Large Scale Battery Energy Storage Systems

2026-11-03

The following summary is not intended as a complete or definitive specification of the requirement. A purpose of this engagement is to seek information from the market to help refine our understanding and aid the development of a future specification. STEP is currently in its Concept Design phase, which is expected to be completed in 2026. The electrical infrastructure of STEP will resemble that of large conventional thermal power stations; however, its design presents unique challenges: Fusion power stations like STEP have exceptionally large parasitic (auxiliary/house) loads required to initiate and sustain fusion reactions—significantly higher than those in conventional power plants. These parasitic loads must be supplied by external sources during plant start-up, before the power generation cycle begins producing electricity. The highly dynamic nature of these loads could make compliance with grid code requirements challenging. For more information, please refer to: Staying positive: producing net power | Philosophical Transactions of the Royal Society A | The Royal Society UKIFS is seeking experts to support the technology selection of a central energy storage system (CESS) that is part of the STEP Electrical infrastructure. Due to the power dynamics of operating the STEP power plant and operating parameters set by the National Energy System Operator (NESO), an energy storage system is required to provide a mechanism to ensure that we remain within the NESO operating parameters. Rather than a continuous output, STEP will operate on a pulsed basis. The power dynamics of the fusion pulses are typically different to a conventional power plant, and a CESS has been identified as a critical system to the design as it provides a mechanism to compensate for the changing load dynamics throughout the pulse. This will ensure STEP remains within the NESO defined operating parameters at the point of grid connection. Current assumptions are to exploit existing Battery Energy Storage Systems (BESS) to fulfil the energy storage needs. We are interested in all battery chemistries used in large-scale energy storage systems, including Lithium Iron Phosphate (LFP), Sodium-Sulfur (NaS), Lithium Titanate (LTO), Vanadium Redox Flow Batteries (VRFB), Nickel Manganese-Cobalt (MNC), Solid State Batteries or others. Due to knowledge gaps in BESS behaviour and limitations, the decision of using a BESS system for the CESS cannot be fully justified. This PME is looking to address this. The proposed technical and operational characteristics of the BESS are: 2 operational cycles per day Pulse length will be over 1 hour (continuous) Power range larger than 300MW Energy capacity 100-300MWh Response in the millisecond range Similar charge and discharge rates. Fast response time during power swings (full charge to discharge) High round trip efficiency: 80% In conjunction the BESS will be required to be operated and maintained for the 20-year life of the STEP machine. For more information about this opportunity, please visit the Delta eSourcing portal at: https://ukifs.delta-esourcing.com/tenders/UK-UK-Culham:-Engineering-design-services./44277P4UUB To respond to this opportunity, please click here: https://ukifs.delta-esourcing.com/respond/44277P4UUB

United Kingdom (UK)

2026-04-02