1 June 2026

Invinity Energy Systems plc

("Invinity" or the "Company")

2 MWh Sale to U.S. C&I Customer

U.S. Department of Energy-funded project will see Endurium Enterprise batteries deployed to tribal reservation in Ashland, Wisconsin

Invinity Energy Systems plc (AIM: IES), a leading global manufacturer of utility-grade energy storage, is pleased to announce the sale of a 2 MWh Endurium Enterprise battery system to a U.S. Department of Energy (DOE)-funded project located in Wisconsin, USA.

Project VITALITY (Vanadium Innovation to Advance LDES & Impact Tribal Sovereignty) will see the battery system installed as part of a microgrid project at a tribal facility on the Bad River reservation in Ashland, Wisconsin, that will demonstrate the benefits of vanadium flow batteries in commercial and industrial (C&I) applications.

The overall Project has been awarded $4.7m in funding from the U.S. DOE's Office of Electricity and is being led by muGrid Analytics, in partnership with the Bad River Band of Lake Superior Chippewa tribe. muGrid Analytics delivers investment-grade modelling and predictive control software that transforms fragile rural grids into optimised, bankable microgrids, providing a scalable blueprint for nationwide energy resilience.

The 2 MWh battery system is planned to be delivered next year and is anticipated to be manufactured in the USA. Invinity expects to receive $3.36m out of the $4.7m grant to fund the manufacture and delivery of the battery system and support further product development activity relating to the Company's Endurium Enterprise product in the United States. Data collected from the demonstration will be shared with the U.S. DOE's rapid operational validation initiative consistent with the recent 12 MWh sale to Pacific Northwest National Laboratory.

Amy Simpkins, Chief Executive Officer at muGrid said:

"C&I and community facilities are hungry for new types of battery technology. We are thrilled to bring Invinity's robust flow battery technology ecosystem to a very innovative community to demonstrate its effectiveness and performance. muGrid is proud to bring our advanced controls software to advance LDES use cases in the commercial marketplace as part of Project VITALITY and our partnership with Invinity."

Matt Harper, President at Invinity said:

"The C&I market continues to be a significant growth area for Invinity, and we are delighted to have announced another deal within this exciting segment. Supported by the Department of Energy, Project VITALITY will accelerate the optimisation of our Enterprise product for customers in the U.S., while delivering operational data from the field to help further validate and enhance the value we deliver to those customers. We are excited to partner with muGrid and the Bad River Tribe for this opportunity and look forward to moving into the delivery phase of this project soon."

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Notes to Editors

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

Invinity's safe, scalable and durable battery technology is a trusted and safer alternative to lithium-ion batteries and our 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 by delivering energy storage without limits, unlocking low-cost, low-carbon power on-demand.

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].