Important information

Gore Street Investment Management
Alex O'Cinneide / Paula Travesso / Ben Paulden
Email: ir@gorestreetcap.com	Tel: +44 (0) 20 3826 0290
Shore Capital (Joint Corporate Broker)
Anita Ghanekar / Sophie Collins (Corporate Advisory)	Tel: +44 (0) 20 7408 4090
Fiona Conroy (Corporate Broking)
J.P. Morgan Cazenove (Joint Corporate Broker)
William Simmonds / Jérémie Birnbaum (Corporate Finance)	Tel: +44 (0) 20 3493 8000
Burson Buchanan (Media Enquiries)
Charles Ryland / Henry Wilson / Nick Croysdill	Tel: +44 (0) 20 7466 5000
Email: gorestreet@buchanan.uk.com
https://www.gsenergystoragefund.com

Interim Report

Gore Street Energy Storage Fund plc

For the six-month period ended 30 September 2025

Key Metrics

For the period ending 30 September 2025

NAV PER SHARE

90.1p

(March 2025: 102.8p)

OPERATIONAL CAPACITY

643.1MW

(March 2025: 417.11MW)

OPERATIONAL EBITDA*

for the 6 month period

£8.6m

(September 2024: £8.6m)

NAV TOTAL RETURN*

for the 6 month period

-10.6%

(September 2024: -3.0%)

DIVIDEND YIELD*

annualised and inclusive of the special dividend paid

8.5%

(September 2024: 7.0%)

DIVIDENDS DECLARED

for the period

2.19p

(September 2024: 2.0p)

Key Metrics	As at 30 September 2025	As at 31 March 2025
Net Asset Value (NAV)	£455.3m	£519.3m
Number of issued Ordinary shares	505.1m	505.1m
NAV per share	90.1p	102.8p
NAV total return since IPO*	31.6%	48.0%
Share price	51.8p	58.2p
Market capitalisation	£261.6m	£294.0m
Share price total return since IPO*	-22.9%	-14.3%
Discount to NAV*	-42.5%	-43.4%
GSF portfolio’s total capacity2	1.16 GW	1.16 GW
GSF portfolio’s operational capacity2	643.1 MW	417.11 MW
Gross Asset Value (GAV)*	£557.2m	£631.9m
Gearing*	18.3%	17.8%
Ongoing Charges Figure*	1.49%	1.38%
Key Metrics for the Period (1 April – 30 September)	As at 30 September 2025	As at 30 September 2024
NAV Total Return for the six month period*	-10.6%	-3.0%
Share Price Total return for the six month period	-9.5%	-8.2%
Average operational capacity2	492.1MW	367.21 MW
Total portfolio revenue for the six month period2	£16.7m	£15.2m
Average revenue (excluding liquidated damages) per MW/year for the six month period2	£67,853	£82,649
Operational EBITDA for the six month period*3	£8.6m	£8.6m
Total Fund earnings (excluding one-off costs) for the six month period*	£3.5m	£6.1m
Total Fund dividend cover for the period*1	1.00x	0.60x
Annualised Dividend Yield*1	8.5%	7.0%
Dividends per Ordinary Share declared during the period	2.19p	2.0p

* Some of the financial measures above are classified as Alternative Performance Measures, as defined by the European Securities and Markets Authority and are indicated with an asterisk (*). Definitions of these performance measures, and other terms used in this report, are given on page 48 of the 2025 Interim Report together with supporting calculations where appropriate.

1. The methodology for calculating dividend yield and dividend cover has been revised. These metrics are now based on dividends declared for the period, rather than dividends paid during the period, to provide a more meaningful measure of the underlying portfolio’s cash generation ability to cover distributions made by the PLC. Comparative figures for prior periods have been updated accordingly. The special dividend of 1.5p previously declared and paid in October 2025 has been excluded from Total Fund Dividend Cover (but not dividend yield) as this was linked to ITC transaction proceeds and not ongoing fund earnings.
2. The total portfolio revenue, operational EBITDA, total capacity, operational capacity and average operational capacity are adjusted to reflect GSF’s equity ownership in each asset. Comparative period figures have also been updated to reflect GSF ownership. For the Northern Irish assets, GSF financed all construction through a shareholder loan structure. Under this arrangement, GSF was entitled to 100% of cash flows until all capital expenditure plus a coupon had been repaid. Due to strong asset performance and a system design of only 26 minutes of duration, thereby minimising capex costs, full repayment occurred in c.3.5 years. From the start of this reporting period, these assets therefore began distributing cash to the minority partner, and the average operational capacity has been adjusted accordingly.
   Additionally, certain assets that reached commercial operations during the period have been weighted to reflect their operational status for only a portion of the reported period. Further, assets that are not yet generating revenue through the full range of revenue generating services available have been excluded for the purposes of determining the total portfolio revenue and the average revenue per MW per year to provide a more accurate reflection of portfolio performance. This includes Enderby in 2025 and Ferrymuir in 2024, which, while generating revenue from some streams, has faced delays preventing access to some available revenue sources. In cases of delay, as previously disclosed, commercial remedies such as liquidated damages may be pursued to compensate for lost revenue periods. Comparative period revenue, operational EBITDA, and average revenue have also been updated for this treatment to exclude liquidated damage payments from portfolio revenue, EBITDA, and average revenue metrics to show more accurately market performance of the portfolio.
3. Operational EBITDA is presented after deducting lease and rent payments for leased land. For comparison, operational EBITDA before rent is disclosed on page 19 of the 2025 Interim Report to reflect scenarios where projects have purchased land and therefore incur no rental costs.

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Chair’s Statement

On behalf of the Board of the Gore Street Energy Storage Fund plc, I am pleased to present the Company’s Interim Report covering the six months ended 30 September 2025.

It was a very difficult six-month period, both for the Company and the market as a whole, key developments over the period are as follows:

• The Company brought its Texas and California assets online, bringing operational and revenue-generating capacity to over 643MW. In GB, the Enderby Project (57MW) faced some delays, and while generating limited income from certain revenue streams, it is not yet able to access all possible revenue streams.
• The Company completed a strategy review, which was announced on 30 July 2025, focused on augmenting existing assets and monetising certain assets, either via disposals or through JV partnerships.
• The Company received c.$84 million net of insurance costs in Investment Tax Credits (ITC) proceeds, which, with operating income, reduced debt and allowed payment of a special dividend of 1.5 pence per share. A second special dividend of 1.5 pence per share will be paid out of ITC proceeds. The proceeds have been received and are being held in a lender-controlled account until certain project financing conditions are met. Once these are satisfied and funds are released, the dividend will be declared.
• The Company secured a material reduction in investment advisory fees from the investment manager.
• Following a pause during the strategy review, the Board restarted its succession process, leading to the appointment of three new, experienced directors, a new Chair, and a clear plan for full Board refreshment over the coming six months.
• The Company saw a challenge from a long-standing shareholder who has turned activist, resulting in a General Meeting (GM) one month before the scheduled Annual General Meeting (AGM), in which that shareholder sought Board changes. The resolutions were decisively defeated, but they evidenced a material minority of disaffected shareholders.
• Saba joined the share register in October with a disclosable c.5% holding.
• The Board engaged in extensive dialogue with shareholders on areas of concern and the various opportunities available to the Company.
• The Company has increased the level of disclosure around operational fees paid to the Manager, to provide clarity to shareholders.

Each of these points is covered below in detail and will continue to be addressed by the Board and the Manager as the Company moves forward under the guidance of a new Board of Directors.

Performance and Unaudited NAV

Average revenue over the half-year period was £7.75 per MW per hour—above that of a GB-only portfolio, underscoring the benefit of geographical diversification. Asset availability remained positive, with average asset uptime exceeding 94% across the portfolio. However, appreciation in the Company’s NAV per share resulting from operational milestones being achieved was offset by reductions in the third-party revenue curves that underpin the asset valuations. These updated revenue curves were the primary driver of NAV during the period, and resulted in a reduction of c.12%, from 102.8 pence per share as at 31 March 2025 to 90.1 pence per share as at 30 September 2025. Further details of valuation movements can be found on page 14 of the 2025 Interim Report.

Capital Allocation

In response to evolving market conditions and following an independent review, the Board introduced a revised capital allocation strategy during the period. The strategy focuses on four key areas:

• Selective sale or co-investment of the 495 MW pre-construction portfolio, starting with the sale of the 22 MW German asset Cremzow. Progress so far: Sell-side advisor appointed ahead of going out to market.
• Augmentation of key GB and Irish assets, including enhancements of the Stony (79.9MW) and Ferrymuir (50MW) sites from 1-hour to 2-hour duration. Progress so far: Initial focus has been on GB assets, with the EPC contract successfully signed post period and works scheduled to commence on site shortly, with a post augmentation COD scheduled for FY 2026 Q3.
• Increasing revenues through additional onboarding of assets to the GSET platform, which continues to consistently outperform third-party benchmarks. Progress so far: During the period, three of the Company’s Texas assets were successfully onboarded onto the GSET platform. This brings the total capacity optimised through GSET to c.192 MW as at 30 September 2025.
• Cost reductions across the portfolio. Progress so far: Post period (effective from 1 October 2025), Investment Manager fees were materially reduced, with performance-based and exit-based fees removed. Additional operational savings have been realised across key areas such as insurance on a per-MW basis, which has resulted in an annual saving of c.£600k with further reductions targeted, including lower financing costs.

