Grid-connected tidal test site
Our grid-connected tidal test site at the Fall of Warness is situated just west of the island of Eday - lying in a narrow channel between the Westray Firth and Stronsay Firth. The site was chosen for its high velocity marine currents which reach almost 4m/sec (7.8 knots) at spring tides. As tides flow from the North Atlantic Ocean to the North Sea, they quicken as they are funneled through Orkney's northern islands.
EMEC offers eight tidal test berths at depths ranging from 12m to 50m in an area 2km across and approximately 4km in length. The 11kv sub-sea cables extend to the middle of the tidal stream from EMEC's substation at Caldale in Eday which houses the main switchgear, backup generator and communications room. The substation controls the supply from each tidal device and connection to the national grid. An adjacent laydown area offers developers the opportunity to use conditioning equipment for converting electricity from the level at which it is generated to grid compliant electricity. In addition to transporting electricity, the cables contain fibre-optics which allow developers to communicate with the devices and transmit monitoring data back to our data centre and office facilities.
The adjacent building on site holds the Scottish and Southern Energy transformer where the 11kv is transformed to 33kv. Eday is linked to both Westray and Sanday by subsea cables that form a ring through the Northern Isles and feed into the national grid. The spur connecting the substation to the grid was buried underground by plough to avoid overhead poles.
A number of current meter deployments have taken place to characterise the tidal and wave conditions, and a purpose-built weather station is situated onshore providing real-time met data for the site. This data is fed into a sophisticated SCADA (Supervisory, Control and Data Acquisition) system, with live data feeds on the met conditions available to view on our website. A fixed ADCP (Acoustic Doppler Current Profiler) is due to be deployed at the site imminently with live data feeds to the website due in early 2013.