The European Marine Energy Centre (EMEC) closed 2024 by completing the decommissioning of the first ever tidal turbine platform to provide electricity to the UK national grid, 18 years after its installation.
The platform, supplied by Dublin-based OpenHydro, was installed at EMEC’s grid-connected tidal test site at the Fall of Warness, off the island of Eday, in 2006. The site is located approximately 20km from Kirkwall in the Orkney Islands, Scotland, where waves exceeding 10m are not unknown in some areas.
The platform featured a 6m-diameter, 250kW-capacity turbine, plus a test rig comprising two 18tonne steel piles, grouted into sockets drilled into the seabed, with a working platform suspended from the piles. The turbine was removed in 2022, following the liquidation of OpenHydro in 2018.
December 2024 saw Scottish marine engineering firms Ocean Kinetics and Green Energy conclude decommissioning of the rest of the platform. Ocean Kinetics contributed divers, riggers, welders and ROVs to the project, while Green Marine provided its offshore vessel Green Isle: a Damen 2712 MultiCat design, featuring an overall length of 27.7m, a 12.5m beam, 165m2 of deck space and a bollard pull of 33tonnes. Operational engineering, cutting and heavy-lift duties were shared between the partners.
EMEC says: “The pile foundations were cut to the seabed using reversed diamond wire cutters, returning the seabed as close as reasonably practicable to its original condition.” These cutter types are significantly harder than most metals, and capable of producing clean cuts without deformations. Terry Norquay, Green Marine operations manager, adds: “Green Isle [was] positioned in a four-point mooring configuration, to remain stationary and allow divers to safely enter the water. This project has expanded Green Marine’s portfolio and demonstrates the turnkey offshore decommissioning solutions we can deliver in partnership with our trusted colleagues.”
OpenHydro tested seven turbines at the Fall of Warness site over the years, with the final turbine notching up 10,000 hours of operational uptime, EMEC reveals. Neil Kermode, EMEC MD, says: “Now that decommissioning has been completed, we can complete a full lifecycle analysis with valuable insights around marine operations, structural integrity of long-term deployments as well as the impact of biofouling and corrosion. These lessons can help guide the tidal energy industry’s continued evolution as we ready our test sites for future clients and building out to tidal energy arrays.”
