TS-FLOW© – JIP – Celtic Sea

Celtic Sea – Temporary Storage, Floating Offshore Wind


The wet storage challenge was thought to be most acute in the Celtic Sea area (due to the limited number of sheltered bays and estuaries) and hence the Celtic Sea was the first area of focus for the first iteration of the TS-FLOW© JIP.

Focussed on supporting the upcoming Celtic Sea licencing round and project delivery, the JIP is supported by The Crown Estate. 5 developers participated in the JIP, with a further 2 signing-up following completion of Phase 1. As the licensing round heats up then more developers are expressing an interest to participate in future phases.

It is expected that developers plans and details for temporary storage must form an integral part of their project execution plan that is presented with their licence application.

Phase 1 of the JIP commenced mid 2022 with completion and delivery of the results to participants in December 2022. The detailed results are confidential to the participants (find out how to obtain the result by contacting OSG), however the key learnings and outcomes are discussed in the Celtic Sea JIP Whitepaper.

Phase 2 will be commencing in Q3 2023.


The Celtic Sea JIP focusses on supporting Celtic Sea developments, with the search area indicated below. The area investigated extended from Southampton in the south of England, up to Ayr in Scotland and included the East cost of Northern Ireland and Ireland.

The temporary storage locations could also support FLOW developments in the Irish Sea and Southern Ireland.

Celtic Sea Challenges

Although the search area for the Celtic Sea is extensive, there are limited bays, estuaries and sea lochs that are sheltered from the prevailing winter conditions. The temporary storage sites needs to be accessible during the winter months in order to be able to tow and moor the FLOW units, whilst also being accessible for monitoring and maintenance.

The key challenges that were initially envisaged for the Celtic Sea were all technical in nature, however as the JIP developed it became evident that there are many equally as significant challenges that require to be addressed (environmental, consenting, competing use). These additional challenges in additional to the technical requirements highlighted the need for further temporary storage assessment in areas that on first look (e.g. Scotland) had sufficient sheltered areas for temporary storage.

Local Content Value

The Crown Estate (TCE) are active supporters of TS-FLOW© (Celtic Sea) and we aim to ensure that our activities are fully aligned with the ambitions and objectives of TCE to deliver floating wind at scale across the Celtic Sea.

The TS-FLOW© approach to the development and delivery of a credible wet storage solution has always been centred on being delivered locally, close to and enabling local ports to deliver floating wind solutions and using local companies & local partners throughout the development and operational Phases.

The TS-FLOW© (Celtic Sea) Phase 2 work programme will include an independent assessment & evaluation of the local value of wet storage., conducted by Dr Michael Warner, the UK’s preeminent floating wind local content specialist, from the Centre for Local Content Innovation. This will be independently assessing and evaluating the TS-FLOW© (Celtic Sea) activities covering all Phases and providing a comprehensive report on the local, regional, and wider UK impact and value of TS-FLOW© (Celtic Sea) wet storage solution. This will include social and environmental value as well as clear economic benefits.

What is the current status

  • Celtic Sea Phase 1 – Completed 2022

    • Contact OSG to sign-up and obtain the results
  • Celtic Sea Phase 2 – Commencing August 2023

    • Contact OSG for further information, sign-up, or 1-2-1 presentation

Who to contact to get involved or find out more:

  • OSG as the JIP lead