Given ongoing uncertainty around interest rates, leverage will continue to be managed prudently.

Opportunities to diversify and secure long-term revenues are being explored. Notably, the pre-construction Middleton project is under final evaluation to become an 8-hour long-duration energy storage (LDES) asset, potentially securing 20 years of revenue certainty via a cap-and-floor mechanism. Other opportunities to realise shareholder value and improve revenue generation from the portfolio are under active evaluation.

The Board has evaluated all available options to address the persistent share price discount, including buybacks. After considering liquidity, scale, effectiveness, and opportunity, we have pursued what we believe is the most effective way to create value for the Company. The Board remains confident that these initiatives will drive long-term value creation and improve shareholder returns.

Dividends

Based on historic cash generation of the Company’s underlying portfolio and a conservative view on future revenue, the Board announced the Company’s dividend policy prior to the FY24/25 Annual Report. Rather than the prior fixed target approach, dividends are now based on actual cash generation from the underlying portfolio.

In addition, we have guided to two 1.5 pence per share special dividends, linked to the receipt of the investment tax credits. The first tranche ITC-linked special dividend of 1.5 pence per share was declared and paid in October 2025. The second special dividend of 1.5 pence per share will be paid out of ITC proceeds. The proceeds have been received and are being held in a lender-controlled account until certain project financing conditions are met. Once these are satisfied and funds are released, the dividend will be declared

In accordance with the dividend policy, the Board has today declared a 0.69 pence per share dividend for the September-end quarter to be paid on or around 23 January 2026.

Activist Shareholders

The Board has engaged extensively with shareholders to address concerns and maintain transparency. This included dialogue with activist investors. Over the period, an activist shareholder convened a General Meeting. Although the requisitioned resolutions were decisively rejected at the GM, the Board acknowledges the perspectives raised and has incorporated relevant feedback and accelerated the Board succession, as evidenced by the announced new Directors and a new Chair to bring fresh perspectives.

Liquidity and Balance Sheet

The balance sheet remains strong, with active efforts underway to unlock value from pre-construction assets and redeploy capital into higher-return opportunities. The group ended the period with £50.5 million in group cash and £41.7 million in undrawn debt capacity.

Total debt drawn, across the Company and its assets, was £101.95 million as at 30 September 2025, resulting in a GAV ratio of 18.3%, in line with the previously guided target ratio of 15-20%.

Board Succession

This period marked a significant phase of Board refreshment. We were pleased to welcome Simon Merriweather to the Board during the period, followed by Norman Crighton and Angus Gordon Lennox post-period. These appointments bring deep expertise across investment trusts, renewables and infrastructure, and corporate activity.

As part of a structured succession process, we have announced the retirement of several long-serving Board members, including myself. Angus Gordon Lennox will assume the role of Chair on 19 January 2026, following a selection process led by the Remuneration and Nomination Committee, as detailed in the Governance section of this report. This process was overseen by a dedicated sub-committee using objective criteria and a structured evaluation framework.

Angus joined the Board on 22 October 2025 and brings extensive leadership experience, including current roles as Chair of Aberforth Geared Value & Income Trust plc and Executive Chair of two private family businesses. He is a former Chair of the Mercantile Investment Trust plc and past Senior Independent Director of Securities Trust of Scotland, with a 24‑year career as a corporate broker at Cazenove & Co and J.P. Morgan Cazenove.

To ensure continuity, I will remain on the Board until 31 March 2026. We also acknowledge the retirement of Thomas Murley and Malcolm King, who have served since the Company’s IPO. We thank them for their invaluable contributions over the past seven years. To complete the refresh, one additional Non-Executive Director will be appointed ahead of the 2026 AGM.

Shareholder Engagement and Reporting

Over the reported period, the Board engaged closely with shareholders through a roadshow to gather feedback on the Company’s market position, cash allocation, US ITCs, and leverage strategy. Options discussed included investing for sustainable growth, dividends, share buybacks, and debt repayment. A majority of investors consulted expressed a preference for distributing ITC proceeds via dividends, which we are in the process of delivering.

Additionally, during the period, the Company held both a GM and its AGM. At the GM, all requisitioned resolutions (1-4) were strongly rejected by poll. At the AGM held on 18 September, all ordinary resolutions were approved, and two of the four special resolutions (Resolutions 16 and 17) were passed. Resolutions 14 and 15, which concern the removal of pre-emption rights for potential new share issuance, received over 74% support but did not meet the 75% threshold required to pass. These outcomes have no immediate operational impact.

Manager Fee Revision

As part of the review of strategy completed during the period, the Board secured a material reduction in fees payable to the Investment Manager. Effective from 1 October 2025, the revised fee structure is rebased to 1% of equal weighting of market capitalisation of the Company and NAV. Based on the prevailing share price, this delivers a material reduction in management fees, reflecting our commitment to cost efficiency and alignment with shareholder interests. This adjustment was achieved following constructive engagement with the Manager and benchmarking against industry standards. In addition, all performance and exit fees have been removed from the Investment Management contract.

Based on the FY2024 average share price, the revised structure would have delivered an estimated 22% reduction in fees (c.£1.14m), excluding additional savings from the removal of performance and exit fees.

Following investor feedback, on 30 September 2025, we published a detailed breakdown of the fees paid to the Managers under the Commercial Management Agreement (CMA), the terms of which were previously disclosed in 2022 and route to market agreements (RTM) at PLC and at the SPVs. CMA fees have been benchmarked against industry standards and reflect the full scope of services provided, including construction management, asset oversight, and commercial optimisation. We are committed to maintaining this level of transparency going forward, and details of fees paid in respect of this reported period are detailed within this report. Further details are available on page 20 of the 2025 Interim Report.

Reporting Framework

We have also significantly improved our reporting framework to provide greater clarity and comparability across the sector. Historically, revenue reporting has varied between the Company and its peers, with figures presented on a gross or net basis, and sometimes net of certain fees such as RTM but inclusive of others. To eliminate ambiguity, we present within the report gross revenue, followed by a more granular breakdown of portfolio costs, bridging these through to total fund earnings. To ensure transparency on GSF’s attributable performance, all revenue and MW figures have been prorated. We have introduced period-on-period revenue curve comparisons by market, supplemented with commentary on portfolio operating costs. This became more important over the period as the Northern Irish assets had a unique structure: originally funded via a shareholder loan, GSF covered all capex and held rights to 100% of cash flow until repayment of principal and coupon. Strong revenues and a low capex build-out enabled full repayment within a short timeframe—given Commercial operations Date (“COD”) in 2021, this demonstrates an attractive payback period. The assets (MEL and DEL, 100MW in total) now distribute to both the minority JV partner and GSF.

This report includes details on operating costs at both the PLC and portfolio level. We have also committed to [quarterly revenue updates in factsheets] and accelerated Board refreshment, which is nearing completion. The Board plans to hold another round of formal shareholder engagement towards the end of the financial year to update on progress against strategy.

Impact and Sustainability

Sustainability remains a core part of the Company’s strategy as reflected in the 2024-2025 ESG and Sustainability Report, which was published on 08 September 2025. Over the year, the operational fleet avoided 11,970 tCO2e and stored 39,290 MWh of renewable electricity, demonstrating the portfolio’s tangible contribution to the energy transition.

The Report also outlines the Company’s commitments as an Article 8 product under the EU Sustainable Finance Disclosure Regulation (SFDR), and its voluntary alignment with the UN Principles of Responsible Investment (PRI) and Task Force on Climate-Related Financial Disclosures (TCFD). Energy storage continues to play a vital role in enabling a low-carbon future, and the strong fundamentals of the portfolio reflect this strategic importance.

As the Board refreshment progresses and the capital allocation strategy is implemented, the Company is well-positioned to navigate market conditions, pursue revenue opportunities across its diversified portfolio, and maintain constructive engagement with shareholders. The Board remains committed to open dialogue and will continue to respond to shareholder feedback.

Patrick Cox
Chair

Dividend & Capital Allocation policy

Dividend Policy Overview

The Board has indicated its intention for dividends to be covered by operational cash flow. In line with this policy, quarterly payments commenced with the September-end quarter 2025, for which the Board has declared a dividend of 0.69 pence per share, fully covered by operational cash flow.

