Record-Scale Battery Storage Comes Online as Kilmarnock South Strengthens UK Grid Stability

EnergyChannel | Energy Storage | Europe

The United Kingdom has taken a decisive step toward reinforcing power system reliability with the commercial operation of Kilmarnock South, one of the country’s largest battery energy storage systems (BESS). Located in Scotland, the project delivers 300 MW of power and 600 MWh of energy capacity, positioning it as a key asset in the UK’s rapidly evolving electricity market.

Beyond its size, Kilmarnock South stands out for its strategic role in grid stability, at a time when the share of variable renewable energy continues to grow across the country.

One of the UK’s Few Grid-Forming BESS Projects

Kilmarnock South becomes only the second battery storage project in the UK to operate with grid-forming inverter technology a capability traditionally provided by conventional thermal and hydro power plants.

With this technology, the system is able to actively support the grid by delivering essential services such as:

• Synthetic inertia

• Short-circuit contribution

• Fast frequency response

• Stable operation under weak grid conditions

These functions are increasingly critical as power systems transition away from synchronous generation.

Fast Delivery Despite High Technical Complexity

The project was completed in less than two years after financial close, an accelerated timeline for an asset of this scale and technical sophistication.

The installation includes 102 Medium Voltage Power Stations (MVPS) equipped with Sunny Central Storage UP inverters, supplied by SMA. In parallel, the project team successfully navigated the UK’s demanding grid code requirements, ensuring full compliance while enabling advanced stability services.

Industrial Collaboration Driving Large-Scale Storage

Kilmarnock South was developed through a strategic partnership between Zenobē, Wärtsilä, and SMA, combining system integration expertise, power electronics, and large-scale energy storage know-how.

Lessons learned from previous projects including the Blackhillock Phase 1 development played a key role in de-risking execution and accelerating deployment.

A Clear Signal of the Future Power System

Projects like Kilmarnock South illustrate how battery storage is evolving from a flexibility tool into a core infrastructure asset for modern electricity systems.

The same grid-forming storage technology is already being deployed by SMA in markets such as Australia, where large renewable portfolios rely on advanced inverter-based solutions to maintain stability, reliability, and operational efficiency.

As energy transitions accelerate worldwide, Kilmarnock South sends a clear message: a renewable-heavy grid cannot be secure without large-scale, grid-forming energy storage.

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Record-Scale Battery Storage Comes Online as Kilmarnock South Strengthens UK Grid Stability