Update on UK LDES Cap and Floor Scheme

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").

26 June 2026

Invinity Energy Systems plc

("Invinity" or the "Company")

Update on UK LDES Cap and Floor Scheme

Invinity VFB technology selected by Ofgem to progress under scheme

Invinity Energy Systems plc (AIM: IES), a global leader in vanadium flow battery technology, notes today's announcement from Ofgem of its "minded-to decisions" for Window 1 of the UK LDES Cap and Floor Scheme and the inclusion of the Frontier Legacy project on this list. This project has a total capacity of 520 MWh and is currently expected to be split approximately equally between Invinity's vanadium flow battery technology and zinc-halide battery technology.

The Company views today's announcement positively and notes Ofgem's specific comment that the inclusion of Invinity's vanadium flow battery technology in the Frontier Legacy project was a key factor in Ofgem reaching its "minded-to decision". The Company sees this as yet another key validation of Invinity's technology and the role it has in delivering vital Long Duration Energy Storage capacity to the UK grid and globally.

The Company retains its belief that projects specifying Invinity technology represent clear alignment with the UK's Industrial Strategy by supporting domestic supply chains, enhancing energy security, and growing a UK-manufacturing base for LDES.

Invinity will now work to support Frontier Power in this process to advance this project towards financial close over the coming months. The Company notes that, while management retains a high degree of confidence, there can be no assurance that financial close will be achieved in the form currently envisaged, if at all.

Jonathan Marren, Chief Executive Officer at Invinity said:

"Ofgem's announcement today, particularly their specific reference to Invinity technology's role within the scheme, underlines the continued progress we are making as a business both in the UK and globally.

"The Company views the cap and floor programme accelerating the benefits of longer duration storage for the UK market as a significant national step in the context of a global market experiencing strong growth of 49% year-on-year. Of the 393 GWh1 grid scale energy storage expected to be installed globally in 2026, 8.3 GWh (2% of the global total) is in the UK, with 58 GWh (15%) and 19 GWh (5%) expected in the U.S. and in Europe (ex UK) respectively. On a broader basis, we are also currently seeing significant traction in both UK and global C&I and data centre sectors both directly and through industrial partners. The Company therefore remains extremely positive about its prospects for growth."

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1 Benchmark Q2 2026 Battery Energy Stationary Storage Forecast

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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 ir@invinity.com.