H&MV Engineering has successfully completed comprehensive electrical and civil works for Europe’s largest battery storage site at Blackhillock, Scotland. Serving as Principal Designer and Contractor, our team delivered the crucial connection between the 200MW/400MWh Battery Energy Storage System (BESS) and SSE’s 275kV transmission network.
Project Overview
The Blackhillock battery storage site is a groundbreaking project in several ways:
- First phase (200MW/400MWh) now operational, with second phase (additional 100MW/200MWh) planned for 2026
- Total capacity of 300MW/600MWh will power the equivalent of over 3.1 million homes for one hour
- World’s first battery project to provide Stability Services to the National Energy System Operator
- Strategically located to address grid congestion from three major offshore wind farms
- Adds over 30% to Scotland’s operational battery storage capacity
H&MV Engineering’s Comprehensive Solution
Our client Zenobē required a competent contractor with both ICP and high voltage experience to connect their BESS to the SSE 275kV transmission system. H&MV Engineering was appointed as Principal Designer and Contractor under CDM 2015 Regulations, providing end-to-end project delivery.
Our scope of works included:
- Design Services: Complete electrical and civil design for the 275kV & 33kV electrical network
- Civil Construction: Delivery of all civil infrastructure required for the grid connection
- Electrical Installation: Supply, installation and commissioning of all electrical equipment
- Commissioning: Full testing and commissioning compliant with and approved by SSE
- Project Management: Overall site and project management responsibility
- Coordination: Liaison with client regarding BESS delivery including PCS, 33kV transformers, containerised batteries, HVAC and fire suppression systems
- Stakeholder Management: Communication with landowners, planning office and local community
H&MV Engineering’s electrical scope encompassed all associated earthing as well as protection schemes, interlocking, controls and metering systems essential for the safe and efficient operation of this critical energy infrastructure.
Technical Innovation
What sets the Blackhillock project apart is its advanced technical capabilities. The site uses Wärtsilä’s Quantum energy storage system technology and GEMS Digital Energy Platform with SMA grid forming inverters. This sophisticated combination enables the system to provide crucial stability services including short-circuit level and true synthetic inertia – essential for maintaining grid reliability as the UK phases out fossil fuel power plants.
H&MV Engineering’s expertise in high voltage electrical systems was crucial for successfully integrating these advanced technologies with the transmission network.

Environmental & Economic benefits
The Blackhillock battery storage facility delivers substantial benefits:
- Expected to save consumers over £170 million over the next 15 years
- Will prevent approximately 2.6 million tonnes of CO₂ emissions
- Reduces wastage of clean energy by storing excess renewable generation
- Enhances the reliability of the UK’s growing renewable power system
Supporting the UK’s Net Zero Goals
Battery storage plays a critical role in the UK’s energy transition. By delivering the electrical infrastructure for the Blackhillock project, H&MV Engineering has directly contributed to the UK government’s mission to achieve a net zero power grid by 2030.
Tim Hewitt, Project Engineering Manager at Zenobē, shared his thoughts on H&MV’s contribution to the Blackhillock project:
“We are pleased to have worked alongside H&MV Engineering in delivering the Blackhillock, Europe’s largest battery energy storage system. Their expertise and commitment as Principal Designer and Contractor contributed to the success of this landmark project, driving progress toward a net-zero power grid by 2025.”
Looking forward
H&MV Engineering is proud to have served as Principal Designer and Contractor for this landmark project. Our successful delivery of the 275kV connection for the Blackhillock battery storage site demonstrates our capability to handle complex, high-voltage infrastructure projects that are essential for the energy transition. As Britain increases its reliance on renewable energy sources such as wind and solar, facilities like Blackhillock will be essential to ensure that excess power can be stored and then used during times of increased demand. H&MV Engineering remains committed to supporting the growth of renewable energy infrastructure through our expertise in high voltage engineering and project delivery.
About H&MV Engineering
H&MV Engineering specialises in design, installation and commissioning of high voltage transmission, medium voltage distribution networks and substations. With expertise in connecting renewable energy projects to the grid, we’re helping build the infrastructure for a cleaner energy future.