18 September 2025

Invinity Energy Systems plc

("Invinity" or the "Company")

4 MWh Sale to Hungarian Reseller Partner

Further sale to Ideona Group for deployment at two solar plus storage projects in Hungary

Invinity Energy Systems plc (AIM: IES) (OTCQX: IESVF), a leading global manufacturer of utility-grade energy storage, is pleased to announce the sale of a total of 4 MWh of VS3 vanadium flow batteries to Central European Vanadium Storage Kft, a subsidiary of Ideona Group ("Ideona") for use in two separate solar plus storage projects in Hungary. These sales are Invinity's second product order from Ideona, which also acts as the Company's partner in the region.

The batteries will be deployed alongside existing on-site solar arrays at two projects in western Hungary, which have been designed to receive grant funding support from the Hungarian government. 2 MWh of energy storage will be deployed at each site and will be used to stabilise solar output and provide flexibility to the local grid networks.

The Company has now received final notice to proceed from Ideona and therefore expects shipping to occur during Q4 2025. This order formed part of the "signed, uncommitted" category of Invinity's commercial orderbook disclosed in the Company's announcement on 9 September 2025.

Matt Harper, President at Invinity said:

"We're very pleased to have reached financial close on another sale in the Hungarian market alongside our partner Ideona, who have again chosen our VS3 product as most appropriate for the size and delivery timescale of this project. This is further validation of the tremendous capabilities our vanadium flow batteries can deliver alongside grid-connected solar generation. The Hungarian energy storage market remains an exciting growth area for Invinity, and we look forward to delivering this project as a step towards further expansion in the region."

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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 less than 250 kilowatt-hours to tens 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].