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Deploying At Celtic Sea Power

Celtic Sea Power offers ‘high grade’ offshore and onshore infrastructure.

Subsea Cable Arrangement

The Celtic Sea Power offshore site is connected to the onshore substation by a live 33kV subsea power cable arrangement.

Starting from the Celtic Sea Power substation at Hayle, the two land cables exit their respective circuit breakers and the substation before passing under the dunes in HDD ducts to enter the buried beach joint. 

Within the beach joint the two land cables are joined to the subsea cable, which runs all the way out to the offshore site.

The subsea cable terminates at the “Wave Hub”, a seabed cable junction, from which four cable tails extend out across the 8 KM2 offshore site to enable project connection. Each cable tail contains 12 fibre optic cores as well as three power cores and is terminated with a highly adaptable dry-mate connector.

The latest safety information relating to the subsea cable system can be found in the Notice to Mariners section and an outline cable system schematic is available for download below.

Onshore Substation

Celtic Sea Power offers grid-connection at either 11kV or 33kV. The two Wave Hub circuits may be operated at either 11kV or 33kV (uniquely, the two circuits may be safely operated at the two voltage levels simultaneously). The system has an agreed export capacity of 30MW with a total potential capacity of 40MW. Grid connection is via the Western Power Distribution 132/33kV Bulk Supply Point at Hayle.

The onshore substation houses 33kV and 11kV switchgear, a 11kV/33kV transformer and power factor correction equipment. This equipment connects the offshore technology to the grid and ensures delivery of power produced is always compliant with the relevant grid codes.

The substation also houses project communications equipment to facilitate the remote control, metering and monitoring of the deployed technology. This is achieved via fibre optic cables within the cable system and onwards via secure high-speed internet connectivity. Project data and associated IT equipment is segregated and secure. Secondary satellite or device to shore radio communication is also an option to developers using the site.

Power metering is required at the lead device for an array and at the substation exit breaker. The Wave Hub SCADA (supervisory control and data acquisition) system collects offshore meter data and facilitates substation switching including central emergency shutdown.

Celtic Sea Power holds a grid connection agreement with Western Power Distribution which defines the required parameters for electrical quality. Projects will be required to operate within these parameters which reflects Grid Code Compliance.

Offshore Safety Management

Marine safety management is core to Celtic Sea Power Ltd's mission of providing a safe and effective site for offshore renewable device and array testing, demonstration and validation. Our operational management system, supported by our team of offshore specialists, is clear and pragmatic and fosters cooperative, efficient and innovative working.

All operators are expected to work to their own safety management systems but are also encouraged to proactively communicate and coordinate with other offshore users. We facilitate and support this through an innovative online operations planning and notification system.

Celtic Sea Power Ltd provides an overall site safety monitoring, communications and central emergency response function.

The Offshore Site

The Celtic Sea Power offshore site has the following outline attributes:

  • A charted, 25km, 33kV live subsea cable.  This is buried wherever possible inshore.  Further offshore the cable is protected with a rock berm.
  • A consented and charted offshore rectangular test site measuring 1950m (west) x 3950m (north) with the following broad characteristics:
    • water depths across the site ranging from a maximum of 57.0 below LAT in the north-west corner to approximately 51.0 below LAT in the south-east corner
    • a seabed characterised by areas of outcropping bedrock and a general veneer of gravelly sand, with occasional boulders.
  • The offshore site is to the south of and clear of main shipping routes and is marked by:
    • north and south cardinal marks - 'Wave Hub NW' and 'Wave Hub SE' - offset from the site. 'Wave Hub NW' is also an AIS station.
    • four special marks with GPS synchronised lights - these are placed near the four corners of the site.
    • the 'Wave Hub' itself (the subsea cable to cable tails seabed junction chamber) is found at the centre of the consented 500m radius Wave Hub Safety Zone in the south west corner of the site. The 'Wave Hub' is also protected by a rock berm.
    • highly adaptable dry mate connector. Half on the seabed, fitted to the Wave Hub cable tail and capped off with accessible lifting eye.  Half will be issued to the developer for fitting to developer array cable ashore ready for rapid connection offshore. As with all the infrastructure, the dry mate connector can accommodate operation at 11 or 33kV.
    • simple and minimal cable stabilisation arrangements utilising ROV-friendly rock bags.
    • cable abrasion protection in the touch down zone to protect the subsea cable during connection operations on deck.
    • access to substation support services to monitor and test power and fibre connections and cables as they are installed. ​

The offshore location plan and site plan can be downloaded from the link at the bottom of this page. Further safety information relating to these offshore assets is available on the Wave Hub Notice to Mariners page.


Celtic Sea Power was granted consent in 2007 under Section 36 of the Electricity Act 1989. This allows a wide variety of different wave energy generation technologies to be deployed at the site.

Celtic Sea Power also has a licence under Section 34 of the Coastal Protection Act 1949 (CPA) and licences under Part II of the Food and Environmental Protection Act (FEPA) 1985 for the installation of the Wave Hub and subsea cable and for the protection of these by rock armouring.

Full details of our consent and decommissioning programme can be found in the downloads area.

The Celtic Sea Power team are in the final stages of negotiating with MMO a Section 36 consent for FLOW and, after Sale, will be able to  advise and support the Wave Hub project and provide support to other Celtic Sea FLOW projects, drawing on existing environmental and other baseline data.

Environmental Impacts

As well as providing a location where wave devices can be demonstrated over several years, Wave Hub has been established with extensive baseline data to enable any project environmental impacts to be determined accurately.


Celtic Sea Power Test Site

Connected to the grid, Celtic Sea Power is the world’s most advanced offshore renewables test and evaluation facility. The site is located off the north coast of Cornwall and has a the potential for up to 40MW of installed floating offshore wind or wave capacity.

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Partner Facilities

Cornwall and the South West have world-leading marine renewable energy research and demonstration facilities offering a pathway to commercial deployment.

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Supply Chain and Port Infrastructure

You can rely on an experienced and well-established local supply chain and a variety of regional ports, all within easy reach.

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