23 September 2026

Gresham House Energy Storage Fund plc

("GRID" or the "Company")

Interim Results for the six months ended 30 June 2026

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 interim results for the six months ended 30 June 2026. All figures presented are unaudited.

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

"The first half of 2026 marked the transition of our Growth Plan from preparation to delivery. In the space of six months, the Company acquired or conditionally acquired over one gigawatt of new capacity, fully funded the first three projects totalling 397MW and got them into construction. We also made solid progress with augmentations of the existing portfolio and successfully completed a trial of the Alternative Revenues strategy.

"We took each of these steps with one objective: to grow the Company's earnings and Net Asset Value and deliver tangible value for shareholders. Our progress in the period is reflected by the increase in the Company's Net Asset Value of 15.8% to 131.30p per share at 30 June 2026, up from 113.34p at 31 December 2025, an early sign of the value that begins to crystallise as projects move into construction.

"Battery storage is strategically vital infrastructure for the UK's energy security and operationally necessary in its transition to clean power, and GRID remains the sector's largest and most established listed owner-operator. The Board remains confident that the delivery of our plan will translate into tangible, sustainable and attractive total returns for shareholders."

H1 2026 Highlights

Progress on the Growth Plan

In November 2024, the Company announced its Three-year Plan to grow the portfolio and identify new revenue streams. At the Capital Markets Webinar in May 2026, the Manager presented a revised set of targets, evolving the Three-year Plan into the Growth Plan. The changes share a single rationale: to direct the Company's capital towards the strategies that generate the highest returns for shareholders per pound invested.

Under the original plan, augmenting the existing portfolio to two-hour duration offered the highest return on the Company's capital - up to 1.5GWh targeting c.£33mn of additional EBITDA - ahead of a 680MW new-build pipeline that would have called substantially on the Company's own capital. Three financing innovations have since changed that assessment: project-level senior debt, export credit agency-backed equipment financing and the strategic joint venture with STP. Together they fund the majority of each new project without the need to issue equity at the Company level, so a megawatt of new capacity now requires only a fraction of the Company's capital that it previously would have.

The Growth Plan therefore reallocates capital towards an enlarged new project pipeline, with the Rayleigh project (480MW) largely offsetting a reduction in planned augmentations on the existing portfolio. The updated plan also takes account of the delays in getting connection offers back, in the context of NESO's Queue. It requires only c.£25mn of equity against the c.£300mn previously envisaged - a reduction of more than 90% in the capital required from the Company. The trade-off is a modestly lower EBITDA target of £141mn, compared with £150mn, targeted for late 2029.

Funding of the new pipeline

The Company completed three transactions in the period, which together form its new project funding model:

The combination fully funds the first three projects, involves no cross-collateralisation between projects or with the operational portfolio, and provides a repeatable template that is already being applied to the remainder of the pipeline. The Company has raised project-level equity at a premium to carrying value, retains 75% of the economics of each project for a small fraction of the capital it would otherwise have committed, and the pipeline is revalued on a DCF basis once construction commences.

Valuations and portfolio performance

The GRID attributable portfolio increased revenues and EBITDA compared to H1 2025, up 9.5% and 14.5% respectively, which included £1.1mn in revenue earned from liquidated damages due to the late commissioning of the West Bradford project. Revenue growth was primarily driven by the increase in operational MW capacity, with revenue generated per operational MW decreasing to £63,200 / MW versus £75,100 / MW in H1 2025, due to a weaker merchant revenue environment and the unavailability of certain assets while augmentation and maintenance works were completed.

The proportion of underlying portfolio revenues coming from contracted revenues increased to 61% (H1 2025: 35%), de-risking the portfolio's revenue profile. Contracted revenues are predominantly from tolling, accounting for nearly a third of all revenue, while Capacity Market revenues increased from 11% to 17% as the operational portfolio has seen new contracts starting over the last year. The portfolio's EBITDA margin increased from 65% to 68% through more efficient management of the cost base, primarily through lower O&M, business rates and insurance costs.

NAV per share increased by 17.96p (15.8%) during the period to 131.30p, up from 113.34p at 31 December 2025. The primary driver was the revaluation in Q2 2026 of the first three new projects, totalling 397MW, after completing their financing and beginning construction. This added 14.33p per share to NAV, illustrating the significant value created by continuing to grow the portfolio. The remaining pipeline projects, totalling 777MW, are currently held at cost on the balance sheet and represent further value creation potential not currently recognised in the NAV.

More on valuations and portfolio performance can be found in the Trading Update released on 2 September 2026 and in the accompanying Interim Report.

Alternative Revenues

The Alternative Revenues strategy has now progressed from concept to delivery, and its target under the Growth Plan remains unchanged at £25mn of incremental annualised EBITDA. These revenues are additive, sitting on top of the existing revenue stack rather than displacing it. They are inversely correlated with the current trading strategy, performing best in the flat, low-volatility markets where that strategy performs worst. The strategy has been extensively validated, both through back-testing across many years of volatile market conditions and through live revenue trials.

With an agreement now signed with a route-to-market provider, a measured, staged scale-up is under way during 2026 and 2027, ultimately building to cover around half of the portfolio. Because the strategy is delivered across assets the Company already owns, it requires only incremental capital, making it one of the highest-returning uses of funds available to the Company. With a targeted capacity of 20MW by the end of 2026, the impact of Alternative Revenues is not expected to be material to the Company and, as such, there is currently no inclusion of Alternative Revenues in the Company's reported NAV. More information is provided in the Interim Report.

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

"The first half of 2026 has been a period of intense focus, executing the milestones in our Growth Plan. During the period, GRID completed three transactions - a strategic joint venture with STP, export credit agency-backed facilities and senior project finance - which together form a repeatable funding model that reduces the total capital required from the Company by more than 90% and transforms the return on the equity our shareholders have invested.

"Our priorities for the second half of the year are clearly defined, and each translates directly into earnings and NAV per share growth. While our objective of maximising shareholder returns remains as steadfast as we set out in November 2024, the ways to achieve it have strengthened in the period. We remain focused on driving value from the operational asset base as well as the design, procurement and funding of the next set of projects, scaling Alternative Revenues to a meaningful level, and progressing the 2026 augmentation programme."

Interim Results webinar

Gresham House will host a webinar for investors at 10:00am BST today. To access the live webinar, please register in advance here.

The Company's Interim Report and Financial Statements for the period ending 30 June 2026 are available on the Company's website at: https://greshamhouse.com/grid and will shortly be available on the FCA's National Storage Mechanism: https://data.fca.org.uk/#/nsm/nationalstoragemechanism.

ENDS

For further information, please contact:

Gresham House Energy Transition                      +44 (0) 20 3837 6270

Ben Guest

James Bustin

Harry Hutchinson

Jefferies International Limited                             +44 (0) 20 7029 8000

Gaudi Le Roux

Stuart Klein

Harry Randall

Peel Hunt                                                                +44 (0) 20 7418 8900

Luke Simpson

Huw Jeremy

KL Communications                                             +44 (0) 20 3882 6644

Charles Gorman

Henry Taylor

[email protected]

JTC (UK) Limited as Company Secretary           +44 (0) 20 7409 0181

Ruth Wright

[email protected]

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.

Each of the Company, the Manager and their affiliates and their respective officers, employees and agents expressly disclaim any and all liability which may be based on this announcement and any errors or omissions from this announcement.

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.