Romeral-Successful installation of new transformer

Prospex Energy plc / Index: AIM / Epic: PXEN / Sector: Oil and Gas

14 September 2026

Prospex Energy plc

(“Prospex” or the “Company”)

El Romeral - Operational Update

Successful installation of new transformer reduces monthly operating costs by c.€14,000

Prospex Energy plc (AIM: PXEN), the AIM-quoted investment company focused on European gas and power projects, confirms that Tarba Energía S.L. (“Tarba”), the operator of the Romeral asset, has successfully installed the new electrical transformer at the Romeral gas-to-power plant in Andalucía, Spain, replacing the rental transformer, which has been returned, and reducing monthly operating costs by c.€14,000.

A rental transformer was installed at the Romeral gas-to-power plant in February 2026 to support generation activity until the replacement transformer – which was ordered in September 2025 – was manufactured and available for installation.

The Tarba team successfully swapped the rental transformer with the new transformer between 9 and 10 September, with generation and power exports resuming on 11 September. All operations were completed safely, and electrical generation resumed. Overnight generation on 10 September reached 15,25 hours, and generation has continued since then.

Consistent production at Tarba, coupled with continued high electricity pricing, has delivered strong revenue performance during the peak summer months. Tarba has been self-sufficient on a cash basis for July and August, removing the need for funding from Prospex. Prospex owns a 100% interest in Tarba.

The final instalment for the new transformer of €187,632 is payable 60 days after installation and will be funded from existing cash resources.

Tom Reynolds, Prospex’s CEO, commented:

“I am delighted that the operation to swap out the rental transformer with its permanent replacement has been achieved safely and with minimum disruption to generation activity. The plant is now exporting electricity, supported by strong electricity pricing.

“It is important to note that Tarba has been self-sufficient through July and August, demonstrating its potential to generate sustainable cash flow; the €14,000 per month reduction in rental fees will further enhance its profitability.  The successful operation is a testament to the hard work and proficiency of the Tarba team.”

New transformer at the Romeral gas-to-power plant in Andalucía, Spain.

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About Prospex Energy

Prospex Energy plc is an AIM-quoted investing company focused on high-impact onshore and shallow offshore European opportunities with short timelines to production. The Company's strategy is to acquire undervalued projects with multiple, tangible value trigger points that can be realised within 12 months of acquisition and then apply low-cost re-evaluation techniques to identify and de-risk prospects.  The Company will rapidly scale up gas production in the short term to generate internal revenue, which can then be deployed to develop the asset base and further increase production.

About El Romeral and Tarba

The El Romeral power plant and natural gas concessions are owned and operated by Tarba Energia S.L., which is based in Carmona east of Seville in the province of Andalucía, Spain. Tarba is 100% owned by PXOG Muirhill Limited, a wholly owned subsidiary of Prospex.

Tarba sells electricity generated from the Romeral plant on the spot market in Spain. Since the installation of a rental transformer in February 2026, generation activity has increased from around four hours per day up to around 16 hours per day in July and August. Strong wholesale electricity prices, combined with increased generation activity, resulted in Tarba being self-sufficient on a cash basis in July and August 2026.

Tarba has applied for permits to drill five further infill wells on the Romeral concessions to increase production and is waiting for approval from Spanish regulators.