Dividends Declared to Date

Quarter ended 30 June 2025: No dividend was declared.

Quarter ended September 2025: A dividend of 0.69 pence per share has been declared today, 15 December 2025.

Special Dividends

In addition to regular dividends under the policy, the Board has announced special distributions linked to the monetisation of the Dogfish and Big Rock Investment Tax Credits (ITCs):

First tranche: 1.5 pence per ordinary share, paid on 31 October 2025.

Second tranche: The second special dividend of 1.5 pence per share will be paid out of ITC proceeds. The proceeds have been received and are being held in a lender-controlled account until certain project financing conditions are met. Once these are satisfied and funds are released, the dividend will be declared.

Capital Allocation

The Board remains committed to delivering value for shareholders through a disciplined and transparent approach to capital allocation. The primary objective is to maximise investment returns while maintaining financial flexibility. This requires continuous monitoring of forecast cash flows and expected returns, undertaken in close collaboration between the Board and the Investment Manager.

The Board have also taken shareholder feedback and engaged a third party to conduct an external review of the Company’s strategy. This process has informed the development of a clear framework designed to optimise resources and enhance returns.

The Company’s capital allocation framework is built on four key pillars:

1       Monetisation of pre-construction assets – Unlocking capital through the sale of the Company’s 22 MW German asset, and the sale or co-investment of c.495 MW of pre-construction projects.

2       Asset augmentation – Targeted augmentation of select GB and Irish assets to increase energy capacity.

Augmentations will be funded from existing cash and debt headroom, with future augmentation expected to be funded through capital recycling.

3       Revenue optimisation – Leveraging proprietary trading models to maximise revenue.

4       Cost efficiency – Drive further reductions in operating costs across the portfolio to improve margins.

This structured approach ensures that capital is deployed where it can generate the greatest long-term benefit, supporting both growth and resilience in a rapidly evolving market environment.

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Investment Manager’s Report

Introduction

Dr. Alex O’Cinneide
Chief Executive Officer, GSC

There’s a clear disconnect between public and private market valuations—listed energy storage funds are trading at deep discounts, while private transactions continue to reflect intrinsic value. We are now recycling capital where private appetite is strongest, investing in high-return opportunities, and scaling the infrastructure that underpins the energy transition.

Navigating a Complex Market and Unlocking Value

The listed energy storage sector remains under pressure, with persistent discounts to NAV and revenue volatility weighing on investor sentiment. Despite these challenges, the long-term fundamentals and growth potential of the asset class remain robust. Global power systems are accelerating towards renewables, driving an urgent need for flexibility and resilience. Battery storage sits at the heart of this transition, providing the critical infrastructure required to balance intermittent generation and maintain grid stability.

This structural role of BESS is reflected in private market transactions. The implied public market valuations for renewable and storage funds have compressed significantly, with London-listed vehicles trading at double-digit discounts. In contrast, private transactions continue to clear at or near stated NAVs, and in some cases at premium multiples. This disconnect is striking and informs our approach: recycle capital where private appetite is consistently strong, deploy into augmentation where returns are highest, and maintain appropriate assumptions in our valuation methodology.

At the same time, the sector’s fundamentals are improving. Battery capex has fallen sharply over the past two years, resetting project IRRs and making longer-duration assets increasingly economical. Regulatory developments such as the UK’s Long Duration Energy Storage (LDES) scheme and the automation of the Open Balancing Platform (OBP) are expected to enhance revenue visibility and market access over the medium term. The Company’s pre-construction GB asset, Middleton has progressed to Stage 2 of the LDES application, with potential for an 800 MWh Track 1 asset in 2029. These efforts underscore our long-duration strategy and commitment to positioning the Company to benefit from these structural tailwinds.

We continue to invest in the Gore Street Capital (GSC) team to drive portfolio value creation. Today, the team currently consists of over 40 FTE, primarily based in GB, with satellite offices worldwide. Our integrated approach spans the entire asset lifecycle, bringing together construction, asset management, commercial, and trading teams. This collaboration ensures rapid communication and maximises economies of scale to deliver sustainable growth.

Over the reported period, the GSC team has acted decisively to enhance shareholder value. We monetised US tax credits above guidance, generating significant liquidity and reducing gearing; we initiated asset sales to realise value from pre‑construction projects and committed capital to high-return augmentation opportunities that strengthen revenue resilience. We have also completed the construction of all prioritised assets within the Company’s portfolio, which now has over 600 MW of operational assets that support cash generation and dividend distribution for shareholders.

Post period, we successfully completed the execution of augmentation EPC contracts for the two GB assets, Stony and Ferrymuir. The cost of the augmentation is at the lower end of the previously guided £18-22 million, and has a strict contractual availability backed into the contract, and a COD for both assets in FY 2026 Q3.

NAV & Financials

Financial performance over the period reflects the resilience of GSF’s portfolio in challenging conditions. Operational EBITDA for the period was £8.60 million with a margin of 51%, supported by disciplined cost management and multi asset contracts which leveraged the portfolio’s scale to manage costs. A detailed breakdown of operating costs have been included to provide the market with higher levels of disclosure to more appropriately value the portfolio which can be found on page 18 of the 2025 Interim Report. Revenue-related costs remained broadly in line with expectations, and operating costs were controlled through leveraging the scale of the fleet for cost efficiencies and the use of technology, something the market should expect to see continue and expand over time.

NAV declined over the period from £519.3 million to £455.3 million, which was driven predominantly by adjustments to forward revenue curves across GB and US markets. These revisions reflect updated third-party market expectations for ancillary service pricing and trading spreads, which have softened in the near term due to increased capacity and evolving system dynamics.

Further detail on the valuation and revenue assumptions can be found on page 14 of the 2025 Interim Report.

Balance Sheet

As at period end, available group cash stood at £50.5 million, with £41.7 million in undrawn debt capacity, providing flexibility to fund ongoing operations and future growth.

Total debt drawn across the Company and its assets was £101.95 million as at 30 September 2025, resulting in a GAV gearing ratio of 18.3%. This remains firmly within the previously guided target range of 15–20%.

Asset Development and Augmentation

Recent trends of declining capital expenditure have enabled the deployment of longer-duration battery systems at significantly reduced marginal costs. The cost of augmentation has now fallen to nearly half of what it was just a few years ago, reinforcing our strategic approach of waiting for optimal pricing windows and deploying capital in a manner that maximises long-term value for investors.

These upgrades enable assets to charge and discharge over longer durations, unlocking additional trading opportunities in particular. Post period the Company executed the EPC contracts for the augmentation of Stony and Ferrymuir to extend their duration to two hours, which is expected to deliver a material uplift in revenue and ultimately EBITDA. Construction will begin in March 2026 for completion in FY 2026 Q3. Beyond near-term cash generation, two-hour systems in the GB market typically command a valuation premium over one-hour assets.

Additionally, the Company’s Middleton asset was one of 77 projects selected from 171 submissions to proceed to second‑stage assessment during the LDES application window. The LDES programme operates under a cap-and-floor regime, which mitigates investment risk by guaranteeing minimum revenues. The second-stage submission has been completed, with initial decisions expected in Spring 2026.

If selected, Middleton will deliver a Track 1 800 MWh asset in 2029, representing a significant step forward in the Company’s long-duration strategy.

Delivering on Strategic Objectives

Following a comprehensive review of the Company’s strategy and in response to feedback from both investors and the Board, we launched a programme to unlock value from the Company’s pre-construction assets through targeted disposals and co-investment opportunities. Alongside evaluating the 495 MW in pre-construction, the Company has also announced the intention to sell the 22 MW Cremzow asset in Germany, allowing GSF to consolidate its operational presence in GB, Ireland and US.

Earlier in the period, we successfully monetised the Big Rock and Dogfish Investment Tax Credits (ITCs) at levels exceeding initial guidance. This achievement enabled a reduction in the Big Rock debt facility, lowering gearing and supporting the payment of a special dividend to shareholders. The first tranche of this dividend has already been distributed and a second special dividend of 1.5 pence per share will be paid out of ITC proceeds. The proceeds have been received and are being held in a lender-controlled account until certain project financing conditions are met. Once these are satisfied and funds are released, the dividend will be declared.

Sustainability and Impact

The Company’s 2025 ESG & Sustainability Report was published in the period, highlighting that the operational portfolio stored 39,290 MWh of renewable electricity and avoided 11,970 tCO2e. This year, the Manager’s ESG function adopted a marginal emission factor methodology, which was developed in consultation with industry groups, to more accurately reflect the emissions displaced by battery assets in GB, Texas, and Ireland. While the previous gas peaking plant proxy‑based approach was retained for Germany, the new model incorporates variables such as turbine efficiency and carbon intensity and improves comparability across funds.

However, limitations remain in calculating avoided emissions from ancillary services due to data constraints and the absence of an industry-standard methodology. The 2025 ESG & Sustainability Report and previous reports and disclosures can be found on the Company’s website.

