Power transfers have begun via Greenlink interconnector, a new 504MW link between UK and the Republic of Ireland. The interconnector connects into the electricity transmission networks of National Grid and EirGrid, and is operated by EirGrid.
The new 320kV interconnector comprises two high voltage direct current (HVDC) subsea cables and associated converter stations. At the Irish end of Greenlink’s 200km span – 160km of which is under the sea – the interconnector connects into EirGrid’s Great Island substation in County Wexford. Its connection to the high voltage network in Wales and England is via National Grid Electricity Transmission’s 400kV Pembroke substation. National Grid installed a new gas-insulated switchgear bay inside its existing air-insulated substation, a hybrid solution to accommodate Greenlink’s connection. NGET says its connection apparatus is mostly free of sulphur hexafluoride (SF6), instead using greener insulating and switching gas, in line with National Grid’s ambition to reduce SF6 emissions from its network by 50% by 2030.
Converter stations located adjacent to the substations at each end of the interconnector convert its direct current (DC) electricity to alternating current (AC) for use when imported onto each country’s grid, with the reverse process taking place to export power over the link.