the Company’s relationships with customers. 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. 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.