Valuation

Valuation Overview

	£m	Pence/share
Opening NAV (31 March 2025)	519.3	102.8
Underlying portfolio return (Rollover & Actuals)	+7.6	+1.5
Revenue curves	-51.3	-10.2
Discount rate & opex	-7.1	-1.4
Fund expenses	-6.3	-1.2
Dividends paid	-10.1	-2.0
Other valuation movements	+3.2	+0.6
Closing NAV (30 September 2025)	455.3	90.1

Portfolio Valuation Overview

	Operational*	Pre-Operational
GB	£164,311,747	£14,696,834
NI	£35,150,166	–
Texas	£39,096,280	£6,693,218
California	£143,139,643	–
Europe (GER/ROI)	£58,126,771	£16,242,128

* Includes the PBSL2 and 57 MW Enderby asset, which, although generating some revenue, has experienced delays and is not yet realising its full revenue potential.

Summary

The Company’s NAV declined from £519.3 million (102.8 pence per share) as at 31 March 2025 to £455.3 million (90.1 pence per share) as at 30 September 2025, driven primarily by a reduction in revenue curves across the Great Britain and the US markets.

The updated curves are more closely aligned with recent actual performance and are notably lower than the latest peer group disclosures.

Operationally, the portfolio continued to generate strong cash flow, and several projects achieved key milestones. However, the positives of the underlying performance were outweighed by the impact of revised merchant revenue curves and increases in discount rates.

Underlying Portfolio Return

This line item reflects actuals and rollover. Revenue generation from the underlying portfolio supported by strong asset availability is captured within the actuals and rollover, as well as the timely receipt of ITC proceeds in the US.

Revenue Forecasts

As at 30 September 2025, the valuation reflects updated mid-case revenue forecasts across all markets where the Company operates. The revenue curves disclosed below reflect the weighted duration of the assets in each respective grid. The approach and underlying data providers remained consistent with those used in the previous valuation period. Revenue curves were a significant driver of valuation movement during the period, contributing to an overall reduction in NAV of c.12%.

Relative to the assumptions applied at 31 March 2025, Great Britain showed a downward adjustment in merchant revenue expectations. This revision reflects the expected increase in installed battery capacity, further supported by the Long Duration Energy Storage Scheme (LDES) cap-and-floor mechanism in GB, which aims to procure significant BESS capacity under its framework. Approximately 28.7 GW of projects are under consideration for the second-stage of assessment, but OFGEM has yet to confirm how much capacity will be awarded in final contracts. These changes are consistent with recent historic run-rate performance. For the GSET optimised GB assets, near-term revenue forecasts have been manually adjusted by a 20% increment up to 2027, to reflect consistent outperformance vs forecasts.

In addition to the weighted average revenue curve used across the Company’s GB fleet, the “GSF 1hr & 2hr Curve-GB” graph included on page 15 of the 2025 Interim Report, shows the one and two hour revenue curves broken out separately.

In the United States, short-term forecasts were also moderated to account for recent policy uncertainties and slower than expected renewable deployment. While these factors reduced near-term expectations, the longer-term outlook remains more positive, with incremental improvements expected over the medium term. Based on the Investment Manager’s close monitoring of market conditions, a prudent step has been taken to manually adjust near-term U.S. revenue curves for ERCOT and CAISO. These adjustments place projections below those provided by third-party forecasters to align with recent historical averages. This approach is consistent with prior disclosures and practices when the Investment Manager identifies discrepancies between actual performance and short-term forecasts.

Germany saw a modest uplift in revenue forecasts, supported by structural shifts in the generation mix and reduced nuclear availability over the medium term.

Ireland remained broadly consistent with the previous period, with no material impact on valuations.

Inflation Assumptions

The short-term inflation assumption for the remainder of 2025 shows a minor increase in Great Britain, a slight decrease in Europe and broadly flat across the US. The net effect of these changes is broadly flat.

Long-term inflation assumptions from 2026 onward remain consistent with the March-end assumptions across all geographies. The long-term figures represent the average inflation expected to occur over the remaining life of each asset, demonstrating how inflation impacts revenue over time.

Assumptions	2025	2026+
GB	3.44%	2.50%
EUR	2.10%	2.25%
US	2.92%	2.25%

Discount Rates

Discount rate assumptions for Great Britain, Ireland and Germany remained unchanged from those applied in the 31 March 2025 valuations. In the U.S. markets, discount rates were increased by 25-basis points to reflect higher market volatility. However, for the Dogfish and Big Rock assets, discount rates were reduced to reflect the lower risk associated with operational assets compared to those under construction leading to a slight net overall increase in the average discount rate applied to the US assets.

As at 30 September 2025, the weighted average discount rate used across the portfolio was 10.2%.

Discount Rate Matrix	Pre-construction phase	Operational phase*
Contracted Income	10.75-12.00%	7.25-9.25%
Uncontracted Income	10.75-12.00%	8.75-9.50%
MW	456.6	700.1

• Includes the 57 MW Enderby asset, which, although generating some revenue, has experienced delays and is not yet realising its full revenue potential.

Other Valuation Movements

This line item reflects adjustments to capex forecast decreases, Commercial Operation Date updates, and the impact of foreign exchange movements over the period.

Sensitivity Analysis

The chart included on page 17 of the 2025 Interim Report, illustrates the sensitivity of GSF’s NAV per share to changes in key input assumptions.

Contracted Revenue

BESS primarily operates as a merchant asset class, generating income through wholesale trading and ancillary services. Through diversification, the number of additional contracted revenue streams available to the portfolio has increased and now includes GB and Irish capacity market contracts, DS3 Capped in Ireland which is a fixed price contract, DS3 uncapped which acts as a cap and floor agreement and the Resource Adequacy program in California.

To mitigate merchant risk, the Company has increased the proportion of contracted revenues within the portfolio.

Over a quarter of revenue for the next calendar year (2026) will be fully contracted, based on secured agreements and the revenue forecasts disclosed above for the merchant portion of the revenue stack. Nominal revenue unadjusted for availability was used for the purpose of calculating this metric.

Valuation Methodology

The Company has maintained a consistent and transparent approach to valuations, using mid-case blended averages from multiple independent providers for revenue curves, and maintained a consistent approach to macro assumptions, which are disclosed on a bi-annual basis. This methodology avoids the use of high or low case forecasts to influence NAV or borrowing capacity, resulting in lower NAV volatility compared to peers. The Company employs an independent valuer (BDO) as well as an independent auditor (EY) to oversee the valuation process.

Within this framework, the valuation of the Company’s pre-construction GB asset, “Middleton”, has reflected sector-wide trends and project-specific developments. Due to the valuable, 15-year Capacity Market contract being gained by Middleton, it was deemed appropriate to apply a DCF valuation to this pre-construction asset; the Company’s other pre-construction assets are valued at cost. Fluctuations in the Middelton’s value have been driven by factors such as the award of a high-value Capacity Market contract, changes to the expected Commercial Operation Date (COD), and updates to revenue curves which follow the wider market trend. Downward revaluations have occurred when the COD was pushed out, due to NGET changing the connection date of the asset. This delay affected the assumed start of operations, which in turn impacted the Capacity Market contract assumptions and have resulted in a higher discount rate being applied to the project. The revenue curves used in the asset valuation, sourced from third-party research houses, have also shown a broadly downward trend in recent periods.

The graph included on page 17 of the 2025 Interim Report shows NAV movements excluding dividends across GSF and its peers, highlighting the consistency and resilience of GSF’s valuation methodology.

Financial Performance

Financial Performance of the Underlying Portfolio

The financial performance of the Company’s underlying portfolio for the interim period to 30 September 2025 demonstrates the continued resilience of the business model. Total revenue for the period was £16.74 million, derived from ancillary services, capacity market payments (or equivalent), and trading activities. The ongoing diversification of income streams with the portfolio spanning five distinct markets materially reduced the portfolio’s exposure to volatility in any single geography or revenue source.

Reflecting the changing portfolio construct with significant assets coming online in the US, the period saw a further reduction in the Company’s concentration in the Great Britain market. This shift was particularly evident in the increased amount of contracted income from capacity market and capacity market-equivalent contracts, such as the Resource Adequacy contract in California. Additionally, the portfolio’s merchant revenue saw a greater emphasis on trading strategies. This was driven by the growing weighting of international operational assets within the portfolio.

Revenue-related costs, which are made up of Route-to-Market (RTM) fees and energy costs, accounted for c.10% of revenue, or £1.70 million in aggregate. RTM fees have not been disclosed standalone given the commercial sensitivity. RTM fees remain the only cost directly linked to revenue, which therefore will scale as a percentage of net revenue. Energy and grid costs, while variable, are more closely linked to operational factors such as asset cycling and dispatch patterns rather than to revenue itself.

