A New 500MW Subsea Cable Connects Britain and Ireland

Both the UK and Ireland can look forward to enhanced energy security and competitive power tariffs now that their grids are connected.
Published: Sat 06 Oct 2012

What happened  

UK and Irish power grids are now connected by a 500MW cable, reports Irish Times. The cable is to secure a sufficient, as well as efficient, power supply for both regions. Excess power, generated in Ireland, can now be exported to Britain.


The east-west interconnector is seen as the “single biggest energy infrastructural investment” since the commissioning of the hydroelectric Ardnacrusha power station in Co Clare 85 years ago.

Built by EirGrid, the project cost US$739m (€570m). The project received the following investments:

  • US$142m (€110m) grant from the European Union
  • US$389m (€300m) loan from the European Investment Bank                
  • US$77m (€60m) from EirGrid and a commercial loan from Barclays/BNP Paribas

The 186km cable runs from Co Meath in Ireland to northern Wales. The subsea cable lay beneath the Irish Sea between Rush, in North Co Dublin, and Barkby beach in northern Wales. A further 80km of cable runs over ground to link the connector to converter stations on either side of the Irish Sea, where the power is adapted to suit the relevant national energy grid, explains Irish Times.

The interconnector is able to transmit sufficient power to supply approximately 350,000 households. Commercial operations will begin by 1 October.

Another 500MW cable, the Moyle interconnector, currently connects Islandmagee in Northern Ireland and Auchencrosh in Scotland.

These interconnections make it possible for the British grid to import power generated by Ireland’s 40 onshore wind farms, explains Business Green. The connections are essential to Britain as the country faces dwindling North Sea gas reserves as well as ageing coal and nuclear power stations. For this reason, “Greenwire” was established.  Greenwire is a series of connected projects which export wind power from Ireland’s Midlands to the UK via subsea cables.

EU energy commissioner Günther Oettinger says that the energy infrastructure development is one of the EU’s major energy challenges. He adds that the east-west interconnector will “double electricity interconnection between the UK and Ireland and will provide a greater opportunity to trade electricity between the two markets. “ He explains that this project is a “key part of building a single European energy market.”

EirGrid’s outgoing chief executive Dermot Byrne said the grid connection will give Ireland access to energy from Britain, as well as the European continent. He explains that this will result in more competitive tariffs in the energy market.

(Exchange rate correct to date published)                           

Last Word

The high voltage transmission cables fall under a wider plan to build a northern European supergrid which will eventually enable the sharing of renewable energy projects across the EU continent. This will help to strengthen energy security in the region, develop renewable energy projects, create a more competitive market to lower power prices, reduce carbon emissions and enhance grid reliability.


Business Green-Ireland edges forward with plan to export wind power to UK

EirGrid-eastwest interconnector          

Element Power-Element Power accepts first grid connection offer between UK and Ireland

Irish Times.com-Electricity cable links UK and Irish grids