Zenobe more than doubles synthetic inertia capability with second grid-forming BESS in Scotland

Zenobe has powered up a 300 MW/600MWh battery energy storage system (BESS) that will provide short circuit support and synthetic inertia at a key point on Great Britain’s electricity grid.

Located near several offshore wind farms in southwest Scotland, Kilmarnock South BESS was granted a grid stability contract through NESO’s Stability Pathfinders 2 tender. It follows the commissioning of Zenobe’s Blackhillock BESS in northeast Scotland, which entered operation in March 2025 as the world’s first battery storage project to provide active and reactive power.   

NESO’s second stability tender was the first time the grid operator procured inertia from BESS assets, seeking to shore up the system in areas of Scotland with high renewables penetration. Zenobe was the most successful developer in the process, securing around 65% of the roughly 6.8 giga volt amperes (GVA) of inertia procured.

The 4.36 GVA contracted to Zenobe batteries comprise 0.3 GVA at Blackhillock, 1.3 GVA at Kilmarnock South and 2.7 GVA at the under-construction Eccles BESS , which is expected to be the largest Zenobe site to date when commissioned. Kilmarnock South also represents a step up in procured short circuit support, and the 400 MW/800 MWh Eccles project will provide even more.

Zenobe announced it had reached financial close and started construction on Kilmarnock South in January 2024. Wärtsilä supplied the site with its Quantum energy storage system and a Zenobe spokesperson told ESS News the project uses the same SMA inverters as its Blackhillock BESS. Omexon carried out balance of plant works and EDF Energy acts as the route to market provider for the site. EDF Energy’s market trading activities will be supported by the Kraken platform, managing control and dispatch of energy at the site.

Kilmarnock South is part of a wider GBP 1 billion ($1.3 billion) investment from Zenobe in battery storage and clean transportation in Scotland. The developer has 1731 MW of operational BESS assets in power output terms, with a further 568 MW/1,230 MWh under construction.

In a press release, Zenobe founder and director James Basden said Kilmarnock South entering commercial operations was a “landmark moment” for Scotland, describing the project as a “world first, subsidy free battery that will reduce energy bills and strengthen Britain’s energy security.”

“This battery will contribute towards ending the absurd waste of clean Scottish wind power.”