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Pioneering marine energy technology developer Minesto designed, developed and successfully installed the world’s first tidal energy project of its kind in 2018.
The Swedish developer designed the DG500 subsea kite turbine system to harness energy from the Irish Sea, 8km off the coast of Wales. We worked with Minesto to verify and finalise the design of the chosen base structure, ensuring it was a suitable design for the turbine technology to be tethered to. We then supported and oversaw the construction process before installation.
Project Summary
500kW marine energy kite turbine technology
1275tonnegravity base structure
4.65mheight on the seabed
Meeting the requirements for new technology
Upon developing the technology, Minesto then required a location for the turbine system. The requirements included reasonable tidal flows, adequate water depth, closeness to the shore and access to the grid. The location of Holyhead Deep was selected to demonstrate functionality and power production performance in utility scale. With varying water conditions, it was critical to have a stable base structure for the tidal system to be tethered to, which was secure and could be efficiently installed in the given timescales.
Developing a suitable base structure
Arup’s energy engineers worked with Minesto to verify and close out the design of a concrete gravity base structure which would be floated out to sea and carefully positioned on the sea bed.
A key factor in verifying the substructure for the developer was the quick turnaround time required. Arup has developed various tools to rapidly evaluate the reinforcement demands in concrete shell structures which can then link the design output to tools for automated detailing and scheduling of reinforcement. With the design verification and detailing of the structure being completed in a short period, Arup’s tools allowed the construction to commence with minimal delay and keep to project schedules.
Successful float out and installation
Utilising our naval architects, structural and marine engineers the design was finalised and verified, with the base then constructed in a dry dock. Arup undertook an on-site role to ensure construction in the dock met the design requirements, with a focus on weight control of the concrete gravity substructure.
The final structure – measuring 22m x 13m - was fully inspected, successfully floated and towed out to the site and lowered to the seabed by a winch wire and ballasting the cells with water.
World first subsea kite renewable energy generation
The subsea kite was successfully tethered to the concrete gravity base structure and secured, making Minesto’s Deep Green technology the first operational tidal kite of this size anywhere in the world. The turbine will operate at a depth of 80-100m, with the site providing low-flow tidal velocities (1.5-2 m/s mean peak flow), to demonstrate Minesto’s unique, patented method of converting low-flow tidal streams to predictable, renewable electricity on a commercial scale.
