11 December 2025

Invinity Energy Systems plc

("Invinity" or the "Company")

U.S. Energy Secretary Charges Invinity VFB at PNNL

Pacific Northwest Laboratory (PNNL) begins testing of Invinity battery at Grid Storage Launchpad (GSL) facility in Richland, Washington

Invinity Energy Systems plc (AIM: IES) (OTCQX: IESVF), a leading global manufacturer of utility-grade energy storage, is pleased to announce that the U.S. Department of Energy's Pacific Northwest National Laboratory has begun testing of an Invinity battery at their new Grid Storage Launchpad.

Above: U.S. Energy Secretary Chris Wright starts the testing of the Invinity VFB at GSL. Watch the video (courtesy of PNNL).

This achievement represents a major milestone for the DOE's investment in advanced energy storage, with U.S. Department of Energy Secretary Chris Wright officially starting the test programme during a visit to GSL.

Over the next year, Invinity's vanadium flow battery system will be subjected to an in-depth testing regime under real-world conditions by PNNL with the intention of unlocking insights into how grid-scale batteries, such as Invinity's, can help support the U.S. grid.

To find out more, read PNNL's press release in full here.

Vince Sprenkle, Director at Grid Storage Launchpad said:

"With this first utility-grade battery test, GSL is now fully operational as the nation's proving ground for grid-scale storage technologies. With the independent, accurate feedback developers receive from GSL's tests, they can ready their technologies for real-world applications."

Matt Harper, President at Invinity said:

"We're very proud to be collaborating with PNNL and the GSL team on their inaugural grid-scale battery testing project. Having our battery extensively tested by PNNL's experts at this advanced facility, in support of the U.S. DOE's long duration energy storage program, is yet another important validation of our technology for deployment on the U.S. grid."

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Notes to Editors

Invinity Energy Systems plc (AIM: IES) (OTCQX: IESVF) manufactures vanadium flow batteries for large-scale, high-throughput energy storage requirements of business, industry and electrical networks.

Invinity's factory-built flow batteries run continually with no degradation for over 30 years, making them suitable for the most demanding applications in renewable energy production. Energy storage systems based on Invinity's batteries are safe, reliable, and economical, and range in size from 1 to hundreds of megawatt-hours.

Invinity was created in April 2020 through the merger of two flow battery industry leaders: redT energy plc and Avalon Battery Corporation. With more than 190 MWh of systems deployed, contracted for delivery or awarded for projects across more than 90 sites in 17 countries, Invinity is active in all major global energy storage markets and has operations in the UK, Canada, USA and China. Invinity Energy Systems plc is quoted in the UK on AIM and trades in the USA on OTCQX.

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].

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