The information contained within this Announcement is deemed by Invinity Energy Systems plc to constitute inside information as stipulated under the Market Abuse Regulation (EU) No. 596/2014 as it forms part of UK law by virtue of the European Union (Withdrawal) Act 2018 ("MAR").

15 June 2026

Invinity Energy Systems plc

("Invinity" or the "Company")

32 MWh Sale to U.S. Steel Mill

California Energy Commission-backed project will produce sustainable steel for U.S. construction industry

Invinity Energy Systems plc (AIM: IES), a leading global manufacturer of utility-grade energy storage, is pleased to announce the sale of a 32 MWh battery system to Pacific Steel Group ("PSG"), a leading reinforcing steel fabricator in the United States, for installation at their Mojave Micro Mill project (the "Mill") in Kern County, California, the first new steel mill to be built in the state in 50 years. The battery is being supported with grant funding from the California Energy Commission's LDES Program that was awarded to PSG in 2025 and, once delivered, is expected to be the largest vanadium flow battery system in North America to date.

Image: Illustrative digital rendering of the proposed facility, courtesy of Pacific Steel Group

Collocated with a 40 MWp PV array, Invinity's battery will be used to supply on-demand, low-carbon, locally generated solar power to the Mill, which will recycle 500,000 tons of scrap metal annually to produce sustainable, seismic-grade steel rebar for the U.S. construction industry.

Invinity's vanadium flow batteries were selected for this project due to their technical, operational and safety characteristics, particularly their ability to cycle heavily to match the energy-intensive power requirements of the Mill. As part of the competitive selection process, Invinity was also able to evidence a strong project delivery track record both globally and in the USA, including a number of other California Energy Commission-funded battery projects delivered in recent years.

Project construction commenced in June 2025 and the Mill is expected to enter operation in H2 2027. Delivery of the batteries, which Invinity plans to manufacture in the USA, is expected to commence in Q1 2027, with associated revenues recognised at that point.

Pacific Steel Group is a leading independent reinforcing steel fabricator and placer with offices throughout the Western United States, with corporate offices located in San Diego, California.

Jonah Steinbuck, Director of the Energy Research & Development Division, California Energy Commission said:

"The California Energy Commission is proud to support this milestone in clean energy innovation - one that advances California's decarbonization goals while strengthening a vital domestic industry. The long-duration capabilities and versatility of Invinity's vanadium flow battery will support the operational efficiency and resilience of the steel plant, and optimize the plant's use of clean, renewable energy."

Mark Olson, VP of Mill Operations, Pacific Steel Group said:

"Pacific Steel Group is currently constructing the first steel mill to be built in California in more than 50 years. From the outset, our vision has been to develop one of the world's cleanest and most sustainable steel manufacturing facilities. To support that goal, we integrated renewable energy generation and advanced battery storage into the project's design. Following a thorough evaluation process and support from the California Energy Commission, we are proud to partner with Invinity Energy Systems on this transformative project, which represents a significant step forward for both California's manufacturing sector and its clean energy future."

Matt Harper, President at Invinity said:

"I'm very pleased that Invinity has again been selected to deliver the heavy-duty storage solutions required by large-scale businesses. Pacific Steel Group's mission is to prove an innovative path towards a fundamentally cleaner steel industry. We believe this project will prove that Invinity's products are second to none in making that mission a reality.

"We also greatly appreciate the support of the California Energy Commission in this project and look forward to working with them, and our growing group of California-based customers, to further plan for how our products can deliver the reliable, low-cost power Californians will demand of their future electric grid.

"Finally, all of us at Invinity are excited for how this project will accelerate plans to expand our U.S.-based manufacturing operations. Those operations will not only enhance our existing service and support capabilities, but also to deliver made-in-America products to customers in the U.S. and beyond. With numerous LDES schemes and a significant need for energy storage in the U.S. already in play, the opportunity to provide American-made vanadium flow batteries is an important next step on our journey."

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Notes to Editors

Invinity Energy Systems plc (AIM: IES) is a world-leading manufacturer of vanadium flow batteries for energy storage. Built in our factories in the UK and Canada, the Company's proven, commercialised, longer duration energy storage technology has been deployed at scale and dispatched gigawatt-hours of electricity for customers across the world.

Invinity's safe, scalable and durable battery technology is a trusted and safer alternative to lithium-ion batteries. Endurium VFBs are engineered for heavy-duty, high throughput applications, they don't wear out, cannot catch fire and are designed to be operated for 30 years or more. Our products address the challenges of our global energy system, unlocking the power of renewable generation by delivering energy storage without limits.

To find out more, visit invinity.com, sign up to our monthly Investor Newsletter here or contact Investor Relations on via +44 (0)20 4551 0361 or [email protected].