Official UK procurement notice
Large Scale Battery Energy Storage Systems
Authority: UK Fusion Energy Ltd (Public body)
What is being bought
Published requirement descriptionThe 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:
ukifs.delta-esourcing.com/tenders/UK-UK-Culham… ↗
To respond to this opportunity, please click here:
CPV: Electrical power systems design services · Engineering design services · Plant engineering design services
The lotProcurement structure
single lot · no lot value publishedPipeline intelligence · planning stage: how this market runs before the tender is published
How UK Fusion Energy Ltd buys Engineering design services (CPV 7132), and who usually turns up
UK Fusion Energy Ltd’s own published record, next to the published market for the same work. Frameworks and DPS are kept out: they attract a different number of bids. Whole-market view: Engineering design services (CPV 7132) →
How the contest usually goes
Winner shares use published awards; bid and price charts use contested lots.
i
How often small and medium firms win.
Share of awards where the winner’s size is known.
The counts under this question show how many awards have a known supplier size.
Small firms have won here. Neither number says whether you qualify; it describes who has been winning.
i
How often local firms win similar work.
Winners with a registered address in the delivery region, out of awards with a known address.
Here, local means registered in South East England (authority’s region).
A local branch does not count if the registered address is elsewhere.
Most of this buyer’s recorded winners are registered in South East England.
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How long buyers here take to decide after bids close.
Middle value in days from the deadline to the first award notice, on competitions that published both dates.
Only decided tenders count, so slow ones still waiting are not in.
Half of these awards were announced within 25 days of the bid deadline.
i
How often work is awarded with no recorded rival.
Direct awards and tenders where every published lot count shows one bid.
Both shares are minimums: some awards have no bid count.
Thin markets produce this too; it is not proof of a tailored specification.
Direct awards or one recorded bid are common here. Check the route before spending time on a bid.
How many bids did past lots attract?
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How many bids past lots received.
Each colour is a bid-count range. Only competed lots with a published count are included.
Past bids do not predict this tender.
1 bid0% / 9%
2–363% / 30%
4–625% / 19%
7+13% / 42%
How did awards compare with estimates?
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Where winning prices landed against estimates.
Each colour shows awards below, close to or above the published estimate, one lot at a time.
Past prices are a guide, not a bid price.
Below estimate33% / 62%
Within ±2%67% / 27%
Above estimate0% / 12%
Assess each lot i
What past awards tell you about each lot.
See the forecast, this buyer’s earlier suppliers and firms with relevant wins.
No supplier is confirmed as a bidder.
i
What past awards tell you about each lot.
See the forecast, this buyer’s earlier suppliers and firms with relevant wins.
No supplier is confirmed as a bidder.
Open a lot for its forecast, this buyer’s previous supplier and possible competitors, from published award history, not a bid list
Lot #1CPV 7132No real estimate
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How many bids this lot may attract.
The forecast uses similar past competitions. The bar shows either that forecast or past bid counts; the line below says which.
Each lot shows its own forecast based on its own category; forecasts for different lots of the same notice are not comparative. The bar shows 128 past lots.
A forecast, not a list of bidders.
1 bid11%
2–320%
4–621%
7+48%
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Where the award price may land.
The forecast uses similar awards and the buyer’s estimate. The band covers the middle half of likely prices.
No comparable awards for this lot yet.
A statistical guide from past awards, not a price to bid.
Who has supplied this buyer on similar work? i
Who has done similar work for this buyer.
Past contracts are matched by buyer, title and type of work.
A past supplier may not bid again.
i
Who has done similar work for this buyer.
Past contracts are matched by buyer, title and type of work.
A past supplier may not bid again.
No earlier contract of this buyer matches this lot on the published record.
Who could compete for this lot? i
Who could compete for this lot?
Firms with relevant past wins. On a framework, we show firms on that agreement.
None is confirmed as a bidder.
i
Who could compete for this lot?
Firms with relevant past wins. On a framework, we show firms on that agreement.
None is confirmed as a bidder.
Candidate suppliers for this notice have not been worked out yet, so this is not a verdict that nobody fits.
About this data
- Source. Official UK public procurement notices (Find a Tender), reused under the Open Government Licence v3.0. New notices arrive through the day; the figures are rebuilt nightly.
- Two views, kept apart. The authority’s own track record and the wider market for the same kind of work sit side by side and are never mixed. Where the local picture is too thin, a figure widens to a broader market and says which one it used.
- Forecasts are labelled. The price forecast and its range, possible competitors and the earlier-work matches are our estimates from past awards: not published facts, not win chances and not price advice. Official notices do not say who is bidding.
- Every figure shows what it rests on. Not every notice publishes a bid count, a value or a delivery region, so each figure carries the number of records behind it, and one built on few records is marked as such. The on a figure explains it; the counting rules are in the methodology. Spotted something wrong? Tell us.
Procedure terms & legal framework
From the official record- Legal basis
- UKPGA · 2023/54 Procurement Act 2023
- Procurement category
- Services
- Notice status
- Planned procurement
- Procurement threshold
- Above threshold (FTS publication)
- Regulatory regime
- Standard
- Commercial structure
- Stand-alone contract (no framework)
- Competition type
- Competitive procedure
- GPA / WTO covered
- Unspecified in notice
- Recurring procurement
- Unspecified in notice
- First published
- 27 Jan 2026, 12:05 GMT
- Last source update
- 27 Jan 2026, 12:05 GMT
- Authority reference
PP-UKIFS-527- FTS notice number
2026/S 000-007049- Latest notice
- Preliminary market engagement notice (UK2)
- Classification (CPV)
- Delivery area
- Official registry OCID
ocds-h6vhtk-060f8eFind a Tender
How it was run
Official notice- Submission deadline
- —
Timeline
27 Jan 2026 → 1 Apr 2029 · 3 dates- Planning notice published266 days ago27 Jan 2026, 12:05 GMT
- Market engagement210 days ago23 Mar 2026, 23:59 GMT
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. UKIFS is seeking experts to support the technology selection of a central energy storage system (CESS) that is part of the STEP Electrical infrastructure.
To participate in this exercise, please complete and submit Appendix 1: Questionnaire and return any documents via the Delta portal. We are conscious of your time (and grateful to you for taking the time to complete the questionnaire), therefore we suggest you limit your responses to a maximum of 5 pages. If there are any areas you would like to expand on, please add a note to the relevant section for future discussion.
If you experience any difficulties with the portal, please contact the portal helpdesk [email protected] cc [email protected]
Information obtained from responses to Appendix 1: Questionnaire will help UKIFS understand current market capabilities and may shape the scope, direction, and design of the future procurement activities.
If you have any questions about this Preliminary Market Engagement, please contact UKIFS through the Delta portal. We are keen to engage with suppliers to assist with the questionnaire if needed, to ensure quality responses enabling us to shape the future requirement and procurement.
Following the submission and review of questionnaires, UKIFS intends to run an online conference call meeting/seminar/Q&A. The closing date for the pre-market engagement is Monday 23rd March 2026, 1 pm.
- Today20 Oct 2026
- Contract starts1 Apr 2029, 00:00 BST
Notice history
1 event · 1 release on Find a Tender- Preliminary market engagement notice published27 Jan 2026, 12:05 GMTUK2
Commercial outcome & contract awards
Pipeline notice- Awards (0)
- No award published
- Contracts (0)
- No contract published
- Bid statistics
- No aggregate bid statistics published
Contracting authority & participating public bodies
Official documents & specifications (1)
Official links; attachments are not copiedNotices published for this procedure
- Preliminary market engagement notice Preliminary market engagement notice on Find a Tender