UNITED KINGDOM: Developer launches sale of 650 MW Braxbess battery storage platform

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An independent developer is understood to have launched the sale of the 650 MW Braxbess and Innerwick Storage standalone battery complex in East Lothian, Scotland.

Private individuals behind Braxbess Ltd and Innerwick Storage Ltd are seeking a full exit from the scheme, which comprises 480 MW (Braxbess) and 170 MW (Innerwick) phases being developed under a shared connection.

Both projects have secured planning consent, long-term land rights and are described as ready-to-build, and both elements have an expected grid connection date of May 31 2029, it is understood.

The projects offer flexibility to deploy storage durations of two, four or eight hours without requiring a planning amendment.

At an eight-hour configuration, the combined platform could ultimately support as much as 5.2 GWh of storage capacity.

The assets will connect at 132 kV via a shared 400/132 kV collector substation linked to Scottish Power Transmission’s new Branxton 400 kV substation.

According to analysis cited by the sellers, expected lifetime grid costs are approximately GBP 12,000 per MW, which, based on the combined 650 MW capacity, implies overall lifetime grid connection costs of around GBP 7.8m.

Both projects hold protected Gate 2 Phase 2 status under the National Energy System Operator’s connections reform process.

The Branxton node is expected to connect the 4.1 GW Berwick Bank offshore wind project, currently one of Europe’s largest consented offshore wind developments. The area also hosts approximately 300 MW of operational onshore wind generation.

The location sits within the wider infrastructure corridor that includes Eastern Green Link 1, the strategic HVDC interconnector linking Scotland and England.

The projects are being marketed as benefiting from future demand for flexibility services associated with increasing renewable generation and transmission flows through the region.

The land agreements run for up to 40 years and additional adjacent land is available from the same landlord for future capacity expansion or repowering.

The sale process has been launched with an objective of completing a transaction during the fourth quarter of 2026.

The sellers have appointed Alvarez & Marsal (financial) to advise on the disposal.

Both the sellers and adviser were approached for comment.