Operating costs, which include recurring operations and maintenance (O&M) contracts, essential repairs, and site-level operational expenses, amounted to £4.68 million. The Company continues to benefit from multi-asset O&M contracts with external providers, which provide both cost certainty and benefit from economies of scale. As the portfolio has expanded, these contracts have enabled the Company to control costs, with increases in operating costs primarily attributable to the larger asset base rather than inefficiencies.

Administrative costs amounted to £1.13 million related to insurance premiums, Tax, Audit, and other administrative expenses. Insurance costs have reduced on a MW basis, leading to an annual saving of c.£600k relative to already well-optimised insurance premiums from the 24/25 policy, due to a softening market further supported by a focus on data‑driven asset management, which has fed into insurance premiums. The majority of these costs are fixed by contract or set annually.

Underlying Operational Portfolio Performance

Average operational MW during the period*	492.1
Average operational MWh during the period	557
Revenue (£)
Ancillary Services	11.66m
Capacity market/Resource Adequacy	3.04m
Wholesale Trading	1.86m
Other	0.18m
Total Revenue (£)	16.74m
Revenue-related costs	(1.70m)
Net Revenue (£)	15.03m
Other operating costs	(4.68m)
Administrative costs	(1.13m)
Operational EBITDA before rent (£)	9.22m
Rent	(0.62m)
Operational EBITDA (£)	8.60m
EBITDA margin	51%

Key Metrics (£)

Revenue/MW	67,853
Revenue/MW/hr	7.75
Revenue/MWh	59,951
Revenue related costs as a % of revenue	(10)%
Total cost/MW	(32,993)
Other operating and admin costs per MW	(26,082)
EBITDA/MW	34,860
EBITDA/MWhr	30,800

* The total operational capacity is adjusted to reflect GSF’s equity ownership in each asset. Certain assets that reached commercial operations during the period have been weighted to reflect their operational status for only a portion of the reported period. Further, assets that are not yet generating revenue through the full range of revenue generating services available have been excluded for the purposes of determining the total portfolio revenue and the average revenue per MW per year to provide a more accurate reflection of portfolio performance. This includes Enderby in 2025, which, while generating revenue from some streams, has faced delays preventing access to some revenue sources. In cases of delay, as previously disclosed, commercial remedies such as liquidated damages may be pursued to compensate for lost revenue periods. Accrued Liquidated damages and net earnings for projects not participating in full revenue services are included in a separate line.

Aggregated Financial Information (£)

Operational portfolio EBITDA	8.60m
Liquidated damages accrued and net earnings for capacity market only period	1.67m
Intermediate HoldCos OpEx (net of interest income)	(0.30m)
Realised gain/(loss) on derivative	0.06m
Portfolio earnings before interest, tax and depreciation	10.03m
GSF Plc admin & other expenses	(3.64m)
GSF Plc - external interest income	0.12m
GSES 1 level debt facility commitment fees	(0.26m)
GSES 1 level debt facility interest expense	(2.21m)
Project level debt interest expense	(0.54m)
Total Fund earnings (excluding one-off costs)	3.50m

Fees Payable to the Gore Street Capital Group

This section outlines the fees incurred by the Company and its subsidiaries for services provided by the Gore Street Capital (GSC) group. These fees cover a range of technical, investment and administrative services delivered under distinct contractual arrangements as set out below.

1. AIFM & Investment Management Agreement

Gore Street Investment Management Limited (a GSC group entity) provides investment and risk management services to the Company. Following a Board-led fee review, a revised agreement was reached and subsequently implemented on 1 October 2025, resulting in a substantial reduction in fees. This change delivers meaningful cost savings and enhances long-term alignment with shareholder interests.

• Services: Investment management and risk oversight
• Terms:
1. Annual fee of 1% of the average (50:50) of market capitalisation and adjusted NAV, subject to a cap of 1% of adjusted NAV
2. Fixed fee of £75,000 per annum for AIFM services
3. No performance fees

2. Commercial Management Agreement (CMA)

Gore Street Services (a GSC group entity) provides essential commercial and operational services to the Company and its subsidiaries. These include construction oversight, fleet management, financial and corporate administration, ESG support, and insurance coordination.

• Services: Construction, operational, administrative, and company secretarial support
• Terms:
1. Fees capped at the lower of cost plus 15% or 1% of NAV
2. Cap applies to all payments, whether made at PLC or SPV level
• Any excess above the cap is reimbursed by GSC within 14 days
• Actual run-rate fees paid were lower for the period than for previous equivalent periods

3. GSET Optimisation Agreement

The Company has onboarded some of its assets to Gore Street Energy Trading (GSET), a GSC entity, to manage revenue optimisation strategies. This internalisation of trading services within the Investment Manager’s group enhances technical integration and supports bespoke optimisation.

• Services: Revenue stacking and asset optimisation
• Terms:
1. Fees based on a percentage of revenue, broadly aligned with prior third-party contracts
2. Capped at not more than or equal to 0.25% of the lower of market capitalisation or NAV
3. Actual fees paid to date remain materially below the stated cap

The proprietary software developed by GSC for this purpose is tailored specifically to energy storage assets, enabling tighter synergy between trading and asset management functions. Performance is reviewed regularly and has consistently outperformed external benchmarks.

	H1 26 (Apr 25 to Sep 25)			H1 25 (Apr 24 to Sep 24)
Fees Payable to Gore Street Capital Group over the period (£)	PLC	SPV	Total	Total
Investment Advisory fee	2,628,793	–	2,628,793	2,620,412
AIFM fee	37,500	–	37,500	37,500
Commercial management services delivered to GSF Plc	346,279	–	346,279	289,210
Commercial management services delivered to operational assets	–	1,347,356	1,347,356	1,324,913
Commercial management services delivered to construction assets	–	910,801	910,801	1,051,164
Total CMA	346,279	2,258,157	2,604,436	2,665,287
GSET Optimisation fees	–	255,956	255,956	–
Total GSC group fees	3,012,572	2,514,113	5,526,685	5,323,199

Revenue Breakdown from Operational Portfolio

This section provides a detailed breakdown of revenue generated by the Company’s underlying operational portfolio. It highlights the contribution of each market to overall revenue, highlighting the performance across different geographies and market services.

	£(000’s)	% within grid
GB 237.5 MW / 228.4 MWh
Ancillary Services	6,027.1	90%
Capacity Market	703.6	10%
Wholesale Trading	(73.1)	(1)%
Other	54.4	1%
Total	£6,712.0	100%
Ireland 81MW / 51.7 MWh
Ancillary Services	4,084.3	83%
Capacity Market	557.5	11%
Wholesale Trading	177.3	4%
Other	108.5	2%
Total	4,927.6	100%
Germany 19.8MW / 26.1 MWh
Ancillary Services	1,394.8	81%
Wholesale Trading	321.9	19%
Other	4.5	0%
Total	1,721.2	100%
Texas 83.95 MW / 113.8 MWh
Ancillary Services	62.6	7%
Wholesale Trading	867.3	93%
Other	1.0	0%
Total	930.9	100%
California 69.77 MW / 139.5 MWh
Ancillary Services	88.5	4%
Wholesale Trading	568.6	23%
Resource Adequacy	1,783.2	73%
Other	7.8	0%
Total	2,448.1	100%
Portfolio Total	16,739.9

	Revenue	£(000’s)/		£(000’s)/
Market	£(000’s)	MW/yr	£/MW/hr	MWh/yr	£/MWh/hr
GB	£6,712.0	£56.4	£6.44	£58.6	£6.7
Ireland	£4,927.6	£121.3	£13.85	£190.0	£21.7
Germany	£1,721.2	£173.4	£19.79	£131.5	£15.0
Texas	£930.9	£22.1	£2.52	£16.3	£1.9
California	£2,448.1	£70.0	£7.99	£35.0	£4.0
Weighted Average	£16,739.9	£67.9	£7.75	£60.0	£6.8

Total Revenue
£(000’s)	Jun-end 2025	Sep-end 2025
GB	3,382.0	3,330.0
Ireland	2,440.3	2,487.3
Germany	877.1	844.1
Texas	367.8	563.1
California	0.0	2,448.1
Total Revenue	7,067.3	9,672.7

 

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Commercial Manager’s Report

Operational Overview from Gore Street Services

Alicja Kowalewska-Montfort
Technical Principal, GSS

The portfolio continued to deliver strong technical performance, with availability exceeding 94% across regions. Over the period we successfully completed construction on all remaining assets and advancing targeted augmentations to unlock further value. These decisions are grounded in data—driven by real-time analytics, enhanced monitoring, and a commitment to operational excellence.

I am pleased to present an overview of the market conditions and technical performance of the Company’s assets over the six-month period ending on 30 September 2025. Over the period, the fleet delivered strong technical performance and demonstrated resilience across diverse markets despite volatility in certain regions.

