THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION AS STIPULATED UNDER THE MARKET ABUSE REGULATION (EU NO. 596/2014) AS IT FORMS PART OF UK DOMESTIC LAW BY VIRTUE OF THE EUROPEAN UNION (WITHDRAWAL) ACT 2018 ("MAR").

21 April 2026

Gresham House Energy Storage Fund plc

("GRID" or the "Company")

Full-Year Results to 31 December 2025

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 its audited annual results for the year ended 31 December 2025.

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

"2025 was a year of strong performance for the Company, with significant growth in operational capacity and cash generation. We have worked hard to execute the early stages of the Three-year Plan and are confident in the value it delivers for shareholders.

"2026 promises to bring tangible signs of progress for GRID as it launches into a significant programme of works, maintaining our leadership in this strategically crucial sector for the UK economy.

"As the impact of the war in the Middle East reverberates around global energy markets, the imperative to reduce dependence on imported fossil fuels is self-evident. Battery storage is a fundamental component of Britain's national energy mix. Since BESS has become more mainstream, its contribution to our national infrastructure and energy resilience is becoming more widely recognised by key policy makers."

2025 Performance highlights

o  NAV per share of 113.34p as of 31 December 2025, up 3.7% year over year (31 Dec 2024: 109.35p).

o  Completion of construction pipeline increasing operational MW/MWh to 1,072MW / 1,701MWh at 31 December 2025, increasing average duration to 1.59 hours (31 Dec 24: 845MW/1,207MWh, average duration 1.43 hours).

o  Unaudited Operational Portfolio revenues in 2025 increased 29.9% to £60.4mn, (FY24: £46.5mn).

o  Unaudited Operational Portfolio EBITDA increased 33.4% to £38.8mn (FY24: £29.1mn), resulting in an EBITDA margin of 64.2% in 2025 (FY24: 62.5%).

o  Contracted revenues more than doubled to £23.8mn in 2025 (FY24: £11.5mn).

o  Signed long-term floor agreements for 939MW of the operational portfolio and 637MW of pipeline projects.

o  Equity funding of c.£9mn secured at NAV on a project level for Glassenbury to fund augmentation of the project to 2 hours.

o  £220mn amortising debt facility closed, replacing the previous facility. This debt was secured on improved terms to the previous facility.

Progress on the Three-year Plan

At our Capital Markets Day on 27 November 2024, we announced a Three-year Plan for the period from 2025-2027. The plan has three prongs:

o  Augmentation of the existing portfolio by up to 1.5GWh, taking all projects to at least a two-hour duration, and a subset to a 4-hour duration, with the whole existing portfolio reaching a 3-hour average duration.

o  A new investment pipeline of 680MW across five projects.

o  Adding to the revenue stack with an Alternative Revenues strategy.

During 2024 and 2025, we delivered 330MWh in augmentations across 7 projects. In 2026, a further 350MWh are being installed across 8 projects. The result of all these works will take the portfolio's average duration to c.2 hours. The portfolio is readily capable of further augmentations beyond this, although these are yet to be confirmed.

As recently announced, NESO's Queue Reform Process has clearly delayed connection dates for the entire market and impacted the timing of our Three-year Plan. GRID has received offers on four of its five projects, reflecting 594MW of its 694MW pipeline. Connection dates for 297MW of projects (Monets Garden and Cockenzie) are confirmed for 2027. The connection date for 100MW Elland 2 has not yet been received from NESO; a 2027 date continues to be expected. Connection dates for a further 297MW (Ocker Hill and Lister Drive) are now confirmed for 2029, beyond the original target date for the Plan. A Capital Markets Day in May will provide a full update on progress with the Three-year Plan to reflect the evolution of strategic milestones and industry events. Further details will be announced closer to the time.

With respect to the Alternative Revenue strategy, the Manager has been conducting formal trials since late 2025, with promising results. The Company continues to target £25mn in incremental EBITDA target from the Alternative Revenues strategy by the end of 2027. Further details are below.

Funding of the new pipeline

In December 2025, the Company signed agreements to acquire three pipeline projects, Cockenzie, Monets Garden and Elland 2, totalling 397MW / 794MWh. In the coming weeks, the project companies expect to reach financial close securing a combination of equity and senior and junior project financing tranches for these projects on attractive terms. Pre-funding construction work is underway.

For the new projects, we are securing project financing as separate facilities. This funding is expected to enable financing up to 70% of the total project cost with senior debt at an attractive margin.

In parallel with the senior debt financing, we are also securing a junior debt tranche which is export credit agency-backed and therefore competitively priced. This tranche of debt capital is specifically financing a portion of the BESS equipment for new projects and is junior to the senior debt and is expected to be priced at an attractive margin.

Taken together, with an element of equity funding, these transactions demonstrate the Fund's ability to attract long term capital from diverse sources, even when the ability to issue shares in the public market is constrained.

We also expect to contract to acquire the remaining two pipeline projects, Lister Drive (57MW) and Ocker Hill (240MW), imminently, with construction now likely to start in early 2027 given the later connection dates due to the Queue Reform delays.

Valuations and portfolio performance

Actions by the Company, including the first year of implementation of the Three-year Plan, drove NAV growth in 2025 despite headwinds from falling third-party revenue curves. These actions included the commissioning of Melksham, West Bradford and Shilton Lane as well as embarking on eight new project augmentations financed through the larger operational debt facility.

