---
title: "J5 Super Grid Transformer Refurbishment"
ocid: "ocds-h6vhtk-06e3ab"
canonical_url: "https://d3tenders.com/contract/?ocid=ocds-h6vhtk-06e3ab"
markdown_url: "https://d3tenders.com/contract/ocds-h6vhtk-06e3ab.md"
json_url: "https://d3tenders.com/contract/ocds-h6vhtk-06e3ab.json"
source: "Find A Tender Service"
current_stage: "Planning"
buyer: "UK Atomic Energy Authority"
published: "2026-08-13"
---

# J5 Super Grid Transformer Refurbishment

Buyer: UK Atomic Energy Authority  
Current stage: Planning  
OCID: ocds-h6vhtk-06e3ab

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## Summary

The UK Atomic Energy Authority is planning works to refurbish three Super Grid Transformers, SGT1A, SGT1B and SGT1C, located north of the J5 Substation. The requirement covers strategic asset life extension, including addressing latent defects and obsolescence during the 2026–2027 shutdown. The transformers are critical assets integrated into the 400kV National Grid network and normally operate in parallel to provide grid stability and redundancy. The intended outcome is to maintain their reliability and operational integrity for a further projected 10 to 15 years. The procurement is categorised as works, with associated transformer repair and maintenance, refurbishment, and mechanical and electrical engineering services. Delivery is identified within the United Kingdom.

This procurement is at the planning stage: UKAEA has stated an intention to procure, but has not yet issued an invitation to tender. It is undertaking cost and scope development alongside preliminary market engagement, including a planned site visit on 26 August 2026 at 09:00; further visits may be arranged. The buyer expected the next notice to be published on 4 September 2026. The estimated value is £700,000 excluding VAT, or £840,000 including VAT. The planned contract period is 9 October 2026 to 1 January 2027. The requirement is presented as a single lot, currently in planning, and is indicated as suitable for small and medium-sized enterprises. The data does not set out an award procedure or evaluation criteria.

The planned work is likely to suit suppliers specialising in high-voltage transformer refurbishment, electrical and mechanical engineering, asset life extension, and maintenance of critical power infrastructure. Relevant businesses would need to understand the inspection, repair and modernisation of ageing transformer assets, including the management of latent defects and obsolete components. Experience working on equipment connected to a 400kV transmission network, maintaining operational reliability and supporting redundancy arrangements, would be commercially relevant. The shutdown-based programme may suit contractors able to plan and deliver concentrated engineering and refurbishment activities within a defined outage window. UKAEA has expressly indicated that small and medium-sized enterprises may be suitable, so capable specialist firms should consider preparing evidence of comparable transformer, substation or high-voltage engineering experience before the tender exercise is released.

## Notice

J5 Super Grid Transformer Refurbishment The United Kingdom Atomic Energy Authority would like to invite suppliers who are interested in this requirement to attend a scheduled site visit, prior to a tender exercise being released for the above requirement. Values listed below are an estimate, and the UKAEA are currently undertaking cost exercises alongside this notice, in order to build upon our current estimates and scope development prior to conducting a tender exercise. Interested parties should contact us via the below link in order to arrange attendance at our site visit. Please use the attached site visit request form and return to us via the EU Supply link below. Scheduled Dates: - Wednesday 26th August, 9:00am Further dates are available on request, as well as further visits to be arranged during the tender period. Outline Scope of Requirement: This project concerns the strategic life-cycle management of Super Grid Transformers SGT1A, SGT1B, and SGT1C, located north of the J5 Substation. These critical assets are currently integrated into the 400kV National Grid network and primarily operate in a parallel configuration to ensure grid stability and redundancy. As these assets approach their fifth decade of service, this project represents a shift from reactive maintenance to a formal Asset Life Extension (ALE) Program. By addressing latent defects and obsolescence during the 2026-2027 shutdown, this scope of work aims to "reset" the aging clock of the SGTs, ensuring their continued reliability and operational integrity for a projected further 10 to 15-year life cycle.

### Planning Information

https://uk.eu-supply.com/app/rfq/rwlentrance_s.asp?PID=108182&TID=100113249&B=

## Key Details

| Field | Value |
| --- | --- |
| Publication source | Find A Tender Service |
| Latest notice | https://www.find-tender.service.gov.uk/Notice/077272-2026 |
| Notice type | UK2 - Preliminary Market Engagement Notice |
| Procurement type | Standard |
| Procurement category | Works |
| Procurement method | Not Specified |
| Procurement method details | Not specified |
| Tender suitability | SME |
| Awardee scale | Not specified |
| All stages | Planning |

## Dates

| Field | Value |
| --- | --- |
| Publication date | 13 Aug 2026 |
| Submission deadline | Not specified |
| Future notice date | 4 Sep 2026 |
| Award date | Not specified |
| Contract period | 9 Oct 2026 - 1 Jan 2027 |
| Recurrence | Not specified |

## Values

| Field | Value |
| --- | --- |
| Tender value | £700,000 |
| Lots value | Not specified |
| Awards value | Not specified |
| Contracts value | Not specified |

## Status

| Field | Value |
| --- | --- |
| Tender status | Planning |
| Lots status | Planning |
| Awards status | Not specified |
| Contracts status | Not specified |

## Buyer

| Field | Value |
| --- | --- |
| Main buyer | UK Atomic Energy Authority |
| Locality | OXFORDSHIRE |
| Postcode area | Oxford |
| Postcode | OX14 3DB |
| Country | England |
| ITL 1 | TLJ South East (England) |
| ITL 2 | TLJ1 Berkshire, Buckinghamshire and Oxfordshire |
| ITL 3 | TLJ14 Oxfordshire CC |
| Local authority | South Oxfordshire |
| Electoral ward | Sandford & the Wittenhams |
| Westminster constituency | Didcot and Wantage |
| Delivery location | Not specified |

## CPV Codes

### Divisions

- 45 - Construction work
- 50 - Repair and maintenance services
- 71 - Architectural, construction, engineering and inspection services

### Codes

- 45453100 - Refurbishment work
- 50532200 - Repair and maintenance services of transformers
- 71334000 - Mechanical and electrical engineering services

## Release History

- 13 Aug 2026 at 14:01 - Planning - UK2 - Preliminary Market Engagement Notice - https://www.find-tender.service.gov.uk/Notice/077272-2026

## Documents

- https://www.find-tender.service.gov.uk/Notice/077272-2026
  13th August 2026 - Preliminary market engagement notice on Find a Tender

## Notice URLs

- https://uk.eu-supply.com/app/rfq/rwlentrance_s.asp?PID=108182&TID=100113249&B=
- https://www.gov.uk/government/organisations/uk-atomic-energy-authority
- https://www.legislation.gov.uk/ukpga/2023/54/contents

## Provenance

This Markdown file is an alternate public rendering of the D3 Tenders contract record. The canonical page is https://d3tenders.com/contract/?ocid=ocds-h6vhtk-06e3ab. The underlying structured data is available as OCDS JSON at https://d3tenders.com/contract/ocds-h6vhtk-06e3ab.json.