Pembrokeshire Demonstration Zone

The Pembrokeshire Demonstration Zone (PDZ) is part of the Pembroke Dock Marine programme whose sponsor is Pembrokeshire County Council and project delivery partners include Port of Milford Haven, Offshore Renewable Energy Catapult and Marine Energy Wales

The emergence of Floating Offshore Wind (FLOW) has catalysed the potential for ‘transmission scale’ test and demonstration activity in line with the original aspirations for the nearby Pembrokeshire Demonstration Zone when it was originally conceived.

Being awarded in 2014, The PDZ lease predates FLOW and naturally excludes the technology from its definition of use. The PDZ as defined is a site for demonstrating multiple wave and tidal energy technologies.  

A reduced project delivery period due to a hard ERDF funding deadline and co-funding delay combined with the commercial opportunity from FLOW focused project delivery activity up to June 2023 on enabling infrastructure. Specifically, this involved de-risking the environmental, technical and commercial aspects of a Multi-connection Offshore Substation (MOS) capable of accommodating 400MW in phased approach of four 100MW stages.

A concept level engineering study for multiple design scenarios that sought to coordinate FLOW and the PDZ’s Test and Demonstration requirements was carried out on by Apollo and Vekta Group.

This has been progressed for a number of reasons.

  1. CSP consulted key stakeholders, funders, and industry in 2022, with the output of this study being highlighted as an area of interest.
  2. The Offshore Transmission Network Review and the Holistic Network Design (HND), The UK Government led Initiatives to ensure that the transmission connections for offshore wind generation are delivered in the most appropriate way, and to find the appropriate balance between environmental, social and economic costs do not consider the Celtic Sea’s Test and Demonstration phase projects.
  3. Being rooted in Pembrokeshire, CSP have increasing concern over the environmental and community impacts associated with delivery of the critically important FLOW test and demonstration phase and the impact these projects could have on the longer-term project pipeline that are included in the HND.
  4. Independently connected projects could, if they constrain routes to Pembroke, being the closest transmission connection could add significant costs to later commercial phase projects and the output of the Holistic Network Design process, adding significant cost and risk to developments, the consumer and the regional opportunity.
  5. CSP believe, which is being increasingly supported by collaborators, that colocation with FLOW will benefit both FLOW and Wave Energy Industry increasing the potential for realisation in a cost-effective way for the consumer whilst also generating significant opportunity for regional industry.

Two animations have been produced, the first being an overview (also available with subtitles and in Welsh) with the second (also available with subtitles) showing how this project concept could be realised in line with the regulatory policy developing around offshore co-ordination.


All information in these animations as presented is subject to change and is for illustrative purposed only.

For more information please click here

MOS Concept study

You can read and download the summary report here:

PDZ Stakeholder Presentation

You can read and download the full engineering concept study here:

400MW MOS Concept Study Report

400MW MOS Concept Study Addendum

Technoeconomic analysis

In addition to the technical studies, a review updating the 2019 technoeconomic analysis was carried out by Black and Veatch and Royal Haskoning with an updated scoping report issued to NRW on 21/02/2023.

CSP’s Scoping Report and Appendices can be accessed here:

CSP Scoping Report to NRW

NRW’s Scoping Opinion can be accessed here:

NRW Screening and Scoping Opinion


Tim James speaking at Destination Renewables event
Proposed Multi-Connection Offshore Substation
Justin Olosunde speaking on workforce at CFA Summit in April 22
Brad Davies and Nigel Jones who are working on the PDZ project
APEM common dolphins

Eisiau darllen hwn yn Gymraeg? Cysylltwch â ni ac fe drefnwn ni hynny!