Both revenues and underlying operational portfolio EBITDA increased meaningfully in 2025, up 29.9% and 33.4% respectively. Revenue growth was primarily driven by stronger revenue generation from existing operational capacity: the portfolio generated £68.6k/MW/year, up 14.7% from £59.8k/MW/year in FY2024. In addition, the three newly commissioned projects served to increase grid connection and energy storage capacity, thereby increasing revenue, although they only became fully operational towards the end of the year and so the full year impact from these projects has yet to come through.

More on valuations and portfolio performance can be found in the Trading Update released on 4 March 2026 and in the accompanying Annual Report.

Alternative revenues

In December 2025, we began formal trials to explore the potential to implement a scalable Alternative Revenue strategy to capture more EBITDA margin available from the electricity value chain. It has so far exceeded expectations by more than doubling existing revenues on our trial capacity. Alternative Revenues generate more revenues than the existing revenue base, which in turn is not displaced.

The trial gradually increased in scale between December 2025 and March 2026 but remained below 10MW during this period. From 1 April 2026, the trial is stepping up to c.10MW which, if successful, could be scaled to a higher level before the end of 2026.

As it is extended to a wider portfolio, subject to staged reviews, this could significantly enhance the portfolio's revenues. We are therefore excited about this opportunity and look forward to progressively scaling it up. More information is provided in the Annual Report.

Ben Guest, Fund Manager of Gresham House Energy Storage Fund plc & Managing Director of Gresham House Energy Transition, added:

"In 2025 we executed on the foundations of the Three-year Plan: completing the initial portfolio, increasing duration, and setting up the financing for the new pipeline. 2026 is all about delivering on the next stage of growth for the Company as we close financing for the pipeline projects and start construction. This will set a template for how we continue to grow GRID going forward, despite traditional equity routes currently being closed. Additionally, we will deliver on the alternative revenue opportunity, increasing scale and enhancing portfolio cashflows.

"By delivering our Three-year Plan we anticipate further growth in 2026 in terms of capacity, revenues, EBITDA and NAV per share, providing comfort and clarity on the future earnings potential of the portfolio. We are excited to continue sharing progress on our plan and the value it will unlock for our shareholders."

Annual Results webinar

Gresham House will host a webinar for investors at 10:30am BST today. To access the live webinar, please register in advance here or using this shortcut url http://bit.ly/4eiPAIu.

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.

DISCLAIMERS

This announcement has been prepared for information purposes only. This announcement does not constitute a prospectus relating to the Company and does not constitute, or form part of, any offer or invitation to sell or issue, or any solicitation of any offer to subscribe for, any shares in the Company in any jurisdiction nor shall it, or any part of it, or the fact of its distribution, form the basis of, or be relied on in connection with or act as any inducement to enter into, any contract therefor. The merits or suitability of any securities must be independently determined by the recipient on the basis of its own investigation and evaluation of the Company. Any such determination should involve, among other things, an assessment of the legal, tax, accounting, regulatory, financial, credit and other related aspects of the securities.

This announcement may not be used in making any investment decision in isolation. This announcement on its own does not contain sufficient information to support an investment decision and investors should ensure that they obtain all available relevant information before making any investment. This announcement does not constitute or form part of and may not be construed as an offer to sell, or an invitation to purchase or otherwise acquire, investments of any description, nor as a recommendation regarding the possible offering or the provision of investment advice by any party. No information in this announcement should be construed as providing financial, investment or other professional advice and each prospective investor should consult its own legal, business, tax and other advisers in evaluating the investment opportunity. No reliance may be placed for any purposes whatsoever on this announcement or its completeness.

The information and opinions contained in this announcement are provided as at the date of the announcement and are subject to change without notice and no representation or warranty, express or implied, is or will be made in relation to the accuracy or completeness of the information contained in this announcement and no responsibility, obligation or liability or duty (whether direct or indirect, in contract, tort or otherwise) is or will be accepted by the Company, the Manager or any of their affiliates or by any of their respective officers, employees or agents to update or revise publicly any of the statements contained in this announcement. No reliance may be placed for any purpose whatsoever on the information or opinions contained in this announcement or on its completeness, accuracy or fairness. The document has not been approved by any competent regulatory or supervisory authority.

Any investment in the Company is speculative, involves a high degree of risk, and could result in the loss of all or substantially all of an investment in the Company. Results can be positively or negatively affected by market conditions beyond the control of the Company or any other person. There can be no assurance that any targeted returns will be achieved or that the Company will be able to implement its investment strategy or achieve its investment objectives. There is no guarantee that any such returns can be achieved or can be continued if achieved, nor that the Company will make any distributions whatsoever.

The information in this announcement may include forward-looking statements, which are based on the current expectations, intentions and projections about future events and trends or other matters that are not historical facts and in certain cases can be identified by the use of terms such as "may", "will", "should", "expect", "anticipate", "project", "estimate", "intend", "continue", "target", "believe" (or the negatives thereof) or other variations thereof or comparable terminology. These forward-looking statements, as well as those included in any related materials, are not guarantees of future performance and are subject to known and unknown risks, uncertainties, assumptions about the Company and other factors, including, among other things, the development of its business, trends in its operating industry, and future capital expenditures and acquisitions. In light of these risks, uncertainties and assumptions, the events in the forward-looking statements may not occur and actual results may differ materially from those expressed or implied by such forward looking statements. Given these risks and uncertainties, prospective investors are cautioned not to place undue reliance on forward-looking statements.

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No representation or warranty is given to the achievement or reasonableness of future projections, management targets, estimates, prospects or returns, if any. Any views contained in this announcement are based on financial, economic, market and other conditions prevailing as at the date of this announcement. The information contained in this announcement will not be updated.