EXECUTIVE SUMMARY
A major battery storage milestone has been reached near Norwich, Norfolk, with Ørsted completing construction of its first large-scale UK BESS. The 300 MW/600 MWh Iceni facility comprises 170 Tesla Megapacks and shares grid infrastructure with the Hornsea 3 Offshore Wind Farm. Final electrical installation, commissioning and testing activities are progressing ahead of full operation.
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Danish renewable energy company Ørsted has completed construction of its first large-scale battery energy storage system (BESS) in the United Kingdom. The 300 MW/600 MWh Iceni BESS is located near Norwich, Norfolk, alongside the onshore converter station for Ørsted's Hornsea 3 Offshore Wind Farm. The construction milestone brings the project closer to full operation, with final electrical installation and commissioning activities continuing.
The facility comprises 170 Tesla Megapacks, each approximately the length of a traditional Routemaster London bus and weighing as much as five buses. With a power rating of 300 MW and an energy storage capacity of 600 MWh, the system is equivalent to the daily electricity consumption of approximately 80,000 UK homes. Once completed and operational, Iceni will be among Europe's largest battery energy storage systems.
The project has been developed through collaboration between Ørsted, Hitachi Energy, Knights Brown and Tesla. Its engineering design includes a split-site arrangement, with two battery installation areas separated by the Hornsea 3 onshore converter station. These sections are connected through 18 cables rated at 33 kV, each extending more than 600 metres.
The shared grid connection with Hornsea 3 has introduced additional technical complexity compared with a standalone connection to the National Grid. This configuration requires coordination between the battery storage infrastructure and the offshore wind project's associated electrical systems.
Although construction has reached a major milestone, the project remains in the final stages of mechanical and electrical installation. Installation and termination of the cross-site 33 kV cables are underway. Initial commissioning and testing have also begun, while preparations continue for energisation of the BESS transformer.
Beatrice d'Eufemia, Project Manager for Iceni BESS at Ørsted, described construction completion as an important milestone for the company's UK battery storage operations. She explained that the system will store excess renewable electricity when generation exceeds demand and release it when electricity requirements increase. This capability is intended to support grid balancing and help reduce electricity costs.
Richard Swann, Construction Manager for Iceni BESS, highlighted the collaboration between the organisations involved in delivering the project.
Knights Brown's Head of Transmission & Distribution, David Shillabeer, also emphasised the project's contribution to local employment, skills development and opportunities across Norfolk and the surrounding region.
The Iceni BESS represents Ørsted's expansion into large-scale UK battery storage, supporting more flexible use of renewable electricity and contributing to the development of a more resilient, lower-carbon power system.