OpenHydro endures Fall of Warness tidal run

The European Marine Energy Centre (EMEC) has last week paid a visit to its tidal testing site at the Fall of Warness – the location of the first grid-connected tidal energy turbine in Scotland.

OpenHydro was the first developer to use the tidal test site at the Fall of Warness off the island of Eday when its test rig and 250kW open centred turbine were installed in 2006.

It was the first tidal turbine to be grid connected in Scotland and the first to generate electricity to the national grid in the UK, according to EMEC.

The Fall of Warness site lies in a narrow channel between the Westray Firth and Stronsay Firth, boasting high velocity marine currents which reach almost 4m/sec or 7.8 knots at spring tides.

As tides flow from the North Atlantic Ocean to the North Sea, they accelerate as they are funneled through Orkney’s northern islands, EMEC said.

The test rig used by OpenHydro consists of two steel monopoles grouted into sockets drilled into the seabed, with a platform suspended from the piles to provide a working area.

The turbine, which is 6 meters in diameter, is fixed to the piles using two steel collars, which allow the unit to be lowered into the sea using two 15 tonne hydraulic winches.

 
It comprises four key components including a horizontal axis rotor, direct-drive permanent magnet generator, hydrodynamic duct and a subsea gravity base foundation, OpenHydro said.

The test rig allows for the turbine to be raised out of the water easily, reducing the cost and time for testing, maintaining and updating the device, according to EMEC.

To aid navigation, the test rig is painted yellow and solar-powered yellow light is fitted in accordance with NLB requirements. The platform is also equipped with an AIS transponder.

OpenHydro has been continually testing at EMEC since 2006. Since installing the seventh iteration of their open-centre turbine in 2014, the company has racked up an impressive 10,000 hours of run time, both EMEC and OpenHydro have confirmed.