Overview of projects:
With the UK government's mission to have a net zero power grid by 2030, integrating battery energy storage technologies with the grid for more efficient and flexible energy dispatchability has become a major priority.
The Blackhillock phase one 200 MW / 400 MWh, Blackhillock phase two 100 MW / 300 MWh, and Kilmarnock South 300 MW / 600 MWh battery energy storage systems (BESS) deliver stability services using transmission-connected batteries, supporting the UK’s transition to a zero-carbon energy network by preparing the grid for an increased supply of renewables.
Wärtsilä retrofitted Zenobē’s 100 MW Capenhurst BESS with its GEMS control and optimisation platform, enabling advanced UK grid‑code compliance, unlocking new revenue streams, and future‑proofing the asset as market and regulatory requirements evolve.
The 68 MW / 130 MWh Shetland Standby Project will enhance energy security, reduce emissions, and support the Shetland Islands’ transition to a cleaner, more resilient power system.
| Customer | Zenobē |
| Site size | Blackhillock 1, 200 MW / 400 MWh Blackhillock 2, 100 MW / 300 MWh Kilmarnock South, 300 MW / 600 MWh Shetland, 68 MW / 130 MWh Capenhurst, 100 MW / 100 MWh |
| Site location | Scotland and England, UK |
| Solutions/Applications | GridSolve™ Quantum, Stability services, GEMS control and optimisation software, grid integration support |
| Scope of services | Engineered Equipment Delivery (EEQ) |
| Delivery | 2024-2026 |
2025 Awards for Blackhillock:
GWh of energy storage capacity
million savings expected for consumers over the next 15 years (Blackhillock project)
million tonnes of CO₂ prevented from entering the atmosphere over the next 15 years (Blackhillock project)
“-Our batteries at Blackhillock are the first to use advanced power electronics to enable a much higher uptake of renewable power on the grid. This dramatically reduces costs to consumers and increases reliability.
- James Basden, Founder and Director, Zenobē
“-Retrofitting our Capenhurst facility with GEMS has made the site future ready, enabling our system to keep pace with evolving UK grid requirements. We value the flexibility and reliability of the GEMS platformand the expertise Wärtsilä brings to getting projects finished efficiently.
- Simon Wood, Global Director of Operations - Network Infrastructure, Zenobē
Read the Blackhillock + Kilmarnock case study to get all the project details.
Read the Capenhurst case study to get all the project details.
Watch the webinar to learn about Blackhillock project and stability services, like synthetic inertia.
Wärtsilä Corporation, Press release, 4 August 2025 at 11:00AM UTC+2
Technology group Wärtsilä will supply a 68-megawatt (MW) battery energy storage system in Lerwick, Shetland, under an Engineered Equipment Delivery (EEQ) contract to Zenobē, the UK’s leading owner and operator of grid-scale battery storage. Known as The Shetland Standby Project, the initiative will enhance energy security, reduce emissions, and support the islands’ transition to a cleaner, more resilient power system. The project is scheduled to go live in 2026. The order was booked in Q2, 2025.
The battery system will enable the Lerwick Power Station to move into a standby role, cutting fossil fuel use and helping integrate more renewable energy from Shetland’s abundant wind resources. In the event of an outage or planned maintenance on the transmission line to mainland Scotland, the battery energy storage system will maintain uninterrupted power to Shetland’s homes and businesses.
The battery system features a range of innovative technologies: it will deliver Distribution Fault Ride Through (DFRT) capabilities and standby solution services to support Shetland's mainland interconnector. These capabilities ensure grid stability in the face of transmission faults by keeping the system powered without interruption.
“As European grids grow increasingly interconnected and interdependent, projects like this signal the importance of energy storage for grid stability,” said Tamara De Gruyter, President, Wärtsilä Energy Storage and EVP, Wärtsilä. “With the advanced and proven capabilities of the GEMS platform, Wärtsilä is helping future-proof the grid with battery systems that can react in microseconds to any type of system disturbance, to maintain security of supply for Shetland.”
Wärtsilä’s GEMS Digital Energy Platform will manage the battery system’s real-time performance, ensuring fast, intelligent responses to fluctuations in supply and demand. With a power output that exceeds Shetland’s local load, the system will provide a crucial buffer against grid instability, enabling a secure and decarbonised energy future for the islands.
“This project combines a battery with an AC chopper in Shetland and will maintain security of supply, ensuring homes and businesses continue to receive the power they need in the event of a transmission system outage, while reducing emissions and utilising more renewables in Shetland,” said James Basden, Zenobē Founder Director. “It marks an important step in the islands' transition to a clean and resilient energy system, and we're proud to bring our battery expertise to a project that will reduce reliance on fossil fuels on the island network."
The Shetland Standby Project marks the third major battery partnership between Wärtsilä and Zenobē. The 200 MW / 400 MWh project in Blackhillock, Scotland, went live in March 2025 and will be one of the largest operating battery energy storage systems in Europe and the first in the world to provide synthetic inertia services. A 300 MW / 600 MWh project in Kilmarnock, Scotland, is also in development.
The Shetland Standby Project will use Wärtsilä’s Quantum energy storage technology and will be supported by a 15-year long-term service agreement (LTSA) to ensure reliable, efficient performance throughout its lifespan.
Media contact:
Amanda Young
Director, Marketing & Communications
Wärtsilä Energy Storage
amanda.young@wartsila.com
Image caption: Wärtsilä has been contracted by Zenobē to deliver 68 MW / 130 MWh of capacity to the Shetland Standby Project in Shetland Islands, Scotland. © Wartsila
All Wärtsilä releases are available at www.wartsila.com/media/news-releases and at news.cision.com/wartsila-corporation where also the images can be downloaded. Use of the image(s) is allowed only in connection with the contents of this press release. Wärtsilä images are available at www.wartsila.com/media/image-bank.
Wärtsilä Energy Storage in brief
Wärtsilä Energy Storage is at the forefront of the transition towards a 100% renewable energy future. We help customers accelerate global decarbonisation efforts by combining proven technologies with deep grid expertise. Our portfolio includes high-performance hardware, intelligent controls and optimisation software, and full-service lifecycle support to deliver lasting value across the project lifespan. From enhancing grid stability to unlocking flexibility and operational efficiency, our utility-scale battery energy storage solutions are built for real-world performance. Trusted by top-tier utilities, developers, and system operators, Wärtsilä Energy Storage has a global footprint across 130+ sites—delivering the scale, safety, and reliability needed to power the energy transition.
www.wartsila.com/energy
Wärtsilä in brief
Wärtsilä is a global leader in innovative technologies and lifecycle solutions for the marine and energy markets. We emphasise innovation in sustainable technology and services to help our customers continuously improve environmental and economic performance. Our dedicated and passionate team of 18,300 professionals in more than 230 locations in 77 countries shape the decarbonisation transformation of our industries across the globe. In 2024, Wärtsilä’s net sales totalled EUR 6.4 billion. Wärtsilä is listed on Nasdaq Helsinki.
www.wartsila.com