Fleet wide performance generated an average revenue of £67.9k per MW per hour which is based on the average operational capacity over the period delivered total revenue of £16.7 million. These figures reflect the benefits of diversification across multiple markets and the continued optimisation of revenue strategies. Asset availability remained strong, with the portfolio achieving a weighted average of c.94%, supported by the increasing access and use of data and remote monitoring.

All assets under construction during the period were successfully energised, including Big Rock in CAISO, which achieved strong early performance following commissioning. This milestone marks the completion of the current construction cycle and positions the portfolio for stable operations and revenue generation across all markets. Strategic initiatives progressed during the period, including the augmentation works at priority sites in GB and Ireland.

The first phase, being Stony and Ferrymuir, are on track to meet the previously guided cost and downtime metrics. These projects are expected to unlock significant commercial upside through increased duration. Alongside this, the deployment of advanced analytics and automated escalation protocols continue to enhance operational resilience and optimise performance.

The Company also participated in Ofgem’s Long Duration Energy Storage (LDES) Cap and Floor programme. This regime is designed to provide revenue certainty for qualifying projects by guaranteeing a minimum revenue floor while capping upside returns, thereby mitigating investment risk for assets. The Company’s Middleton asset was one of 77 projects selected from 171 submissions to progress to the second-stage assessment during the first application window. The Stage 2 submission has been completed, with initial decisions expected in Spring 2026. If successful, Middleton will deliver an 800 MWh Track 1 asset in 2029, representing a significant milestone for the Company. The Cap and Floor framework is expected to play a critical role in supporting the UK’s decarbonisation targets under the Clean Power 2030 Action Plan, and the Company’s engagement positions it to benefit from stable, long-term revenues while contributing to system flexibility and security of supply.

Market Updates

Great Britain (GB)

Average BESS revenue in GB increased by 18% compared to FY24/25, and by 63% compared to the equivalent six‑month period last year (April to September 2024). Volume-weighted Dynamic Containment, Moderation, and Regulation (DCMR) prices rose 45% year-on-year, with procurement volumes up 17%. As a result of rule changes for ABSVD (Applicable Balancing Services Volume Data), and the introduction of QR for non-BM (Balancing Mechanism) assets, September 2025 saw an additional 11% increase in DCMR prices compared to earlier months in the interim period. Day-ahead spreads increased by 11% compared to the preceding six-months, and the occurrence of negatively priced periods decreased by 7%. During the period, 1.1 GW of new battery capacity was installed. This represents 78% of the total built capacity of the preceding 12-months, demonstrating the increased growth rate in BESS capacity in GB.

The period saw changes in ABSVD rules for BESS in Ancillary Services. ABSVD repayments previously only applied to BM registered assets and served to net-off imbalance volumes from Ancillary Services delivery. Prior to the changes, non-BM assets and BM assets typically opted from opposite strategies in Ancillary Services. These changes have aligned incentives for all BESS in GB more closely.

During the period, OFGEM introduced a Cap and Floor tender for LDES (Long Duration Energy Storage). This tender seeks to procure capacity for projects with at least 8 hours of duration above 100 MW. The Cap and Floor would provide revenue certainty for LDES projects over 25 years, from 2029. The Company’s Middleton asset successfully passed stage 1 of the tender, and the Manager has submitted a tender response for stage 2.

Ireland

The Irish Market operates under the combined Republic of Ireland (ROI) and Northern Ireland (NI) market called the Single Energy Market (SEM). The Delivering a Secure Sustainable Electricity System (DS3) initiative was introduced in Ireland to facilitate the integration of non-synchronous renewable energy sources, primarily wind power onto the grid. Under the DS3 regime, batteries in Ireland hold long term DS3 contracts which allow systems to participate in Ancillary Services.

The portfolio’s Northern Irish assets, Mullavilly and Drumkee, hold DS3 uncapped contracts. The Republic of Ireland site, Porterstown, holds a DS3 capped contract. DS3 capped contracts are fixed price contracts. DS3 uncapped contract prices vary according to scaling factors linked to the System Non-Synchronous Penetration (SNSP). SNSP is a real-time metric that gauges the level of intermittent renewable generation and net interconnector flows within the grid, defined as a percentage of electricity demand on the system. DS3 rates increase as SNSP increases, meaning that batteries delivering DS3 services see increasing remuneration for their response at times when the system needs it the most.

In the interim period, high SNSP (System Non-Synchronous Penetration) events, where enhanced TSS apply, increased by 86%, driven by more renewables and the commissioning of the Greenlink interconnector. Day-ahead spreads rose by about 6% compared to the previous interim period.

The Scheduling Dispatch Programme (SDP) was launched on 12 November. The SDP will allow batteries to participate more freely in wholesale markets by providing greater certainty of dispatch. This is expected to increase revenue from trading, providing an alternative to DS3 participation.

The TSOs have extended DS3 arrangements until the earliest of DASSA Go-Live or September 2028. DASSA, which will be the successor to DS3 for Ancillary Service procurement, is currently expected in May 2027. The extension of DS3 arrangements ensures stability until new market structures are implemented.

ERCOT

During the period, the Texas BESS market experienced a significant downturn, with revenues falling c.90% below initial expectations. This decline was driven primarily by two factors.

Depressed gas prices reduced pricing volatility, limiting opportunities for batteries to capture high spreads through arbitrage. The second course was market saturation, with the rapid deployment of BESS assets in the state causing margins to compress and reduced ancillary service revenues.

In ERCOT, average day-ahead (DA) and real-time (RT) spreads in the West trading hub were around 35% and 26% lower respectively than the equivalent period in the previous Financial Year. ERCOT summer revenues remain driven by periods of scarcity caused by high net loads, and low reserve margins on the grid. ERCOT average load increased by 4% this summer compared to summer 2024, however, net load decreased by 2%, as higher renewable support offset the increased demand. ERCOT load is forecast to grow significantly in coming years.

Installed BESS capacity has increased by 4 GW since October 2024. ERCOT issued a notice in April 2025 on the seasonal increase of Ancillary Service volumes for May, driven by higher load volatility and increased outages. Average ECRS (ERCOT Contingency Reserve Service) and Non-Spin prices increased in May, up 133% and 275% respectively compared to the preceding 6-months. During the period, the Company’s 75 MW/75 MWh Dogfish asset became operational.

CAISO

During the period, the Company’s 200 MW/400 MWh Big Rock asset became operational and began delivering against its resource adequacy (RA) contract.

In CAISO, BESS revenue declined by 35% compared to the same period in the previous financial year according to industry benchmarks. The peak summer demand decreased by 4 GW compared to the summer of 2024 due to lower average temperatures. A 6.3 GW increase in RA capacity also contributed to more flexible capacity on the grid.

Average real-time (RT) 5-min prices were 26% higher in electricity trading hub South of Path 15 (SP15) compared to the same period in the previous financial year. However, RT 5-min trading spreads decreased by 8%, as, due to an increase in the daily trough price.

In June 2025, CAISO implemented an energy storage enhancement for Flexible Ramping Products (FRP). Batteries awarded Flex Ramp Up/Down must now maintain sufficient state of charge (SOC) to ensure delivery when needed. FRP is not an ancillary service that can be bid into; CAISO procures it in real-time based on available capacity and ramp rate.

Germany

In Germany, Ancillary Services represented the majority of revenue. aFRR (automatic Frequency Restoration Reserve) pricing remains elevated due to high grid balancing costs and represented 62% of Cremzow’s revenue for the period. FCR (Frequency Containment Reserve) prices decreased by 9% compared to the same period in the previous Financial Year (Apr-24 to Sept-24). Battery buildout accelerated since September 2024 period, with capacity increasing by 46% to 2.2GW as of September 2025. Simultaneously, peak Solar generation increased by 10% year-on-year, further increasing balancing requirements on the German grid.

On 30 September, the day-ahead auction settlement shifted from hourly to 15-minute settlement intervals. This change provides further granularity for DA trading positions for market participants, especially for renewable energy. This change allows for further flexibility of participants in DA trading.

Asset Performance & Availability

Overall, project capacity levels met or exceeded expectations, and availability remained steady and consistent. This strong performance reflects the deployment of enhanced battery analytics and improved approaches to maintenance with O&M partners. The rollout of an automated data collection approach is ongoing and expected to further improve availability, particularly at newer flagship assets with enhanced operational data available from inception.

The Commercial Manager continues to invest in tools to improve project performance through automated analytics and escalation protocols, improving response times to unplanned events. With these initiatives and anticipated operational improvements, the portfolio is expected to maintain or exceed current availability levels for the remainder of the year.

