29 June 2026

Gresham House Energy Storage Fund plc

(GRID or the Company)

Ocker Hill provisionally awarded 25-year LDES cap and floor contract

Gresham House Energy Storage Fund plc (LSE:GRID), the UK's largest listed fund investing in utility-scale battery energy storage systems (BESS), is pleased to announce that its Ocker Hill project has been provisionally included by Ofgem in a portfolio of projects to receive 25-year cap and floor support under the Long Duration Energy Storage (LDES) scheme for 145MW / 1,160MWh (8 hour duration).

The award

Ocker Hill, a 240MW BESS project in Wednesbury, West Midlands with an expected connection date of October 2029, is one of 16 projects selected by Ofgem in its "minded to" decision announced on 26 June.  As stated during the 2026 Capital Markets Webinar, this project has the optionality of being built to either 2 hours or at a longer duration. The 145MW 8-hour duration award announced by Ofgem would draw on that longer duration optionality.

The 25-year Government cap and floor support underwrites LDES project revenues for the duration of the award. The regime is designed to unlock investment in long duration energy storage whilst protecting consumers from over-payment, with the floor designed to provide the revenue certainty for investors to receive a return of at least 4.47% in real teams (i.e. before inflation adjustment) on invested capital. Revenues above the cap are shared with consumers.

Under the framework set out in Ofgem's September 2025 Financial Framework decision, cap and floor levels are derived from benchmark target rates of return of 4.47%[1] at the floor and 7.31% at the cap. Project-specific levels are to be confirmed at Final Investment Decision and updated again following the Post Construction Review.

Industry context

Ofgem's provisional award follows a multi-year effort by leading BESS operators to participate in and secure a level playing field within the cap and floor regime. In April 2025 Gresham House, alongside other large UK battery storage businesses, was a signatory to an open letter to Ofgem, Government, and the National Energy System Operator (NESO). Drawing on independent analysis by LCP Delta, the letter argued that BESS is the most cost-effective LDES technology and that disadvantaging it within the scheme would impose unnecessary costs on consumers. Friday's provisional award reflects that argument.

LDES refers to energy storage able to store and release electricity for eight hours or more. These assets help to balance supply and demand across the system, particularly as intermittent renewables make up a larger share of generation in support of the government's Clean Power 2030 ambitions.

Next steps

Ofgem has invited consultation responses on its "minded to" decision by 7 August. Final cap and floor awards are expected to be published in Autumn 2026. Further announcements will be made in due course.

John Leggate CBE, Chair of Gresham House Energy Storage Fund plc, said:

"We welcome Ofgem's provisional award of 25-year cap and floor support to Ocker Hill. The decision underlines the strategic importance of long duration battery storage to Britain's energy security and clean power ambitions and provides a long-term revenue framework that recognises the critical role BESS will play. For shareholders, it reinforces the strategic importance and underlying value embedded in GRID's pipeline as we progressively deliver on the plans we set out at last month's Capital Markets Webinar."

Ben Guest, Fund Manager of Gresham House Energy Storage Fund plc and Managing Director of Gresham House Energy Transition, said:

"Gresham House has consistently argued, alongside other leading UK BESS operators, that batteries are the most cost-effective technology and with the least environmental impact for long duration storage, and that consumers are best served when technology solutions are treated on a level basis. The direction of travel set out in Friday's announcement is welcome on both counts.

"Ocker Hill is well placed to deliver on this award. Configuring the project to an 8-hour duration draws on the optionality we identified at acquisition and would bring a high-quality Long Duration Energy Storage asset with long term Government backed, index-linked, revenue into GRID's portfolio, and supports the wider system task of integrating renewables whilst helping to keep bills down for consumers."

The full Ofgem announcement is available on its website.

ENDS

For further information, please contact:

LEI: 213800MSJXKH25C23D82

About the Company and the Manager

Gresham House Energy Storage Fund plc aims to invest in a diversified portfolio of utility-scale battery energy storage systems (known as BESS) located in Great Britain and internationally. The Company seeks to provide investors with the prospect of capital growth through the re-investment of net cash generated in excess of its target dividend in accordance with the Company's investment policy.

Gresham House Asset Management Ltd is the FCA authorised operating business of Gresham House Ltd, a specialist alternative asset manager. Gresham House is committed to operating responsibly and sustainably, taking the long view in delivering sustainable investment solutions.

www.greshamhouse.com

Definition of utility-scale battery energy storage systems (BESS)

Utility-scale battery energy storage systems (BESS) are the enabling infrastructure that will support the continued growth of renewable energy sources such as wind and solar, essential to the UK's stated target to reduce carbon emissions. They store excess energy generated by renewable energy sources and then release that stored energy back into the grid during peak hours when there is increased demand.