ESS to Deliver Long-Duration Energy Storage Solutions to Sapele Power to Improve Generation Efficiency

ESS Tech, Inc. ("ESS") (NYSE: GWH), a leading manufacturer of long-duration energy storage systems (LDES) for commercial and utility-scale applications, today announced that it has partnered with Sapele Power Plc ("Sapele"), a leading Nigerian integrated energy company specializing in power generation, to provide an initial 1 MW / 8 MWh of long-duration energy storage. This agreement represents the largest battery storage system export to Africa financed by the Export-Import Bank of the United States of America to date and will improve the efficiency of Sapele's existing assets by providing ancillary services.

According to the International Energy Agency, an estimated 40% of all the electricity consumed in Nigeria is produced from backup generators due to unreliable power supply caused by limited grid infrastructure, underinvestment and ineffective regulatory frameworks. Projects such as this demonstrate the opportunity to improve grid reliability and efficiency through the addition of battery storage resources.

As ESS' first project in Africa, the company's iron-flow technology will provide safe and sustainable LDES which will enable load-smoothing, peak demand shifting and enable the Sapele power station's turbines to ramp up and down efficiently.

"As we continue to grow and meet global demand for long-duration energy storage, we are proud to serve innovative use cases, demonstrating the many potential applications for ESS technology," ESS CEO Eric Dresselhuys said. "This project demonstrates Sapele's leadership in ensuring reliable electricity for homes and businesses with greater capital efficiency, which will be key to creating a sustainable and resilient energy system across Africa."

"This project will deliver improved reliability and efficiency for our generation assets in Nigeria," said Sapele Board Member Heather Onoh. "We are pleased to partner with ESS to deploy the first iron flow battery system in Africa. Long-duration energy storage will play a critical role in a resilient, reliable energy system and this is just the first of many LDES projects that we anticipate in coming years."

ESS' sale to Sapele was supported by the Export-Import Bank of the United States (EXIM), the official export credit agency of the United States that aims to support American jobs by facilitating the export of U.S. goods and services. The deal will be financed in part by EXIM and is one of the first energy storage projects in Nigeria and the entire sub-Saharan Africa region.

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 and performance of ESS equipment deployments with its customers and partners. 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.