The Holmston Battery Energy Storage System (BESS) has achieved a significant construction milestone with the successful completion of all civil foundation works and the delivery and installation of the first transformers and battery banks on site.
The 50 MW / 100 MWh utility-scale project is now fully prepared for the main phase of BESS equipment installation, marking a major step forward toward energisation and grid connection. Today’s activities represent the first coordinated delivery of major electrical plant to site and demonstrate strong progress against the construction programme.
As planned, the first BESS Transformer (SKID & PCS) was delivered and installed safely and efficiently with no technical or logistical issues. This was followed by the scheduled delivery of two battery banks, both of which were installed swiftly and without incident.
Construction momentum will continue tomorrow with the delivery of two additional BESS Transformers (and four further battery banks. Subject to weather conditions, deliveries and installations will continue over the next seven days as the project moves through this critical phase.
Strengthening Scotland’s Energy Infrastructure
Holmston BESS is a 50 MW / 100 MWh battery energy storage facility developed by Field, with Envision Energy providing advanced Lithium Iron Phosphate (LFP) containerised battery technology. The project includes a new 33kV grid connection to Ayr Grid Substation and is located within the Scottish Power Energy Networks (SPEN) distribution area.
Once operational, the facility will play a key role in grid balancing, reducing renewable energy curtailment, strengthening grid performance, and supporting the continued integration of renewable generation across Scotland.
Delivering a Complex Infrastructure Programme
Powersystems is delivering the complete Civil and Electrical Balance of Plant (EBoP) works package for the project. This includes extensive enabling and infrastructure works such as public road improvements, dual high-pressure gas main crossings, site access road construction, compound development, civil bases and buildings, landscaping, and earthing systems.
The scope also covers the installation of battery systems, transformers, switchgear, backup power supplies, network communications, and the full commissioning of the project through to successful connection to the electricity grid.
Part of a Growing Energy Storage Portfolio
The project benefited from financing secured as part of a £42 million funding package in 2025, supporting the accelerated deployment of grid-scale energy storage assets.
With construction progressing on schedule and major equipment now arriving on site, Holmston BESS continues to demonstrate the vital role of battery energy storage in supporting a resilient, low-carbon electricity system.
Notes to Editors:
Contact Information:
- This article is written by Jules Daly, Marketing and Communications Manager at Powersystems.
- Email jules.daly@powersystemsuk.com Telephone 01454 318000
- Photography Copyright please credit all images used to powersystemsuk.co.uk
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