Asset Availability by Region

Region	Sep-end 2025
Great Britain	93.5%
Island of Ireland	97.1%
Germany	90.4%
Texas	90.7%
California	96.3%
Portfolio	94.3%

The fleet achieved a weighted average asset availability of 94.3% during the period, with performance impacted primarily by issues at Boulby and GS10, including spare part obsolescence and resolved connection and communication issues at Lower Road and Lascar. Availability is expected to remain stable, with a modest improvement anticipated as technical resolutions, and a focus on optimising Capacity Market participation. The Irish portfolio (Mullavilly, Drumkee and Porterstown) maintained strong performance, achieving a weighted average of 97.1%. Minor inverter issues at the Northern Irish sites were resolved remotely, supported by enhanced remote 24/7 operations support and rapid response times (often <5 minutes).

The German project Cremzow achieved 90.4% availability for the period, with early challenges largely stemming from the 2 MW ‘pilot’ project, not the 20 MW ‘expansion’ site. Availability improved to 96.1% in Q2 following resolution of long-standing issues. With enhanced support from the OEM site controller, future downtime is expected to be reduced, supporting continued high performance.

In ERCOT, availability averaged 90.7% during the period, supported by the strong performance of Dogfish since its May energisation. The Investment Manager is actively working with the O&M contractor to address persistent issues at the 10MW “Texas Trio” assets, primarily related to HVAC pump failures and inverter faults. The financial impact of disruptions at older sites were effectively mitigated through successful liquidated damages claims under their O&M contracts. Manufacturer-funded equipment replacements are under review, and the sites performed well over the summer without notable weather-related disruptions. Big Rock, the portfolio’s CAISO asset, achieved 96.3% availability during the period, reflecting strong early performance despite commission-related delays and corrections, a planned metering upgrade, and unplanned downtime on one of the two grid transformers. With these issues now resolved, near-100% availability is expected through the second half of the year.

Enderby Project Update

While the Enderby site has begun generating revenue from certain streams, full access to all revenue opportunities will only be possible once the asset achieves full operational capability, now scheduled for FY2026/27 Q4.

The connection point for Enderby is on the tertiary winding of a Super Grid Transformer (400/132/13kV) at the Enderby 400kV Substation. This configuration is uncommon and introduces additional complexity from a control and compliance perspective. During Grid Code Compliance Testing, voltage instability was observed, highlighting the inherent “weakness” of the grid at this point.

The EPC contractor is completing a comprehensive review of the control system, compliance submission, and testing methodology to resolve this issue. The issue has been identified, and proposed changes are being submitted to NESO for review and approval.

Augmentation Works

Following a fleet-wide review, Great Britain and Ireland have been identified as priority markets for augmentation. GB currently operates with an average duration of 1-hour and both markets have significant commercial upside from targeted duration increases. and have significant commercial upside from targeted duration increases.

The first phase of augmentation works will increase energy capacity at Stony and Ferrymuir. Subsequent phases are planned for Hulley, Lascar, Larport, Breach, Mullavilly, Drumkee, and Enderby. Across all sites, grid upgrades are not required, land rights and lease conditions are supportive of construction, and planning consents are not expected to present any issues.

Stony and Ferrymuir

Post-period, the Investment Manager successfully completed the execution of Augmentation EPC contracts for Stony and Ferrymuir. The Investment Manager expects Stony A, Stony B and Ferrymuir to return to a full suite of commercial services at nameplate power capacity in FY 2026, Q3. The total cost of the augmentation was at the lower end of the previously guided £18-22 million range. Each project’s programme of works was fine-tuned to optimise project commercial availability against a target completion date for the augmentation works, with a contractual target imposed of c.75% availability across 2026. This is an aggressive target illustrating the Investment Manager’s foresight for the augmentation requirements of these projects.

The EPC contracts represent an exciting move forward for the GB BESS industry. The contracts are materially more technically complex due to their interaction with existing O&M contracts for the projects and the need to define performance warranties and availability levels at portions of the projects whilst the rest is constructed, and vice versa. The technical solution was optimised to avoid major downtime through grid compliance testing or remodelling of the project’s impact on the grid (as “DC augmentation” will be employed).

Asset	Capacity (MW)	Current Duration (MWh)	Post Augmentation Duration (MWh)	COD Target Post Augmentation
Stony	79.9	79.9	159.8	FY 2026/27 Q3
Ferrymuir	50	50	100	FY 2026/27 Q3

Investment Portfolio

Operational Portfolio

Market	Asset	MW	MWh	Ownership (%)
GB	Lascar	20	20	100%
	GS10	11.2	11.2	100%
	Larport	19.5	19.5	100%
	Hulley	20	20	100%
	Breach	10	10	100%
	Cenin	4	4.8	49%
	Boulby	6	6	100%
	POTL	9	4.5	100%
	LOR	10	5	100%
	Stony	79.9	79.9	100%
	Ferrymuir	49.9	49.9	100%
NI	MEL	50	21.3	51%
	DEL	50	21.3	51%
ROI	PBSL	30	30	100%
TEXAS	Snyder	9.95	19.9	100%
	Sweetwater	9.95	19.9	100%
	Westover	9.95	19.9	100%
	Dogfish	75	75	100%
CALIFORNIA	Big Rock	200	400	100%
GER	Cremzow	22	29	90%
	Total Operational Capacity	696.4	867.1
	Total Operational Capacity (Adjusted For Ownership)	643.1	840.9

Energised Portfolio

Market	Asset	MW	MWh	Ownership (%)
GB	Enderby	57	57	100
	Total Energised Capacity (Adjusted For Ownership)	57	57

Pre-Construction Portfolio

Market	Asset	MW	MWh	Ownership (%)
GB	Middleton	200	400	100%
ROI	PBSL-expansion	60	60	100%
	KBSL	30	30	100%
	KBSL-expansion	90	90	100%
	Mucklagh	75	75	51%
	Mineral Wells	9.95	9.95	100%
	Cedar Hill	9.95	9.95	100%
TEXAS	Wichita Falls	9.95	9.95	100%
	Mesquite	9.95	9.95	100%
	Total Pre-Construction Capacity	494.8	694.8
	Total Pre-Construction Capacity (Adjusted For Ownership)	458.05	658.05

Total Operational Capacity

Market	Asset		MW	MWh
GB	Operational		239.5	230.8
	Energised		57	57
	Pre-construction		200	400
NI	Operational		100	42.6
	Pre-construction		0	0
ROI	Operational		30	30
	Pre-construction		255	255
Texas	Operational		104.85	134.7
	Pre-construction		39.8	39.8
California	Operational		200	400
	Pre-construction		0	0
GER	Operational		22	29
	Pre-construction		0	0
	Total Capacity		1.25 GW	1.62 GWh
	Total Capacity (Adjusted for Ownership)		1.16 GW	1.56 GWh

Trading Report

Trading Performance Overview

Gore Street Energy Trading (GSET)

Alan Smallwood

Optimisation Principal, GSET

GSET continues to outperform the Modo 1hr benchmark, achieving a 23% revenue premium across the GB fleet while expanding into new markets. Our in-house optimisation systems are built for precision and adaptability— capturing value in real time and safeguarding asset health through continuous monitoring and data-driven decision-making.

Gore Street Energy Trading (GSET) continues to generate revenues in excess of the Modo 1hr benchmark, while also monitoring assets and ensuring their long-term health. From April through September 2025, revenue generated by GSET was 23% above the Modo 1-hr benchmark, (£6.61/MW/h against £5.39/MW/h). This equated to an additional £867k across the GB fleet over this period.

At the start of September, there were significant changes to the dynamic frequency markets, with ABSVD (Applicable Balancing Service Volume Data) rules being applied to non-BM assets for the first time. While September saw a slight dip in performance, due to temporary grid unavailability and poor market opportunities, we saw continued strong performance in October, with initial estimates indicating a return to a ~25% premium over the Modo 1-hr benchmark.

From August, GSET onboarded three assets in Texas (Sweetwater, Westover, and Snyder) totalling 30 MW. Our ERCOT optimisation software, developed entirely in-house, borrows elements from our GB system, but uses an engine designed specifically for the Texas market. Although market conditions in ERCOT remain challenging, our optimisation system is working well, capturing all available value.

Summary of Assets Optimised by GSET

Asset	Capacity	Commencement of GSET Optimisation
GB
Port of Tilbury	9 MW / 4.5 MWh	Oct-24
Breach	10 MW / 10.0 MWh	Nov-24
Larport	19.5 MW / 19.5 MWh	Nov-24
Hulley	20 MW / 20 MWh	Dec-24
Lascar	20 MW / 20 MWh	Dec-24
Cenin	4 MW / 4.8 MWh	Apr-25
Stony	79.9 MW / 79.9 MWh	Apr-25
GB TOTAL	162.4 MW / 158.7 MWh
ERCOT
Snyder	9.95 MW / 19.9 MWh	Aug-25
Sweetwater	9.95 MW / 19.9 MWh	Aug-25
Westover	9.95 MW / 19.9 MWh	Aug-25
ERCOT TOTAL	29.85 MW / 59.7 MWh
Total as of September 2025	192.25 MW / 218.4 MWh

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Directors’ Interim Report

Principal Risks and Uncertainties

The principal risks and uncertainties with the Company’s business fall into the following categories: Changes to Market Design; Inflation; Exposure to Lithium-Ion Batteries, Battery Manufacturers, and technology changes; Service Provider; Valuation of Unquoted Assets; Delays in Grid Energisation or Commissioning; Currency Exposure; Cyber-Attack and Loss of Data; and Physical and transitional climate-related risks. A detailed explanation of the risks and uncertainties in each of these categories can be found on pages 37 to 39 of the Company’s published annual report for the year ended 31 March 2025.

