This announcement contains inside information

11 May 2021

Invinity Energy Systems plc

("Invinity" or the "Company")

Joint Development of Grid-Scale Flow Battery

Invinity Energy Nexus Limited, a wholly-owned subsidiary of Invinity Energy Systems plc (AIM:IES) is pleased to announce it has entered into a Joint Development and Commercialization Agreement ("JDCA") with Gamesa Electric S.A.U. ("Gamesa Electric"), a wholly-owned subsidiary of Siemens Gamesa Renewable Energy ("SGRE"), to:

·  jointly develop a grid-scale vanadium flow battery ("VFB") based on Invinity's proven technology and incorporating Gamesa Electric's advanced power conversion systems;

·    cooperatively manufacture the VFB upon achieving a jointly validated design; and

·    commercialize the VFB through each company's sales channels.

The JDCA sets out a detailed development program for the next-generation VFB that is expected to take approximately two years to reach commercialisation. Over this period, Gamesa Electric has agreed to fund an aggregate US$4.62 million of Invinity's activities within the joint development program, payable as development milestones are met. The JDCA may be terminated by Gamesa Electric should there be a failure to advance through development stages. In addition to the joint activities, each company will independently advance their core technology to support program deliverables.

Invinity and Gamesa Electric have also entered into an Option Agreement granting Gamesa Electric or its nominee within the SGRE group an option for 9.99 per cent. of Invinity's issued share capital as at the date of this announcement (the "Option", the "Option Shares") at £1.75 per share, the same as Invinity's most recent placing in December 2020. If the option were to be exercised, Gamesa Electric or its nominee would have the right to appoint a director to Invinity's board subject to Gamesa Electric or its nominee maintaining a minimum 5% shareholding in Invinity. The ability to exercise the Option is subject to Company shareholders' approval. Further updates will be provided to shareholders in due course.

Invinity will continue to vigorously pursue development and commercialization of its current VFB products in response to robust and growing demand.

"We are delighted to enter into this JDCA with Gamesa Electric," said Larry Zulch, Invinity CEO. "Delivering a next-generation VFB to meet the need for safe, dependable and economical energy storage requires deep expertise in both energy technology development and commercialization, making Gamesa Electric an ideal partner for us in that effort. We appreciate this validation of VFB's potential and the implications for our existing products."

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Notes to Editors

Invinity Energy Systems plc (AIM:IES) manufactures vanadium flow batteries for the large-scale energy storage requirements of businesses, industry and electricity networks.

Developed specifically for high-utilisation applications, Invinity's highly scalable, factory-built flow battery products make low-carbon renewable generation reliable and can run continually with no degradation, charging and discharging for over 25 years. 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 over 10MWh of systems deployed to date across 40 sites in 14 countries, Invinity is active in all major global energy storage markets and has operations in the UK, Canada, USA, China and South Africa. Invinity Energy Systems plc is listed on the London Stock Exchange.

To find out more, visit invinity.com or call Investor Relations on +44 (0) 207 121 6111.