Danish energy major Ørsted said on 20 October 2026 that construction of its Iceni battery storage system near Norwich in Norfolk, England, is complete. The 600-megawatt-hour system, built around 170 Tesla Megapacks, is the company’s first large-scale battery in the United Kingdom and is set to become one of the largest battery storage projects in Europe.
The Iceni battery storage project sits on the same site as the onshore converter station serving Ørsted’s Hornsea 3 offshore wind farm, and will share transmission assets and a grid connection with the wind farm — a world-first for a utility-scale battery.
What the Iceni battery storage project includes
According to Ørsted, the site is split in two by the Hornsea 3 converter station, with the two battery areas linked by 18 cables at 33 kilovolts, each more than 600 metres long. The 170 integrated Tesla Megapack units give the system 600 megawatt-hours of storage capacity; Ørsted reports a power rating of 300 megawatts, while one industry outlet reported 200 megawatts. The company says the battery can store the equivalent of the daily electricity consumption of 80,000 UK homes.
The project was built with Hitachi, Knights Brown and Tesla. London-based renewables services firm Arenko has been selected to run its Nimbus optimisation, asset management and trading platform on the battery. Construction work is finished and commissioning and testing are now under way, including the commissioning of the 33 kV cables.
Iceni battery storage and Hornsea 3: a shared grid connection
Hornsea 3, the roughly 2.9-gigawatt offshore wind farm off England’s east coast whose converter station hosts the battery, is due to be commissioned in 2027. By sharing one grid connection between two generators, the project avoids the need for a separate standalone connection for the battery.
Industry reporting describes Iceni as the world’s first utility-scale battery directly integrated into an offshore wind farm’s transmission infrastructure, and as one of the United Kingdom’s first large-scale “pathfinder” co-location projects under the Offshore Transmission Network Review. The battery is designed to store electricity when generation exceeds demand and discharge it later to help balance the grid.
“This is a very exciting project to be a part of, not only for Ørsted as it is our first large-scale battery installation in the UK, but also for the UK energy industry as this project involves two generators using one shared grid connection,” said Beatrice d’Eufemia, Ørsted’s project manager.
Why the Iceni battery storage matters for Britain’s clean-power goal
Battery storage is seen as essential for absorbing more variable renewable generation, because it addresses intermittency and curtailment. The UK’s state-owned system operator NESO estimates the country needs 23 to 27 gigawatts of battery storage by the end of the decade to meet its target of generating up to 100 percent of its electricity from clean sources; UK government data put installed battery capacity at 7.5 gigawatts at the end of 2025.
Ørsted originally targeted operation by the end of 2026; recent industry reports point to the first quarter of 2027. Read more climate and energy coverage on Watan News.
FAKTA: Iceni battery storage at a glance
- Capacity: 600 MWh of storage; power rating reported at 300 MW by Ørsted (one outlet reported 200 MW)
- Units: 170 Tesla Megapacks, linked by 18 cables at 33 kV
- Location: Swardeston, near Norwich, Norfolk, England — on the Hornsea 3 converter station site
- Status: construction complete 20 October 2026; commissioning and testing under way
- Significance: Ørsted’s first large-scale UK battery; among Europe’s largest; a world-first shared grid connection with an offshore wind farm
Conclusion
The completion of the Iceni battery storage system marks a practical step in pairing very large offshore wind with storage on shared infrastructure. If the co-location model works at this scale, it could unlock more of the UK’s congested grid for clean power without building entirely new connections.