These risks and uncertainties have not materially changed during the six months ended 30 September 2025. However, the Board has noted that geopolitical factors continue to create uncertainties, including relating to energy policy, supply chains and interest rates.

These risks and uncertainties have not materially changed during the six months ended 30 September 2025. The board has however identified a new principal risk to draw to shareholders’ attention. Share price performance, and its impact on the share price to NAV discount, provides an opportunity for new entrants to the share register to seek to realise short-term gains, which could prejudice the interest of the longer-term shareholders. To mitigate this, the Board and the Manager will continue to engage with all shareholders, to better understand investors’ requirements.

In addition, the Board has noted that geopolitical factors continue to create uncertainties, including relating to energy policy, supply chains and interest rates, as do trade wars and tariffs.

Going Concern

Having assessed the principal risks and uncertainties, and the other matters discussed in connection with the viability statement as set out on page 40 of the published annual report for the year ended 31 March 2025, the Directors consider it appropriate to adopt the going concern basis in preparing the accounts.

Related Party Transactions

There have been no transactions with related parties that have materially affected the financial position or the performance of the Company during the six months ended 30 September 2025.

Directors’ Responsibility Statement

The Directors confirm that, to the best of their knowledge, this set of condensed financial statements has been prepared in accordance with UK adopted IAS 34 Interim Financial Reporting and with the Statement of Recommended Practice, “Financial Statements of Investment Companies and Venture Capital Trusts” issued in July 2022, and that this half year report includes a fair review of the information required by 4.2.7R and 4.2.8R of the FCA’s Disclosure Guidance and Transparency Rules.

Chair Designate selection process Post-period end, a subcommittee of the Remuneration and Nomination Committee was formed to select the Chair Designate. The process was led by Simon Merriweather and did not include the Chair or the candidates.

The sub-committee assessed the candidates against criteria including experience as a chair, knowledge of investment trusts, and experience of working with shareholders and stakeholders in a wide range of scenarios.

Patrick Cox
Chair

 

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Interim Condensed Statement of Comprehensive Income

For the Period ended 30 September 2025

		1 April 2025 to 30 September 2025			1 April 2024 to 30 September 2024
	Notes	Revenue (£)	Capital (£)	Total (£)	Revenue (£)	Capital (£)	Total (£)
Net loss on investments at fair value through profit and loss		–	(69,245,088)	(69,245,088)	–	(21,512,393)	(21,512,393)
Investment income		19,451,460	–	19,451,460	9,488,686	–	9,488,686
Administrative and other expenses		(4,108,188)	–	(4,108,188)	(3,632,205)	–	(3,632,205)
Profit/(loss) before tax		15,343,272	(69,245,088)	(53,901,816)	5,856,481	(21,512,393)	(15,655,912)
Taxation	4	–	–	–	–	–	–
Profit/(loss) after tax for the period		15,343,272	(69,245,088)	(53,901,816)	5,856,481	(21,512,393)	(15,655,912)
Total comprehensive income/(loss) for the period		15,343,272	(69,245,088)	(53,901,816)	5,856,481	(21,512,393)	(15,655,912)
Loss per share (basic and diluted) – pence per share	5			(10.67)			(3.10)

All Revenue and Capital items in the above statement are derived from continuing operations.

The Total column of this statement represents Company’s Income Statement prepared in accordance with UK adopted International Accounting Standards. The loss after tax and loss for the period is the total comprehensive income and therefore no additional statement of other comprehensive income is presented.

The supplementary revenue and capital columns are presented for information purposes in accordance with the Statement of Recommended Practice issue by the Association of Investment Companies.

The notes on pages 40 to 47 of the 2025 interim report form an integral part of these financial statements.

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Interim Condensed Statement of Financial Position

As at 30 September 2025

Company Number 11160422

		30 September	31 March
		2025	2025
	Notes	(£)	(£)
Non – current assets
Investments at fair value through profit or loss	6	447,057,319	510,251,383
		447,057,319	510,251,383
Current assets
Cash and cash equivalents	8	9,854,381	9,595,425
Trade and other receivables		210,291	114,354
		10,064,672	9,709,779
Total assets		457,121,991	519,961,162
Current liabilities
Trade and other payables		1,831,574	666,939
		1,831,574	666,939
Total net assets		455,290,417	519,294,223
Shareholders equity
Share capital	10	5,050,995	5,050,995
Share premium	10	331,302,899	331,302,899
Merger reserve	10	10,621,884	10,621,884
Capital reduction reserve	10	37,401,431	47,503,421
Capital reserve	10	23,119,628	92,364,716
Revenue reserve	10	47,793,580	32,450,308
Total shareholders equity		455,290,417	519,294,223
Net asset value per share	9	0.90	1.03

The interim financial statements were approved and authorised for issue by the Board of directors and are signed on its behalf by;

Patrick Cox
Chair

Date: 12 December 2025

The notes on pages 40 to 47 of the 2025 interim report form an integral part of these financial statements.

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Interim Condensed Statement of Changes in Equity

For the Period ended 30 September 2025

	Share	Share premium	Merger	Capital reduction	Capital	Revenue	Total shareholders
	capital	reserve	reserve	reserve	reserve	reserve	equity
	(£)	(£)	(£)	(£)	(£)	(£)	(£)
As at 1 April 2025	5,050,995	331,302,899	10,621,884	47,503,421	92,364,716	32,450,308	519,294,223
(Loss)/profit for the period	–	–	–	–	(69,245,088)	15,343,272	(53,901,816)
Total comprehensive (loss)/income for the period	–	–	–	–	(69,245,088)	15,343,272	(53,901,816)
Transactions with owners
Dividends paid	–	–	–	(10,101,990)	–	–	(10,101,990)
As at 30 September 2025	5,050,995	331,302,899	10,621,884	37,401,431	23,119,628	47,793,580	455,290,417

For the Period Ended 30 September 2024

	Share	Share premium	Merger	Capital reduction	Capital	Revenue	Total shareholders
	capital	reserve	reserve	reserve	reserve	reserve	equity
	(£)	(£)	(£)	(£)	(£)	(£)	(£)
As at 1 April 2024	5,050,995	331,302,899	10,621,884	75,089,894	95,542,635	23,088,186	540,696,493
Profit/(loss) for the period	–	–	–	–	(21,512,393)	5,856,481	(15,655,912)
Total comprehensive income/(loss) for the period	–	–	–	–	(21,512,393)	5,856,481	(15,655,912)
Transactions with owners
Dividends paid	–	–	–	(17,484,483)	–	–	(17,484,483)
As at 30 September 2024	5,050,995	331,302,899	10,621,884	57,605,411	74,030,242	28,944,667	507,556,098

Capital reduction reserve and revenue reserves are available to the Company for distributions to Shareholders as determined by the Directors.

The notes on pages 40 to 47 of the 2025 interim report form an integral part of these financial statements.

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Interim Condensed Statement of Cash Flows

For the Period ended 30 September 2025

		1 April 2025 to	1 April 2024 to
		30 September	30 September
		2025	2024
	Notes	(£)	(£)
Cash flows used in operating activities
Loss for the period		(53,901,816)	(15,655,912)
Net loss on investments at fair value through profit and loss		69,245,088	21,512,393
(Increase)/decrease in trade and other receivables		(95,937)	271,020
Increase/(decrease) in trade and other payables		1,164,635	(376,512)
Net cash generated from operating activities		16,411,970	5,750,989
Cash flows used in investing activities
Funding of investments		(11,167,767)	(29,832,113)
Loan principal repayment from investment		5,116,743	–
Net cash used in investing activities		(6,051,024)	(29,832,113)
Cash flows used in financing activities
Dividends paid		(10,101,990)	(17,484,483)
Net cash outflow from financing activities		(10,101,990)	(17,484,483)
Net increase/(decrease) in cash and cash equivalents for the period		258,956	(41,565,607)
Cash and cash equivalents at the beginning of the period		9,595,425	60,667,572
Cash and cash equivalents at the end of the period		9,854,381	19,101,965

During the period, interest received by the Company totalled £19,451,460 (2024: £9,488,686).

The notes on pages 40 to 47 of the 2025 interim report form an integral part of these financial statements.