Ampeak Energy Limited has set out progress on its battery storage pipeline and proposed revised terms for three debentures as it awaits further grid connection information from the National Energy System Operator.
The update centres on the company’s battery energy storage system, or BESS, projects at Uskmouth in South Wales and Mey in Caithness, North Scotland. Together, the portfolio described in the update totals about 770MW / 2.6GWh of battery storage capacity.
Progress at Afon Wysg 1
The flagship Afon Wysg 1 project at Uskmouth is a 240MWh battery storage scheme. Ampeak said it reached financial close on the project in August 2025, securing £67.4 million of funding, including £45.3 million of non-recourse project finance from Norddeutsche Landesbank Girozentrale.
Construction is now close to completion. Civil works have finished, all batteries and other key equipment have been delivered to site, and the project remains on budget and on schedule. Energisation is expected later this month, with full commercial operations expected in the first quarter of 2027.
The company is also planning to double the site’s capacity to 480MWh. Ampeak said it wants to achieve financial close on that expansion shortly after the 240MWh project enters full commercial operation. It expects the enlarged project to be deliverable in well under 12 months from financial close, with minimal disruption to the operating asset.
According to the update, the expansion would also trigger a contractual overage payment to Ampeak linked to the land sold at financial close.
Other project milestones
In January 2026, Ampeak announced that its Mey BESS project had received Section 36 consent from Scottish Ministers for a battery storage project with an installed capacity of up to 300MW / 1,200MWh.
At Uskmouth, the 460MWh Uskmouth Energy Storage project is also being prepared for a significant expansion. Ampeak sold that project and the underlying land in 2023 before construction, but retained contractual rights to development premium payments tied to future increases in capacity. If the expansion goes ahead alongside the AW1 expansion, Uskmouth Sustainable Energy Park would host more than 1GWh of BESS systems.
The company said the wider site also has further land for additional battery and other energy projects beyond this.
Ampeak’s strategy, as outlined in the update, is to develop projects through construction and operation, create long-term value through operating revenues, and selectively use equity sell-down opportunities and land sales to access the underlying land value at Uskmouth, which remains in its ownership. The company said delivery of that strategy depends on secure and timely grid connections.
Proposed bond repayment changes
Alongside the project update, Ampeak is contacting bondholders about three debentures issued through Atlantis Future Energy and Atlantis Ocean Energy with support from Abundance Investment Limited in 2017 to 2019.
Under the current schedule, capital repayments are due in three tranches: £2.0 million on 31 December 2026, £3.0 million on 31 December 2027 and about £7.7 million on 30 June 2029. Ampeak is proposing to defer each of those payments by two years, moving them to 31 December 2028, 31 December 2029 and 30 June 2031 respectively.
The company is also asking to defer the interest payment due on 30 June 2027 to 31 December 2027.
Ampeak said it believes Connections Reform, implemented in 2025 and rolled out by NESO from late 2025, may have changed the timing of value realisation from its BESS portfolio rather than the underlying value itself. It is still awaiting confirmation of grid connection dates for its projects and said the extension would align debenture repayments with possible delays to its development timetable while preserving value for stakeholders.
Ampeak has adopted a planning assumption of an approximately two-year delay to principal repayments because NESO has not yet issued all revised connection offers.
In return for the proposed extension, the company wants the interest rate on all the debentures increased to 13% per annum from 1 January 2027. Under the current terms, the rate was scheduled to rise from 10% to 11% on 1 January 2027, to 12% on 1 January 2028 and to 13% on 1 January 2029. Interest would continue to be paid every six months on 30 June and 31 December, including the payment due on 31 December 2026, apart from the deferred 30 June 2027 payment.
Ampeak expects to fund operating costs and the higher interest payments from existing cash resources and future AW1 project-related operating cashflow.
The requested amendments need the support of debenture holders representing 75% by value for each class of debenture. Voting results are expected during December 2026, with a further update due at that time.
